Drive device and electric power steering device including the drive device

A drive device includes a rotating electric machine, a substrate, a first drive element, a second drive element, a first extension line, and a second extension line. The rotating electric machine including a stator with a first winding group and a second winding group wound on the stator in at least three phases. The first extension line and the first drive element, as well as the second extension line and the second drive element have respectively reversed phase orders in an arrangement of the phase orders from an end close to a reference position toward an other end of the arrangement. In such manner, variation of wiring lengths from an electric power supply region among different phases is reduced.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on and claims the benefit of priority of Japanese Patent Applications No. 2014-156484, filed on Jul. 31, 2014, and No. 2015-113189, filed on Jun. 3, 2015, the disclosure of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a drive device and an electric power steering device using including a drive device.

BACKGROUND INFORMATION

Conventionally, a close positioning of a motor and an inverter circuit that controls the motor is well known. For example, according to a disclosure of a Japanese Patent Laid-Open No. 2003-153552, (patent document 1) a circuit board having an inverter circuit arranged thereon is housed in one case, which is then attached on an outer shell of a compressor.

FIG. 4of the patent document 1 illustrates that six power controller semiconductors are mounted on a circuit board. However, the patent document 1 is silent about a phase arrangement order of the three-phase inverter.

SUMMARY

It is an object of the present disclosure to provide a drive device that reduces a variation of wiring length among plural phases and an electric power steering device using such a drive device.

In an aspect of the present disclosure, the drive device includes a rotating electric machine, a substrate, a first drive element, a second drive element, a first extension line, and a second extension line.

The rotating electric machine including a stator with a first winding group and a second winding group wound on the stator in at least three phases. A rotor is located relative to the stator, and a shaft rotates with the rotor.

The substrate is located on one axial end of the rotating electric machine. The first drive element is arranged on one surface of the substrate in a first region and constitutes a first inverter that switches a power supply to the first winding group. The second drive element is arranged on a same surface of the substrate as the first drive element in a second region and constituting a second inverter that switches a power supply to the second winding group.

The second region is symmetric to the first region relative to a shaft of the rotating electric machine. The first extension line extends from each of the at least three phases of the first winding group to be connected to the substrate The second extension line extending from each of the at least three phases of the second winding group to be connected to the substrate.

The first extension line and the first drive element, as well as the second extension line and the second drive element have respectively reversed phase orders in an arrangement of the phase orders from an end close to a reference position toward an other end of the arrangement. In such manner, a variation of the wiring lengths among the plural phases on the substrate is reduced.

DETAILED DESCRIPTION

Hereafter, the drive device in the present disclosure and the electric power steering are described with reference to the drawings.

First Embodiment

The drive device in the first embodiment of the present disclosure and the electric power steering device are shown inFIGS. 1-11. Hereafter, in all embodiments described in the following, the same numerals represent the same parts, for the brevity of the description.

As shown inFIG. 1, a drive device1is applied to an electric power steering device8for assisting the steering operation by the driver. The drive device1is a one-body combination of a motor10serving as a rotating electric machine and an ECU40serving as a controller for controlling the motor10.

FIG. 1shows a system diagram of a steering system100having the electric power steering device8. The steering system100comprises a steering wheel101, a column shaft102, a pinion gear104, a rack shaft105, wheels106, and the electric power steering device8etc. respectively serving as a component of the system.

The steering wheel101is connected to the column shaft102. The column shaft102has a torque sensor103disposed thereon, which is used for detecting a steering torque which is input thereto when the driver operates the steering wheel101. At a tip of the column shaft102, the pinion gear104is disposed, which engages with the rack shaft105. On both ends of the rack shaft105, a pair of wheels106is disposed via a tie rod and the like.

Thereby, when the driver rotates the steering wheel101, the column shaft102connected to the steering wheel101rotates. The rotational movement of the column shaft102is turned into a translational movement of the rack shaft105by the pinion gear104, and the pair of wheels106is steered by an angle according to an amount of displacement of the rack shaft105.

The electric power steering device8is provided with a speed reduction gear9, which serves as a power transmission part, and the drive device1. The electric power steering device8outputs the assisting torque from the motor10based on the signals from the torque sensor103and the vehicle speed obtained from a Controller Area Network (CAN) which is not illustrated, and transmits the torque to the column shaft102via the speed reduction gear9, for assisting the steering operation of the steering wheel101. That is, the electric power steering device8of the present embodiment is what is designated as a “column assistance” type, which assists a rotation of the column shaft102with the torque generated by the motor10. However, the device8may also be used as a “rack assistance” type, which assists the drive of the rack shaft105. In other words, the column shaft102serving as “a drive object” in the present embodiment may be replaced with other objects, e.g., with the rack shaft105.

Next, the electrical configuration of the electric power steering device8is described based onFIG. 2. InFIG. 2, for the readability of the drawing, a part of the control lines etc. are omitted therefrom.

The motor10is a three-phase brushless motor, and has a first winding group13and a second winding group14respectively wound on a stator12which are mentioned later.

The first winding group13comprises a U phase coil131, a V phase coil132, and a W phase coil133. The second winding group14comprises a U phase coil141, a V phase coil142, and a W phase coil143.

The ECU40is provided with a first inverter part50, a second inverter part60, power relays71,72, reverse connection protection relays73and74, a control unit80, a rotational angle sensor85, capacitors86and87, and a choke coil89, which are respectively mounted on a substrate41mentioned below. In the present embodiment, the electronic components which constitute the ECU40are mounted on one substrate41. In such configuration, the number of components on the ECU40is reduced in comparison to a case where plural substrates41are used, thereby reducing the volume of the drive device1.

The first inverter part50has six switching elements (SW elements)51-56combined in a bridge connection form, for the switching of the power supply to the first winding group13. The second inverter part60has six SW elements61-66in a bridge connection form, for the switching of the power supply to the second winding group14.

Although the SW elements51-56,61-66of the present embodiment are Metal Oxide Semiconductor Field Effect Transistor (MOSFET), other elements such as Insulated Gate Bipolar Transistor (IGBT) and the like may also be used.

As for the SW elements51,52, and53arranged on the high potential side of the first inverter part50, the drain is connected to a positive electrode of a battery109that serves as a power supply, and the source is connected to the drain of the SW elements54,55, and56arranged on the low potential side.

The source of the SW elements54,55, and56is connected to a negative electrode of the battery109via current detection elements57,58, and59. The junction points between the SW elements51,52,53on the high potential side and the SW elements54,55,56on the low potential side are connected to the U phase coil131, the V phase coil132, and the W phase coil133, respectively.

As for the SW elements61,62, and63arranged on the high potential side of the second inverter part60, the drain is connected to the positive electrode of the battery109, and the source is connected to the drain of the SW elements64,65, and66arranged on the low potential side.

The source of the SW elements64,65,66is connected to the negative electrode of the battery109via current detection elements67,68, and69. The junction points between the SW elements61,62,63on the high potential side and the SW elements64,65,66on the low potential side are connected to the U phase coil141, the V phase coil142, and the W phase coil143, respectively.

In the present embodiment, the SW elements51-56correspond to “the first plurality of drive elements,” or as “the first drive element” in the claims, and the SW elements61-66correspond to “the second plurality drive elements” or as “the second drive element.” Further, the SW elements51-53,61-63correspond to “the high potential side elements” in the claims, and the SW elements54-56,64-66correspond to “the low potential side elements”.

The current detection elements57,58, and59are disposed on the low potential side of the SW elements54-56respectively corresponding to the three phases of the first winding group13, for detecting the electric current in each of the three phases of the first winding group13.

