Current sensor

A current sensor includes an electrical-conduction member, a magnetoelectric converter, and a shield. The shield includes a first shield and a second shield each having a plate shape. The first shield and the second shield being arranged such that surfaces are opposed to and spaced away from each other. A part of the electrical-conduction member and the magnetoelectric converter are located between the surface of the first shield and the surface of the second shield. The part of the electrical-conduction member extends in an extension direction that is along the surface of the first shield. At least one of the first shield and the second shield has an anisotropy in magnetic permeability in which the magnetic permeability in a lateral direction that is along the surface of the first shield and perpendicular to the extension direction is higher than the magnetic permeability in the extension direction.

TECHNICAL FIELD

The present disclosure relates to a current sensor to detect a measurement current to be measured.

BACKGROUND

A current detection system, such as a current sensor, generally detects a current by converting a magnetic field caused with a current flowing through a bus bar into an electric signal.

SUMMARY

The present disclosure describes a current sensor including an electrical-conduction member, a magnetoelectric converter, and a shield. The shield includes a first shield and a second shield each having a plate shape. The first shield and the second shield being arranged such that surfaces are opposed to and spaced away from each other. A part of the electrical-conduction member and the magnetoelectric converter are located between the surface of the first shield and the surface of the second shield. The part of the electrical-conduction member disposed between the surfaces of the first and second shield extends in an extension direction that is along the surface of the first shield. At least one of the first shield and the second shield has an anisotropy in magnetic permeability that is higher in a lateral direction than in the extension direction, the lateral direction being along the surface of the first shield and being perpendicular to the extension direction.

DETAILED DESCRIPTION

According to an embodiment of the present disclosure, a current sensor includes an electrical-conduction member, a magnetoelectric converter, and a shield. The electrical-conduction member allows a measurement current to be measured to flow therein. The magnetoelectric converter converts a measurement magnetic field caused by a flow of the measurement current into an electric signal. The shield restricts an electromagnetic noise into the magnetoelectric converter. The shield includes a first shield and a second shield each having a plate shape. The first shield and the second shield are arranged such that surfaces thereof are opposed to and spaced away from each other. A part of the electrical-conduction member and the magnetoelectric converter are located between the surface of the first shield and the surface of the second shield. The part of the electrical-conduction member located between the first shield and the second shield extends in an extension direction that is along the surface of the first shield. At least one of the first shield and the second shield has an anisotropy in magnetic permeability in which the magnetic permeability in a lateral direction that is along the surface of the first shield and perpendicular to the extension direction is higher than the magnetic permeability in the extension direction.

In such a configuration, at least one of the first shield and the second shield has the anisotropy in magnetic permeability in which the magnetic permeability in the lateral direction is higher than the magnetic permeability in the extension direction. Therefore, components of the electromagnetic noise in the lateral direction easily permeates through at least one of the first shield and the second shield.

As such, in a situation where the electromagnetic noise in the lateral direction is easily allowed to permeate, the entry of the electromagnetic noise to the magnetoelectric converter is effectively suppressed. As a result, the degradation of accuracy in the measurement current detection can be suppressed.

Hereinafter, embodiments of the present disclosure will be further described with reference to the drawings.

First, an in-vehicle system100to which a current sensor is applied will be described. The in-vehicle system100forms a hybrid system. As shown inFIG. 1, the in-vehicle system100has a battery200, a power converter300, a first motor400, a second motor500, an engine600, and a power divider700.

The in-vehicle system100has multiple ECUs.FIG. 1illustrates a battery ECU801and an MG ECU802as representatives of the multiple ECUs. The multiple ECUs mutually transmit and receive a signal(s) via a bus wiring800, and perform cooperative control on a hybrid vehicle. With this cooperative control, regeneration and power running of the first motor400, power generation of the second motor500, and output of the engine600and the like are controlled in correspondence with a SOC of the battery200. SOC is an abbreviation for a state of charge. ECU is an abbreviation for an electronic control unit.

Note that the ECU has at least one calculation processing unit (CPU), and at least one memory device (MMR) as a storage medium to hold a program and data. The ECU is provided with a microcomputer having a computer-readable storage medium. The storage medium is a non-transitory substantive storage medium to non-temporarily hold a computer-readable program. The storage medium may be provided by a semiconductor memory, a magnetic disk or the like. Hereinafter, the constituent elements of the in-vehicle system100will be individually summarized.

The battery200has multiple rechargeable batteries. The multiple rechargeable batteries form a serially-connected battery stack. As a rechargeable battery, a lithium ion rechargeable battery, a nickel-metal hydride rechargeable battery, an organic radical battery and the like may be employed.

The rechargeable battery generates an electromotive voltage by chemical reaction. The rechargeable battery has a property that deterioration accelerates when the charge amount is too large or too small. In other words, the rechargeable battery has a property that deterioration accelerates when the SOC is overcharge or overdischarge.

The SOC of the battery200corresponds to the SOC of the above-described battery stack. The SOC of the battery stack is the total sum of the SOCs of the multiple rechargeable batteries. The overcharge and overdischarge of the SOC of the battery stack can be avoided by the above-described cooperative control. On the other hand, the overcharge and overdischarge of the respective SOCs of the multiple rechargeable batteries can be avoided by equalization processing of equalizing the respective SOCs of the multiple rechargeable batteries.

The equalization processing is performed by individually charging/discharging the multiple rechargeable batteries. The battery200includes a switch to individually charge/discharge the multiple rechargeable batteries. Further, the battery200includes a voltage sensor, a temperature sensor and the like to detect the respective SOCs of the multiple rechargeable batteries. The battery ECU801controls to open and close the switch based on outputs from these sensors and a first current sensor11to be described later. With this configuration, the respective SOCs of the multiple rechargeable batteries are equalized.

The power converter300performs power conversion between the battery200and the first motor400. Further, the power converter300also performs power conversion between the battery200and the second motor500. The power converter300converts direct current power of the battery200into alternating current power at a voltage level appropriate to power running of the first motor400and the second motor500. The power converter300converts alternating current power generated by power generation with the first motor400and the second motor500into direct current power at a voltage level appropriate to charging of the battery200. The power converter300will be described in detail later.

The first motor400, the second motor500, and the engine600are connected to the power divider700. The first motor400is directly connected to an output shaft of a hybrid vehicle, which is not illustrated. The rotational energy of the first motor400is transmitted via the output shaft to a running wheel. On the contrary, the rotational energy of the running wheel is transmitted via the output shaft to the first motor400.

Power running of the first motor400is performed with the alternating current power supplied from the power converter300. Rotational energy generated by the power running is distributed with the power divider700to the engine600and the output shaft of the hybrid vehicle. With this configuration, cranking of a crankshaft and application of a propulsive force to the running wheel are performed. Further, regeneration of the first motor400is performed with the rotational energy transmitted from the running wheel. Alternating current power generated by the regeneration is converted with the power converter300into direct current power and voltage-reduced. This direct current power is supplied to the battery200. Further, the direct current power is also supplied to various electric load mounted on the hybrid vehicle.

Power generation of the second motor500is performed with the rotational energy supplied from the engine600. Alternating current power generated by the power generation is converted with the power converter300into direct current power and voltage-reduced. This direct current power is supplied to the battery200and the various electric load.

The engine600generates rotational energy by combustion driving using fuel. The rotational energy is distributed via the power divider700to the second motor500and the output shaft. With this configuration, power generation of the second motor500and application of a propulsive force to the running wheel are performed.

The power divider700has a planetary gear mechanism. The power divider700has a ring gear, a planetary gear, a sun gear, and a planetary carrier.

The ring gear has a ring shape. Multiple teeth are formed to be arrayed in a circumferential direction respectively on an outer peripheral surface and an inner peripheral surface of the ring gear.

The planetary gear and the sun gear each have a disk shape. Multiple teeth are formed to be arrayed in the circumferential direction on the respective circumferential surfaces of the planetary gear and the sun gear.

The planetary carrier has a ring shape. Multiple planetary gears are connected to a flat surface connecting an outer peripheral surface and an inner peripheral surface of the planetary carrier. The respective flat surfaces of the planetary carrier and the planetary gear are opposite to each other.

The multiple planetary gears are positioned on the circumference about a rotational center of the planetary carrier. The multiple planetary gears are provided at an equal interval between adjacent gears. In the present embodiment, three planetary gears are arrayed at an interval of 120°.

The sun gear is provided at the center of the ring gear. The inner peripheral surface of the ring gear and the outer peripheral surface of the sun gear are opposite to each other. Three planetary gears are provided between the ring gear and the sun gear. The teeth of the respective three planetary gears are engaged with the respective teeth of the ring gear and the sun gear. With this configuration, the respective rotation of the ring gear, the rotation of the planetary gears, the rotation of the sun gear, and the rotation of the planetary carrier are mutually transmitted.

The output shaft of the first motor400is connected to the ring gear. The crankshaft of the engine600is connected to the planetary carrier. The output shaft of the second motor500is connected to the sun gear. With this configuration, the rotation speed of the first motor400, the rotation speed of the engine600, and the rotation speed of the second motor500are in a linear relationship in an alignment chart.

Torque is generated with the ring gear and the sun gear by supplying alternating current power from the power converter300to the first motor400and the second motor500. Torque is generated with the planetary carrier by combustion driving with the engine600. With this configuration, the power running and the regeneration of the first motor400, the power generation of the second motor500, and the application of a propulsive force to the running wheel, respectively, are performed.

The behavior of the first motor400, the behavior of the second motor500, and the behavior of the engine600, respectively, are subjected to cooperative control with the multiple ECUs. For example, the MG ECU802determines a target torque for the first motor400and the second motor500based on the physical quantities detected with the various sensors mounted on the hybrid vehicle and vehicle information inputted from other ECUs, and the like. The MG ECU802performs vector control so as to bring the torque, respectively generated with the first motor400and the second motor500, to the target torque.

Next, the power converter300will be described. The power converter300has a converter310, a first inverter320, and a second inverter330. The converter310performs a function of stepping up and down the voltage level of direct current power. The first inverter320and the second inverter330perform a function of converting direct current power into alternating current power. The first inverter320and the second inverter330perform a function of converting alternating current power into direct current power.

In the in-vehicle system100, the converter310boosts the direct current power of the battery200to a voltage level appropriate to power running of the first motor400and the second motor500. The first inverter320and the second inverter330convert the direct current power into alternating current power. The alternating current power is supplied to the first motor400and the second motor500. Further, the first inverter320and the second inverter330convert the alternating current power generated with the first motor400and the second motor500into direct current power. The converter310reduces the direct current power to a voltage level appropriate to charging of the battery200.

As shown inFIG. 1, the converter310is electrically connected via a first power line301and a second power line302to the battery200. The converter310is electrically connected via a third power line303and a fourth power line304to the first inverter320and the second inverter330respectively.

One end of the first power line301is electrically connected to the cathode of the battery200. One end of the second power line302is electrically connected to the anode of the battery200. The respective other ends of the first power line301and the second power line302are electrically connected to the converter310.

A first smoothing capacitor305is connected to the first power line301and the second power line302. One of two electrodes of the first smoothing capacitor305is connected to the third power line303, and the other electrode is connected to the fourth power line304.

Note that the battery200has a system main relay (SMR), which is not illustrated. The electric connection between the battery stack of the battery200and the power converter300is controlled by opening and closing of the system main relay. That is, continuation and interruption of power supply between the battery200and the power converter300is controlled by the opening and closing of the system main relay.

One end of the third power line303is electrically connected to a high side switch311of the converter310. One end of the fourth power line304is electrically connected to the other end of the second power line302. The respective other ends of the third power line303and the fourth power line304are electrically connected to the first inverter320and the second inverter330respectively.

A second smoothing capacitor306is connected to the third power line303and the fourth power line304. One of two electrodes of the second smoothing capacitor306is connected to the third power line303, and the other electrode is connected to the fourth power line304.

The first inverter320is electrically connected via first energization bus bar341to third energization bus bar343to first U phase stator coil401to first W phase stator coil403of the first motor400. The second inverter330is electrically connected via fourth energization bus bar344to sixth energization bus bar346to second U phase stator coil501to second W phase stator coil503of the second motor500.

The converter310has the high side switch311, a low side switch312, a high side diode311a, a low side diode312a, and a reactor313. As the high side switch311and the low side switch312, an IGBT, a power MOSFET or the like may be employed. In the present embodiment, an n-channel type IGBT is employed as the high side switch311and the low side switch312.

Note that when the high side switch311and the low side switch312are each provided by the MOSFET, a body diode is formed in the MOSFET. Accordingly, the high side diode311aand the low side diode312amay be omitted. The semiconductor device forming the converter310may be manufactured with a semiconductor such as Si, or a wide gap semiconductor such SiC.

The high side diode311ais connected in anti-parallel to the high side switch311. That is, the cathode electrode of the high side diode311ais connected to the collector electrode of the high side switch311. The anode electrode of the high side diode311ais connected to the emitter electrode of the high side switch311.

Similarly, the low side diode312ais connected in anti-parallel to the low side switch312. The cathode electrode of the low side diode312ais connected to the collector electrode of the low side switch312. The anode electrode of the low side diode312ais connected to the emitter electrode of the low side switch312.

As shown inFIG. 1, the third power line303is electrically connected to the collector electrode of the high side switch311. The emitter electrode of the high side switch311and the collector electrode of the low side switch312are connected to each other. The second power line302and the fourth power line304are electrically connected to the emitter electrode of the low side switch312. With this configuration, the high side switch311and the low side switch312are connected in series, in order, from the third power line303toward the second power line302. In other words, the high side switch311and the low side switch312are connected in series, in order, from the third power line303toward the fourth power line304.

A middle point between the high side switch311and the low side switch312, which are connected in series, is electrically connected to one end of the reactor313via the energization bus bar307. The other end of the reactor313is electrically connected to the other end of the first power line301.

With the above-described configuration, the direct current power of the battery200is supplied via the reactor313and the energization bus bar307to the middle point between the high side switch311and the low side switch312, which are connected in series. The alternating current power of the motor, converted with at least one of the first inverter320and the second inverter330into the direct current power, is supplied to the collector electrode of the high side switch311. The alternating current power of the motor, converted into the direct current power, is supplied via the high side switch311, the energization bus bar307, and the reactor313, to the battery200.

In this manner, the direct current power inputted to or outputted from the battery200flows through the energization bus bar307. When the flowing physical quantities are limited, the direct current inputted to or outputted from the battery200flows through the energization bus bar307.

The high side switch311and the low side switch312of the converter310are controlled to be open and closed with the MG ECU802. The MG ECU802generates a control signal and outputs the control signal to a gate driver803. The gate driver803amplifies the control signal and outputs the control signal to the gate electrode of the switch. With this configuration, the MG ECU802steps up or down the voltage level of the direct current power inputted into the converter310.

The MG ECU802generates a pulse signal as a control signal. The MG ECU802controls the voltage stepping up and down levels of the direct current power by controlling the on duty ratio and frequency of the pulse signal. The voltage stepping up and down levels are determined in correspondence with the above-described target torque and the SOC of the battery200.

When the direct current power of the battery200is stepped up, the MG ECU802alternately opens and closes the high side switch311and the low side switch312respectively. For this purpose, the MG ECU802inverts the voltage level of the control signal outputted to the high side switch311and the low side switch312.

When a high level signal is inputted into the gate electrode of the high side switch311, a low level signal is inputted into the gate electrode of the low side switch312. In this case, the direct current power of the battery200is supplied via the reactor313and the high side switch311to the first inverter320and the second inverter330. At this time, electrical energy is stored in the reactor313by flow of the current. Further, electric charge is stored in the second smoothing capacitor306. The second smoothing capacitor306is charged.

When a low level signal is inputted into the gate electrode of the high side switch311, a high level signal is inputted into the gate electrode of the low side switch312. In this case, a closed loop passing through the first smoothing capacitor305, the reactor313, and the low side switch312is formed. As described above, since the electrical energy is stored in the reactor313, the reactor313attempts to pass the current. The current caused by the electrical energy in the reactor313flows through the above-described closed loop.

In this case, supply of the direct current power via the high side switch311to the first inverter320and the second inverter330stops. However, the second smoothing capacitor306is charged. Accordingly, electric power is supplied from the second smoothing capacitor306to the first inverter320and the second inverter330. The power supply to the first inverter320and the second inverter330is continued.

Thereafter, a high level signal is inputted into the high side switch311, while a low level signal is inputted into the low side switch312. At this time, the electrical energy stored in the reactor313is supplied, together with the direct current power of the battery200, as direct current power, to the first inverter320and the second inverter330. With this configuration, the direct current power of the battery200, stepped up in a time-average manner, is supplied to the first inverter320and the second inverter330. Further, the charging of the second smoothing capacitor306is recovered, and the charging amount is increased. The voltage level of the direct current power supplied from the second smoothing capacitor306to the first inverter320and the second inverter330is raised.

When the direct current power supplied from at least one of the first inverter320and the second inverter330is stepped down, the MG ECU802fixes the control signal outputted to the low side switch312at the low level. At the same time, the MG ECU802switches the control signal outputted to the high side switch311to the high level and the low level sequentially.

