Controller-integrated electric rotating machine with a shifted control circuit

In a controller-integrated electric rotating machine provided with a power circuit unit and a control circuit unit, a cooling property is improved so that the control circuit unit does not impair a flow of air for cooling the power circuit unit.A power circuit unit (30) having switching elements (30a, 30b) for converting DC power to AC power for supplying the AC power to an electric rotating machine (2), a control circuit unit (32) for controlling the switching elements (30a, 30b) of the power circuit unit (30), and a rotational position detection sensor (4) arranged on a rotating shaft (22) for detecting the rotation of the rotating shaft (22) are provided, and the control circuit unit (32) is disposed at a position where the power circuit unit (30) is not disposed when viewed in the direction of the rotating shaft, and is disposed at a position shifted radially outward so as not to be overlapped with the rotational position detection sensor (4) when viewed in the direction of the rotating shaft.

TECHNICAL FIELD

The present invention relates to a structure of a controller-integrated electric rotating machine in which a controller for controlling drive of an electric rotating machine is integrated.

BACKGROUND ART

For example, an idle-stop controller is disclosed in Patent Document 1 (JP-A-2004-156589). The controller includes a switching element directly fixed to a substantially disk-shaped heat sink and a circuit board having a printed wiring layer fixed on the heat sink, and includes a control IC or the like on the circuit board. The heat sink is provided with double side frames on the entire outer periphery and the entire inner periphery attached thereto, and is fixed to an outer wall at the rear end of a bracket via the outer peripheral side frames. Resin is injected into a ring-shaped recess surrounded by the inner and outer peripheral frames of the heat sink, whereby the switching element, the circuit board and the control IC or the like are protected from salty mud water or the like.

The controller has a cooling structure in which a resin cover is fixed to the bracket so as to cover the heat sink, so that cooling air flowing from an air-intake hole provided on the resin cover flows into the bracket while cooling the heat sink, and cools a stator winding and a rotor winding, and then flows out from the bracket.

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

The related art described above has a problem that electronic components having low heat resistance such as the control IC on the circuit board may become damaged due to heat when the circuit board is arranged in the vicinity of the heat sink on which the switching element as a heat-generating element is fixed. Furthermore, since it is integrally sealed with resin, there is also a problem that heat of the switching element is transferred through the resin and hence the temperature of the electronic components on the circuit board is increased.

Since the substantially disk-shaped heat sink is employed as frames for sealing the switching element and the circuit board with resin, there is a problem that the shape and the layout of the heat sink are limited.

In order to solve such problems, it is an object of the present invention to provide a controller-integrated electric rotating machine having a power circuit unit and a control circuit unit in which cooling property is improved and the control circuit unit mounted thereto is downsized because of efficient pattern design.

Means for Solving the Problems

A controller-integrated electric rotating machine according to the present invention includes an electric rotating machine having a rotor with a rotating shaft and a stator disposed so as to surround the rotor, a power circuit unit having switching elements for converting DC power to AC power for supplying AC power to the electric rotating machine, a control circuit unit for controlling the switching elements of the power circuit unit, and a rotational position detection sensor arranged on the rotating shaft for detecting the rotation of the rotating shaft, and the control circuit unit is disposed at a position where the power circuit unit is not disposed when viewed in the direction of the rotating shaft, and is disposed at a position shifted radially outward so as not to be overlapped with the rotational position detection sensor when viewed in the direction of the rotating shaft.

Advantages of the Invention

According to the controller-integrated electric rotating machine in the present invention, since the control circuit unit is arranged at the position where the power circuit unit is not arranged when viewed from the direction of the rotating shaft, a cooling structure for cooling the power circuit can be optimized irrespective of the shape of the control circuit, and flow of cooling air into the power circuit unit is not impaired by the existence of the control circuit unit. In addition, thermal adverse effects due to heat conduction from the power circuit unit or radiant heat can also be avoided on the control circuit unit.

Since the power circuit unit and the control circuit unit are shifted so as not to be overlapped with each other in the direction of the rotating shaft, an effect of EMI on the circuit control unit due to the ON/OFF operation of the switching elements of the power circuit unit can be restrained.

Furthermore, since the control circuit unit is arranged at the position shifted radially outward so as not to be overlapped with the rotational position detection sensor on the rotating shaft, the effect of noise from the control circuit unit on the rotational position detection sensor is reduced.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, a best mode for carrying out the invention will be described below.