The current detection elements67,68, and69are disposed on the low potential side of the SW elements64-66respectively corresponding to the three phases of the second winding group14, for detecting the electric current in each of the three phases of the second winding group14.

The current detection elements57-59,67-69of the present embodiment are implemented as shunt resistors.

The power relay71is disposed at a position between the battery109and the first inverter part50, and conducts or intercepts the electric current between the battery109and the first inverter part50.

The power relay72is disposed at a position between the battery109and the second inverter part60, and conducts or intercepts the electric current between the battery109and the second inverter part60.

The reverse connection protection relay73is disposed at a position between the power relay71and the first inverter part50. The reverse connection protection relay74is disposed at a position between the power relay72and the second inverter part60.

The reverse connection protection relays73and74prevent the electric current flowing in a reverse direction for the protection of the ECU40, when, e.g., in the case when the battery109is connected in reverse, by having a parasitic diode connected in reverse relative to the power relays71,72.

In the present embodiment, the power relays71,72and the reverse connection protection relays73,74are all MOSFETS. However, other semiconductor elements such as IGBT and the like may also be used as those relays71,72. In the present embodiment, the power relays71,72are a “relay”.

The control unit80has a microcomputer81, which serves as an electronic component and a calculation component, and an Application Specific Integrated Circuit (ASIC)82, which serves as an Integrated Circuit (IC), together with other parts, which are integrated circuit components.

The microcomputer81calculates an instruction value concerning the power supply to the first winding group13and the second winding group14based on the signal from the torque sensor103or the rotational angle sensor85and the like.

The ASIC82comprises a pre-driver, a signal amplifier, a regulator, and the like. The pre-driver generates a driving signal based on the instruction value, and outputs the generated driving signal to the first inverter part50and to the second inverter part60. More practically, the pre-driver outputs the generated driving signal to the gate of the SW elements51-56,61-66. By the switching operation of the SW elements51-56,61-66according to the driving signal, an Alternating Current (AC) according to the instruction value is supplied to the first winding group13and to the second winding group14from the first inverter part50and the second inverter part60, respectively. Thereby, the motor10is driven.

The signal amplifier amplifies the detection signal (i.e., a voltage between both terminals in the present embodiment) of the current detection elements57-59,67-69, and the detection value of the rotational angle sensor85, and outputs them to the microcomputer81. Further, the regulator is a stabilization circuit which stabilizes the voltage supplied to the microcomputer81and the like.

The rotational angle sensor85is constituted by a magnetism detection element, and detects a rotation angle of a rotor15by detecting a rotating magnetic field from a magnet18provided on an other end162of a shaft16mentioned later.

The capacitor86is connected in parallel with the first inverter part50. The capacitor87is connected in parallel with the second inverter part60. In the present embodiment, the capacitors86and87are the aluminum electrolytic capacitors, and are disposed on the inverter side (i.e., on one side close to the inverter parts50,60) of the relays71-74. The choke coil89is connected at a position between the battery109and the positive electrodes of the capacitors86and87. In the present embodiment, the choke coil89is disposed on the battery side (i.e., on one side close to the battery109) of the relays71-74).

The capacitors86and87and the choke coil89serve as a filter circuit, reducing the noise transmitted from the drive device1to the other devices that share the power supply from the battery109with the drive device1, and also reducing the noise transmitted from the other devices back to the drive device1sharing the battery109. The capacitors86and87store the electric charge, and support the electric power supply to the first inverter part50and the second inverter part60.

In the present embodiment, the first inverter part50, the power relay71, the reverse connection protection relay73, and the capacitor86are grouped as a first system201, corresponding to the first winding group13. Further, the second inverter part60, the power relay72, the reverse connection protection relay74, and the capacitor87are grouped as a second system202, corresponding to the second winding group14. That is, a drive control of the motor10is performed in plural systems, i.e., in two systems in the present embodiment.

Next, a structure of the drive device1is described based onFIGS. 3-11. In the following, an axial direction, i.e., a virtual line extending along the shaft of the motor10, may simply be designated as an “axial direction,” and a radius direction, i.e., a virtual line extending outward from the shaft of the motor10, may simply be designated as a “radius direction.”FIG. 3is a sectional view along a III-III line ofFIG. 5.

As shown inFIGS. 3-8, the drive device1is provided with the motor10, a frame member20, the ECU40, and a cover member90, together with other parts.

As shown inFIG. 3, the motor10has a motor case11, the stator12, the first winding group13, the second winding group14, the rotor15, the shaft16and other parts.

The motor case11has a bottom part111and a cylinder part114, for example, is formed in a cylinder shape closed on one end, i.e., having a bottom on one end, and is made from metal, such as aluminum. The motor case11of the present embodiment is made from aluminum, and, as for the surface of the case11, the anodized aluminum treatment is performed. The bottom part111of the motor case11is positioned away from the ECU40, i.e., on an opposite side, and an opening of the motor case11is close to the ECU40, i.e., on the ECU side. In the present embodiment, the cylinder part114corresponds to a “cylinder part of the rotating electric machine” and a projection area of the cylinder part114along the axial direction corresponds to a “motor region.”

A shaft hole112into which one end161of the shaft16is inserted is disposed substantially at the center of the bottom part111. Further, a bearing166is fitted to the bottom part111.

On or around the opening of the cylinder part114, a fixing tab116for fixedly disposing the substrate20is formed, i.e., projecting radially outward from an outer wall of the cylinder part114. The fixing tab116has a screw-threaded hole117bored thereon. The fixing tab116of the present embodiment is disposed at three positions around the cylinder part114at the same interval.

The stator12has a layered part, i.e., a layered structure of a magnetizable thin metal such as iron, and an insulator disposed on a radial outside of the layered part, and the stator12is fixedly disposed in an inside of the motor case11. The number of sheets of the thin metal in the layered part of the stator12may be changed according to the output required for the motor10. Thereby, the output of the motor10can be changed by changing the axial length of the stator12, without changing the radius length of the motor10.

The first winding group13and the second winding group14are wound on the insulator of the stator12. For each of the three phases, a first motor line135is taken out from the first winding group13, and, for each of the three phases, a second motor line145is taken out from the second winding group14. The motor lines135and145are taken out, i.e., extend, from the motor case11toward the ECU40(seeFIG. 7).

In the present embodiment, the first motor line135corresponds to a “first extension line” and the second motor line145corresponds to a “second motor line”.

The rotor15has a rotor core151and a permanent magnet152. The rotor core151is formed in an approximately cylindrical shape, for example, and is made from a magnetic material, e.g. iron, and is coaxially arranged in an inside of the stator12, i.e., in a radius inside of the stator12.

The permanent magnet152is disposed on a radius outside of the rotor core151, and the N poles and the S poles of the rotor core151alternate with each other.

The shaft16is formed in a rod shape, for example, with metal, and is fitted at the center position, i.e., on a rotation axis of the rotor core151. The shaft16is rotatably supported by the bearing166fitted on the bottom part111of the motor case11and by a bearing167fitted on the frame member20. Thereby, the shaft16is rotatable with the rotor15. Further, an outer wall of the rotor15and an inner wall of the stator12are interposed with an air gap.

The one end161of the shaft16is inserted into the shaft hole112that is bored on the bottom part111of the motor case11, and projects toward an outside of the motor case11. The one end161of the shaft16serves as an output end, which is connected to the speed reduction gear9, for outputting the torque from the motor10toward the column shaft102via the speed reduction gear9(seeFIG. 1), even though a connection between the output end and the speed reduction gear9is not explicitly illustrated.

The other end162of the shaft16has a magnet holder part17that holds the magnet18.