When a high level signal is inputted into the gate electrode of the high side switch311, the direct current power of at least one of the first inverter320and the second inverter330is supplied via the high side switch311and the reactor313to the battery200.

When a low level signal is inputted into the gate electrode of the high side switch311, the direct current power of at least one of the first inverter320and the second inverter330is not supplied to the battery200. As a result, the direct current power reduced in a time-average manner is supplied to the battery200.

To be more exact, when a high level signal is inputted into the gate electrode of the high side switch311as described above, the first smoothing capacitor305is charged. Electrical energy is stored in the reactor313. Thereafter, when a low level signal is inputted into the gate electrode of the high side switch311and the output voltage and time constant of the second smoothing capacitor306and those of the battery200are different, charging/discharging is performed between the second smoothing capacitor306and the battery200. Further, a diode, which is not illustrated, connects the first power line301and the second power line302. The anode electrode of the diode is connected to the second power line302, and the cathode electrode of the diode is connected to the first power line301. Accordingly, a closed loop passing through the diode, the reactor313, and the first smoothing capacitor305is formed. The current caused by the electrical energy in the reactor313flows through the closed loop.

The first inverter320has first switch321to sixth switch326, and first diode321ato sixth diode326a. As the first switch321to the sixth switch326, an IGBT, a power MOSFET or the like may be employed. In the present embodiment, an n-channel type IGBT is employed as the first switch321to the sixth switch326. When the MOSFET is employed as these switches, the above-described diode may be omitted. The semiconductor device forming the first inverter320may be manufactured with a semiconductor such as Si, or a wide gap semiconductor such as SiC.

The first diode321ato the sixth diode326acorresponding to the first switch321to the sixth switch326are connected in anti-parallel. That is, assuming that k is a natural number of 1 to 6, the cathode electrode of the k-th diode is connected to the collector electrode of the k-th switch. The anode electrode of the k-th diode is connected to the emitter electrode of the k-th switch.

The first switch321and the second switch322are connected in series, in order, from the third power line303toward the fourth power line304. The first switch321and the second switch322form a first U phase leg. One end of the first energization bus bar341is connected to a middle point between the first switch321and the second switch322. The other end of the first energization bus bar341is connected to the first U phase stator coil401of the first motor400.

The third switch323and the fourth switch324are connected in series, in order, from the third power line303toward the fourth power line304. The third switch323and the fourth switch324form a first V phase leg. One end of the second energization bus bar342is connected to a middle point between the third switch323and the fourth switch324. The other end of the second energization bus bar342is connected to the first V phase stator coil402of the first motor400.

The fifth switch325and the sixth switch326are connected in series, in order, from the third power line303toward the fourth power line304. The fifth switch325and the sixth switch326form a first W phase leg. One end of the third energization bus bar343is connected to a middle point between the fifth switch325and the sixth switch326. The other end of the third energization bus bar343is connected to the first W phase stator coil403of the first motor400.

The second inverter330has a similar configuration to that of the first inverter320. The second inverter330has seventh switch331to twelfth switch336and seventh diode331ato twelfth diode336a.

The seventh diode331ato the twelfth diode336acorresponding to the seventh switch331to the twelfth switch336are inversely parallel-connected. Assuming that n is a natural number of 7 to 12, the cathode electrode of the n-th diode is connected to the collector electrode of the n-th switch. The anode electrode of the n-th diode is connected to the emitter electrode of the n-th switch.

The seventh switch331and the eighth switch332are connected in series between the third power line303and the fourth power line304, and form a second U phase leg. One end of the fourth energization bus bar344is connected to a middle point between the seventh switch331and the eighth switch332. The other end of the fourth energization bus bar344is connected to the second U phase stator coil501of the second motor500.

The ninth switch333and the tenth switch334are connected in series between the third power line303and the fourth power line304, and form a second V phase leg. One end of the fifth energization bus bar345is connected to a middle point between the ninth switch333and the tenth switch334. The other end of the fifth energization bus bar345is connected to the second V phase stator coil502of the second motor500.

The eleventh switch335and the twelfth switch336are connected in series between the third power line303and the fourth power line304, and form a second W phase leg. One end of the sixth energization bus bar346is connected to a middle point between the eleventh switch335and the twelfth switch336. The other end of the sixth energization bus bar346is connected to the second W phase stator coil503of the second motor500.

As described above, the first inverter320and the second inverter330respectively have three phase legs corresponding to the respective U phase to W phase stator coils of the motor. The control signal of the MG ECU802, amplified with the gate driver803, is inputted into the gate electrode of the switch of the respective three phase legs.

When the motor is subjected to power running, the respective switches are PWM controlled by output of the control signal from the MG ECU802. With this configuration, a three-phase alternating current is generated with the inverter. When the motor generates power, the MG ECU802stops, for example, output of the control signal. The alternating current power generated by power generation with the motor passes through the diode. As a result, the alternating current power is converted into direct current power.

The above-described alternating current power inputted to or outputted from the first motor400flows through the first energization bus bar341to the third energization bus bar343connecting the first inverter320to the first motor400. Similarly, the alternating current power inputted to or outputted from the second motor500flows through the fourth energization bus bar344to the sixth energization bus bar346connecting the second inverter330to the second motor500. When the flowing physical quantities are limited, the alternating current inputted to or outputted from the first motor400flows through the first energization bus bar341to the third energization bus bar343. The alternating current inputted to or outputted from the second motor500flows through the fourth energization bus bar344to the sixth energization bus bar346.

Next, a current sensor applied to the in-vehicle system100described above will be described.

As a current sensor, the first current sensor11, a second current sensor12, and a third current sensor13are provided. The first current sensor11detects a current which flows through the converter310. The second current sensor12detects a current which flows through the first motor400. The third current sensor13detects a current which flows through the second motor500.

The first current sensor11is provided on the energization bus bar307. As described above, the direct current inputted to or outputted from the battery200flows through the energization bus bar307. The first current sensor11detects the direct current.

The direct current detected with the first current sensor11is inputted into the battery ECU801. The battery ECU801monitors the SOC of the battery200based on the direct current detected with the first current sensor11, the voltage of the battery stack detected with a voltage sensor, which is not illustrated, and the like.

The second current sensor12is provided on the first energization bus bar341to the third energization bus bar343. As described above, the alternating current inputted to or outputted from the first motor400flows through the first energization bus bar341to the third energization bus bar343. The second current sensor12detects the alternating current.

The alternating current detected with the second current sensor12is inputted into the MG ECU802. The MG ECU802vector-controls the first motor400based on the alternating current detected with the second current sensor12, the rotation angle of the first motor400detected with a rotation angle sensor, which is not illustrated, and the like.

The third current sensor13is provided on the fourth energization bus bar344to the sixth energization bus bar346. As described above, the alternating current inputted to or outputted from the second motor500flows through the fourth energization bus bar344to the sixth energization bus bar346. The third current sensor13detects the alternating current.

The alternating current detected with the third current sensor13is inputted into the MG ECU802. The MG ECU802vector-controls the second motor500based on the alternating current detected with the third current sensor13, the rotation angle of the second motor500detected with a rotation angle sensor, which is not illustrated, and the like.

Note that the first U phase stator coil401, the first V phase stator coil402, and the first W phase stator coil403of the first motor400are star-connected. Similarly, the second U phase stator coil501, the second V phase stator coil502, and the second W phase stator coil503of the second motor500are star-connected. Accordingly, by detecting the currents in the two of the three phase stator coils, it is possible to detect the current in the remaining one phase stator coil.

A structure where these three phase stator coils are delta-connected may be employed. In this structure, by detecting the currents in the two of the three phase stator coils, it is possible to detect the current in the remaining one phase stator coil.

The second current sensor12is provided on two of the first energization bus bar341to the third energization bus bar343connected to the first U phase stator coil401to the first W phase stator coil403. More specifically, the second current sensor12is provided on the first energization bus bar341and the second energization bus bar342.

Accordingly, the second current sensor12detects the current which flows through the first U phase stator coil401and the current which flows through the first V phase stator coil402. The MG ECU802detects the current which flows through the first W phase stator coil403based on the current which flows through the first U phase stator coil401and the current which flows through the first V phase stator coil402.

Similarly, the third current sensor13is provided on two of the fourth energization bus bar344to the sixth energization bus bar346connected to the second U phase stator coil501to the second W phase stator coil503. More specifically, the third current sensor13is provided on the fourth energization bus bar344and the fifth energization bus bar345.

Accordingly, the third current sensor13detects the current which flows through the second U phase stator coil501and the current which flows through the second V phase stator coil502. The MG ECU802detects the current which flows through the second W phase stator coil503based on the current which flows through the second U phase stator coil501and the current which flows through the second V phase stator coil502.

The above-described direct current inputted to or outputted from the battery200and the alternating currents inputted to or outputted from the first motor400and the second motor500respectively correspond to a measurement current to be measured. The magnetic field generated by flow of these currents corresponds to a measured magnetic field to be measured.

As described above, the first current sensor11is provided on the energization bus bar307. The energization bus bar307is divided into a part adjacent to the reactor313and a part adjacent to the high side switch311(low side switch312). The first current sensor11is provided on the energization bus bar307, in a form of bridging the divided parts of the energization bus bar307. With this configuration, the current which flows through the energization bus bar307, i.e., the direct current inputted to or outputted from the battery200flows through the first current sensor11.

The configuration where the energization bus bar307is divided into the part adjacent to the reactor313and the part adjacent to the high side switch311is merely an example. For example, when the energization bus bar307is not divided and connected only to the high side switch311side, the first current sensor11bridges the reactor313and the energization bus bar307.

As shown inFIG. 2toFIG. 5, the first current sensor11has a wiring board20, an electrical-conduction bus bar30, a shield40, and a sensor housing50. The electrical-conduction bus bar30bridges the above-described energization bus bar307. Accordingly, the direct current flows through the electrical-conduction bus bar30. The electrical-conduction bus bar30corresponds to an electrical-conduction member.

InFIG. 4, (a) shows a top view of the first current sensor11; (b) shows a front view of the first current sensor11; and (c) shows a bottom view of the first current sensor11. InFIG. 5, (a) shows a front view of the first current sensor11; (b) shows a side view of the first current sensor11; and (c) shows a rear view of the first current sensor11. Note that (b) ofFIG. 4and (a) ofFIG. 5show the same figure.

As clearly indicated in these figures, a part of the electrical-conduction bus bar30is insert-molded in the sensor housing50. The wiring board20and the shield40are disposed in the sensor housing50. The sensor housing50is made of an insulating resin material.

The wiring board20is fixed in the sensor housing50to be opposed to the part of the electrical-conduction bus bar30insert-molded in the sensor housing50. A magnetoelectric converter25, which will be described later, is mounted on the opposing part of the wiring board20to the electrical-conduction bus bar30. The magnetoelectric converter25converts a magnetic field caused by the direct current which flows through the electrical-conduction bus bar30into an electric signal.

The shield40has a first shield41and a second shield42. The first shield41and the second shield42are fixed, away from each other, to the sensor housing50. The respective mutually opposing parts of the wiring board20and the electrical-conduction bus bar30are positioned between the first shield41and the second shield42.

The first shield41and the second shield42are made of a material with higher magnetic permeability than that of the sensor housing50. Accordingly, electromagnetic noise (external noise), which attempts to permeate from the outside of the first current sensor11into the inside, actively attempts to pass through the first shield41and the second shield42. With this configuration, the input of the external noise into the magnetoelectric converter25is suppressed.

A connection terminal60shown inFIG. 4is insert-molded in the sensor housing50. The connection terminal60is electrically and mechanically connected to the wiring board20with solder61. The connection terminal60is electrically connected via a wire harness or the like to the battery ECU801. The electric signal converted with the magnetoelectric converter25is inputted via the connection terminal60, a wire harness (not illustrated), and the like, into the battery ECU801.

Next, the constituent elements of the first current sensor11will be individually described in detail. In the following description, three directions in mutual orthogonal relationship are referred to as x direction, y direction, and z direction. The x direction corresponds to a lateral direction. The y direction corresponds to an extension direction.

As shown inFIG. 6, the wiring board20has a flat plate shape. The wiring board20has a thin flat shape having a thickness in the z direction. The wiring board20is formed by laminating multiple insulating resin layers and conductive metal layers in the z direction. In the wiring board20, an opposing surface20ahaving the largest area and a rear surface20bon the rear side of the opposing surface20aface in the z direction. InFIG. 6, (a) shows a top view of the wiring board20; and (b) shows a bottom view of the wiring board20.

A first sensing unit21and a second sensing unit22shown in (a) ofFIG. 6and inFIG. 7are mounted on the opposing surface20aof the wiring board20. The first sensing unit21and the second sensing unit22each have an ASIC23and a filter24. The ASIC23and the filter24are electrically connected to each other via a wiring pattern of the wiring board20. The connection terminal60is electrically connected to the wiring pattern. ASIC is an abbreviation for application specific integrated circuit. Note that a structure where the first sensing unit21and the second sensing unit22are mounted on the rear surface20bmay be employed.

The ASIC23has a magnetoelectric converter25, a processing circuit26, a connection pin27, and a resin section28. The magnetoelectric converter25and the processing circuit26are electrically connected to each other. One end of the connection pin27is electrically connected to the processing circuit26. The other end of the connection pin27is electrically and mechanically connected to the wiring board20. A part of the connection pin27including the one end, the processing circuit26, and the magnetoelectric converter25are covered with the resin section28. A part of the connection pin27including the other end is exposed from the resin section28.

The magnetoelectric converter25has multiple magnetoresistive effect elements having a resistance value variable in correspondence with magnetic field (transmission magnetic field) which permeates the magnetoelectric converter25itself. In the magnetoresistive effect element, the resistance value varies in correspondence with transmission magnetic field along the opposing surface20a. That is, the resistance value of the magnetoresistive effect element varies in correspondence with a component of the transmission magnetic field along the x direction and a component of the transmission magnetic field along the y direction.

On the other hand, the resistance value of the magnetoresistive effect element does not vary in correspondence with transmission magnetic field along the z direction. Accordingly, even when the external noise along the z direction permeates the magnetoresistive effect element, the resistance value of the magnetoresistive effect element does not vary.

The magnetoresistive effect element has a pinned layer, the magnetization direction of which is fixed, a free layer, the magnetization direction of which changes in correspondence with transmission magnetic field, and an intermediate layer provided between the pinned layer and the free layer. When the intermediate layer has a non-conductive property, the magnetoresistive effect element is a giant magnetoresistive effect element. When the intermediate layer has a conductive property, the magnetoresistive effect element is a tunnel magnetoresistive effect element. Note that the magnetoresistive effect element may be an anisotropic magnetoresistive effect element (AMR). Further, the magnetoelectric converter25may have a hall element in place of the magnetoresistive effect element.

The resistance value of the magnetoresistive effect element varies in accordance with angle formed with respective magnetization directions of the pinned layer and the free layer. The magnetization direction of the pinned layer is along the opposing surface20a. The magnetization direction of the free layer is determined based on the transmission magnetic field along the opposing surface20a. The resistance value of the magnetoresistive effect element is the minimum when the respective magnetization directions of the free layer and the fixed layer are in parallel. The resistance value of the magnetoresistive effect element is the maximum when the respective magnetization directions of the free layer and the fixed layer are antiparallel.

The magnetoelectric converter25has a first magnetoresistive effect element25aand a second magnetoresistive effect element25bas the above-described magnetoresistive effect elements. The magnetization direction of the pinned layer of the first magnetoresistive effect element25aand the magnetization direction of the pinned layer of the second magnetoresistive effect element25bare different by 90°. The relationship of increase and decrease of resistance value is inverted between the magnetoresistive effect element25aand the second magnetoresistive effect element25b. When the resistance value of one of the first magnetoresistive effect element25aand the second magnetoresistive effect element25bis reduced, the resistance value of the other is increased by the equivalent amount to the reduced amount.

The magnetoelectric converter25have two first magnetoresistive effect elements25aand two second magnetoresistive effect elements25b. The first magnetoresistive effect element25aand the second magnetoresistive effect element25bare connected in series, in order, from a power source potential toward a reference potential, to form a first half bridge circuit. The second magnetoresistive effect element25band the first magnetoresistive effect element25aare connected in series, in order, from the power source potential toward the reference potential, to form a second half bridge circuit.

Between the two half bridge circuits, the arrangement order of the first magnetoresistive effect element25aand the second magnetoresistive effect element25bis inverted. Accordingly, when a middle point potential of one of the two half bridge circuits is lowered, a middle point potential of the other is raised. In the magnetoelectric converter25, a full bridge circuit is formed by combination of these two half bridge circuits.

The magnetoelectric converter25has, in addition to the magnetoresistive effect elements forming the above-described full bridge circuit, a differential amplifier25c, a feedback coil25d, and a shunt resistor25e. The middle point potentials of the two half bridge circuits are inputted into an inverted input terminal and a non-inverted input terminal of the differential amplifier25c. The feedback coil25dand the shunt resistor25eare connected in series, in order, from an output terminal of the differential amplifier25ctoward the reference potential.

