Motor drive control for a vehicle

Abstract

A motor drive control (10) for a vehicle, comprising: a motor (12) having a rotary body (22) which rotates due to an applied magnetic field generated by the voltage applied to the windings (26), a drive shaft (14) formed integrally with the rotary body, and a bearing member (15A) which holds the drive shaft so that the drive shaft rotates freely; a circuit board (18) on which a circuit is mounted which generates the voltage applied to the windings, the circuit board having a ground region (54); a heat dissipating element (20) which dissipates the heat of the circuit board and is electrically connected to the grounding region of the circuit board; a support member (32) holding the circuit board and the bearing member and having an insulating surface; and an electrically conductive member (32A) disposed on the surface of the support member, which grounds the rotating body, the drive shaft, and the bearing member by electrically connecting the bearing member and the heat-dissipating member.

Description

BACKGROUNDField of the invention

[0001] The present disclosure relates to a motor drive control for a vehicle. Related technology

[0002] A motor drive controller that controls the rotation of a motor converts a sinusoidal signal into a rectangular signal using a circuit such as a comparator or the like. For example, when a Hall sensor sends a sinusoidal signal corresponding to a magnetic field that changes according to the rotation of the motor's drive shaft, the motor drive controller calculates the rotational position of the drive shaft by detecting the point where the rectangular signal changes from a high level to a low level or from a low level to a high level.

[0003] A circuit such as a comparator or the like that converts an analog signal into a digital signal converts an analog signal into a rectangular digital signal by comparing the analog signal with a threshold having a predetermined voltage value.

[0004] When controlling the voltage applied to the motor windings, the calculation section of the motor drive controller also calculates the duty cycle of the square wave in relation to the voltage applied to the motor windings by comparing a control voltage and a counter value whose voltage fluctuates in a regular rhythm.

[0005] Accordingly, if the potentials of the sensor and the calculation range of the motor drive controller do not match, there is a possibility that problems may occur in the operation of the motor drive controller, such as converting a sinusoidal signal into a rectangular signal, so that the calculation of the duty cycle of the voltage applied to the motor and the like cannot be carried out normally.

[0006] In some cases, the motor drive controller is formed integrally with the motor main body. In such cases, it is desirable that the potential of the motor, except at the points where voltage is applied, such as the motor windings or the like, and the potential of the motor drive controller's calculation area be the same.

[0007] Japanese Laid-Open Patent Application JP 2001 - 251 833 A discloses a brushless motor that equalizes the potentials of the motor, except at the points where voltage is applied, and the potential of the motor drive controller by electrically connecting a yoke structuring the exterior of the motor, the drive shaft of the motor, and a bearing portion of the drive shaft to a grounding portion of the circuit board.

[0008] Japanese Patent Application Laid-Open No. JP 2014-60206 A discloses a motor unit with a rotor. Coils generate a rotating magnetic field, which rotates the rotor. The current flow to the coils is controlled by a drive control circuit mounted on a substrate. The substrate is connected to a heat sink that dissipates heat generated by the elements mounted on the substrate. Furthermore, conductors are provided to shield electromagnetic interference emanating from the elements mounted on the substrate. SUMMARY

[0009] However, according to the arrangement disclosed in JP 2001-251833 A, the yoke and the bearing portion are electrically connected to the grounding portion of the circuit board by means of a shield plate, which is a metal plate arranged on the inner wall surface of an upper case, as well as clip members and a bus bar for wiring. The elements constituting the shield plate, the clip members, the bus bar for wiring, and the like are required, and the path by which the yoke is electrically connected to the grounding portion of the circuit board is complex.

[0010] In view of the above circumstances, an object of the present disclosure is to provide a motor drive controller for a vehicle that can achieve equalization of the potentials of their respective portions by a simple structure.

[0011] A motor drive controller for a vehicle according to a first aspect comprises: a motor having a rotating body that rotates by the application of a magnetic field generated by a voltage applied to the windings, a drive shaft formed integrally with the rotating body, and a bearing member that supports the drive shaft so that it rotates freely; a circuit board on which a circuit that generates the voltage applied to the windings is mounted and which has a grounding portion; a heat-dissipating member that dissipates heat from the circuit board and is electrically connected to the grounding portion formed on the circuit board; a support member that supports the circuit board and the bearing member and whose surface is insulating;and an electrically conductive member disposed on the surface of the support member, which, by electrically connecting the bearing member and the heat-dissipating member, grounds the rotating body, the drive shaft, and the bearing member;

[0012] According to the first aspect, the electrically conductive member electrically connecting the bearing member of the motor and the grounded heat dissipating member is arranged on the insulating surface of the support member.

[0013] The electrically conductive element may be a thin metal plate arranged on the surface of the support member or a metal plating applied to the surface of the support member. Therefore, the present disclosure can provide a motor drive controller for a vehicle that balances the potentials of its respective regions through a simple structure.

[0014] A motor drive controller for a vehicle according to a second aspect is the motor drive controller for a vehicle of the first aspect, wherein the support member has a support member holding portion that holds the support member, a first end of the electrically conductive member extends to an inner wall of the support portion of the support member and is in circumferential contact with a side surface of the support member, and when the circuit board on which the heat-dissipating member is mounted is held by the support member, a second end of the electrically conductive member is in contact with the heat-dissipating member.

[0015] Since the first end of the electrically conductive element according to the second aspect has surface contact with the side surface of the bearing element in the circumferential direction, the rotating body, the drive shaft and the bearing element of the motor can be reliably electrically connected.

[0016] A motor drive controller for a vehicle according to a third aspect is the motor drive controller for a vehicle of the second aspect, wherein the inner wall of the holding portion of the bearing member has a recess that holds the bearing member, and the first end of the electrically conductive member is housed in the recess of the holding portion of the bearing member.