As shown inFIG. 3andFIG. 7, for example, the frame member20made from highly-heat-conductive metal, such as aluminum or the like, is formed in a lid shape for closing the opening of the motor case11, i.e., is inserted into a radial inside of the cylinder part114. Here, one side of the frame member20close to the motor10is designated as a motor side face21, and the other side of the frame member20away from the motor10and close to the ECU40is designated as an ECU side face31.

A shaft hole23is bored substantially at the center of the frame member20. The other end162of the shaft16is inserted into the shaft hole23.

Thereby, the magnet18disposed on the other end162of the shaft16is exposed to, i.e., faces, the ECU40. The bearing167is fitted on the frame member20.

Further, the frame member20has a motor line insertion hole24into which the motor line135is inserted and a motor line insertion hole25into which the motor line145is inserted. Thereby, the motor lines135and145are taken out therefrom to extend toward the ECU40.

The frame member20has a fixing tab26which projects outward in a radius direction at corresponding positions (i.e., three positions in the present embodiment) corresponding to the fixing tab116of the motor case11. The fixing tab26has a through hole27bored thereon. A frame lockscrew38“ ” is inserted into the through hole27, and is tightly screwed into the screw-threaded hole117. Thereby, the frame member20is fixed onto the motor case11.

At an outer periphery of the frame member20and around the motor side face21which is close to the bottom part111than the fixing tab26, an O ring groove29is provided, into which an O ring39is fitted, and the O ring39bound by the O ring groove29and the cylinder part114provides a watertight structure. Thereby, water and the like are prevented from intruding into the motor10via a position between the motor case11and the frame member20.

The ECU side face31of the frame member20has a substrate fixing tab32, relay rooms33and34, an ASIC room35, a terminal receptacle groove36, and an adhesion groove37.

As shown inFIGS. 3, 7-11, the ECU40is disposed away from the motor10relative to the frame member20, i.e., with the frame member20interposed therebetween. The ECU40is positioned substantially within the motor region, and is substantially coaxially disposed with the motor10.

The ECU40has the substrate41on which many electronic components are mounted.

The substrate41is formed in a shape that fits in the motor region. In the present embodiment, more practically, the substrate41is contained within the groove region, i.e., in a radius inside of the adhesion groove37provided on the ECU side face31of the frame member20. In other words, the ECU components on the substrate41, such as the SW elements51-56,61-66, the current detection elements57-59,67-69, the capacitors86,87, and the choke coil89, are positioned within the motor region.

Here, one side of the substrate41close to the motor10is designated as a heat generation element mounting surface42, and the other side, a surface away from the motor10, is designated as an electronic component mounting surface43.

As shown inFIG. 8andFIG. 10, for example, the SW elements51-56,61-66as well as the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, the ASIC82, and the rotational angle sensor85are surface-mounted on the heat generation element mounting surface42together with other parts. The rotational angle sensor85is omitted from the illustration inFIG. 10. InFIG. 11, a dashed line shows a region where a mold case of the ASIC82is disposed.

The rotational angle sensor85is mounted substantially at a center position on the heat generation element mounting surface42, which faces the magnet18which is exposed from the frame member20. Here, when the axis line of the shaft16and its extension are considered as the center axis O of the motor10, the rotational angle sensor85is mounted on the center axis O of the heat generation element mounting surface42(seeFIG. 3).

A first region R1, where the SW elements51-56and the current detection elements57-59of the first inverter part50are mounted, and a second region R2, where the SW elements61-66and the current detection elements67-69of the second inverter part60, are symmetrically arranged on the opposite sides of the center axis O of the motor10. In the present embodiment, the SW elements51-56and the SW elements61-66are arranged as axisymmetric on both sides of a straight line passing through the center axis O of the motor10.

Further, when a driver element region R3is defined as an area including the first region R1and the second region R2and the center axis O, (i) the power supply relays71,72and the reverse connection protection relays73,74and (ii) the ASIC82are positioned outside of the driver element region R3on opposite sides relative to the region R3. That is, the component group (i) described above is positioned on one side of the region R3, and the component (ii) described above is positioned on the other side of the region R3.

A motor line insertion section44is formed on a radius outside of the first region R1. The motor line insertion section44has the motor line135inserted therein. A motor line insertion portion45is formed on a radius outside of the second region R2. The motor line insertion portion45has the motor line145inserted therein.

In the present embodiment, the regions R1to R3are rectangular areas, the regions R1to R3may be in any shape other than the rectangular shape, depending on the implementation positions of the SW elements51-56,61-66and the current detection elements57-59,67-69, e.g., in a polygon shape including all elements.

Further, the SW elements54-56connected to the low potential side are arranged on the outside of the SW elements51-53connected to the high potential side, and the current detection elements57-59are arranged further on the outside thereof.

Similarly, the SW elements64-66connected to the low potential side are arranged on the outside of the SW elements61-63connected to the high potential side, and the current detection elements67-69are arranged further on the outside thereof.

On one side of each of the SW elements51-56,61-66, the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82which are mounted on the heat generation element mounting surface42, i.e., a side facing the frame member20, a heat dissipation slug made of heat conductive metal, e.g., cupper, is disposed.

Further, the SW elements51-56,61-66, the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82respectively contact the ECU side face31of the frame member20in a heat transferable manner via a heat dissipation gel which is not illustrated. Thereby, heat generated by the SW elements51-56,61-66, the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82is dissipated via the heat dissipation gel to the frame member20. InFIG. 3or other FIGS., the ASIC82and the frame member20may look like disposed in a non-contacting state, as a result of the omission of the heat dissipation gel. That is, the SW element51-56,61-66, the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82constitute a heat generation element70in the present embodiment.

The power relays71,72, which are a large size element in comparison to the SW elements51-56,61-66and the reverse connection protection relays73,74, are accommodated in the relay rooms33,34provided on the ECU side face31of the frame member20.

The ASIC82, which is a large size element in comparison to the SW elements51-56,61-66and the reverse connection protection relays73,74, is accommodated in the ASIC room35provided on the ECU side face31of the frame member20.

In the present embodiment, the frame member20defines an outline of the motor10, provides a support for the ECU40, and provides a heat dissipation path for dissipating heat from the heat generation element70. Thereby, as compared with a case in which a heat sink is provided separately, the number of components is reduced, and the volume of the drive device is reduced as a whole.

Here, the motor lines135and145and the phase order of the inverter parts50and60are described. According to the present embodiment, inFIG. 10, a circuit pattern of the substrate41connected to the drain of the power relays71,72is shown in a one-dot broken line illustratively, and is designated as an electric power supply region Rin. The electric power supply region Rin is outside of the first region R1, the second region R2, and the driver element region R3including the center axis O of the motor10, and is a region containing the circuit pattern which supplies the electric power from the battery109to the first inverter part50and to the second inverter part60.

According to the present embodiment, the electric power supply region Rin corresponds to a “reference position” in the claims.

As shown inFIGS. 7 and 10, the motor line135is made up from a first U phase motor line136connected to a U phase coil131, a first V phase motor line137connected to a V phase coil132, and a first W phase motor line138connected to a W phase coil133. In the present embodiment, the first U phase motor line136, the first V phase motor line137, and the first W phase motor line138are arranged in order from the power supply region Rin side to be inserted in the motor line insertion section44of the substrate41. In the present embodiment, the first U phase motor line136, the first V phase motor line137, and the first W phase motor line138are positioned along a straight line on an outside of the current detection elements57-59on the substrate41. Further, the same interval is provided between the first U phase motor line136and the first V phase motor line137, and between the first V phase motor line137and the first W phase motor line138. In other words, the first U phase motor line136and the first W phase motor line138are positioned symmetrically with reference to the first V phase motor line137.