With the above-described connection configuration, an output is made in correspondence with variation of the resistance values of the first magnetoresistive effect elements25aand the second magnetoresistive effect elements25b, forming the full bridge circuit, from the output terminal of the differential amplifier25c. The variation of resistance value is caused by permeation of the magnetic field along the opposing surface20athrough the magnetoresistive effect element. The magnetic field (measurement current) caused by the current which flows through the electrical-conduction bus bar30permeates the magnetoresistive effect element. Accordingly, a current corresponding to the measurement current flows through the input terminal of the differential amplifier25c.

The input terminal and the output terminal of the differential amplifier25care connected to each other via a feedback circuit, which is not illustrated. With this configuration, virtual short-circuit occurs in the differential amplifier25c. The differential amplifier25coperates so as to cause the inverted input terminal and the non-inverted input terminal to have the same potential. That is, the differential amplifier25coperates such that the current which flows through the input terminal and the current which flows through the output terminal are zero. As a result, a current corresponding to the measurement current (feedback current) flows from the output terminal of the differential amplifier25c.

The feedback current flows via the feedback coil25dand the shunt resistor25ebetween the output terminal of the differential amplifier25cand the reference potential. An offset magnetic field is generated in the feedback coil25dby the flow of the feedback current. The offset magnetic field permeates the magnetoelectric converter25. With this permeation, the measurement current which permeates the magnetoelectric converter25is offset. The magnetoelectric converter25operates so as to bring the measurement current which permeates the magnetoelectric converter25itself and the offset magnetic field into equilibrium.

A feedback voltage corresponding to the current amount of the feedback current which generates the offset magnetic field is generated in a middle point between the feedback coil25dand the shunt resistor25e. The feedback voltage is outputted as an electric signal of detection of the measurement current, to the processing circuit26at the subsequent stage.

The processing circuit26has an adjustment amplifier26aand a threshold power source26b. The middle point between the feedback coil25dand the shunt resistor25eis connected to a non-inverted input terminal of the adjustment amplifier26a. The threshold power source26bis connected to an inverted input terminal of the adjustment amplifier26a. With this configuration, a differential-amplified feedback voltage is outputted from the adjustment amplifier26a.

The respective resistance values of the first magnetoresistive effect elements25aand the second magnetoresistive effect elements25bforming the full bridge circuit each have a temperature-dependent property. The output of the adjustment amplifier26avaries in accordance with temperature change. The processing circuit26has a temperature detection element (not illustrated), a nonvolatile memory to store the relationship between the temperature and the resistance value of the magnetoresistive effect element, and the like. The nonvolatile memory is electrically rewritable. The gain and offset of the adjustment amplifier26aare adjusted by rewriting values stored in the nonvolatile memory. With this configuration, the variation of output of the adjustment amplifier26adue to temperature change is cancelled.

The filter24has a resistor24aand a capacitor24b. As shown inFIG. 7, a power source wiring20c, a first output wiring20d, a second output wiring20e, and a ground wiring20f, as wiring patterns, are formed on the wiring board20.

The ASIC23of the first sensing unit21is connected to the power source wiring20c, the first output wiring20d, and the ground wiring20f, respectively. An output terminal of the adjustment amplifier26aof the ASIC23of the first sensing unit21is connected to the first output wiring20d.

The resistor24aof the filter24of the first sensing unit21is provided on the first output wiring20d. The capacitor24bconnects the first output wiring20dand the ground wiring20f. With this configuration, the filter24of the first sensing unit21forms a low-pass filter with the resistor24aand the capacitor24b. An output from the ASIC23of the first sensing unit21is provided via the low-pass filter to the battery ECU801. With this configuration, an output of the first sensing unit21, from which high-frequency noise is eliminated, is provided to the battery ECU801.

The ASIC23of the second sensing unit22is connected to the power source wiring20c, the second output wiring20e, and the ground wiring20f, respectively. The output terminal of the adjustment amplifier26aof the ASIC23of the first sensing unit21is connected to the second output wiring20e.

The resistor24aof the filter24of the second sensing unit22is provided on the second output wiring20e. The capacitor24bconnects the second output wiring20eand the ground wiring20f. With this configuration, the filter24of the second sensing unit22forms a low-pass filter with the resistor24aand the capacitor24b. An output from the ASIC23of the second sensing unit22is provided via the low-pass filter to the battery ECU801. An output of the second sensing unit22, from which high-frequency noise is eliminated, is provided to the battery ECU801.

As described above, the first sensing unit21and the second sensing unit22of the present embodiment have the same configuration. The respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are aligned in the y direction. As described later, the magnetic field which permeates the respective magnetoelectric converter25of the first sensing unit21and the magnetic field which permeates the respective magnetoelectric converter25of the second sensing unit22are the same.

Accordingly, the electric signal provided from the first sensing unit21to the battery ECU801and the electric signal provided from the second sensing unit22to the battery ECU801are the same. The battery ECU801determines whether or not an abnormality occurs in one of the first sensing unit21and the second sensing unit22by comparing the two electric signals provided. In this manner, the first current sensor11according to the preset embodiment has redundancy.

Note that the above-described shunt resistor25emay be provided in the resin section28, or may be provided outside of the resin section28. When the shunt resistor25eis provided outside of the resin section28, the shunt resistor25eis mounted on the wiring board20. Then the shunt resistor25eis externally attached to the ASIC23.

Further, as long as at least one of these four resistors is a magnetoresistive effect element, the respective four resistors forming the full bridge circuit are not necessarily magnetoresistive effect elements. In place of the full bridge circuit, only one half bridge circuit may be formed.

When the above-described redundancy is not required, as the first current sensor11, a configuration having one of the first sensing unit21and the second sensing unit22may be employed.

The electrical-conduction bus bar30is made of a conductive material such as copper, brass, or aluminum. The electrical-conduction bus bar30may be manufactured by the following methods, for example. The electrical-conduction bus bar30may be manufactured by press-working a flat plate. The electrical-conduction bus bar30may be manufactured by integrally joining multiple flat plates. The electrical-conduction bus bar30may be manufactured by welding multiple flat plates. The electrical-conduction bus bar30may be manufactured by pouring a molten-state conductive material into a mold. The manufacturing method of the electrical-conduction bus bar30is not particularly limited.

As shown inFIG. 8, the electrical-conduction bus bar30has a thin flat shape having the thickness in the z direction. In the electrical-conduction bus bar30, a front surface30aand a rear surface30bon the rear side of the front surface30a, respectively, face in the z direction. InFIG. 8, (a) shows a top view of the electrical-conduction bus bar; and (b) shows a side view of the electrical-conduction bus bar.

The electrical-conduction bus bar30extends in the y direction. As marked off with two broken lines inFIG. 8, the electrical-conduction bus bar30has a covered part31covered with the sensor housing50, and first exposed part32and second exposed part33exposed from the sensor housing50. The first exposed part32and the second exposed part33are aligned via the covered part31in the y direction. The first exposed part32and the second exposed part33are connected integrally via the covered part31.

As shown in (b) ofFIG. 8, the respective dimensions (thicknesses) of the covered part31, the first exposed part32, and the second exposed part33in the z direction are equal to each other. That is, respective distances in the z direction between the front surfaces30aand the rear surfaces30bof the covered part31, the first exposed part32, and the second exposed part33, are equal to each other.

A bolt hole30cfor electrical and mechanical connection via a bolt to the energization bus bar307is formed in each of the first exposed part32and the second exposed part33. The bolt hole30cpasses through each of the first exposed part32and the second exposed part33from the front surface30ato the rear surface30b.

As described above, the energization bus bar307is divided into the part adjacent to the reactor313and the part adjacent to the high side switch311. An attachment hole corresponding to the bolt hole30cis formed respectively in the part adjacent to the reactor313and in the part adjacent to the high side switch311of the energization bus bar307.

The attachment hole of the energization bus bar307in the part adjacent to the reactor313and the bolt hole30cof the first exposed part32are aligned in the z direction. The attachment hole of the energization bus bar307in the part adjacent to the high side switch311and the bolt hole30cof the second exposed part33are aligned in the z direction. In this status, a bolt shaft is inserted through the bolt hole30cand the attachment hole. Then a nut is fastened from the end of the bolt shaft toward a bolt head. The energization bus bar307and the electrical-conduction bus bar30are held between the bolt head and the nut. With this configuration, the energization bus bar307and the electrical-conduction bus bar30are brought into contact, and the energization bus bar307and the electrical-conduction bus bar30are electrically and mechanically connected to each other. As described above, in the energization bus bar307, the divided part adjacent to the reactor313and the divided part adjacent to the high side switch311are bridged with the electrical-conduction bus bar30. A common current flows through the energization bus bar307and the electrical-conduction bus bar30.

As shown in (a) ofFIG. 8, the covered part31has a narrow part31aat which the dimension in the x direction is locally short. In the narrow part31aof the present embodiment, the dimension in the x direction is reduced in stepwise. In the narrow part31a, the dimension in the x direction is reduced in two steps, from the first exposed part32side of the covered part31toward a center point CP of the covered part31in they direction. Similarly, in the narrow part31a, the dimension in the x direction is reduced in two steps, from the second exposed part33side of the covered part31toward the center point CP of the covered part31in the y direction. Note that the dimension of the narrow part31ain the x direction may be reduced in more steps, or may be continuously reduced.

The above-described center point CP is equivalent to the center of gravity of the covered part31. The covered part31and the narrow part31aare in a line-symmetrical shape with a center line passing through the center point CP in the z direction as a symmetry axis AS.

In the narrow part31a, the dimension in the x direction is shorter than that of the first exposed part32and the second exposed part33. The density of a current flowing through the narrow part31ais higher than the density of a current flowing through the first exposed part32and the second exposed part33. As a result, the intensity of a measured magnetic field to be measured, caused by the current flowing through the narrow part31ais high.

As indicated with the magnetoelectric converter25in the first sensing unit21and the magnetoelectric converter25in the second sensing unit22, schematically surrounded with broken lines respectively, in (a) and (b) ofFIG. 8, the first sensing unit21and the second sensing unit22are each arranged to be opposed to and to be spaced from the narrow part31ain the z direction. Accordingly, the high-intensity measured magnetic field, caused by the current flowing through the narrow part31a, permeates the first sensing unit21and the second sensing unit22respectively.

As described above, the electrical-conduction bus bar30extends in the y direction. In the electrical-conduction bus bar30, the current flows in the y direction. A measured magnetic field in accordance with Ampere's law is generated in a circumferential direction about the y direction by the flow of the current in the y direction. The measured magnetic field flows in a ring shape about the electrical-conduction bus bar30in a plane defined by the x direction and the z direction. The first sensing unit21and the second sensing unit22each detect a component of the measured magnetic field along the x direction.

As indicated with a broken line inFIG. 8, the respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are aligned in the y direction. The two magnetoelectric converters25are symmetrically arranged with respect to the symmetry axis AS. The positions of the two magnetoelectric converters25in the x direction and the position of the symmetry axis AS (center point CP) in the x direction are the same. Accordingly, the two magnetoelectric converters25are aligned via the center point CP in the y direction.

Further, the distances between the two magnetoelectric converters25and the covered part31in the z direction are the same. As described above, the covered part31and the narrow part31aare in a line-symmetrical shape with respect to the symmetry axis AS. As described above, measured magnetic fields having equivalent x-direction components permeate the two magnetoelectric converters25.

Note that the electrical-conduction bus bar30of the present embodiment is produced by press-working a conductive flat plate. In the press working, the flat plate is placed on a die, a puncher is brought to be close to the die to apply a tensile force to the flat plate. With this work, the flat plate is divided into the electrical-conduction bus bar30and chips, thus the electrical-conduction bus bar30is produced.

When the electrical-conduction bus bar30is produced by the above-described press working, a shear plane is formed in the electrical-conduction bus bar30. A sag occurs in the shear plane on the side of a surface of the electrical-conduction bus bar30, which is brought into contact with the puncher first. With this sag, there is a fear of perpendicularity impairment of the shear plane. As a result, the distribution of the measured magnetic field caused by the current flowing through the electrical-conduction bus bar30may be deviated from the design.

In the present embodiment, the electrical-conduction bus bar30is arranged such that, not the surface that is brought into contact with the puncher first, but a surface that is lastly separated with the puncher is adjacent to the wiring board20. That is, the surface that is firstly brought into contact with the puncher is the rear surface30b, and the surface that is lastly separated from the puncher is the front surface30a. The shear plane corresponds to a side surface between the front surface30aand the rear surface30b. Accordingly, the perpendicularity impairment on the front surface30aside in the side surface of the electrical-conduction bus bar30is suppressed. The front surface30aof the electrical-conduction bus bar30opposes the wiring board20. With this configuration, the deviation of the distribution of the measured magnetic field which permeates the first sensing unit21and the second sensing unit22mounted on the wiring board20is suppressed.

Note that when the electrical-conduction bus bar30is produced by press working as described above, it is necessary to determine whether or not a sag has occurred on any of the front surface30aside and the rear surface30bside in the side surface. For the purpose of the above determination, a notch33aas a mark is formed in the second exposed part33of the electrical-conduction bus bar30. The notch33aof the present embodiment has a semicircular shape.

As described above, the shield40has the first shield41and the second shield42. As shown inFIG. 9andFIG. 10, the first shield41and the second shield42each have a thin plate shape having the thickness in the z direction. In the first shield41, one surface41ahaving a largest area and a rear surface41bon the rear of the one surface41aface in the z direction respectively. In the second shield42, one surface42ahaving a largest area and a rear surface42bon the rear of the widest surface42aface in the z direction respectively.

As shown inFIG. 2andFIG. 3, the first shield41and the second shield42are provided, in a state where the one surface41aand the one surface42aoppose each other in the z direction, in the sensor housing50. The rear surface41bof the first shield41and the rear surface42bof the second shield42are exposed to the outside of the sensor housing50respectively. The rear surface41band the rear surface42beach form a part of an outer-most surface of the first current sensor11.

InFIG. 9, (a) shows a top view of the first shield; and (b) shows a bottom view of the first shield. InFIG. 10, (a) shows a top view of the second shield; and (b) shows a bottom view of the second shield.

The first shield41and the second shield42may be produced by press-joining multiple flat plates made of a soft magnetic material with high magnetic permeability such as permalloy. Otherwise, the first shield41and the second shield42may be produced by press-extending magnetic steel.

The first shield41and the second shield42of the present embodiment are each produced by press-joining multiple flat plates made of a soft magnetic material. Each of the multiple flat plates is formed with four protrusions which protrude from a main surface toward a rear surface. In correspondence with the protrusions, each of the multiple flat plates is formed with four recesses which are recessed from the rear surface toward the main surface. The multiple flat plates are respectively arranged such that the main surface and the rear surface oppose to each other. Further, the multiple flat plates are laminated such that the protrusions of one of two opposing flat plates are received in the recesses of the other of the two opposing flat plates. In this laminated state, the multiple flat plates are press-joined. With this configuration, the first shield41and the second shield42are produced.

Note that, in the case where the first shield41and the second shield42are produced by press-extending magnetic steel, the direction in which the magnetic steel is extended with the press-extension is, for example, defined in the x direction. In this case, the atomic arrangement (crystal) of the magnetic steel is aligned in the x direction. As a result, the magnetic permeability in the x direction is higher than the magnetic permeability in the y direction. In this manner, it is possible to provide the magnetic permeability of the shield with anisotropy by specifying the extending direction of the magnetic steel.

As shown inFIG. 9, the planar shape of the first shield41is a rectangular shape with the x direction as a longitudinal direction. Notches41care formed at four corners of the first shield41of the present embodiment. InFIG. 9, to clarify the border between the center of the first shield41and the opposite ends of the first shield41in the y direction, two broken lines extending in the x direction are given to the first shield41. In the following description, the center of the first shield41in the y direction is indicated as a first center part41d. The opposite ends of the first shield41in the y direction are indicated as a first opposite end part41e. The first center part41dis positioned between the two ends of the first opposite end part41ein the y direction.

As clearly indicated with the broken lines, the first opposite end part41ehas the length in the x direction shorter than that of the first center part41d. In the first opposite end part41e, the magnetic permeability in the x direction is thus lower than that in the first center part41d. The magnetic field hardly enters the first opposite end part41e. Accordingly, the permeation of the magnetic field, via portions (parallel portions) of the first center part41ddirectly connected to the first opposite end part41eand aligned in the y direction, from one of the two ends of the first opposite end part41eto the other end, is suppressed. The magnetic field hardly permeates the parallel portions of the first center part41d. As a result, the parallel portions of the first center part41dare hardly magnetically saturated.

The parallel portions of the first center part41d, at which the magnetic saturation is suppressed, are aligned with the first sensing unit21and the second sensing unit22mounted on the wiring board20in the z direction. The respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are positioned between the first center part41dand the narrow part31a.

As shown inFIG. 10, the planar shape of the second shield42is a rectangular shape with the x direction as a longitudinal direction. InFIG. 10, to clarify the border between the center of the second shield42and the opposite ends of the second shield42in the y direction, two broken lines extending in the x direction are given to the second shield42. In the following description, the center of the second shield42in the y direction is indicated as a second center part42d. The opposite ends of the second shield42are indicated as a second opposite end part42e. The second center part42dis positioned between the two ends of the second opposite end part42ein the y direction.