First Embodiment

FIG. 1is a cross-sectional view showing a controller-integrated electric rotating machine according to a first embodiment of the present invention. InFIG. 1, a controller-integrated electric rotating machine1in this embodiment includes an electric rotating machine2which is an AC power generating electric motor (motor generator), a controller3for controlling drive of the electric rotating machine2, a rotational position detection sensor4for detecting the rotational position of the electric rotating machine2, and a connector5for external connection and a power source terminal6.

The electric rotating machine2includes a front bracket20and a rear bracket21as a case, a rotating shaft22rotatably supported by the case via a bearing, a stator23being fixed to the case and having an armature winding23a, a rotor24being fixed to the rotating shaft22and having a field winding24a, a cooling fan24bbeing fixed to both axial end surfaces of the rotor24, a pulley25secured to a front end of the rotating shaft22, a brush holder26mounted to the rear bracket21so as to position on an outer periphery of the rotating shaft22on the rear side, a pair of brushes28arranged in the brush holder26so as to in sliding contact with a pair of slip rings27mounted to the rear side of the rotating shaft22, and the rotational position detection sensor4provided at a rear end of the rotating shaft22. The electric rotating machine2is connected to a rotating shaft (not shown) of an engine via the pulley25and a belt (not shown).

The controller3includes a power circuit unit30for converting DC power to AC power or AC power to DC power, a field circuit unit31for supplying field current to the field winding24a, and a control circuit unit32for controlling the power circuit unit30and the field circuit unit31, and is connected to an external peripherals via the external connector5and the power source terminal6.

The power circuit unit30includes a plurality of power elements (switching elements described later)30aand30b, and an inner heat sink30gand an outer heat sink30hwhich also serve as electrode members to be electrically connected to the power elements30aand30b. Connection between the respective power elements is achieved by a conductive member30iinsert-molded in resin and the heat sinks30gand30h, and electrical connection to the control circuit unit32is achieved via a relay wiring member34b.

The power circuit unit30is arranged on one end wall of the rear bracket21of the electric rotating machine2, is laid out so as to surround the rotating shaft22as described later, and is covered by a cover34for preventing entry of foreign substances from the outside.

The control circuit unit32includes a control circuit board32aand a resin case33for storing the control circuit board32a. The case33has a water-proof structure that can prevent entry of salty mud water into the control circuit board32aby a water-proof cover33aor the like, and is provided with a water-drain hole33bfor discharging water drops formed by dew condensation in the case33. In this example, insulating properties and resistance to environment of the control circuit unit32are improved by filling insulated resin33cin the case33.

The field circuit unit31may be mounted on the same board as the control circuit board32a, and may be configured separately from the control circuit board32a. In this example, it is mounted to the case33of the control circuit unit32.

The rotational position detection sensor4includes a stator40and a rotor41, is disposed on the rotating shaft22which is rather rear side of the brushes28, and is substantially sealed by a water-proof structure in the same manner as the control circuit unit32. In this example, the water-proof structure is achieved by a seal packing42mounted to the rear bracket21, and a water-drain hole43is provided like the case33. The rotational position detection sensor4is used for vector control when electrically driving the electric rotating machine2.

The external connector5is disposed in the vicinity of the control circuit unit32, and is electrically connected to the control circuit unit32.

FIG. 2is a circuit diagram for explaining the operation of the electric rotating machine2in this embodiment. In the drawing, the electric rotating machine2as the AC power generating electric motor includes the armature winding23afor the stator23and the field winding24afor the rotor24, and the armature winding23aof the stator23includes coils of three phases (U-phase, V-phase, and W-phase). The power circuit unit30includes an inverter having three sets of a switching element (power transistor, MOSFET, IGBT, etc.)30awhich constitutes an upper arm30A with a parallel diode and a switching element30bwhich constitutes a lower arm30B with a parallel diode connected in series, and the three sets are arranged in parallel. A capacitor102is connected to the inverter in parallel. Ends of the respective phases of the armature winding23aare connected respectively to mid nodes between the switching elements30aof the upper arms30A and the switching elements30bof the lower arms30B which are connected in series via the AC wiring. A positive terminal and a negative terminal of a battery101are connected to a positive side and a negative side of the power circuit unit30via a series wiring.