Further, the motor line145is made up from a second U phase motor line146connected to a U phase coil141, a second V phase motor line147connected to a V phase coil142, and a second W phase motor line148connected to a W phase coil143. In the present embodiment, the second W phase motor line148, the second V phase motor line147, and the second U phase motor line146are arranged in order from the power supply region Rin side to be inserted in the motor line insertion section44of the substrate41. In the present embodiment, the second U phase motor line146, the second V phase motor line147, and the second W phase motor line148are positioned along a straight line on an outside of the current detection elements67-69on the substrate41. Further, the same interval is provided between the second U phase motor line146and the second V phase motor line147, and between the second V phase motor line147and the second W phase motor line148. In other words, the second U phase motor line146and the second W phase motor line148are positioned symmetrically with reference to the second V phase motor line147.

In the present embodiment, the first U phase motor line136and the second U phase motor line146are arranged as point-symmetric to the center axis O of the motor10. Similarly, the first V phase motor line137and the second V phase motor line147are arranged as point-symmetric to the center axis O of the motor10, and the first W phase motor line138and the second W phase motor line148are arranged as point-symmetric to the center axis O of the motor10.

In such a structure, the magnetic flux leakage from the first motor line135and the magnetic flux leakage from the second motor line145cancel each other, thereby an influence of the magnetic flux leakage on the rotational angle sensor85mounted on the center axis O of the motor10is reduced. Here, “symmetry” means a substantially-symmetric arrangement of those lines, for the cancellation of the magnetic flux leakage, allowing a dimension error in the actual product.

Further, a distance between the two motor lines, i.e., between the first U phase motor line136and the first V phase motor line137or between the first V phase motor line137and the first W phase motor line138, is reduced to the minimum, i.e., down to a smallest value as long as the motor lines do not contact with each other, so that the magnetic flux leakage is minimized. The same applies to the second motor line145.

The first inverter part50has, in the same manner as the first motor line135, the phase arrangement of U phase, V phase and W phase from the electric power supply region Rin side. More specifically, the SW elements51,52,53connected to the high potential side are arranged in order, from the electric power supply region Rin side, the U phase SW element51, the V phase SW element52, and the W phase SW element53. Further, the SW elements54,55,56connected to the low potential side are arranged in order, from the electric power supply region Rin side, the U phase SW element54, the V phase SW element55, and the W phase SW element56. Similarly, the current detection elements57,58,59are arranged in order, from the electric power supply region Rin side, the current detection element57which detects the electric current of the U phase coil131, the current detection element58which detects the electric current of the V phase coil132, and the current detection element58which detects the electric current of the W phase coil133.

The second inverter part60has, in the same manner as the second motor line145, the phase arrangement of W phase, V phase and U phase from the electric power supply region Rin side. More specifically, the SW elements61,62,63connected to the high potential side are arranged in order, from the electric power supply region Rin side, the W phase SW element63, the V phase SW element62, and the V phase SW element61. Further, the SW elements64,65,66connected to the low potential side are arranged in order, from the electric power supply region Rin side, the W phase SW element66, the V phase SW element65, and the V phase SW element64. Similarly, the current detection elements67,68,69are arranged in order, from the electric power supply region Rin side, the current detection element69which detects the electric current of the W phase coil143, the current detection element68which detects the electric current of the V phase coil142, and the current detection element67which detects the electric current of the U phase coil141.

Here, the wiring length in U phase is defined as a sum of the wiring length from the electric power supply region Rin to the motor line136, and the wiring length from the electric power supply region Rin to the motor line146. Similarly, the wiring length in V phase is defined as a sum of the wiring length from the electric power supply region Rin to the motor line137, and the wiring length from the electric power supply region Rin to the motor line147. Further, the wiring length in W phase is defined as a sum of the wiring length from the electric power supply region Rin to the motor line138, and the wiring length from the electric power supply region Rin to the motor line148.

In the present embodiment, the first system201has a phase order of U, V, W phase from the electric power supply region Rin side, and the second system202has a phase order of W, V, U from the electric power supply region Rin side. In other words, the first system201and the second system202have the reversed phase order, in terms of the phase arrangement order of the power supply from the electric power supply region Rin side. Further, in the present embodiment, a distance from the center of the electric power supply region Rin to the center of the first region R1, and a distance from the center of the electric power supply region Rin to the center of the second region R2are substantially the same.

Therefore, the U phase wiring length, the V phase wiring length, and the W phase wiring length vary very little. Especially, by symmetrically arranging (a) the SW elements51-56and the current detection elements57-59and (b) the SW elements61-66and the current detection elements67-69, by symmetrically forming the circuit pattern on the substrate41, and by symmetrically arranging the motor line135and the second motor line145, variation of the U phase wiring length, the V phase wiring length, and the W phase wiring length is further reduced. The reduction of the wiring length thus enables a reduction of variation of wiring impedances among different phases.

Further, the phase order is the same in both of the first inverter part50and the first the motor line135, and, in each phase, the SW elements51-53on the high potential side, the SW elements54-56on the low potential side, the current detection elements57-59, and the motor lines136-138are respectively arranged from the center axis O side toward the radius outside on the substrate41. In each of the SW elements51-56, the drain is formed on the side facing the substrate41, and the wiring pattern connected to the drain of the SW elements54-56on the low potential side and the motor line135are connected. Therefore, as compared with a case where the SW elements51-53on the high potential side are arranged outside, the wiring on the substrate41becomes easy by arranging the SW elements54-56on the low potential side at the outside position than the SW elements51-53on the high potential side.

The same applies to the second inverter part60and the second motor line145.

As shown inFIG. 7andFIG. 11, for example, the microcomputer81, the capacitors86,87, and the choke coil89are mounted on the electronic component mounting surface43, together with other parts. The microcomputer81is mounted at a position on a reverse side of the substrate41which at least partially overlaps with the ASIC82.

The capacitor86is mounted on a reverse side of the substrate41, i.e., at least partially overlapping with the first region R1, in which the SW elements51-56of the first inverter part50are mounted. The capacitor87is mounted on a reverse side of the substrate41, i.e., at least partially overlapping with the second region R2, in which the SW elements61-66of the second inverter part60are mounted. The noise reduction effect increases by arranging the capacitors86,87on the reverse side of the inverter parts50,60.

In the present embodiment, by mounting relatively large-size electronic components, e.g., the capacitors86,87and the choke coil89, on the electronic component mounting surface43, the substrate41is positioned at a proximity of the frame member20. Thereby, heat generated by the heat generation element70on the heat generation element mounting surface42is dissipated to the frame member20from the “back” of those components.

On the electronic component mounting surface43, a motor line connector46made from a conductive metal or the like is provided at a position where the motor line insertion holes44and45are bored. The motor line connector46has a press-fit part, and the press-fit part receiving the motor lines135and145establishes an electrical connection between the substrate41and the motor lines135,145.

A hole48is bored at a position corresponding to the substrate fixing tab32of the substrate41. A substrate lockscrew49(seeFIGS. 7 and 8) is inserted into the hole48, and is tightly screwed onto the substrate fixing tab32of the substrate20. In such manner, the substrate41is fixed onto the substrate20.

As shown inFIGS. 3-8, a cover member90has a cover body91, a power supply connector96, and a signal connector97, and covers the electronic component mounting surface43side of the substrate41.

An insert portion921is provided at one end of a peripheral wall92of the cover body91. The insert portion921is inserted into the adhesion groove37of the frame member20, and is fixed by the adhesive. Thereby, water or the like is prevented from intruding into the motor10from a connection portion between the frame member20and the cover member90.