The second shield42has two sides42faligned in the x direction. Each of the two sides42fis formed with an extending part42cextending in the z direction in an area adjacent to the second center part42d. The two extending parts42cextend in a direction from the rear surface42btoward the one surface42ain the z direction. The extending part42chas a rectangular parallelepiped shape with the y direction as a longitudinal direction. The extending part42cis formed, upon production of the second shield42as described above, after the press-joining of the multiple flat plates made of a soft magnetic material, by bending the joined flat plates.

As described above, the first shield41and the second shield42are provided, in a state where the one surface41aof the first shield41and the one surface42aof the second shield42are opposed to each other in the z direction, in the sensor housing50. In this state where the first shield41and the second shield42are provided in the sensor housing50, the extending part42cextends toward the first shield41. An end surface of the extending part42cand the one surface41aof the first center part41dof the first shield41are opposed to each other in the z direction.

With this configuration, the clearance between the first center part41dof the first shield41and the extending part42cof the second shield42in the z direction is shorter than the clearance between the one surface41aof the first shield41and the one surface42aof the second shield42in the z direction. Accordingly, the magnetic field entered the first shield41easily permeates the second shield42via the extending part42c.

As described above, the extending part42cextends from the side42fin the area adjacent to the second center part42din the z direction. The extending part42cis not formed on the side42fin the area adjacent to the second opposite end part42e. Therefore, the magnetic field entered the first shield41easily permeates the second center part42dof the second shield42via the extending part42c.

The second center part42dis opposed to the first sensing unit21and the second sensing unit22mounted on the wiring board20in the z direction. The magnetoelectric converters25and the narrow parts31aof the first sensing unit21and the second sensing unit22are positioned between the first center part41dand the second center part42d.

Further, the positions of the magnetoelectric converters25in the x direction are between the two extending parts42cof the respective two sides42f. When external noise along the x direction attempts to permeate a region between the one surface41aof the first shield41and the one surface42aof the second shield42in which the magnetoelectric converters25are positioned, the external noise attempts to enter not the magnetoelectric converters25but the extending parts42c. In the extending parts42c, the external noise bents its permeation direction so as to permeate through the second shield42. As a result, permeation of the external noise through the magnetoelectric converters25is suppressed.

As shown inFIG. 3andFIG. 11, the electrical-conduction bus bar30and the connection terminal60are insert-molded in the sensor housing50. The wiring board20and the shield40are provided in the sensor housing50. The electrical-conduction bus bar30, the wiring board20, and the shield40are aligned, away from each other, in the z direction. InFIG. 11, (a) shows a top view of the sensor housing; and (b) shows a bottom view of the sensor housing.

As shown inFIG. 5andFIG. 11, the sensor housing50has a base51, insulating parts52, a first surrounding part53, a second surrounding part54, and a connector part55.

The base51has a rectangular parallelepiped shape with the x direction as a longitudinal direction. The base51has six surfaces. The base51has a left surface51aand a right surface51bfacing in the y direction. The base51has an upper surface51cand a lower surface51dfacing in the x direction. The base51has an upper end surface51eand a lower end surface51ffacing in the z direction.

As shown in (a) and (c) ofFIG. 5, the insulating parts52are formed in a part of the left surface51aand a part of the right surface51bin the base51, respectively. The two insulating parts52extend, away from the base51, in the y direction. The two insulating parts52are aligned via the base51in the y direction. The covered part31of the electrical-conduction bus bar30is covered respectively with the two insulating parts52and the base51.

In a broad way, portions of the covered part31adjacent to the first exposed part32and the second exposed part33are covered with the two insulating parts52. The narrow part31aof the covered part31is covered with the base51. The narrow part31ais positioned between the upper end surface51eand the lower end surface51fof the base51in the z direction. An insulating resin material forming the base51is positioned between the narrow part31aand the upper end surface51eand between the narrow part31aand the lower end surface51frespectively. As shown in (a) ofFIG. 11, the first surrounding part53is formed on the upper end surface51eof the base51. The first surrounding part53has a left wall53aand a right wall53baligned in the y direction. The first surrounding part53has an upper wall53cand a lower wall53daligned in the x direction.

These walls forming the first surrounding part53are formed along the edge of the upper end surface51e. In a circumferential direction about the z direction, the left wall53a, the upper wall53c, the right wall53b, and the lower wall53dare connected in sequence. With this configuration, the first surrounding part53has a ring shape opened in the z direction. The first surrounding part53surrounds the upper end surface51e. The wiring board20and the first shield41are provided in first storage space provided by the first surrounding part53and the upper end surface51e.

As shown in (b) ofFIG. 11, the second surrounding part54is formed on the lower end surface51fof the base51. The second surrounding part54has a left wall54aand a right wall54baligned in the y direction. The second surrounding part54has an upper wall54cand a lower wall54daligned in the x direction.

These walls forming the second surrounding part54are formed around the above-described part of the base51aligned with the narrow part31ain the z direction on the lower end surface51f. In the circumferential direction about the z direction, the left wall54a, the upper wall54c, the right wall54b, and the lower wall54dare connected in sequence. With this configuration, the second surrounding part54has a ring shape opened in the z direction. The second surrounding part54surrounds a part of the lower end surface51f. The second shield42is provided in second storage space provided by the second surrounding part54and the lower end surface51f.

In the second storage space, the size of a plane orthogonal to the z direction is smaller than that of the first storage space. The second storage space is aligned with a part of the first storage space in the z direction. A part of the first storage space, which is not aligned with the second storage space in the z direction, is aligned with the connector part55in the z direction.

As shown in (b) ofFIG. 5and (b) ofFIG. 11, the connector part55is formed on the lower end surface51fof the base51. The connector part55extends, away from a part of the lower end surface51fnot surrounded with the second surrounding part54(non-surrounded part), in the z direction. The connector part55forms a part of the lower wall54d.

The connector part55has a pillar part55aextending from the lower end surface51fin the z direction, and a surrounding part55csurrounding an apical surface55bof the pillar part55ain the circumferential direction about the z direction. The connection terminal60extends in the z direction. The connection terminal60is covered respectively with the pillar part55aand a part of the base51aligned with the pillar part55ain the z direction.

One end of the connection terminal60is exposed from the apical surface55bto the outside of the pillar part55a. The periphery of the one end of the connection terminal60exposed from the apical surface55bis surrounded by the above-described surrounding part55c. With this configuration, the surrounding part55cand the one end of the connection terminal60form a connector. A connector of a wire harness or the like is connected to the connector.

The other end of the connection terminal60is exposed from the upper end surface51eto the outside of the base51. The other end of the connection terminal60is provided in the above-described first storage space. The connection terminal60is away from the part of the electrical-conduction bus bar30covered with the base51(narrow part31a) in the x direction. The other end of the connection terminal60is positioned adjacent to the lower wall53din the x direction. The narrow part31ais positioned adjacent to the upper wall53c. The insulating resin material forming the base51is positioned between the part of the connection terminal60and the part of the narrow part31arespectively insert-molded in the sensor housing50.

As described above, the direct current inputted to or outputted from the battery200flows through the electrical-conduction bus bar30. In the connection terminal60, an electric signal with a smaller current amount than the direct current flows between the wiring board20and the battery ECU801. When the creepage distance between the electrical-conduction bus bar30and the connection terminal60is short, there is a fear of short-circuit due to conduction between the electrical-conduction bus bar30and the connection terminal60.

A rib52afor suppressing such inconvenience is formed in the insulating part52. The rib52aprotrudes from the insulating part52in the z direction. The rib52aextends in the x direction. The length of the rib52ain the x direction is longer than the respective lengths of the first exposed part32and the second exposed part33in the x direction.

The rib52ais positioned between each of the first exposed part32and the second exposed part33of the electrical-conduction bus bar30, which are positioned outside of the insulating part52, and the other end of the connection terminal60, which is exposed from the upper end surface51eto the outside. With the ribs52a, the creepage distance between the electrical-conduction bus bar30and the connection terminal60on the surface of the sensor housing50is elongated. With this configuration, the short circuit between the electrical-conduction bus bar30and the connection terminal60is suppressed.

Further, the ribs52aare positioned, respectively, between the first exposed part32and the second exposed part33, and the first shield41and the second shield42. With this configuration, short circuit between the electrical-conduction bus bar30and the shield40is also suppressed.

It is possible to reduce the length of the insulating part52in the y direction by the extension of the creepage distance with the ribs52a. The length of the insulating part52in the y direction is reduced by about 85%. With this configuration, an increase of the physical constitution of the first current sensor11is suppressed.

<Wiring Board Fixing Form to Sensor Housing>

As shown in (a) ofFIG. 11and (a) ofFIG. 12, a board support pin56aand a board adhesion pin56blocally extending in the z direction are formed on the upper end surface51eof the base51. Multiple board support pins56aand board adhesion pins56bare formed on the upper end surface51e. InFIG. 12, (a) shows a perspective view of the sensor housing; and (b) shows a perspective view of the sensor housing in which the wiring board is provided. InFIG. 12, for explanation of these pins, a part of reference numerals is omitted.

The multiple board support pins56aeach have an apical surface56cfacing in the z direction. The positions of the multiple apical surfaces56cin the z direction are equal to each other. Similarly, the multiple board adhesion pins56beach have an apical surface56dfacing in the z direction. The positions of the multiple apical surfaces56din the z direction are equal to each other.

As shown inFIG. 13, the length between the apical surface56cof the board support pin56aand the upper end surface51ein the z direction is defined as L1. The length between the apical surface56dof the board adhesion pin56band the upper end surface51ein the z direction is defined as L2. As clearly indicated in the figure, the length L1is longer than the length L2.

Therefore, the apical surface56cof the board support pin56ais away from the upper end surface51e, further than the apical surface56dof the board adhesion pin56b, in the z direction. The wiring board20is mounted, in a state where the opposing surface20ais in contact with the apical surfaces56cof the board support pins56a, in the sensor housing50. The board support pin56acorresponds to a board support part. The apical surface56ccorresponds to a support surface.

In the state where the wiring board20is mounted on the apical surfaces56cof the board support pins56a, the opposing surface20aof the wiring board20is spaced from the apical surfaces56dof the board adhesion pins56bin z direction. A board adhesive56efor adhesion fixing of the wiring board20and the board adhesion pin56bis provided between the wiring board20and the board adhesion pin56b. The board adhesion pin56bcorresponds to a board bonding member. The apical surface56dcorresponds to a mounting surface.

Upon adhesion fixing of the wiring board20and the sensor housing50with the board adhesive56e, the temperature of the board adhesive56eis set to be higher than the temperature of an environment where the first current sensor11is provided. In this case, the temperature of the board adhesive56emay be set to about 150° C., for example. At this temperature, the board adhesive56ehas fluidity. As the board adhesive56e, a silicone adhesive may be employed.

The board adhesive56ehaving fluidity at about 150° C. is applied to the apical surfaces56dof the board adhesion pins56b. Then, the wiring board20is placed in the sensor housing50so that the apical surfaces56cof the board support pins56aand the board adhesive56eare brought into contact with the opposing surface20aof the wiring board20. Thereafter, the board adhesive56eis cooled down to a room temperature to be solidified.

At the temperature of the environment where the first current sensor11is provided, a residual stress condensing to its own center occurs to the board adhesive56e. The wiring board20and the board adhesion pin56bare brought closer to each other with the residual stress. The contact state between the opposing surface20aof the wiring board20and the apical surfaces56cof the board support pins56ais maintained.

As a result, misalignment of the wiring board20with respect to the sensor housing50does not depend on shape variation of the board adhesive56ehaving fluidity upon adhesion fixing any longer. The misalignment of the wiring board20with respect to the sensor housing50is caused by a manufacturing error of the sensor housing50. In other words, the misalignment of the wiring board20with respect to the electrical-conduction bus bar30insert-molded in the sensor housing50depends on the manufacturing error of the sensor housing50.

In the present embodiment, three board support pins56aare formed on the upper end surface51e. Two of the three board support pins56aare aligned, away from each other, in the y direction. The remaining one board support pin56ais away from a middle point between the two board support pins56aaligned in the y direction, in the x direction. The apical surfaces56cof the three board support pins56aform apexes of an isosceles triangle. The narrow part31aof the electrical-conduction bus bar30is positioned between the two board support pins56aaligned in the y direction and the remaining one board support pin56a.

In the present embodiment, three board adhesion pins56bare formed on the upper end surface51e. Two of the three board adhesion pins56bare aligned, away from each other, in the y direction. The remaining one board adhesion pin56bis away from a middle point between the two board support pins56aaligned in the y direction, in the x direction. The apical surfaces56dof the three board adhesion pins56bform apexes of an isosceles triangle.

The other ends of the multiple connection terminals60are aligned between the two board support pins56aaligned in the y direction. The remaining one board support pin56ais positioned in the middle point between the two board adhesion pins56baligned in the y direction. Accordingly, the remaining one board support pin56ais aligned with the remaining one board adhesion pin56bin the x direction. The center point CP of the narrow part31ais positioned between the remaining one board support pin56aand the remaining one board adhesion pin56bin the x direction.

With the above-described configuration, the isosceles triangle formed by connecting the apical surfaces56cof the three board support pins56aand the isosceles triangle formed by connecting the apical surfaces56dof the three board adhesion pins56boverlap each other in the z direction. The center point CP of the narrow part31ais positioned in the region provided by these two isosceles triangles overlapping in the z direction.

The wiring board20is provided in the sensor housing50to be opposed to the two isosceles triangles, respectively, in the z direction. In the wiring board20, the connection between a part opposing to the two isosceles triangles and the sensor housing50is more stable, because of the contact with the board support pins56aand the connection with the board adhesion pins56bvia the board adhesive56e, than the connection between a part without opposing to the two isosceles triangles and the sensor housing50. The first sensing unit21and the second sensing unit22are mounted on the part of the wiring board20with stable connection with the sensor housing50.

In a state where the wiring board20is mounted on the board support pins56aand fixed via the board adhesive56eto the board adhesion pins56b, the opposing surface20aof the wiring board20and the upper end surface51eof the base51are opposed to each other and spaced from each other in the z direction. If there is no manufacturing error or the like, the clearance between the opposing surface20aand the upper end surface51eis constant over the entire surface, and the opposing surface20aand the upper end surface51eare in parallel relationship.

As described above, the narrow part31aof the electrical-conduction bus bar30is insert-molded in the base51. If there is no manufacturing error or the like, the clearance between the surface30aof the narrow part31aand the upper end surface51eof the base51is constant over the entire surface, and the surface30aof the narrow part31aand the upper end surface51eof the base51are in parallel relationship.

Because of the parallel relationship described as above, if there is no manufacturing error or the like, the clearance between the opposing surface20aof the wiring board20and the surface30aof the narrow part31ais also constant over the entire surface, and the opposing surface20aof the wiring board20and the surface30aof the narrow part31aare in parallel relationship.

As described above, the wiring board20is formed by laminating multiple resin layers and metal layers in the z direction. Therefore, the manufacturing error of the thickness of the wiring board20in the z direction is likely to be large. The manufacturing error of the thickness of the wiring board20in the z direction is about twice of the manufacturing error due to the position of the electrical-conduction bus bar30insert-molded in the sensor housing50in the z direction and the arrangement error of the wiring board20in the z direction with respect to the sensor housing50.

In the wiring board20, the first sensing unit21and the second sensing unit22are provided on the opposing surface20a, which opposes to the electrical-conduction bus bar30. Therefore, the distance between the first sensing unit21and the electrical-conduction bus bar30and the distance between the second sensing unit22and the electrical-conduction bus bar30in the z direction do not depend on the thickness of the wiring board20in the z direction. Thus, variations of the distance between the first sensing unit21and the electrical-conduction bus bar30and the distance between the second sensing unit22and the electrical-conduction bus bar30in the z direction due to the manufacturing error of the thickness of the wiring board20in the z direction are suppressed.

Note that the number of the board support pins56aand the number of the board adhesion pins56bare not limited to three. The number of the board support pins56amay be four or more. The number of the board adhesion pins56bmay be one, two, four or more.

When three or more board support pins56aand three or more board adhesion pins56bare provided, it is desirable to configure such that the polygon formed by connecting the apical surfaces56cof the three or more board support pins56aand the polygon formed by connecting the apical surfaces56dof the three or more board adhesion pins56boverlap each other in the z direction. In this configuration, the first sensing unit21and the second sensing unit22may be mounted in a region of the wiring board20opposing to the two polygons in the z direction. With this configuration, the misalignment of the first sensing unit21and the misalignment of the second sensing unit22respectively with respect to the sensor housing50are suppressed.

As the names of board support pin56aand board adhesion pin56bindicate, the example where these pins have pillar shapes extending in the z direction has been shown. However, the shapes of these pins are not limited to the pillar shapes. As long as the apical surface56cof the board support pin56ais away from the upper end surface51efurther than the apical surface56dof the board adhesion pin56b, the shape is not particularly limited.