The field circuit unit31includes two semiconductor elements31aand31bconnected in series via the brush28and the slip ring27(seeFIG. 1) with the intermediary of the field winding24a, and a flywheel diode31dconnected in parallel to a shunt resistor31c. A drain of the upper semiconductor element31ais connected the heat sink30gconnected to the power source terminal6, and a source of the lower semiconductor element31bis grounded to the rear bracket21via the shunt resistor31c.

The control circuit unit32controls switching operation of the switching element30aof the upper arm30A and the switching element30bof the lower arm30B of the power circuit unit30, and controls the field circuit unit31for adjusting the field current to be flown through the field winding24aof the rotor.

Referring now toFIG. 2, general circuit operation of the electric rotating machine2in the present embodiment will be described. When the engine is started, DC power is supplied from the battery101to the power circuit unit30via the power source terminal6. The control circuit unit32controls the respective switching elements30aand30bof the power circuit unit30with the ON/OFF control to convert the DC power to three-phase AC power. Then, the thee-phase AC power is supplied to the armature winding23aof the electric rotating machine2as the AC power generating electric motor. On the other hand, the field circuit unit31supplies field current to the field winding24aof the rotor24on the basis of a command from the control circuit unit32. Linkage of magnetic flux generating around the field winding24aand current flowing in the armature winding23aof the stator23generates drive torque. The drive torque drives the rotor24to rotate, which is transmitted from the pulley25to a crankshaft of the engine via a belt (not shown), so that the engine is started.

On the other hand, in a state in which the engine is in operation, a rotational power of the engine is transmitted from the crankshaft to the pulley25via the belt (not shown). With this drive force, the rotor24fixed to the rotating shaft22of the electric rotating machine2rotates. Accordingly, the magnetic flux generated by the field winding24aof the rotor24interlinks with the armature winding23aof the stator23, so that a three-phase AC voltage is induced in the armature winding23a. Then, the control circuit unit32controls the respective switching elements30aand30bof the power circuit unit30with the ON/OFF control, so that the three-phase AC power induced in the armature winding23ais converted into the DC power to charge the battery101.

On the other hand, referring back toFIG. 1, the cooling fan24bfixed to the rotor24generates cooling air flow F by the rotation of the rotor24of the electric rotating machine2. The cooling air flow F is sucked from inlet holes34aof the cover34on the rear side, passes between heat discharge fins of the heat sinks30gand30hprovided along the direction of the rotating shaft, and cools the respective switching elements30aand30b. Then, the cooling air flow F passed through a ventilation hole of the rear bracket21is bent in the radial direction by 90° and is discharged while cooling the stator23.

FIG. 3is a front view showing the controller-integrated electric rotating machine according to the first embodiment of the present invention when viewed from the direction of the rotating shaft, andFIG. 4is a front view corresponding toFIG. 3in a state in which the cover34of the electric rotating machine2and the case33of the control circuit unit32are removed.

In the electric rotating machine in this embodiment, the controller3is disposed in the axial direction of the one end wall of the rear bracket21, and the control circuit unit32of the controller3has a substantially rectangular shape when viewed in the direction of the rotating shaft. As shown inFIG. 3andFIG. 4, the control circuit unit32is laid out at a position (double dashed line32inFIG. 4) where the power circuit unit30is not disposed when viewed in the direction of the rotating shaft. The control circuit unit32is disposed at a position shifted radially outward so as not to be overlapped with the rotational position detection sensor4disposed on the rotating shaft22. Connecting portions of the control circuit unit32connected to the power circuit unit30or the rotational position detection sensor4are arranged intensively on one side320aof the control circuit unit32and connecting portions with respect to the external connector5are provided on another side320bthereof.

In the first embodiment, the control circuit unit32has the substantially rectangular shape when viewed in the direction of the rotating shaft. However, the shape of the control circuit unit32is not limited thereto. It may be any shape as long as it has one side or two sides for arranging the respective connecting portions intensively at least when viewed in the direction of the rotating shaft.

As described thus far, according to this embodiment, since the control circuit unit32is arranged at the position where the power circuit unit30is not disposed when viewed in the direction of the rotating shaft, the flow of the cooling air into the power circuit unit30is not impaired by the existence of the control circuit unit32. In addition, the positions or the sizes of the inlet holes34aprovided on the cover34which covers the power circuit unit30can be optimized, so that the power circuit unit30can be cooled sufficiently. In addition, thermal adverse effects due to heat conduction from the power circuit unit30or radiant heat on the control circuit unit32can also be avoided.