A capacitor room93is formed substantially at the center of the cover body91. The capacitor room93protrudes from the cover body91, i.e., away from the motor10, for accommodating the capacitors86,87. A breathing hole94is bored on the capacitor room93. The breathing hole94is closed by a filter member95attached thereon. The filter member95is made from a material that passes air but does not pass the water. By having the filter member95in the breathing hole94, the inner pressure of the driver unit1stays constant at a certain value even when the temperature changes.

The power supply connector96and the signal connector97(i.e., “connectors96and97” hereinafter) respectively protrude away from the cover body91, i.e., away from the motor10. In the present embodiment, the connectors96and97are integrally formed with the cover body91in one body.

The power supply connector96has an opening961disposed on one end which extends away from the motor10, for a connection to a harness (not illustrated) that extends from the battery109. Further, the power supply connector96has a power supply connector terminal962connected to the substrate41. The power supply connector terminal962is inserted into a terminal insertion hole965bored on the substrate41, and is connected to the substrate41by solder or the like. Thereby, the ECU40is connected to the battery109.

The signal connector97has an opening971disposed on one end which extends away from the motor10, for a connection to a harness (not illustrated). In the present embodiment, two signal connectors97are provided, among which one is connected to a harness extending from the torque sensor103and the other is connected to a harness extending from CAN. Further, the signal connector97has a signal connector terminal972connected to the substrate41. The signal connector terminal972is inserted into a terminal insertion hole975disposed on the substrate41, and is connected to the substrate41by solder or the like. Thereby, information from the torque sensor103and information from CAN are input into the ECU40.

The tip of each of the power supply connector terminal962and the signal connector terminal972(i.e., “terminals962and972” hereinafter) is inserted into the terminal receptacle groove36that is formed on the ECU side surface31of the substrate20, so that the terminals962,972and the frame member20are not short-circuited with each other.

As described in full detail above, the drive device1of the present embodiment is provided with the motor10, the substrate41, the SW elements51-56, the SW elements61-66, the first the motor line135, and the second the motor line145.

The motor10is a three-phase motor in which the stator12having the first winding group13and the second winding group14wound thereon, the rotor15rotatable relative to the stator12, and the shaft12rotating with the rotor15are provided.

The substrate41is disposed on one end side of the shaft16of the motor10.

The SW elements51-56constituting the first inverter part50that switches the power supply to the first winding group13is arranged on the heat generation element mounting surface42which is one surface of the substrate41.

The SW elements61-66constituting the second inverter part60that switches the power supply to the second winding group14are mounted on the same surface of the substrate41as the SW elements51-56, and is arranged in the second region R2, which is on an opposite side of the first region R1relative to the axial center O of the motor10, in which the SW elements51-56are mounted.

The first the motor line135is taken out from each of the plural phases of the first winding group13, and is arranged on the substrate41.

The second the motor line145is taken out from each of the plural phases of the second winding group14, and is arranged on the substrate41.

The phase order from the electric power supply region Rin side on the substrate41is reversed, in a first group of the first motor line135and the SW elements51-56, and in a second group of the second motor line145and the SW elements61-66.

In other words, if U, V, W phases are respectively designated as the first, the second, and the third phases, the order of the phases in the first group of the first motor line135and the SW elements51-56are, from the electric power supply region Rin side, the first phase (=U phase), the second phase (=V phase), and the third phase (=W phase), and the order of the phases in the second group of the second motor line145and the SW elements61-66are, from the electric power supply region Rin side, the third phase (=W phase), the second phase (=V phase), and the first phase (=U phase).

According to the present embodiment, the phase order from the reference position side (i.e., in the present embodiment, the electric power supply region Rin side) is in a reverse order (i) in the first group of the first motor line135and the SW elements51-56which is the first system201, and (ii) in the second group of the second motor line145and the SW elements61-66which is 1 to the second system202. In such manner variation of the wiring lengths in different phases on the substrate41is reduced, thereby reducing variation of the impedance among the different phases.

The reference position is the electric power supply region Rin, which is an outside of the first region R1, the second region R2, and the driver element region R3including the center axis O of the motor10, and is a region containing the circuit pattern which supplies the electric power from the battery109to the first inverter part50and to the second inverter part60. That is, in the present embodiment, the arrangement of the first motor line135and the SW elements51-56and the arrangement of the second motor line145and the SW elements61-66are reversed to each other in terms of the phase order from the Rin side. Therefore, the variation of the wiring lengths for a portion the wire extending from the electric power supply region Rin to the motor lines135,145is reduced, the variation of the impedances in each of the plural phases is reduced.

The drive device1is further provided with the power relays71,72that are capable of switching the supply of the electric current from the battery109to the first inverter part50or to the second inverter part60. The power relays71,72are mounted in the electric power supply region Rin on the heat generation element mounting surface42, which is the surface having the SW elements51-56,61-66. By arranging the power relays71,72in the electric power supply region Rin, the wiring on the substrate41is made easy, and a mounting area of the substrate41is efficiently utilized.

The drive device1is further provided with the frame member20that is disposed at a position between the motor10and the substrate41.

The SW elements51-56,61-66are mounted on the heat generation element mounting surface42which is a surface of the substrate41facing the frame member20in a heat dissipatable manner to dissipate heat to the frame member20. That is, the frame member20serves as an outline of the motor10, and serves as a heat sink. In such manner, the volume of the drive device1is reduced, especially along the axial direction, in comparison to a case in which the heat sink is separately provided, due to the reduction of the number of the components.

The first motor line135is connected to the substrate41on the radius outside of the first region R1. The second motor line145is connected to the substrate41on the radius outside of the second region R2. Thereby, the mounting area of the substrate41is efficiently utilized.

The drive device1is further provided with the current detection elements57-59,67-79which detect the power supply to each of the phases in the first winding group13or the second winding group14. The current detection elements57-59,67-79are mounted at positions between the SW elements51-56and the first motor line135, or the positions between the SW elements61-66and the second motor line145on the same surface of the substrate41as the SW elements51-56,61-66.

Thereby, the detection of the electric current is appropriately performed in the first winding group13or in the second winding group14.

As for the SW elements51-56,61-66, the SW elements51-53,61-63on high potential side are arranged close to the axial center O of the motor10, and the SW elements54-56,64-66on the low potential side are arranged on the outside of the SW elements51-53,61-63on the high potential side. By arranging the SW elements in such way, the wiring on the substrate41becomes easy as compared with a case in which the SW elements51-53,61-63on the high potential side are arranged on the outside.

The first motor line135and the second motor line145are arranged as point-symmetric with reference to the center axis O of the motor10on the substrate41. Thereby, the corresponding phases of the first motor line135and the second motor line145are arranged as point-symmetric, thereby cancelling the magnetic flux leakage with each other and reducing the total magnetic flux leakage. Further, when the rotational angle sensor85is arranged on the center axis O of the motor10, for example, the detection error of the rotational angle sensor85under the influence of the magnetic flux leakage is reduced.

For the first motor line135and the second motor line145, the center phase of the three phases serves as a reference phase for the both side phases. That is, in the first motor line135and the second motor line145, the V phase serves as a standard phase for the symmetrical arrangement of the U phase and the W phase on both sides. Thereby, variation of the wiring lengths among the different phases is reduced, and variation of the impedance among the different phases is further reduced.

On the substrate41, the motor lines136,137, and138are arranged along a straight line.

On the substrate41, the motor lines146,147, and148are arranged along a straight line.

The drive device1of the present embodiment is applied to the electric power steering device8. That is, the electric power steering device8is provided with the drive device1and the speed reduction gear9which transmits a torque outputted from the motor10to the column shaft102, drives the column shaft102by the torque of the motor10, and assists the steering operation of the steering wheel101by a driver.