<Fixing Form of First Shield to Sensor Housing>

As shown in (a) ofFIG. 11and (a) ofFIG. 14, a shield support pin57aand a shield adhesion pin57bare formed on the upper end surface51eof the base51to locally extending in the z direction. Multiple shield support pins57aand shield adhesion pins57bare formed on the upper end surface51e. InFIG. 14, (a) shows a perspective view of the sensor housing provided with the wiring board; and (b) shows a perspective view of the sensor housing provided with the wiring board and the shield. InFIG. 14, a part of reference numerals is omitted for explanation of these pins.

The multiple shield support pins57aeach have an apical surface57cfacing in the z direction. The positions of the multiple apical surfaces57cin the z direction are equal to each other. Similarly, the multiple shield adhesion pins57beach have an apical surface57dfacing in the z direction. The positions of the apical surfaces57din the z direction are equal to each other.

As shown inFIG. 15, in the respective shield support pin57aand shield adhesion pin57b, the length in the z direction is longer than that of the board support pin56a. More specifically, in the respective shield support pin57aand shield adhesion pin57b, the length in the z direction is longer than that of the board support pin56aby an amount equal to or larger than the thickness of the wiring board20. As described above, in the state where the wiring board20is mounted in the sensor housing50, the apical surface57cof the shield support pin57aand the apical surface57dof the shield adhesion pin57bare respectively further from the upper end surface51ethan the rear surface20bof the wiring board20in the z direction. Note that a configuration where the difference between the length of the shield adhesion pin57band the length of the board support pin56ain the z direction is shorter than the thickness of the wiring board20in the z direction may be employed.

As shown inFIG. 15, the length between the apical surface57cof the shield support pin57aand the upper end surface51ein the z direction is L3. The length between the apical surface57dof the shield adhesion pin57band the upper end surface51ein the z direction is L4. As clearly indicated in the figure, the length L3is longer than the length L4.

The apical surface57cof the shield support pin57ais away from the upper end surface51efurther than the apical surface57dof the shield adhesion pin57bin the z direction. The first shield41is mounted in the sensor housing50in the state where the one surface41ais in contact with the apical surface57cof the shield support pin57a. The shield support pin57acorresponds to a shield support part. The apical surface57ccorresponds to the contact surface.

In the state where the one surface41aof the first shield41is mounted on the apical surface57cof the shield support pin57a, the one surface41aof the first shield41and the apical surface57dof the shield adhesion pin57bare away from each other in the z direction. The board adhesive56efor adhesion fixing is provided between the first shield41and the shield adhesion pin57b. The shield adhesion pin57bcorresponds to a shield adhesion part. The apical surface57dcorresponds to the application surface.

Upon the adhesion fixing between the first shield41and the sensor housing50with the shield adhesive57e, the temperature of the shield adhesive57eis set to be higher than the temperature of the environment where the first current sensor11is provided. The temperature of the shield adhesive57ein this case may be set to about 150° C., for example. At this temperature, the shield adhesive57ehas fluidity. As the shield adhesive57e, a silicone adhesive may be employed.

The shield adhesive57ehaving fluidity at about 150° C. is applied to the apical surface57dof the shield adhesion pin57b. Then, the first shield41is placed in the sensor housing50so as to bring the apical surface57cof the shield support pin57aand the shield adhesive57erespectively into contact with the one surface41aof the first shield41. Thereafter, the shield adhesive57eis cooled down to the room temperature to be solidified.

Thus, in the shield adhesive57e, a residual stress condensing to its own center occurs at the temperature of the environment where the first current sensor11is provided. The first shield41and the shield adhesion pin57bare brought closer to each other with the residual stress. The contact state between the one surface41aof the first shield41and the apical surface57cof the shield support pin57ais maintained.

As a result, the misalignment of the first shield41with respect to the sensor housing50does not depend on the shape variation of the shield adhesive57ehaving fluidity upon adhesion fixing any longer. The misalignment of the first shield41with respect to the sensor housing50is caused by the manufacturing error of the sensor housing50. In other words, the misalignment of the first shield41with respect to the wiring board20fixed to the sensor housing50depends on the manufacturing error of the sensor housing50.

In the present embodiment, three shield support pins57aare formed on the upper end surfaces51e. One of the three shield support pins57ais connected integrally with the left wall53a. One of the remaining two shield support pins57ais connected integrally with the right wall53b. The remaining one shield support pin57ais connected integrally with the upper wall53c. The apical surfaces57cof the three shield support pins57aform apexes of a triangle.

The shield support pin57aconnected integrally with the left wall53aand the shield support pin57aconnected integrally with the right wall53bare aligned in the y direction. The interval between the two shield support pins57aand the shield support pin57aconnected integrally with the upper wall53care away from each other in the x direction. The first sensing unit21and the second sensing unit22of the wiring board20are positioned in the triangular region formed by connecting the apical surfaces57cof the three shield support pins57a.

In the present embodiment, three shield adhesion pins57bare formed on the upper end surface51e. One of the three shield adhesion pins57bis connected integrally with the left wall53a. One of the remaining two shield adhesion pins57bis connected integrally with the right wall53b. The remaining one shield adhesion pin57bis connected integrally with the upper wall53c. The apical surfaces57dof the three shield adhesion pins57bform apexes of a triangle.

The shield adhesion pin57bconnected integrally with the left wall53a, and the shield adhesion pin57bconnected integrally with the right wall53b, are aligned in the y direction. The interval between the two shield adhesion pins57band the shield adhesion pin57bconnected integrally with the upper wall53care away from each other in the x direction. The triangular region formed by connecting the apical surfaces57dof the three shield adhesion pins57bis aligned with the first sensing unit21and the second sensing unit22in the z direction.

Further, one shield support pin57aand one shield adhesion pin57bare aligned with each other on each of the left wall53aand the right wall53b. One shield support pin57aand one shield adhesion pin57bare aligned with each other on the upper wall53c. The triangle formed by connecting the apical surfaces57cof the three shield support pins57aand the triangle formed by connecting the apical surfaces57dof the three shield adhesion pins57boverlap each other in the z direction. The overlapping region of the triangles in the z direction and the center point CP of the narrow part31aare aligned in the z direction.

The first shield41is provided in the sensor housing50so as to oppose the two triangles in the z direction. In the first shield41, the connection with the sensor housing50of the part opposing to the two triangles is more stable, by the contact with the shield support pin57aand the connection with the shield adhesion pin57bvia the shield adhesive57e, than that of the part without opposing to the two triangles.

The part of the first shield41with stable connection to the sensor housing50is aligned with both of the first sensing unit21and the second sensing unit22of the wiring board20in the z direction. Specifically, the first center part41dof the first shield41is aligned with each of the first sensing unit21and the second sensing unit22in the z direction.

In the state where the first shield41is mounted on the shield support pin57aand fixed via the shield adhesive57eto the shield adhesion pin57b, the one surface41aof the first shield41and the rear surface20bof the wiring board20are opposed to and away from each other in the z direction. If there is no manufacturing error or the like, the distance between the one surface41aand the rear surface20bis constant over the entire surface, and the one surface41aand the rear surface20bare in parallel relationship. Accordingly, the distance between the opposing surface20aof the wiring board20and the one surface41aof the first shield41is also constant over the entire surface, and the opposing surface20aof the wiring board20and the one surface41aof the first shield41are in parallel relationship.

Note that, as shown inFIG. 6and (a) inFIG. 14, notches20gto allow the above-described shield support pins57aand shield adhesion pins57brespectively to pass through to positions above the wiring board20are formed at ends the wiring board20. Multiple through holes20hto allow the other ends of the connection terminals60to pass through are formed in the wiring board20.

As shown inFIG. 6, the multiple through holes20hare aligned in the y direction. In the wiring board20, the part in which the multiple through holes20hare formed is aligned with the part on which the first sensing unit21and the second sensing unit22are mounted in the x direction. In the wiring board20, a first notch20ito guide the position of the wiring board20with respect to the sensor housing50in the x direction when the wiring board20is mounted in the sensor housing50is formed between the two parts aligned in the x direction. Further, in the wiring board20, a second notch20jto guide the position of the wiring board20with respect to the sensor housing50in the y direction when the wiring board20is mounted in the sensor housing50is formed in the part where the first sensing unit21and the second sensing unit22are mounted.

In correspondence with the above configuration, as shown in (a) ofFIG. 11and (b) ofFIG. 12, a first projection53eto be received in the first notch20iis formed on each of the left wall53aand the right wall53bof the sensor housing50. A second projection53f, which is to be opposed to the second notch20jin the y direction, is formed on each of the left wall53aand the right wall53b. The first notch20iand the first projection53ehave similar shapes and extend in the y direction. The second notch20jand the second projection53fhave similar shapes and extend in the x direction.

The number of the above-described shield support pins57aand the number of the shield adhesion pins57bare not limited to the above-described example. The number of the shield support pins57amay be four or more. The number of the shield adhesion pins57bmay be one, two, four or more.

When three or more shield support pins57aand three or more shield adhesion pins57bare employed, it is desirable to configure such that the polygon formed by connecting the apical surfaces57cof the three or more shield support pins57aand the polygon formed by connecting the apical surfaces57dof the three or more shield adhesion pins57boverlap each other in the z direction. In this configuration, the part of the first shield41opposing to the two polygons in the z direction may be aligned with both of the first sensing unit21and the second sensing unit22of the wiring board20in the z direction. In such a case, the misalignment of the first shield41with respect to the first sensing unit21and the misalignment of the first shield41with respect to the second sensing unit22are suppressed.

As the names of shield support pin57aand shield adhesion pin57bindicate, the example where these pins have pillar shapes extending in the z direction has been shown. However, the shapes of the pins are not limited to the pillar shapes. As long as the apical surface57cof the shield support pin57ais away from the upper end surface51efurther than the apical surface57dof the shield adhesion pin57b, the shape is not particularly limited.

<Fixing Form of Second Shield to Sensor Housing>

As shown in (b) ofFIG. 11andFIG. 15, multiple shield support pins57aare formed also on the lower end surface51fof the base51.

Differently from the first shield41, the wiring board20is not provided between the sensor housing50and the second shield42. Therefore, in the shield support pin57aformed on the lower end surface51f, the length in the z direction is shorter than that of the shield support pin57aformed on the upper end surface51e. The positions of the respective ends of the multiple board support pins56ain the z direction are equal to each other. The second shield42is mounted in the sensor housing50in the state where the one surface42ais in contact with the apical surface57cof the shield support pin57a.

The one surface42aof the second shield42, mounted on the apical surface57cof the shield support pin57a, is away from the lower end surface51fin the z direction. The shield adhesive57eis provided between the second shield42and the lower end surface51f.

Upon adhesion fixing between the second shield42and the sensor housing50with the shield adhesive57e, the temperature of the shield adhesive57eis also set to be higher than the temperature of the environment where the first current sensor11is provided.

The shield adhesive57ehaving fluidity is applied to the lower end surface51f. Then, the second shield42is placed in the sensor housing50so as to bring the apical surface57cof the shield support pin57aand the shield adhesive57erespectively into contact with the one surface42aof the second shield42. Thereafter, the shield adhesive57eis cooled down to the room temperature to be solidified.

With this configuration, also in the shield adhesive57eprovided on the lower end surface51f, a residual stress condensing to its own center occurs at the temperature of the environment where the first current sensor11is provided. The second shield42and the shield adhesion pin57bare brought closer to each other with the residual stress. The contact status between the one surface42aof the second shield42and the apical surface57cof the shield support pin57ais maintained.

As a result, the misalignment of the second shield42with respect to the sensor housing50does not depend on the shape variation of the shield adhesive57ehaving fluidity upon the adhesion fixing any longer. The misalignment of the second shield42with respect to the sensor housing50is caused by the manufacturing error of the sensor housing50. In other words, the misalignment of the second shield42with respect to the wiring board20fixed to the sensor housing50depends on the manufacturing error of the sensor housing50.

In the present embodiment, four shield support pins57aare formed on the lower end surface51f. The apical surfaces57cof the four shield support pins57aform vertices of a rectangle. The rectangle formed by connecting the apical surfaces57cof the four shield support pins57ais aligned with the center point CP of the narrow part31ain the z direction. The shield adhesive57eis applied to a region opposing to the rectangle in the lower end surface51f.

The second shield42is provided in the sensor housing50to be opposed to the above-described rectangle in the z direction. In the part of the second shield42opposing to the rectangle, the connection to the sensor housing50is more stable by the contact with the shield support pin57aand the connection via the shield adhesive57eto the lower end surface51f, than the connection of the part without opposing to the rectangle to the sensor housing50.

The part of the second shield42, with stable connection to the sensor housing50, is aligned with both of the first sensing unit21and the second sensing unit22of the wiring board20in the z direction. Specifically, the second center part42dof the second shield42is aligned respectively with the first sensing unit21and the second sensing unit22in the z direction.

Note that the number of shield support pins57aformed on the lower end surface51fis not limited to four. As long as the number of shield support pins57ais equal to or larger than three, any number of shield support pins57amay be employed.

When three or more shield support pins57aare provided, it may be configured such that a region of the second shield42, opposing to the polygon formed by connecting the apical surfaces57cof the three or more shield support pins57ain the z direction, is aligned respectively with the first sensing unit21and the second sensing unit22in the z direction. With this configuration, the misalignment of the second shield42with respect to the first sensing unit21and the misalignment of the second shield42with respect to the second sensing unit22are suppressed.

As described above, the extending parts42cextending in the z direction are formed on the two sides42fof the second shield42aligned in the x direction. Two grooves51gfor arranging the extending parts42care formed in the lower end surface51f.

As shown in (b) ofFIG. 11and inFIG. 13, the two grooves51gare aligned in the x direction between the upper wall54cand the lower wall54d. The two grooves51gare each formed from the lower end surface51ftoward the upper end surface51ein the z direction. A part of one of the two grooves51gis formed by the upper wall54c. A part of the remaining one groove51gis formed by the lower wall54d. The covered part31is positioned between the two grooves51g. Accordingly, the covered part31is positioned between the two extending parts42cof the second shield42.

<Lengths of Support Pin and Adhesion Pin>

The upper end surface51eof the base51is divided into an exposed part from which the other end of the connection terminal60expose and a part which covers the narrow part31a, which are aligned in the x direction but with the above-described first projections53ein the y direction as a boundary. In the upper end surface51e, the exposed part from which the other end of the connection terminal60expose is positioned adjacent to the lower end surface51fthan the part which covers the narrow part31ain the z direction. Accordingly, the distance between the exposed part of the upper end surface51efrom which the other end of the connection terminal60expose and the opposing surface20aof the wiring board20in the z direction is longer than the distance between the part of the upper end surface51ewhich covers the narrow part31aand the opposing surface20aof the wiring board20in the z direction. The distance between the exposed part of the upper end surface51efrom which the other end of the connection terminal60expose and the opposing surface20aof the wiring board20is provided so as to ensure a distance for insertion of the other end of the connection terminal60into the through hole20hof the wiring board20.

In this manner, in the upper end surface51e, the position of the exposed part from which the other end of the connection terminal60expose and the position of the part which covers the narrow part31aare different in the z direction. The board support pins56aare formed respectively in these two parts. In the present embodiment, although the parts of the upper end surface51eare at different positions in the z direction, the apical surfaces56cof the multiple board support pins56aare at the same positions in the z direction. Thus, the lengths of the multiple board support pins56ain the z direction are different.

The lengths of the multiple board support pins56ain the z direction are not uniformly equal to the length L1shown inFIG. 13. The length L1indicates the length of the board support pin56aformed on the part of the upper end surface51ewhich covers the narrow part31ain the z direction. The length of the board support pin56aformed in the exposed part of the upper end surface51efrom which the other end of the connection terminal60expose in the z direction is longer than the length L1by the difference in position of the divided two parts of the upper end surface51ein the z direction.

As described above, the length of the support pin in the z direction may differ in correspondence with the position of the surface where the pin is formed in the z direction as long as the positions of the respective apical surfaces56cof the multiple board support pins56ain the z direction are the same. The configuration is true for the multiple shield support pins57a.

Note that, when the wiring board20is mounted in the sensor housing50, the board adhesive56ehaving fluidity is applied to the apical surfaces56dof the board adhesion pins56b. The shape of the board adhesive56e, having fluidity, is variable in the z direction. Accordingly, the positions of the apical surfaces56dof the multiple board adhesion pins56bmay be different. This is also true for the multiple shield adhesion pins57b.

<Second Current Sensor and Third Current Sensor>

Next, the second current sensor12will be described in detail. Note that the configuration of the second current sensor12and the configuration of the third current sensor13are substantially the same. Accordingly, explanation of the third current sensor13will be omitted.

Further, the second current sensor12has constituent elements common to the first current sensor11. In the following description, explanation of the points same as those of the first current sensor11will be omitted, and the differences will be mainly described.

As described above, the second current sensor12is provided on the first energization bus bar341and the second energization bus bar342. To detect the current flowing in the first energization bus bar341and the current flowing in the second energization bus bar342respectively, the second current sensor12has two individual sensors71having a function equivalent to the function of the first current sensor11. Further, the second current sensor12has a wiring case72accommodating the two individual sensors71.