Also, since the power circuit unit30and the control circuit unit32are shifted so as not to be overlapped with each other in the direction of the rotating shaft, an effect of EMI on the control circuit unit31due to the ON/OFF operation of the switching elements30aand30bof the power circuit unit30when the electric rotating machine2is in operation can be reduced.

Also, since the control circuit unit32is disposed at the position shifted radially outward so as not to be overlapped with the rotational position detection sensor4on the rotating shaft22, the effect of noise from the control circuit unit32on the rotational position detection sensor4is reduced.

In the control circuit unit32, since the connecting portions with respect to the power circuit unit30and the rotational position detection sensor4are intensively provided on the one side320aof the control circuit unit32, wiring design of the pattern circuit of the control circuit unit32can easily be performed and, simultaneously, assembleability is improved. Therefore, the control circuit unit32can be downsized.

In the control circuit unit32, since the connecting portions with respect to the power circuit unit30and the rotational position detection sensor4are intensively provided on the one side320aof the control circuit unit32, and the connecting portions with respect to the external connector5are arranged on the another side320bof the control circuit unit32, which is different from the one side shown above, the wiring design of the pattern circuit of the control circuit unit32is further facilitated, so that the circuit configuration can be rationalized, and hence the control circuit unit32in a reliable and simple configuration can be obtained.

Since the control circuit unit32is formed into the substantially rectangular shape when viewed in the direction of the rotating shaft, flexibility in arrangement of elements such as a custom IC or a drive to be mounted is improved. Therefore, the pattern design of the control circuit unit32can be rationalized, whereby the possibility of downsizing of the control circuit unit32is further increased. In addition, by providing the connecting portions intensively on the side of the control circuit unit32, assembleability and reliability such that soldering work of the connecting portions is achieved easily, and the joint state of the solder can easily be checked are improved.

Since the cover34having the holes34afor cooling the power circuit unit30and the case33for storing the control circuit unit32are provided, and the power circuit unit30and the control circuit unit32are thermally separated, they are not thermally affected from each other and hence high cooling property can be secured.

The interior of the case33for storing the control circuit unit32is sealed with resin to provide a water-proof property to the control circuit unit32. With such simple configuration, the insulating property and the resistance to environment of the control circuit unit32are improved, and heat conductivity of the elements on the control circuit board32ato the outside can be improved with the employment of the heat conductive resin, so that increase in temperature can be restrained.

InFIG. 4, the switching elements which constitute the power circuit unit30are divided into the three-phase portions of U, V and W. The respective portions each include the pair of heat sinks, the inner heat sink30gand the outer heat sink30h. The respective heat sinks30gand30heach include the several switching elements30aand30bas discrete type power elements in parallel (not shown). The heat sinks30gand30heach include a cooling fin extending along a cooling air channel in the direction of the rotating shaft. In this configuration, the cooling efficiency of the respective switching elements30aand30bof the power circuit unit30increases, and the power circuit unit30can be downsized and optimized.

Second Embodiment

FIG. 5is a cross-sectional view showing part of the controller-integrated electric rotating machine according to a second embodiment of the present invention.FIG. 6is a front view of the controller-integrated electric rotating machine according to the second embodiment of the present invention when viewed in the direction of the rotating shaft.

In the first embodiment, the position of the external connector5with respect to the control circuit unit32is the position (radially outer side) opposing the connecting portions with respect to the power circuit unit30and the rotational position detection sensor4(the radially inner side). In this embodiment, the connecting portions with the power circuit unit30, the field circuit unit31, and the rotational position detection sensor4are provided intensively to the long side320awhich is the radially inner side of the control circuit unit32in substantially the rectangular shape, and the connecting portions with respect to the external connector5are provided on the short side320bon the circumferentially outside.

In this configuration, although the pattern design of the control circuit unit32is slightly difficult in comparison with the first embodiment, the surface area occupied by the control circuit unit32when viewed in the direction of the rotating shaft can be increased in the circumferential direction, and hence the amount of projection of the external connector S in the radial direction can be reduced. Connection wirings of the external connector5, the rotational position detection sensor4and the power circuit unit30can be arranged rationally, and hence the control circuit unit32can be downsized.

As shown inFIG. 5andFIG. 6, the case33for storing the control circuit unit32is formed integrally with the cover34of the power circuit unit30or the external connector5with resin. With such a configuration, the number of components can be reduced, and the necessity to fix the case33of the control circuit unit32and the cover34of the power circuit unit30individually can be eliminated, so that assembleability is improved.