The drive device1of the present embodiment has the motor10and the ECU40substantially coaxially disposed, has a reduced product volume along the axial direction, and is substantially contained within the motor region. Thereby, the drive device1is installable even in a small space. Further, since the O ring39is disposed at a position between the motor case11and the substrate20and the substrate20and the cover member90are attached with the adhesive, the drive device1of the present embodiment has a waterproof construction. Therefore, the drive device1may be installed in an engine room, for example. In other words, the drive device1is suitably used for a rack assistant type electric power steering device.

Second Embodiment

The drive in the second embodiment of the present embodiment is shown inFIGS. 12-17.FIG. 12is a sectional view of the drive device along a XII-XII line ofFIG. 15. In each of the drawings concerning the present embodiment, the capacitors86and87are omitted in some case.

A drive device2is provided with a motor210as a rotating electric machine, a front frame end215, a rear frame end220, an ECU240as a controller, a connector280, a cover member290and the like. According to the present embodiment, the rear frame end220corresponds to a “substrate” in the claims. Since the electric configuration of the drive device2is the same as that of the above-mentioned embodiment, description of the electric configuration is omitted.

The motor210is provided with a stator212, the rotor15, the shaft16and the like as shown inFIGS. 12-15.

The stator212has the front frame end215and the rear frame end220fixed thereto. In the present embodiment, a motor case is omitted and the stator212is exposed. About the other points, the stator212is the same as the stator12in the above-mentioned embodiment. That is, in the drive device2of the present embodiment, the stator212is “naked” and does not have a waterproof construction. Therefore, the drive device2of the present embodiment may preferably be disposed in a vehicle compartment, and is preferably applicable to a column assistance type electric power steering device.

According to the present embodiment, since the motor case is omitted, a projection region, or a “silhouette”, of the stator212is considered as a “motor region.”

The front frame end215is made from, for example, metal, e.g. aluminum or the like, and is provided on the opposite end of the motor210relative to the ECU240. The front frame end215has a shaft hole216bored substantially at the center thereof. The bearing166is attached to the front frame end215, and one end161of the shaft16is inserted thereinto. The one end161of the shaft16is exposed from the front frame end215. The one end161of the shaft16is provided as an output end165. The output end165is connected to the speed reduction gear9. Thereby, the torque generated by the rotation of the rotor15and the shaft16is output to the column shaft102via the speed reduction gear9.

As shown inFIGS. 12-15, the rear frame end220has a frame part222, a heat dissipator230, and a connector receiver236, for example, and is made with thermally-conductive metal, e.g. aluminum or the like, and is disposed on the ECU240side of the motor210. The front frame end215and the rear frame end220are combined by using a through bolt (not illustrated), with the motor210interposed therebetween. Further, the rear frame end220has a motor line insertion hole (not illustrated) bored thereon. The motor lines135and145are inserted into the motor line insertion hole, and are taken out to extend toward the ECU240.

The frame part222has a ring shape, and is attached to the stator212of the motor210.

The heat dissipator230is fixed and stands up on the frame part222to extend toward the ECU240.

A shaft hole231is bored at the center axis O of the heat dissipator230. The shaft hole231has a bearing167disposed therein, and an other end162of the shaft16is inserted thereinto. Thereby, the magnet18provided on the other end162of the shaft16is exposed to the ECU240.

A substrate fixing part232is provided on an outside of the heat dissipator230. An ECU240side surface of the heat dissipator230is formed as a radiation surface235.

The connector receiver236protrudes from the heat dissipator230toward a radius outside thereof. Next to the connector receiver236, a connector280is disposed on the ECU240side. The connector receiver236and the connector280are separated with a gap in between.

The ECU240is disposed on an opposite side of the rear frame end220relative to the motor210, and is positioned substantially co-axially with the motor210.

The ECU240has a substrate241on which various electronic components are mounted.

The substrate241takes a shape that fits in the projection region of the rear frame end220. Further, the components of the ECU240, i.e., the SW elements51-56,61-66, the current detection elements57-59,67-69, the capacitors86,87, and the choke coil89which are mounted on the substrate241, are contained within the motor region.

Here, a motor side surface of the substrate241, which faces the motor210, is designated as a heat generation element mounting surface242, and an opposite surface of the substrate241, which faces away from the motor210, is designated as an electronic component mounting surfaces243. In the present embodiment, the heat generation element mounting surface242corresponds to a “one surface” in the claims.

As shown inFIG. 16, the heat generation element mounting surface242has the SW elements51-56,61-66, the current detection elements57-59, the power relays71,72, reverse connection protection relays73,74, the ASIC82, the rotational angle sensor85and the like mounted thereon.

In the present embodiment, the SW elements51-56,61-66, the current detection elements57-59,67-69, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82respectively contact the radiation surface235of the heat dissipator230of the rear frame end220via the heat dissipation gel in a heat dissipatable manner. Thereby, heat generated by the SW elements51-56,61-66, the power relays71,72, the reverse connection protection relays73,74, and the ASIC82is dissipated to the rear frame end220via the heat dissipation gel. Further, on the electronic component mounting surface243, the microcomputer81is mounted in a region which at least partially overlaps with the ASIC82, (refer toFIG. 12andFIG. 17).

In the present embodiment, the SW elements51-56constituting the first inverter part50and the SW elements61-66constituting the second inverter part60are symmetrically arranged around the center axis O of the motor10(i.e., a part where the rotational angle sensor85is disposed in the present embodiment). In the present embodiment, the SW elements51-56and the SW elements61-66are arranged around center axis O of the motor10in a point-symmetric manner. In addition, the phase order is arranged in the same manner as the above-mentioned embodiment, i.e., U, V, W phases in order from the electric power supply region Rin side in the first inverter part50, and the W, V, U phases in order from the electric power supply region Rin side in the second inverter part60.

The arrangement and other matter not mentioned above regarding the electronic components on the substrate241are also the same as the above-mentioned embodiment.

A motor line insertion section244is bored at a radius outside position at a more outer part of the substrate41than that of the first region R1where the elements constituting the first inverter part50on the substrate241are mounted, relative to the center axis O. The motor line135is inserted into the motor line insertion section244, and is connected to the section244by solder or the like.

A motor line insertion section245is bored at a radius outside position at a more outer part of the substrate41than the second region R2where the elements constituting the second inverter part60on the substrate241are mounted, relative to the center axis O. The motor line145is inserted into the motor line insertion section245, and is connected to the section245by solder or the like.

The motor line insertion sections244and245are positioned on a circle C that is centered on the center axis O. That is, the motor lines135and145are arranged on the substrate241on the circle C. In the present embodiment, the motor lines135and145are taken out from the winding groups13and14winding wire of which is wound on the stator212having a ring shape. By arranging the motor line insertion sections244and245on the same circle, the motor lines135and145extend straight from the stator212toward the substrate41, thereby making it easy for the motor lines135and145to be connected to the substrate241.

A hole248is bored at a position corresponding to the substrate fixing part232of the substrate241. A substrate lockscrew49is inserted into the hole248, and is screwed onto the substrate fixing part232of the rear frame end220. Thereby, the substrate241is fixed onto the rear frame end220.

The substrate241has an arc part251having an arc shape and a connector fixing part252disposed on a radius outside of the arc part251. The connector fixing part252has a hole253bored thereon into which a connector lockscrew289is inserted.

The connector fixing part252is positioned outside of the power relays71,72and the reverse connection protection relays73,74on the heat generation element mounting surface242of the substrate241, and the connector280is positioned on the connector fixing part252.

As shown inFIGS. 12-15, the connector280is fixed onto the substrate241by the connector lockscrew289inserted from the electronic component mounting surface243side of the substrate241.