One of the two individual sensors71detects the magnetic field generated from the alternating current which flows through the first energization bus bar341. The other one of the two individual sensors71detects the magnetic field generated from the alternating current which flows through the second energization bus bar342.

FIG. 16shows the two individual sensors71. The two individual sensors71have the same shape. The structural differences between the individual sensor71and the first current sensor11include the connecting part in the electrical-conduction bus bar30with respect to the energization bus bar, the shape of the connector part55which covers the connection terminal60, and the like. That is, the structural differences between the individual sensor71and the first current sensor11include the shape of the first exposed part32and the second exposed part33of the electrical-conduction bus bar30, and elimination of the surrounding part55c, and the like.

The individual sensor71and the first current sensor11have the structural differences because the objects to which the individual sensor71and the first current sensor11are connected are difference. The first current sensor11is connected to the energization bus bar307of the converter310. The second current sensor12is connected to the first energization bus bar341and the second energization bus bar342of the first inverter320. Note that the internal structure of the individual sensor71and the internal structure of the first current sensor11are the same. Accordingly, the individual sensor71achieves similar effects to those of the first current sensor11.

The multiple individual sensors71are accommodated in the wiring case72shown inFIG. 17. As shown inFIG. 18, the multiple individual sensors71can be accommodated collectively in the wiring case72. As shown inFIG. 19, the second current sensor12is configured by accommodating the multiple individual sensors71in the wiring case72.

Note that in the case of this configuration, the first shields41and the second shields42of the respective individual sensors71are alternately aligned in the x direction. The magnetoelectric converter25of the individual sensor71has sensing directions of the magnetic field in the z direction and in the y direction.

Further, six individual sensors71are accommodated in the wiring case72shown in the previously shownFIG. 17toFIG. 19and the following figures. The number of the individual sensors71accommodated in the wiring case72is merely an example. As long as the wiring case72is capable of accommodating at least two individual sensors71, any number of individual sensors71may be accommodated in the wiring case72.

Further, a current sensor that detects a current in another in-vehicle equipment may be accommodated in the wiring case72of the second current sensor12. Further, it is possible to employ a configuration where the second current sensor12and the third current sensor13share a wiring case72, and the individual sensors71of the second current sensor12and the third current sensor13are accommodated in the same wiring case72.

As shown inFIG. 17, the wiring case72has an integrated housing73, a terminal housing74, and an energization terminal75. The integrated housing73and the terminal housing74are made of an insulating resin material. The integrated housing73and the terminal housing74are integrally connected to each other. As shown inFIG. 18andFIG. 19, multiple individual sensors71are accommodated in the integrated housing73. Accordingly, the physical constitution of the integrated housing73is larger than the physical constitution of the sensor housing50of the individual sensor71. Multiple energization terminals75are insert-molded in the terminal housing74. As shown inFIG. 20toFIG. 23, one ends and the other ends of the multiple energization terminals75are exposed to the outside of the terminal housing74.

InFIG. 20, (a) shows a rear view of the wiring case; (b) shows a top view of the wiring case; and (c) shows a bottom view of the wiring case. InFIG. 21, (a) shows a left side view of the wiring case; (b) shows a top view of the wiring case; and (c) shows a right side view of the wiring case. Note that (b) ofFIG. 20and (b) ofFIG. 21show the same figure.

InFIG. 22, (a) shows a front view of the second current sensor; (b) shows a top view of the second current sensor; and (c) shows a bottom view of the second current sensor. InFIG. 23, (a) shows a side view of the second current sensor; and (b) shows a top view of the second current sensor. Note that (b) ofFIG. 22and (b) ofFIG. 23show the same figure.

As respectively shown in (c) ofFIG. 20and (c) ofFIG. 22, the wiring case72has an integrated wiring board76. The one end of the connection terminal60of the individual sensor71is connected to the integrated wiring board76. One end of the energization terminal75is connected to the integrated wiring board76. With this configuration, the individual sensor71and the energization terminal75are electrically connected to each other via the wiring pattern of the integrated wiring board76. The other end of the energization terminal75is electrically connected via a wire harness or the like to the MG ECU802. As described above, output of the individual sensor71is transmitted via the integrated wiring board76, the energization terminal75, and the wire harness, into the MG ECU802. The integrated wiring board76and the energization terminal75correspond to an input/output wiring.

As described above, the second current sensor12is provided on the first energization bus bar341and the second energization bus bar342. These energization bus bars are respectively divided into a part adjacent to the first inverter320and a part adjacent to the first motor400. The energization bus bar has a part to connect the first inverter320to the second current sensor12and a part to connect the second current sensor12to the first motor400.

In the energization bus bar of the present embodiment, the part to connect the first inverter320to the second current sensor12is provided by a conductive plate made of a metal material. The part of the energization bus bar to connect the second current sensor12to the first motor400is provided by a wire. In the following description, the part of the energization bus bar to connect the first inverter320to the second current sensor12will be simply referred to as the conductive plate. The part of the energization bus bar to connect the second current sensor12to the first motor400will be simply referred to as the wire.

Note that the form of the energization bus bar is arbitrarily modified in correspondence with respective shapes of the inverter and the motor, and in correspondence with mounting form of the inverter and the motor in the vehicle and the like. Accordingly, the specific form of the energization bus bar is not limited to the above-described example. In correspondence with form of the energization bus bar, the respective forms of the electrical-conduction bus bar30in the wiring case72and the individual sensor71are arbitrarily modified. Especially, the form of the electrical-conduction bus bar30in the individual sensor71can be modified only by changing the respective shapes of the first exposed part32and the second exposed part33. Accordingly, it is not necessary to modify the internal shape of the individual sensor71. With this configuration, it is not necessary to change a production line of the individual sensor71.

As shown inFIG. 20andFIG. 21, the integrated housing73has a bottom wall77and a peripheral wall78. The bottom wall77faces in the z direction. The planar shape of the bottom wall77is a rectangular shape with the x direction as a longitudinal direction.

The peripheral wall78rises in the z direction from an inner bottom surface77aof the bottom wall77facing in the z direction. The peripheral wall78has a left wall78aand a right wall78baligned in the x direction. The peripheral wall78has an upper wall78cand a lower wall78daligned in the y direction. The left wall78a, the upper wall78c, the right wall78b, and the lower wall78dare connected in sequence in the circumferential direction about the z direction. With this configuration, the peripheral wall78forms a cylindrical shape having an opening in the z direction. The multiple individual sensors71can be housed in the storage space provided by the bottom wall77and the peripheral wall78.

As shown inFIG. 18, the individual sensor71is inserted along the z direction into the storage space of the integrated housing73. As shown inFIG. 19, the multiple individual sensors71are aligned in the x direction in the storage space.

Similarly to the first current sensor11, the multiple individual sensors71each have the first shield41and the second shield42. The first shield41and the second shield42are opposed to and away from each other in the x direction. Accordingly, in the storage space, the first shields41and the second shields42of the multiple individual sensors are alternately aligned.

As shown inFIG. 16, the first exposed part32and the second exposed part33extend in the y direction from the sensor housing50of the individual sensor71. The upper wall78cof the integrated housing73is formed with slits78efor allowing the ends of the first exposed parts32of the sensor housings50of the individual sensors71accommodated in the storage space to be placed outside of the storage space. The slits78eare each formed along the z direction from the apical surface of the upper wall78ctoward the bottom wall77.

In the stats where the individual sensor71is accommodated in the integrated housing73, the end of the first exposed part32of the individual sensor71is positioned via the slit78eon the outside of the storage space. The end of the first exposed part32is electrically connected to the above-described conductive plate by laser welding or the like.

Further, a conductive terminal79is insert-molded in the bottom wall77of the integrated housing73. As shown in (b) ofFIG. 20and (b) ofFIG. 21, a part of the conductive terminal79is exposed from the inner bottom surface77aof the bottom wall77.

In the state where the individual sensor71is accommodated in the integrated housing73, the second exposed part33of the individual sensor71is opposed to the part of the conductive terminal79exposed from the inner bottom surface77a. The second exposed part33and the conductive terminal79are electrically connected to each other by laser welding or the like.

Further, the integrated housing73has a terminal block80to support the multiple conductive terminals79. The terminal block80is formed integrally with the lower wall78dadjacent to the bottom wall77. The terminal block80has a rectangular parallelepiped shape extending in the x direction. The multiple conductive terminals79are insert-molded also in the terminal block80. The multiple conductive terminals79are partly exposed from the terminal block80. The part of the conductive terminal79exposed from the terminal block80extends away from the terminal block80in the z direction. The part of the conductive terminal79exposed from the terminal block80opposes the lower wall78din the y direction. The parts of the multiple conductive terminals79exposed from the terminal block80are aligned with each other across spaces in the x direction.

The part of the conductive terminal79exposed from the terminal block80has a flat shape in which the thickness in the y direction is thin. The part of the conductive terminal79exposed from the terminal block80has an energization surface79afacing in the y direction and its rear surface79b. In the conductive terminal79, a bolt hole79cis formed to pass through from the energization surface79ato the rear surface79bin the y direction.

Further, the rear surface79bof the conductive terminal79is provided with a nut81opened in the y direction. The opening of the nut81and the opening of the bolt hole79care aligned in the y direction.

A terminal of the wire is disposed on the energization surface79aof the conductive terminal79. The terminal of the wire also has a bolt hole penetrating in the y direction. In the terminal of the wire, the surface on which the bolt hole is formed is opposed to the energization surface79aof the conductive terminal79. In this state, a bolt shaft (not illustrated) is inserted through the bolt holes of the conductive terminal79and the terminal of the wire. Then, the end of the bolt shaft is fastened to the nut81. The bolt is fastened to the nut81from the end of the bolt shaft toward a bolt head. The conductive terminal79and the terminal of the wire are held between the bolt head and the nut81. With this configuration, the terminal of the wire and the conductive terminal79are brought into contact and electrically and mechanically connected to each other. As described above, the second exposed part33of the individual sensor71and the wire terminal are electrically connected to each other via the conductive terminal79.

The connection terminal60extends from the sensor housing50of the individual sensor71in the z direction. An insertion hole for allowing the one end of the connection terminal60to be placed on the outside of the storage space is formed in the bottom wall77of the integrated housing73. The insertion hole is formed to pass through from the inner bottom surface77aof the bottom wall77to an outer bottom surface77bon the rear side of the inner bottom surface77a. The one end of the connection terminal60protrudes, away from the outer bottom surface77bvia the insertion hole, to the outside of the storage space. Since the insertion hole is a minute hole, it is not shown in the figure.

The terminal housing74is aligned with the integrated housing73in the x direction. The terminal housing74is connected integrally with the left wall78aof the integrated housing73. The terminal housing74extends in the z direction. The terminal housing74has an upper surface74aand a lower surface74baligned in the z direction.

The multiple energization terminals75insert-molded in the terminal housing74extend in the z direction. One end of the energization terminal75projects from the lower surface74bof the terminal housing74. The other end of the energization terminal75projects from the upper surface74aof the terminal housing74.

As shown in (a) and (c) ofFIG. 20, the outer bottom surface77bof the bottom wall77of the integrated housing73and the lower surface74bof the terminal housing74continuous each other in the x direction and the y direction. The integrated wiring board76is provided on the outer bottom surface77band the lower surface74b, which are continuous to each other.

The integrated wiring board76has a flat shape in which the thickness in the z direction is thin. The integrated wiring board76has a mounting surface76afacing in the z direction and a rear surface76b. The integrated wiring board76is fixed, in a state where the mounting surface76aopposes respectively to the outer bottom surface77band the lower surface74bin the z direction, to the integrated housing73and the terminal housing74.

As described above, the one end of the energization terminal75projects from the lower surface74b. The one end of the connection terminal60projects from the outer bottom surface77b. On the other hand, a first through hole76cis formed in the integrated wiring board76to receive the one end of the energization terminal75. A second through hole76dis formed in the integrated wiring board76to receive the one end of the connection terminal60. The first through hole76cand the second through hole76dpenetrate the integrated wiring board76from the mounting surface76ato the rear surface76bin the z direction. Further, a wiring pattern which electrically connects the first through hole76cto the second through hole76dis formed on the integrated wiring board76.

The integrated wiring board76is arranged on the outer bottom surface77band the lower surface74bsuch that the one end of the energization terminal75is inserted into the first through hole76c. Then, the first through hole76cand the energization terminal75are electrically connected to each other via solder or the like.

The individual sensor71is arranged in the storage space such that the one end of the connection terminal60is inserted through the insertion hole of the bottom wall77and the second through hole76d. Then, the second through hole76dand the connection terminal60are electrically connected to each other via solder or the like. As described above, the connection terminal60of the individual sensor71is electrically connected via the second through hole76d, the wiring pattern on the integrated wiring board76, and the first through hole76c, to the energization terminal75.

The wiring case72has multiple flanges82for mounting the second current sensor12in the vehicle. The multiple flanges82aeach have a bolt hole82afor bolt-fixing the second current sensor12to the vehicle.

The wiring case72of the present embodiment has three flanges82. One of the three flanges82is formed on the bottom wall77adjacent to the right wall78b. One of the remaining two flanges82is formed on the terminal housing74adjacent to the lower wall78d. This flange82is connected integrally with the terminal block80. The remaining one flange82is formed on the opposite side to the connection part of the terminal housing74to the integrated housing73.

As described above, the two of the three flanges82are aligned via the integrated housing73and the terminal housing74in the x direction. The remaining one flange82is away from the two flanges82that are aligned in the x direction, in the y direction. In this manner, the three flanges82form apexes of a triangle.

As described above, the one end of the connection terminal60projects from the outer bottom surface77b, and the one end of the energization terminal75projects from the lower surface74b. Further, the integrated wiring board76is disposed on the outer bottom surface77band the lower surface74b. To avoid contacts with the vehicle of the one end of the connection terminal60, the one end of the energization terminal75, and the integrated wiring board76, the three flanges82each have a leg83extending in the z direction. In the state where the second current sensor12is mounted in the vehicle, the one end of the connection terminal60, the one end of the energization terminal75, and the integrated wiring board76are separated from the vehicle, with the legs83, in the z direction.

<Advantageous Effects of Current Sensor>

Next, the advantageous effects of the current sensor according to the present embodiment will be described. As described above, the first current sensor11and the individual sensor71of the second current sensor12and third current sensor13have equivalent configurations. Accordingly, the respective sensors achieve the similar advantageous effects. In the following description, to avoid complications, the first current sensor11and the individual sensor71are not discriminated but merely referred to as a current sensor. The degradation of detection accuracy to detect the current is suppressed with the following various advantageous effects.

As described above, in the first opposite end part41eof the first shield41, the length in the x direction is shorter than that of the first center part41d. Accordingly, entrance of magnetic field into the first opposite end part41eis suppressed. The permeation of magnetic field through the portions of the first center part41d, directly connected to and aligned with the first opposite end part41ein the y direction (parallel portions), from one to the other of the two ends of the first both end part41e, is suppressed. As a result, magnetic saturation in the parallel portions of the first center part41dis suppressed. Leakage of electromagnetic noise from the first center part41dis suppressed.

FIG. 24shows, by schematically hatching, a region of the first shield41easily magnetically saturated by magnetic field permeation. InFIG. 24, (a) schematically shows the magnetic saturation occurring in the first shield without notch as a comparative configuration; and (b) schematically shows a magnetically saturated region of the first shield41according to the present embodiment. InFIG. 24, a bold solid arrow indicates a current which flows through the electrical-conduction bus bar30.

As shown in the figure, in the first shield without notch, magnetic saturation uniformly and easily occurs. On the other hand, in the first shield41in which the notches41care formed, even when magnetic saturation occurs in a region other than the parallel portions of the first center part41d, the occurrence of magnetic saturation is suppressed in the parallel portions.

FIG. 25shows a simulation result of distribution of the magnetic field which permeates the shield. InFIG. 25, (a) shows the magnetic field distribution in a cross section along an XXVa-XXVa line shown inFIG. 24; and (b) shows the magnetic field distribution in a cross section along an XXVb-XXVb line shown inFIG. 24.

Note that inFIG. 25, (a) shows a simulation result when the first shield41and the second shield42each have a rectangular shape; and (b) shows a simulation result when the notches41care formed in the first shield41and the second shield42. The intensity of the magnetic field is expressed with coarseness/fineness of hatching. As the coarseness of the hatching is increased, the intensity of the magnetic field becomes lower, while as the fineness of the hatching is increased, the intensity of the magnetic field becomes higher.

As it is obvious from the simulation result, when the notch41cis omitted, the magnetic field distributions in the first shield and the second shield are uniform. The intensities of the respective entire magnetic fields in the first shield and the second shield are high. On the other hand, when the notches41care formed, the intensities of the respective entire magnetic fields in the first shield and the second shield are low. Especially, the intensities of magnetic field distributions in the respective parallel portions in the first center part41dand the second center part42dare low. With this configuration, the leakage of the electromagnetic noise from the first center part41dand the second center part42dby the magnetic saturation is suppressed.

Note that as shown inFIG. 25, the intensities of the respective magnetic field distributions in the first shield41and the second shield42are different. The difference is caused since the distance between the first shield41and the electrical-conduction bus bar30and the distance between the second shield42and the electrical-conduction bus bar30are different. In both of the magnetic field distributions, the intensity is low in the parallel portions, while the intensity is high in the other region than the parallel portions.