In addition, the cover34of the power circuit unit30includes the relay wiring member34bwhich connects the power circuit unit30and the control circuit unit32by insert molding, and the case33for storing the control circuit unit32includes a relay wiring member which connects the external connector5and the control circuit unit32by insert molding. In this configuration, the relay wiring member34bwhich connects the power circuit unit30and the control circuit unit32, and the relay wiring member which connects the external connector5and the control circuit unit32are reliably provided with a high insulating property, and handling of the case33after molding is easily, which improves assembleability.

The case33for storing the control circuit unit32has a common space used as a space for storing the control circuit board32aand a space for storing the rotational position detection sensor4. In this configuration, the rotational position detection sensor4by itself and a lead wire40alead therefrom can be water-proofed with ease.

The case33for storing the control circuit unit32has a water-proof structure which prevents entry of salty mud water into the control circuit board32aand the rotational position detection sensor4by the water-proof cover33aor the like, and is provided with the water-drain hole33bfor discharging water drops formed by dew condensation in the case33. With such structure, the insulating property and the resistance to environment of the control circuit unit32and the rotational position detection sensor4are improved.

It is also possible to form a relay wiring member40bfor connecting the control circuit unit32and the rotational position detection sensor4on the case33for storing the control circuit unit32by insert molding (not shown). In this case, the vibration proof and insulating property of the lead wire40aof the rotational position detection sensor4can be improved.

Third Embodiment

FIG. 7is a cross-sectional view showing the controller-integrated electric rotating machine according to a third embodiment of the present invention.FIG. 8is a front view corresponding toFIG. 7in a state in which the cover of the electric rotating machine and the case of the control circuit unit are removed when viewed in the direction of the rotating shaft.

In the configurations according to the first and second embodiments shown above, cooling air flows into the power circuit unit30in the substantially axial direction through the holes34aof the cover34from behind the controller-integrated electric rotating machine1, and the respective heat sinks30gand30hhaving the switching elements30aand30bas the power elements each are provided with the cooling fins extending along the cooling air channel in the axial direction. In the third embodiment, the cooling air is sucked from the inlet hole34aprovided on a side wall in the radial direction of the cover34of the power circuit unit30. The heat sinks30gand30hhaving the switching elements30aand30bmounted thereon are formed into a horseshoe shape, and are each provided with a cooling fin along the cooling air channel in the radial direction of the rotating shaft. In this configuration, the positions and the sizes of the air channel holes for cooling the power circuit unit30can be optimized irrespective of the shape of the control circuit unit32.

In this example, the connections between the respective switching elements are achieved by the conductive member30iinsert-molded in resin, and the heat sinks30gand30h. Here, the conductive member30iused for connecting between the respective switching elements may be connected directly to the control circuit unit32. In this case, since the relay wiring member which connects the control circuit unit32and the power circuit unit30can be omitted, so that the number of components and the number of connection nodes are reduced owing to the aggregation of the components, whereby the assembleability is improved and the insulating property is also improved.

The case33for the control circuit unit32includes the relay wiring member40bfor connecting the control circuit unit32and the rotational position detection sensor4with insert molding, so that the vibration proof and insulating property of the lead wire40aof the rotational position detection sensor4are improved.

Fourth Embodiment

FIG. 9is a cross-sectional view of the controller-integrated electric rotating machine according to a fourth embodiment of the present invention. In the above-described embodiments, the case33for storing the control circuit unit32is integrally formed with the cover34of the power circuit unit30or the external connector5with resin. However, the invention is not limited thereto.

As shown inFIG. 9, when the control circuit unit32is downsized, the storing case33of the control circuit unit32and the external connector5may be formed integrally with the brush holder26with resin. In this case, it is achieved by, disposing the control circuit unit32on the brush holder26, soldering the wiring and then effecting resin sealing with insulated resin33cfor improving resistance to environment. Since the above-described processes can be performed with the single brush holder26, workability and assembleability of the electric rotating machine are further improved. By performing the resin sealing with the insulated resin33c, heat of the control circuit unit32is transferred to the brush holder26, and is indirectly cooled by the entire brush holder.

INDUSTRIAL APPLICABILITY

As described thus far, the present invention can be widely applied to the controller-integrated electric rotating machine provided with the power circuit unit and the control circuit unit.