The connector280is made from resin or similar material, is disposed to protrude radially outwardly from the substrate241, and is positioned on the ECU240side facing the rear frame end220within proximity of the connector receiver236, i.e., the connector280is positioned between the rear frame end220and the ECU240. In other words, the connector280is positioned on the ECU240side of the frame part222, near the connector receiver236of the rear frame end220, and more closely describes how the connector280is positioned on the controller side of the frame member.”

In the present embodiment, the connector280is positioned on the heat generation element mounting surface242side of the substrate241, which is beneficial for heat dissipation, because the heat dissipator230can rise up from the rear frame end220by the height of the connector280, expanding a heat dissipation surface area and increasing a heat mass dissipated therefrom. That is, heat generated by the heat generation element70may be efficiently dissipated from the heat dissipator230.

An opening281of the connector280faces outward, and is connectable to a harness incoming from radius outside of the drive device2. Further, the connector280has a terminal282. The terminal282is connected to the substrate241.

The connector280of the present embodiment has a power supply connector283and a signal connector284, which are integrally combined to have one body. The outer periphery of the connector280is formed as a flange285.

A cover member290is made from metallic material, and is formed to have a separate body from the connector280. The cover member290has a top part291and a side wall292formed along the periphery of the top part291, and covers the ECU240, and is fixed onto the rear frame end220by caulking or the like.

The side wall292has a notch293suitably formed to accommodate the connector280. The opening281side of the connector280is thus exposed from the cover member290.

In the present embodiment, the flange285has a motor side face exposed from the cover member290, based on an assumption that the motor10is positioned on a vertically-lower side in the drive device2after installation into the vehicle. By disposing the flange285, water or the like is prevented from intruding into the inside of the drive device2via a connection part between the cover member290and the connector280. Further, water permeated in the inside is transported toward an outside of the drive device2along the flange285.

In the present embodiment, the first motor line135and the second motor line145are arranged on the same circle on the substrate241. Therefore, the connection between the first/second motor lines135,145, which extend from the first/second winding groups13,14, and the substrate241is easily established. Further, the configuration of the present embodiment also achieves the same effects as the above-mentioned embodiment.

Third Embodiment

The third embodiment of the present disclosure is described with reference toFIG. 18.FIG. 18is an illustrative cross section of a drive device3, from which the connector and the like are omitted. Further, a hatching of the SW elements is also omitted.FIGS. 19 and 20also have the same treatment.

An ECU340of the drive device3is different from the above embodiment. The ECU340has a substrate341, a middle member350and a heat sink355arranged in this written order from a motor10side. A heat generation element mounting surface342of the substrate341, which faces the motor10, has the SW elements51-56,61-66mounted thereon. The arrangement of the SW elements51-56,61-66on the surface342is the same asFIG. 10. That is, just like the above-described embodiments, the arrangement of the first motor line135and the SW elements51-56and the arrangement of the second motor line145and the SW elements61-66are reversed to each other in terms of the phase arrangement from the electric power supply region Rin side. In the present embodiment, the heat generation element mounting surface342corresponds to a “one surface”. Further, the reversed side of the substrate341, i.e., a surface343, may also be considered as a “one surface”, and the SW elements51-56,61-66may be mounted on the surface343.

The middle member350includes a board shape part351and a periphery wall part352. The board shape part351is formed substantially in a circular disk shape, and, on one surface of the middle member350facing the substrate341, an electronic component181is mounted. The periphery wall part352stands on the board shape part351to extend toward the heat sink355and toward the substrate341, at least a part of the periphery of the board shape part351. The substrate341and the middle member350are electrically to connected by a wiring pattern or the like. A hole is bored substantially at the center of the substrate341and the middle member350, for having a shaft160inserted thereinto.

A bearing168is disposed substantially at the center of the heat sink355, for supporting the shaft160in a rotatable manner. An electronic component182is arranged on one surface of the heat sink355facing the motor10. The electronic component182is connected with the middle member350by a terminal or the like, which is not illustrated. The electronic components181,182are, for example, a relay, a capacitor, a coil, a microcomputer, an ASIC or the like. The electronic components181,182may be mounted on the substrate341, or on a surface of the board shape part351facing the heat sink355. Even in such configuration, the same effects as the above-described embodiments are achieved.

Fourth and Fifth Embodiments

As shown inFIG. 19, the fourth embodiment of the present disclosure has a drive device4, in which an ECU440is different from the third embodiment. In the fourth embodiment, the SW elements51-56,61-66are arranged on a surface of the board shape part351facing the motor10. In the present embodiment, the board shape part351is considered as a “substrate”. The SW elements51-56,61-66may also be arranged on the other surface of the board shape part351facing the heat sink355.

As shown inFIG. 20, the fourth embodiment of the present disclosure has a drive device5, in which an ECU550is different from the third embodiment. In the fifth embodiment, the SW elements51-56,61-66are arranged on a surface of the heat sink355facing the motor10. In the present embodiment, the heat sink355is considered as a “substrate”.

The heat sink355is not electrically connected with the SW elements51-56,61-66and with the motor lines135,145. The SW elements51-56,61-66may be electrically connected with the middle member350or with the substrate341by a non-illustrated terminal or the like.

Further, even though the SW elements51-56,61-66and the board shape part351are interposed with a gap inFIG. 20, the SW elements51-56,61-66may be electrically connected with the other surface of the board shape part351facing away from the motor10, and may be disposed to dissipate heat to the heat sink355.

The phase order arrangement of the SW elements51-56,61-66and the motor lines135,145on the board shape part351or on the heat sink355is the same as the above-described embodiment. Further, when the electric power supply region Rin is disposed on the substrate341, a projection area of the electric power supply region Rin projected along the shaft of the drive device4or5may be considered as the “reference position”. The electric power supply region may also be disposed on the board shape part351.

InFIGS. 19 and 20, the motor lines135,145extend to reach the board shape part351or to reach the heat sink355. However, (i) the substrate341and (ii) the board shape part351or the heat sink355may be considered as a “substrate”, and the motor lines135,145may be connected with the substrate341. That is, the motor lines135,145do not have to extend to reach the board shape part351or to reach the heat sink355. Even in such configuration, the same effects as the above-described embodiment are achieved.

Further, the substrate341inFIGS. 19, 20and the middle member350inFIG. 20do not have the electronic component, the electronic component such as the capacitor, the coil, the microcomputer, the ASIC and the like may be mounted on the substrate341and the middle member350.

Further, the electronic component arranged on the middle member350or on the heat sink355inFIGS. 18, 19may be omitted.

OTHER EMBODIMENTS

(a) Frame Member

According to the above-mentioned embodiments, the frame member is fixed onto the motor case by the frame lockscrew. According to other embodiments, the frame member may be fixed onto the motor case by using a component other than a screw. Further, the frame member may be fixed onto the motor case by press-fitting. In such manner, the number of components may be reduced. Further, the volume along the radius of the drive device may be reduced.

In the third to fifth embodiments, the frame member is not present. In other embodiments, the drive device having the middle member may have the frame member disposed therein, just like the third to fifth embodiments.

According to the above-mentioned embodiments, the heat generation element may contact the frame member via the heat dissipation gel. According to other embodiment, the heat dissipation gel may be replaced with a heat dissipation sheet, or the heat generation element and the frame member may contact directly.

According to the above-mentioned embodiments, the SW elements have the heat dissipation slug exposed from the mold part. According to other embodiments, the heat dissipation slug may not be necessarily exposed from the SW element. The same applies to the power relay, the reverse connection protection relay, and the ASIC.

According to the above-mentioned embodiments, the drive element, the current detection element, the power relay, the reverse connection protection relay, and the ASIC respectively correspond to the heat generation element, and these heat generation elements are disposed to dissipate heat from their backs to the frame member.