The parallel portions of the first center part41dwhere the magnetic saturation is suppressed, and the first sensing unit21and the second sensing unit mounted on the wiring board20, are aligned in the z direction. Accordingly, the input of the electromagnetic noise, leaked by the magnetic saturation in the first center part41d, into the magnetoelectric converter25of the first sensing unit21and the second sensing unit22, is suppressed.

The first shield41is mounted on the shield support pin57a, and fixed via the shield adhesive57eto the shield adhesion pin57b. The second shield42is mounted on the shield support pin57a, and fixed via the shield adhesive57eto the base51.

With this configuration, the misalignment of the first shield41and the misalignment of the second shield42respectively with respect to the sensor housing50do not depend on the shape variation of the shield adhesive57ehaving fluidity upon the adhesion fixing any longer. The misalignment of the first shield41and the misalignment of the second shield42respectively with respect to the sensor housing50are caused by the manufacturing error of the sensor housing50. It is possible to shift the factor of the misalignment of the first shield41and the misalignment of the second shield42respectively with respect to the wiring board20fixed to the sensor housing50to the manufacturing error of the sensor housing50. As a result, it is possible to suppress reduction of input suppression of electromagnetic noise caused by the first shield41and the second shield42into the magnetoelectric converter25.

The temperature of the shield adhesive57eupon the adhesion fixing of the first shield41and the second shield42respectively to the sensor housing50is set to be higher than the temperature of the environment where the current sensor is provided. The shield adhesive57eis cooled down to the room temperature and is thus solidified. With this configuration, in the shield adhesive57e, a residual stress condensing to its own center occurs at the temperature of the environment where the first current sensor is provided. The contact state between the first shield41and the shield support pin57aand the contact status between the second shield42and the shield support pin57aare respectively maintained.

With this configuration, the displacement of the first shield41and the displacement of the second shield42respectively with respect to the sensor housing50in the z direction are suppressed. In other words, the displacement of the first shield41and the displacement of the second shield42respectively with respect to the wiring board20fixed to the sensor housing50in the z direction are suppressed. With this configuration, the reduction of input suppression of electromagnetic noise, cased in the first shield41and the second shield42into the magnetoelectric converter25, is suppressed.

The wiring board20is mounted on the board support pin56aand is fixed via the board adhesive56eto the board adhesion pin56b.

With this configuration, the misalignment of the wiring board20with respect to the sensor housing50does not depend on the shape variation of the board adhesive56ehaving fluidity upon the adhesion fixing any longer. The misalignment of the wiring board20with respect to the sensor housing50is caused by the manufacturing error of the sensor housing50. It is possible to shift the factor of the misalignment of the wiring board20with respect to the electrical-conduction bus bar30fixed to the sensor housing50to the manufacturing error of the sensor housing50. As a result, the variation of the measurement current which permeates the magnetoelectric converter25mounted on the wiring board20is suppressed.

The temperature of the board adhesive56eupon the adhesion fixing of the wiring board20to the sensor housing50is set to be higher than the temperature of the environment where the current sensor is provided. The board adhesive56eis cooled down to the room temperature and is thus solidified. With this configuration, in the board adhesive56e, a residual stress condensing to its own center occurs at the temperature of the environment where the current sensor is provided. The contact status between the wiring board20and the board support pin56ais maintained with the residual stress.

With this configuration, the displacement of the wiring board20with respect to the sensor housing50in the z direction is suppressed. In other words, the displacement of the wiring board20with respect to the electrical-conduction bus bar30fixed to the sensor housing50in the z direction is suppressed. With this configuration, the variation of the measurement current which permeates the magnetoelectric converter25mounted on the wiring board20is suppressed.

<Manufacturing Error of Wiring Board>

The first sensing unit21and the second sensing unit22are provided on the opposing surface20aof the wiring board20with respect to the electrical-conduction bus bar30. With this configuration, the distances between the first sensing unit21and the electrical-conduction bus bar30and between the second sensing unit22and the electrical-conduction bus bar30in the z direction do not depend on the thickness of the wiring board20in the z direction any longer. The variation of the distances between the sensing units and the electrical-conduction bus bar30in the z direction, due to the manufacturing error of the thickness of the wiring board20in the z direction, is suppressed.

<Separation of Wiring Case and Individual Sensor>

In a case where an electrical-conduction bus bar is fixed to a housing made of an insulating resin material, misalignment occurs in the bus bar with respect to the housing due to a manufacturing error of the housing or time deterioration such as creep of the housing. The larger the physical constitution of the housing is, the larger the misalignment is.

As described above, the second current sensor12and the third current sensor13have the integrated housing73, the physical constitution of which is larger than that of the sensor housing50of the current sensor (individual sensor71). The current sensor is accommodated in the integrated housing73. The electrical-conduction bus bar30is fixed, not to the integrated housing73having the large physical constitution, but to the sensor housing50. The magnetoelectric converter25detects the current which flows through the electrical-conduction bus bar30.

According to the configuration, the occurrence of relative misalignment between the electrical-conduction bus bar30and the magnetoelectric converter25, due to the above-described manufacturing error of the housing or time deterioration such as creep of the housing, is suppressed.

Next, a second embodiment will be described with reference toFIG. 26andFIG. 27. The current sensors of the following respective embodiments have many points common to the above-described embodiment. Accordingly, in the following descriptions, explanation of the common parts will be omitted, and the differences will be mainly explained. Further, in the following descriptions, the constituent elements the same as the constituent elements shown in the above-described embodiment will have the same reference numerals.

<Extending Part at Both Ends>

In the first embodiment, the example where the second shield42has the extending parts42c, which extends in the z direction, at the two sides42faligned in the x direction and adjacent to the second center part42dhas been shown. In the present embodiment, as shown inFIG. 26, in the second shield42, the extending parts42care formed at the two sides42fand adjacent to second opposite end parts42e. InFIG. 26, (a) is a perspective view for explaining the arrangement of the shield, the magnetoelectric converter, and the electrical-conduction bus bar; and (b) is a side view for explaining the arrangement of the shield, magnetoelectric converter, and the electrical-conduction bus bar.

With this configuration, the magnetoelectric field entered the second shield42easily permeates via the extending parts42cformed at the second opposite end parts42ein the first shield41. As schematically shown inFIG. 27, in the first shield41, the permeation pathway is adjacent to the first opposite end parts41e. Similarly, the permeation pathway of the magnetic field in the second shield42is adjacent to the second opposite end parts42e.

InFIG. 27, a bold solid arrow indicates the current which flows through the electrical-conduction bus bar30; a solid arrow indicates the magnetic field which permeates the first shield41; and a broken arrow indicates the magnetic field which permeates the second shield42. In the figure, an enclosed middle dot symbol indicates the magnetic field which directs from the second shield42toward the first shield41in the z direction; and an enclosed cross symbol indicates the magnetic field which directs from the first shield41toward the second shield42in the z direction.

Accordingly, the electromagnetic noise entered the second shield42hardly flows via the second center part42dto the first shield41. Similarly, the electromagnetic noise entered the first shield41hardly permeates via the first center part41dto the second shield42.

The second center part42dand the first center part41dare hardly magnetically saturated respectively. As a result, the leakage of the magnetic field respectively from the second center part42dand the first center part41ddue to magnetic saturation is suppressed.

Further, as clearly indicated in (b) ofFIG. 26, the magnetoelectric converters25of the first sensing unit21and the second sensing unit22are positioned between the two extending parts42cin the y direction. That is, the magnetoelectric converters25are positioned between the second center part42dand the first center part41din the z direction. Accordingly, input of the magnetic field, leaked respectively due to magnetic saturation of the second center part42dand the first center part41d, into the magnetoelectric converters25, is suppressed. As a result, the degradation of accuracy in the measurement current detection is suppressed.

In the present embodiment, the example where the extending part42cis formed respectively on the second opposite end parts42eof the two sides42fof the second shield42has been shown. However, as shown in (a) ofFIG. 28, for example, a configuration where the extending part42cis also formed on the second center part42dof the two sides42fof the second shield42may be employed. Note that in the extending part42cformed on the second center part42d, the length in the z direction is shorter than that of the extending part42cformed on the second opposite end parts42e. With this configuration, the magnetic field entered the shield40permeates the end part more easily than the center part.

Further, as shown in (b) ofFIG. 28, a configuration where the extending part42cis formed on the second opposite end parts42eof one of the two sides42f, and the extending part42cis formed on the second opposite end parts42eand the second center part42dof the other one of the two sides42f, may be employed. Note that in the other one of the two sides42f, the lengths of the extending parts42c, formed on the second opposite end parts42eand the second center part42d, in the z direction, are the same. With this configuration, the magnetic field entered the shield40also permeates the end part more easily than the center part. InFIG. 28, (a) and (b) shows a perspective view for explaining the arrangement of the shield, the magnetoelectric converter, and the electrical-conduction bus bar.

Further, as shown in (a) ofFIG. 29, a configuration where the extending part42cis formed on one of the two second opposite end parts42eof one of the two sides42f, and on the other one of the two second opposite end parts42eof the other one of the two sides42f, may be employed. The extending part42cformed on one of the two sides42fand the extending part42cformed on the other one of the two sides42fare away from each other respectively in the y direction and in the x direction.

Further, a configuration where the extending part42cis formed on the first shield41in addition to the second shield42may be employed. The first shield41has two opposing sides41faligned in the x direction. For example, as shown in (b) ofFIG. 29, a configuration where the extending parts42care formed on the first opposite end parts41eof the two opposing sides41fin the first shield41may be employed. InFIG. 29, (a) and (b) show a perspective view for explaining the arrangement of the shield, magnetoelectric converter, and the electrical-conduction bus bar.

As the form of the extending part42cwhich can be formed on the first shield41, a form equivalent to the extending part42cformed on the second shield42shown above may be employed. The extending part42cformed on the first shield41corresponds to an extension part.

Note that the current sensor according to the present embodiment and the following embodiments include constituent elements equivalent to the constituent elements of the current sensor described in the first embodiment. Therefore, it goes without saying that the current sensor according to the present embodiment and the following embodiments achieve the similar advantageous effects.

Next, a third embodiment will be described based onFIG. 30toFIG. 32.

In the present embodiment, a stress relaxation member34is formed in the electrical-conduction bus bar30of the first current sensor11. The stress relaxation member34is formed in the first exposed part32and the second exposed part33of the electrical-conduction bus bar30.

As described above, the electrical-conduction bus bar30has the covered part31covered with the sensor housing50. The first exposed part32and the second exposed part33are respectively exposed from the sensor housing50, and connected integrally with the covered part31. The bolt hole30cfor electrical and mechanical connection with the energization bus bar307via the bolt is formed respectively in the first exposed part32and the second exposed part33. The stress relaxation member34is formed respectively in the connection parts between the first exposed part32and the covered part31and between the second exposed part33and the covered part31, and in the connection parts between the first exposed part32and the forming part of the bolt hole30cand between the second exposed part33and the forming part of the bolt hole30c.

As shown inFIG. 31, the stress relaxation member34is locally bent from the rear surface30bof the electrical-conduction bus bar30toward the front surface30a. With this bending, the stress relaxation member34is elastically deformable by bending with respect to a force in the z direction applied to the electrical-conduction bus bar30. InFIG. 31, the stress relaxation member34is bent like a weaving at once. The number of times of waving and the bending form are not limited to the above described example.

As described above, the electrical-conduction bus bar30is bolt-fixed to the energization bus bar307. The energization bus bar307of the present embodiment corresponds to a first terminal block307aand a second terminal block307bshown inFIG. 32. The electrical-conduction bus bar30is bolt-fixed to the first terminal block307aand the second terminal block307b. With this configuration, the first terminal block307aand the second terminal block307bare bridged with the energization bus bar307. The first terminal block307aand the second terminal block307bare electrically connected to each other via the energization bus bar307. Note that in the following description, as shown inFIG. 32, the bolt inserted through the bolt hole30cof the electrical-conduction bus bar30is denoted by a reference numeral307c. The first terminal block307aand the second terminal block307bcorrespond to an external energization unit.

The first terminal block307ahas a first mounting surface307dfacing in the z direction. Similarly, the second terminal block307bhas a second mounting surface307efacing in the z direction. A fastening hole307ffor fastening the shaft of the bolt307cis formed in each of the first mounting surface307dand the second mounting surface307e. The fastening holes307fare opened in the first mounting surface307dand the second mounting surface307e. The fastening hole307fextends in the z direction. InFIG. 32, (a) shows a case where the positions of the first mounting surface and the second mounting surface in the z direction correspond with each other; and (b) shows a case where the positions of the first mounting surface and the second mounting surface in the z direction do not correspond with each other.

The rear surface30bof the first exposed part32opposes to the first mounting surface307din the z direction. The rear surface30bof the second exposed part33opposes to the second mounting surface307ein the z direction. In this state, the first current sensor11is provided on the first terminal block307aand the second terminal block307b.

As shown in (a) ofFIG. 32, when the positions of the first mounting surface307dand the second mounting surface307ein the z direction correspond with each other, the rear surface30bof the first exposed part32is in contact with the first mounting surface307d, and the rear surface30bof the second exposed part33is in contact with the second mounting surface307e. In this contact state, the end of the shaft of the bolt307cis inserted into the bolt hole30cof the electrical-conduction bus bar30and the fastening hole307fof the terminal block along the z direction. Then, the bolt307cis fastened to the terminal block so as to bring the head of the bolt307ccloser to the first mounting surface307d(second mounting surface307e). The first exposed part32and the second exposed part33are held between the head of the bolt307cand the terminal block. With is configuration, the first current sensor11is mechanically and electrically connected to the terminal block.

On the other hand, as shown in (b) ofFIG. 32, when the positions of the first mounting surface307dand the second mounting surface307ein the z direction do not correspond with each other, upon contact between the rear surface30bof the first exposed part32and the first mounting surface307d, the rear surface30bof the second exposed part33is not in contact with the second mounting surface307e. The second mounting surface307eand the rear surface30bof the second exposed part33are away from each other in the z direction, and a gap is formed between the second mounting surface307eand the rear surface30b.

In this separated state, when the shaft of the bolt307cis inserted in the bolt hole30cand the fastening hole307fand the head of the bolt307cis brought into contact with the front surface30aof the second exposed part33, a force toward the z direction acts on the second exposed part33.

As described above, to enhance the intensity of the measurement current which permeates the magnetoelectric converter25, the narrow part31ain which the length in the x direction is locally short is formed in the covered part31. Since the length of the narrow part31ain the x direction is short, the rigidity of the narrow part31ais lower than that of other parts. The narrow part31acan be easily deformed.

Accordingly, when the force toward the z direction upon fastening of the bolt307cacts on the second exposed part33as described above, there is a fear of deformation of the narrow part31adue to the force. There is a fear of position displacement of the narrow part31ain the sensor housing50. Even when the narrow part31ais not formed in the covered part31, there is a fear of position displacement of the covered part31in the sensor housing50. With the position displacement, there is a fear of change of distribution of the measurement current which permeates the magnetoelectric converter25.

As described above, the stress relaxation member34is formed in each of the first exposed part32and the second exposed part33. Accordingly, with the above-described positional difference in the z direction between the first mounting surface307dand the second mounting surface307e, even when there is a gap between the second mounting surface307eand the rear surface30bof the second exposed part33, the stress relaxation member34is elastically deformed in correspondence with the force of the bolt307cin the z direction. With this configuration, the deformation of the narrow part31ais suppressed. The position displacement of the narrow part31ain the sensor housing50is suppressed. As a result, the change of the distribution of the measurement current which permeates the magnetoelectric converter25is suppressed. The degradation of accuracy in the measurement current detection is suppressed.

Note that the length (thickness) of the stress relaxation member34between the front surface30aand the rear surface30bis equal to the respective thicknesses of the covered part31, the first exposed part32, and the second exposed part33. With this configuration, different from a configuration where, e.g. the thickness of the stress relaxation member is locally thin in comparison with the thicknesses of the covered part and the exposed part, local heat generation in the stress relaxation member34by the current energization is suppressed. As a result, life reduction of the electrical-conduction bus bar30is suppressed.

Next, a fourth embodiment will be described with reference toFIG. 33toFIG. 35. InFIG. 33, (a) shows a top view of the electrical-conduction bus bar; and (b) shows a side view of the electrical-conduction bus bar. InFIG. 34, (a) shows the position of the wiring board20on which the respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are mounted and the position of the electrical-conduction bus bar30; (b) shows displacement of the wiring board20with respect to the electrical-conduction bus bar30; and (c) shows a magnetic field which permeates the respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22.

In the first embodiment, the example where the respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are aligned in the y direction has been shown. In the present embodiment, as indicated with a broken line inFIG. 33, the respective magnetoelectric converters25of the first sensing unit21and the second sensing unit22are aligned in the x direction. The magnetoelectric converter25of the first sensing unit21corresponds to a first magnetoelectric converter. The magnetoelectric converter25of the second sensing unit22corresponds to a second magnetoelectric converter.