According to other embodiments, the current detection element, the power relay, and the reverse connection protection relay may be mounted on a different surface from the one having the first/second drive elements, or may be omitted. Further, the first/second drive elements may be mounted on an opposite surface of the frame member relative to the rotating electric machine, i.e., on the electronic component mounting surface. In such case, the electronic component mounting surface corresponds to a “one surface”.

Further, the current detection element may be implemented not as the shunt resistor, but as a hall IC etc., and the current detection element may only be provided for two phases or less. That is, the current detection element may be partially omitted. The power relay may be implemented as a mechanical relay.

Further, electronic components other than the above may also be mounted on the heat generation element mounting surface of the substrate as heat generation elements, to be enabled to dissipate heat from their backs toward the frame member.

Further, all or a part of the electronic components mounted on the heat generation element mounting surface may be configured not to dissipate heat toward the frame member.

According to the above-mentioned embodiments, among the electric components constituting the control unit, the ASIC is mounted on the heat generation element mounting surface, and the microcomputer is mounted on the electronic component mounting surface. According to the other embodiments, any electronic component constituting the control unit, i.e., the components other than the ASIC and the microcomputer may be arbitrarily combined to make a package.

Further, the ASIC may be mounted on the electronic component mounting surface, and the microcomputer may be mounted on the heat generation element mounting surface, for example. In other words, the electronic components regarding the control unit may be mounted on either one of the two surfaces, depending on the package configuration and/or the heat generation situation. Further, the microcomputer may be mounted in a non-overlapping region relative to the ASIC. The heat generation element mounting surface and the electronic component mounting surface simply indicate that the heat generation elements or the electronic components may be mountable on those surfaces, which does not necessarily mean that those surfaces should have the heat generation elements or the electronic components mounted thereon.

According to the above-mentioned embodiments, the SW element constituting the first inverter part and the SW element constituting the second inverter part are arranged axi-symmetric in the first embodiment, and the SW element constituting the first inverter part and the SW element constituting the second inverter part are arranged point-symmetric in the second embodiment.

According to other embodiments, the SW elements having the first embodiment configuration may have a point-symmetric arrangement, or the SW element having the second embodiment configuration may have an axi-symmetric arrangement.

Further, the SW element may also be arranged arbitrarily, i.e., not necessarily be in a symmetrical arrangement.

Further, the electronic components other than the SW element may also be arranged arbitrarily.

Further, according to the above-mentioned embodiments, the phase order in the first system is U, V, W from the near side of the electric power supply region, and the phase order in the second system is W, V, U from the near side of the electric power supply region. According to other embodiments, the phase order in the first system may be arbitrarily ordered, i.e., not necessarily be U, V, W order from the electric power supply region side. In other words, the first, second, and the third phases may respectively be any one of U, V, W phases. Further, the phase order in the second system may be in the reverse order of the first system. In such manner, the influence of the magnetic flux leakage on the rotational angle sensor may be reduced, just like the above-mentioned embodiments due to the cancellation of the leakage with each other. Further, the variation of the wiring impedance among the different phases may be reduced.

Further, the phase orders in the first extension line and the first drive element as well as the second extension line and the second drive element may be reversed with reference to other position other than the electric power supply region.

According to the above-mentioned embodiments, the first and second extension lines are arranged in a point-symmetric manner. According to other embodiments, the arrangement of the first and second extension lines may be other than point-symmetric. Further, at least one of the first and second extension lines may have no symmetric arrangement, i.e., may only have one side of a symmetric, both side arrangement. Furthermore, the first extension line may be disposed on the substrate at other position other than the radius outside position of the first region. Similarly, the second extension line may be disposed on the substrate at other position other than the radius outside position of the second region.

According to the above-mentioned embodiments, the elements are arranged, from the center axis side toward the radius outside, in an order of the high potential side elements, the low potential side elements, and the current detection elements. According to other embodiments, the element arrangement may be other orders other than the above, i.e., may be in a low potential side elements first order from the center axis side, or any other orders. Further, the current detection elements may be partially omitted, i.e., the current detection elements may be provided only for the two phases among the three.

According to the above-mentioned embodiments, the first distance from the center of the electric power supply region to the center of the first region and the second distance from the center of the electric power supply region to the center of the second region are substantially the same. According to other embodiments, the first distance and the second distance may be not necessarily the same. For example, the electric power supply region may be defined as an area close to a mounting position of the reverse connection protection relay73inFIG. 11. In such case, the “electric power supply region” may be defined flexibly as an inclusive area extending from an inverter side to an away-from-inverter side, including the power supply wiring pattern, and the phase order of the first system and the second system may be arranged with reference to the above-described electric power supply region, i.e., from the electric power supply region side to the away side in an order of the first, the second and the third phase in the first system and in an order of the third, the second, and the first phase in the second system. Even in such configuration, the variation of the impedances in different phases is reduced in comparison to the other phase order arrangement.

According to the first embodiment, the metal piece used for connection to the motor line is mounted on the substrate, and the substrate and the motor line are connected by press-fitting. Further, in the second embodiment, the substrate and the motor line are connected by soldering or the like.

According to other embodiments, the substrate and the motor line in the first embodiment configuration may be connected by solder, or the substrate and the motor line in the second embodiment configuration may be connected by the press-fitting of the metal piece that is disposed on the substrate, for example. Further, the connection between the substrate and the motor line may be established by any method other than soldering or press-fitting.

According to the above-mentioned embodiments, the substrate is fixed onto the substrate by using the substrate lockscrew. In other embodiments, the substrate may be fixed onto the substrate not only by using a screw thread but by any other method.

According to the first embodiment, the connector comprises one power supply connector and two signal connectors. According to other embodiments, one or both of the power supply and signal connectors may be provided two sets or more. Those connectors may have separate bodies as in the first embodiment, or may have an integrated body as in the second embodiment.

Further, when no motor case is provided as shown in the second embodiment, the stator may serve as the “rotating electric machine” and the connector may be positioned within the projection area of the stator along the axial direction. Further, based on an assumption that the connector and the cover member are provided as separate bodies, the connector may be fixed onto the large-size component mounting surface of the substrate (i.e., on an opposite side relative to the motor).

Further, the number of connectors, the orientation of the opening of the connector, and the cover member arrangement as to having one body with the connector or not, may all be arbitrarily combined in configuration.

(d) Cover Member

According to the first embodiment, the cover member is fixed onto the frame member with adhesives. According to the second embodiment, the cover member is caulked to the frame member. The cover member may be fixed onto the frame member by any other method such as fixing by using a screw or the like.

(e) Drive Unit

According to the above-mentioned embodiments, the rotating electric machine is a three-phase brushless motor. According to other embodiments, the motor may be any kind, i.e., not necessarily the three-phase brushless motor but any kind of motor having three or more phases.

Further, the rotating electric machine may be not only a motor (i.e., an electric motor) but a generator, and may also be a motor-generator having a motor function and a generator function.

According to the above-mentioned embodiments, the output end connected to the gear is disposed on an opposite side of the ECU relative to the motor. In other words, the drive device in the above-mentioned embodiments, the output end, the motor, and the ECU are arranged in this written order.

According to other embodiments, the output end may be arranged on the same side relative to the motor. In other words, the output end, the ECU and the motor may be arranged in this written order in other embodiments.

According to the above-mentioned embodiments, the drive device is applied to an electric power steering device. According to other embodiments, the drive device may be applied to a device other than the electric power steering device.

Such changes, modifications, and summarized schemes are to be understood as being within the scope of the present disclosure as defined by appended claims.