The two magnetoelectric converters25are symmetrically arranged via the symmetry axis AS. The positions of the two magnetoelectric converters25in the y direction and the position of the symmetry axis AS (center point CP) in the y direction are the same. Accordingly, the two magnetoelectric converters25are aligned via the center point CP in the x direction.

Further, the distances between the two magnetoelectric converters25and the covered part31in the z direction are the same. The covered part31and the narrow part31aform a line-symmetrical shape via the symmetry axis AS. Accordingly, measurement currents, having different z-direction components but equivalent x-direction components, permeate the two magnetoelectric converters25. The absolute values of electric signals outputted from the two magnetoelectric converters25are equivalent to each other.

As described above, the covered part31is covered with the base51of the sensor housing50. The wiring board20on which the two magnetoelectric converters25are mounted is mounted on the board support pin56aformed on the sensor housing50. Accordingly, the displacement of the wiring board20in the z direction is regulated with the board support pin56a.

However, the wiring board20is fixed via the board adhesive56eto the board adhesion pin56b. In the board adhesive56e, time deterioration such as creep or expansion due to change of the environmental temperature may occur. There is a fear of displacement of the wiring board20relatively in the x direction and the y direction with respect to the covered part31.

When the wiring board20is displaced in the y direction, with the above-described symmetrical arrangement of the two magnetoelectric converters25in the x direction, the x-direction component of the measurement currents which permeate the two magnetoelectric converters25is not changed. However, as shown inFIG. 34, when the wiring board20is displaced in the x direction, the x-direction component of the measurement currents which permeate the two magnetoelectric converters25is changed. As a result, the absolute values of the electric signals outputted from the two magnetoelectric converters25are not equivalent to each other any longer.

InFIG. 34, a broken line indicates the placement locations of the two magnetoelectric converters25with respect to the electrical-conduction bus bar30. An alternate long and short dash line indicates the symmetry axis AS passing through the center point CP of the electrical-conduction bus bar30. An alternate long and two short dashes line indicates the positions of the two magnetoelectric converters25displaced with respect to the electrical-conduction bus bar30. An outlined arrow indicates the direction of the displacement of the wiring board20on which the two magnetoelectric converters25are mounted, caused with the board adhesive56e, with respect to the electrical-conduction bus bar30. In (a) and (b) ofFIG. 34, a solid arrow indicates the magnetic field which passes through the magnetoelectric converter25. In (c) ofFIG. 34, a solid arrow indicates the direction of change of the magnetic field which permeates the magnetoelectric converter25.

As described above, both of the two magnetoelectric converters25are mounted on the wiring board20. Even when the relative positions of the wiring board20and the covered part31in the x direction are changed by deformation of the board adhesive56eas described above, the relative distance between the two magnetoelectric converters25mounted on the wiring board20is not changed. Accordingly, when the relative positions of the wiring board20and the covered part31are changed in the x direction by the deformation of the board adhesive56e, one of the two magnetoelectric converters25is closer to the symmetry axis AS, while the other one of the two magnetoelectric converters25is away from the symmetry axis AS. The perspective distances are equivalent to each other. In (b) ofFIG. 34, the perspective distance is denoted by A.

As shown in (c) ofFIG. 34, the measurement current which permeates one of the two magnetoelectric converters25is reduced, while the measurement current which permeates the other one of the two magnetoelectric converters25is increased. It is expected that the decrement and the increment of the measurement currents which permeate the two magnetoelectric converters25become equivalent to each other. In (b) ofFIG. 34, the change amount of the measurement current is indicated as AB.

In the present embodiment, the polarity of the electric signals outputted from the two magnetoelectric converters25is inverted. The inversion of the polarity is realized by, for example as shown inFIG. 35, reversing the arrangement of the first magnetoresistive effect element25aand the second magnetoresistive effect element25bin the two magnetoelectric converters25. Otherwise, it is possible to invert the polarity of the two electric signals by, more simply, reversing the inverted input terminal and the non-inverted input terminal of the differential amplifier25cshown inFIG. 7in the first sensing unit21and the second sensing unit22.

As described above, the electric signals, having absolute values of increment/decrement equivalent to each other, and different polarities, are outputted from the two magnetoelectric converters25. The two electric signals generated respectively with the first current sensor11are inputted into the battery ECU801. The two electric signals generated in the second current sensor12and the third current sensor13are inputted into the MG ECU802.

The battery ECU801and the MG ECU802take the difference between the two electric signals. Assuming that the absolute values of the electric signals outputted from the two magnetoelectric converters25are B, and that the absolute values of change amounts of the electric signals due to the displacement are ΔB, as the difference processing, B+ΔB−(−(B−ΔB))=2B holds. Otherwise, as the difference processing, B−ΔB−(−(B+AB))=2B holds. “+” corresponds to one of the first polarity and the second polarity, and “−” corresponds to the other one of the first polarity and the second polarity.

The decrement and the increment of the electric signal caused by the change of the relative positions of the wiring board20and the covered part31due to the above-described deformation of the board adhesive56eare cancelled by performing the difference processing in this manner. The battery ECU801and the MG ECU802correspond to a difference part.

Note that as shown inFIG. 36, for example, a configuration where a difference circuit29to take the difference between the outputs from the two magnetoelectric converters25is mounted on the wiring board20may be employed. The first output wiring20dand the second output wiring20eare connected to the inverted input terminal and the non-inverted input terminal of the difference circuit29. In this case, the difference circuit29corresponds to the difference part.

The above-described change of the relative positions of the wiring board20and the covered part31in the x direction may be caused, not only by the above-described deformation of the board adhesive56e, but also by vibration by external stress which acts on the vehicle or driving of the engine600and the like. However, even when the relative positions of the wiring board20and the covered part31in the x direction are changed by these factors, the difference between the two electric signals outputted from the two magnetoelectric converters25is taken as described above. With this configuration, the decrement and the increment of the electric signals by change of the relative positions of the wiring board20and the covered part31are cancelled. Accordingly, the degradation of detection accuracy of the measurement magnetic field is suppressed.

Next, a fifth embodiment will be described with reference toFIG. 37andFIG. 38.

In the first embodiment, the example where the first shield41and the second shield42are respectively manufactured by press-joining multiple flat plates made of a soft magnetic material has been shown. In the present embodiment, the first shield41and the second shield42are respectively manufactured by rolling magnetic steel.

As described in the first embodiment, it is possible to provide the magnetic permeability of the shield with anisotropy by specifying the rolling direction of the magnetic steel. In the present embodiment, the rolling direction of the first shield41and the second shield42is along the z direction. With this configuration, the magnetic permeability of the first shield41and the second shield42has anisotropy. Note that the manufacturing method of the first shield41and the second shield42is not limited to the above-described example. The first shield41and the second shield42may be manufactured with a material, the magnetic permeability of which has anisotropy. Further, it may be configured such that the magnetic permeability of one of the first shield41and the second shield42has anisotropy.

As described inFIG. 37, in the second current sensor12and the third current sensor13, the respective individual sensors71are aligned in the x direction. The first shield41and the second shield42of the respective individual sensors71are alternately aligned in the x direction. In this configuration, the directions of the magnetic-field detection of the magnetoelectric converters25of the individual sensor71are the z direction and the y direction. Note that a configuration where, in two individual sensors71aligned in the x direction, the first shield41of the one of the two individual sensors71and the second shield42of the other one of the two individual sensors71may be bundled together as one may be employed.

In the configuration where the multiple individual sensors71are aligned in the x direction, the measured magnetic field emitted from the electrical-conduction bus bar30of one individual sensor71becomes external noise to the other individual sensor(s)71. The external noise is formed in a ring shape in a plane regulated with the x direction and the z direction about the electrical-conduction bus bar30. The external noise has components along the x direction and the z direction. In this manner, in the environment of the configuration, the external noise along the x direction and the z direction easily permeates the individual sensor71.

FIG. 37shows two individual sensors71. The measurement current flows through one of the two individual sensor71having the electrical-conduction bus bar30with an enclosed cross symbol. The measured magnetic field is emitted from this electrical-conduction bus bar30. To the adjacent individual sensor71, the measured magnetic field emitted from the electrical-conduction bus bar30with the enclosed cross symbol is electromagnetic noise.FIG. 37indicates the magnetic field with an arrow.

As described above, the first shield41and the second shield42respectively have anisotropy in the z direction. Accordingly, the component of the external noise along the z direction attempts to enter the first shield41and the second shield42respectively. On the other hand, the component of the external noise along the x direction does not depend on the anisotropy of the first shield41and the second shield42any longer. The component along the x direction attempts to permeate the magnetoelectric converter25.

For example, when the magnetic field indicated with a broken arrow inFIG. 37attempts to pass through the magnetoelectric converter25, the component of the magnetic field along the z direction actively attempts to pass through the first shield41and the second shield42respectively. However, the component of the magnetic field in the x direction somewhat remains. Accordingly, the component of the magnetic field in the x direction attempts to permeate the magnetoelectric converter25.

On the other hand, the detecting directions of measured magnetic field of the magnetoelectric converter25are the z direction and the y direction. The magnetoelectric converter25does not detect the magnetic field in the x direction. Even when the above-described component of the magnetic field in the x direction permeates the magnetoelectric converter25, the degradation of detection accuracy of the measurement magnetic field, due to the permeation of the electromagnetic noise, is suppressed.

The alignment of the individual sensors71is not limited to the above-described example. For example, as shown inFIG. 38, a configuration where the individual sensors71are aligned in the x direction is conceivable. In this configuration, the first shields41, the second shields42, and the magnetoelectric converters25, of the individual sensors71, are aligned in the x direction. The magnetic-field detection directions of the magnetoelectric converter25of the individual sensor71are the x direction and the y direction. In this configuration, it may be configured such that the first shields41of the multiple individual sensors71aligned in the x direction are bundled together as one. Similarly, it may be configured such that the second shields42of the multiple individual sensors71are bundled together as one.

FIG. 38also shows two individual sensors71. The measurement current flows through one of the two individual sensor71having the electrical-conduction bus bar30with an enclosed cross symbol.FIG. 38also indicates the magnetic field with an arrow. The magnetic field has components along the x direction and the z direction. Accordingly, the configuration has an environment where the external noise along the x direction and the z direction easily permeates the individual sensor71.

In this configuration, the magnetic permeability of the first shield41and the second shield42in the x direction is higher than that in the y direction. Accordingly, the component of the external noise along the x direction attempts to enter the first shield41and the second shield42respectively. On the other hand, the component of the external noise along the z direction does not depend on the anisotropy of the first shield41and the second shield42any longer. The component along the z direction attempts to permeate the magnetoelectric converter25.

For example, when the magnetic field indicated with a broken arrow in FIG.38attempts to pass through the magnetoelectric converter25, the component of the magnetic field along the x direction actively attempts to pass through the first shield41and the second shield42respectively. However, the component of the magnetic field in the x direction somewhat remains. Accordingly, the component of the magnetic field in the z direction attempts to permeate the magnetoelectric converter25.

The detecting directions of the measurement magnetic field of the magnetoelectric converter25are the z direction and the y direction. The magnetoelectric converter25does not detect the magnetic field in the z direction. Even when the above-described component of the electromagnetic noise in the z direction permeates the magnetoelectric converter25, the degradation of detection accuracy of the measured magnetic field, due to the permeation of the electromagnetic noise, is suppressed.

The embodiments of the present disclosure have been explained hereinabove. The present disclosure is not limited to the above-described embodiments, but various changes can be made and implemented within the gist of the present disclosure.

In the first embodiment, the example where the notches41care formed at the four corners of the first shield41has been shown. In this example, in the first opposite end part41eof the first shield41, the length in the x direction is shorter than that of the first center part41d. The extending part42cis formed in the second shield42.

As shown inFIG. 39, a configuration where the notches41care formed at the four corners of each of the first shield41and the second shield42may be employed. In the second opposite end part42e, the length in the x direction is shorter than that of the second center part42d. As shown in (b) ofFIG. 39, the magnetoelectric converters25of the first sensing unit21and the second sensing unit22mounted on the wiring board20are positioned between the first center part41dand the second center part42d. InFIG. 39, (a) shows a perspective view for explaining the arrangement of the shield, the magnetoelectric converter, and the electrical-conduction bus bar; and (b) is a side view for explaining the arrangement of the shield, the magnetoelectric converter, and the electrical-conduction bus bar.

Further, as shown in (a) ofFIG. 40, it may be configured such that the extending part42cand the notch41care not formed in the second shield42. As shown in (b) ofFIG. 40, a configuration where the notches41care formed at two of the four corners of the first shield41may be employed. Note that in (b) ofFIG. 40, two notches41care aligned in the x direction. InFIG. 40, (a) and (b) are perspective views for explaining the arrangement of the shield, the magnetoelectric converter, and the electrical-conduction bus bar. As shown above, the forming position of the notch41cis not particularly limited as long as the length of the first both end part41eof the first shield41in the x direction is shorter than that of the first center part41d.

In the first embodiment, the example where the integrated housing73has the bottom wall77and the peripheral wall78, and the multiple individual sensors71are accommodated in the storage space provided by the bottom wall77and the peripheral wall78of the integrated housing73, has been shown. However, as shown inFIG. 41toFIG. 43, it may be configured such that the integrated housing73does not have the peripheral wall78. In this case, the individual sensor71, rotated at 90°, is provided with respect to the bottom wall77. Thus, the front surface30aand the rear surface30bof the electrical-conduction bus bar30in the individual sensor71respectively face in the z direction. The one surface41aand the rear surface41bof the first shield41respectively face in the z direction. Similarly, the one surface42aand the rear surface42bof the second shield42respectively face in the z direction. The detection directions of the magnetoelectric converters25of the individual sensor71are the x direction and the y direction.

With this configuration, as shown inFIG. 38, the first shields41of the multiple individual sensors71are aligned in the x direction. The second shields42of the multiple individual sensors71are aligned in the x direction. The magnetoelectric converters25of the multiple individual sensors71are aligned in the x direction.

Note that inFIG. 42, (a) shows a top view of the second current sensor; (b) shows a front view of the second current sensor; and (c) shows a bottom view of the second current sensor. InFIG. 43, (a) shows a side view of the second current sensor; and (b) shows a front view of the second current sensor. (b) ofFIG. 42and (b) ofFIG. 43show the same figure.

In the present modification, bolt holes, the number of which is the same as the number of the individual sensors71, are formed along the z direction in the terminal block80. The bolt hole30cis formed in the second exposed part33of the individual sensor71. The bolt is inserted through the bolt hole in the terminal block80, the bolt hole30cin the second exposed part33, and the bolt hole formed in the wire terminal. Further, the nut is fastened to the end of the bolt. The nut is fastened to the bolt from the end of the bolt shaft toward the bolt head. The second exposed part33and the wire terminal are held between the bolt head and the terminal block80. With this configuration, the second exposed part33and the wire terminal are brought into contact, and electrically and mechanically connected to each other.

As shown in the first embodiment, the rib52ais formed in the sensor housing50of the first current sensor11. Similarly, as shown inFIG. 44, the rib52amay be formed in the sensor housing50of the individual sensor71. A guide part72afor insertion of the individual sensor71into the wiring case72may be formed on the bottom wall77of the integrated housing73. The guide part72aforms a groove having a hollow part in a similar shape to that of the rib52a. The guide part72ais opened in the z direction. The rib52ais passed via the opening into the hollow part of the guide part72a. With this configuration, the individual sensor71is easily assembled to the integrated housing73of the individual sensor71. Note that in the modification shown inFIG. 44, a groove77cfor providing the protruding end of the connection terminal60in the individual sensor71is formed in the bottom wall77.

As schematically shown in (a) ofFIG. 45, in the respective embodiments, the example where the individual sensors71are provided on the U phase stator coil and the V phase stator coil of the motor has been shown. In the example, these individual sensors71have the first sensing unit21and the second sensing unit22.

However, as schematically shown in (b) ofFIG. 45, a configuration where the individual sensors71are provided on the U phase stator coil, the V phase stator coil, and the W phase stator coil of the motor may be employed. These individual sensors71may only have the first sensing units21.

As described above, in the three phase stator coils, based on the currents which flow through the two stator coils, the remaining one current can be detected. Accordingly, based on outputs from two of the first sensing units21of the three individual sensors71provided on the three phase stator coils, the current which flows through the remaining one stator coil can be detected. Further, with the first sensing unit21of the individual sensor71provided on this remaining one stator coil, the current which flows through the remaining one stator coil can be detected. It is possible to determine whether or not an abnormality occurs in one of the two stator coils by comparing the two detected currents.

In the respective embodiments, the example where the current sensor is applied to the in-vehicle system100which forms a hybrid system has been shown. However, the in-vehicle system to which the current sensor is applied is not limited to the above-described example. For example, the current sensor may be applied to the in-vehicle system of an electric vehicle or an engine vehicle. The system to which the current sensor is applied is not particularly limited.

While only the selected exemplary embodiments and examples have been chosen to illustrate the present disclosure, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made therein without departing from the scope of the disclosure as defined in the appended claims. Furthermore, the foregoing description of the exemplary embodiment and examples according to the present disclosure is provided for illustration only, and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.