[0017] According to the third aspect, the first end of the electrically conductive element is accommodated in the recess of the holding portion of the bearing element. Accordingly, the first end of the electrically conductive element has planar contact with the side surface of the bearing element in the circumferential direction.

[0018] A motor drive controller for a vehicle according to a fourth aspect is the motor drive controller for a vehicle of the second aspect or the third aspect, wherein the heat dissipating member has a portion opposing the support member when the circuit board on which the heat dissipating member is mounted is held by the support member, and when the circuit board on which the heat dissipating member is mounted is held by the support member, the second end of the electrically conductive member is sandwiched between the support member and the portion of the heat dissipating member opposing the support member.

[0019] According to the fourth aspect, since the other end of the electrically conductive member is clamped between the support member and the heat-dissipating member, the electrical connection between the rotating body, the drive shaft, and the bearing member of the motor, as well as between the electrically conductive member and the grounded heat-dissipating member, can be reliably established. Consequently, the rotating body, the drive shaft, and the bearing member of the motor can be grounded.

[0020] A motor drive controller for a vehicle according to a fifth aspect is the motor drive controller for a vehicle of any one of the first to fourth aspects, wherein a potential of the grounding portion of the circuit board is a ground potential because a connector member is electrically connected to the grounding portion.

[0021] According to the fifth aspect, the grounding region of the circuit board is grounded via the connector element electrically connected to the grounding region. Consequently, the potentials of the rotating body, the drive shaft, the bearing element, the electrically conductive element, the heat-dissipating element, and the grounding region of the circuit board can be released, thus balancing the potentials of the respective regions. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view showing a motor drive controller for a vehicle according to an embodiment in a disassembled state. Fig. 2 is a cross-sectional view showing a cross section of the motor drive controller for a vehicle according to the embodiment along the axial direction of a motor. Fig. Figure 3 is a drawing showing the upper case from one side where a printed circuit board is mounted. Fig. 4 is a drawing of an example of a grounding region which is a ground potential on the circuit board according to the embodiment. Fig. Figure 5 is a schematic diagram of the connection of the circuit board and a heat sink. Fig. Figure 6 is a schematic diagram of an example of the side of the heat sink mounted on the circuit board. DETAILED DESCRIPTION

[0022] Based on the Fig. 1 to 6, a motor drive control for a vehicle according to one embodiment is described below. As shown in Fig. 1 and Fig. 2, a motor drive controller 10 for a vehicle according to the present embodiment is, for example, a unit of a blower motor that blows air by means of an air conditioner installed in a vehicle. Specifically, the motor drive controller 10 for a vehicle includes a motor 12 that rotates a drive shaft 14 about its axis, and a motor drive controller 34 that includes a circuit 16 that controls the rotation of the motor 12, a circuit board 18, and a heat sink 20 that dissipates heat from the circuit 16. Here, the motor drive controller 10 for a vehicle, the motor 12, and the motor drive controller 34 that controls the rotation of the motor 12 are integrally formed. (Engine 12)

[0023] The motor 12 comprises the following main components: a drive shaft 14, a rotor 22 and a stator 24.

[0024] The drive shaft 14 is made of a cylindrical steel material by means of a surface treatment such as carbonization or the like. The drive shaft 14 is axially supported by a lower bearing member 15A and an upper bearing member 15B, allowing it to rotate freely.

[0025] The rotor 22 is in the shape of a cylindrical tube having a bottom and one end open; it further includes a disc-shaped bottom wall 22A and a curved peripheral wall 22B extending from the outer peripheral end of the bottom wall 22A to one end side of the rotor 22. Furthermore, an insertion hole 22C into which the drive shaft 14 is inserted is formed in a central portion of the bottom wall 22A. Since the drive shaft 14 is press-fitted into the insertion hole 22C, the rotor 22 and the drive shaft 14 can rotate integrally. A rotor magnet 23 is arranged on the inner side of the peripheral wall 22B.

[0026] The stator 24 also includes electrically conductive windings 26 wound around an annular stator core 28. The stator 24 is arranged radially on the inner side of the peripheral wall 22B of the rotor 22. The rotor 22 receives the magnetic field generated by the stator 24 and rotates together with the drive shaft 14. Specifically, the stator 24 is an electromagnet whose windings 26 are wound around core elements 30 that form the stator core 28 and that includes three phases—a U phase, a V phase, and a W phase. The U phase, the V phase, and the W phase of the stator 24 each generate a so-called rotating magnetic field because the polarity of the magnetic field generated by the electromagnet changes under the control of the motor drive controller 34, which will be described below. In addition, the stator 24 is attached to the motor drive control 34 by means of an upper housing 32 serving as a housing. (Printed circuit board 18 and switching element 16)

[0027] The circuit board 18 has a rectangular shape and, together with the switching element 16 and the heat sink 20 described below, forms the motor drive control 34 (a switching circuit). A connector 38, to which a control device such as an ECU (Electronic Control Unit) or the like is connected via a wiring harness and a connector, is mounted on the circuit board 18. Furthermore, an inverter circuit that switches the power source voltage and generates voltage applied to the windings 26 of the respective phases of the stator 24 of the motor, and a microcomputer that controls this inverter circuit based on command signals from the ECU, and the like are mounted on the circuit board 18.

[0028] The inverter circuit is formed by a FET (field-effect transistor), a switching element. Since the heat generated by the FET during operation is considerable, the heat sink 20, which is a heat-dissipating element, is arranged near the location on the circuit board 18 where the inverter circuit is mounted.

[0029] Since a lower housing 48 serving as a housing is attached to the upper housing 32, the printed circuit board 18, as shown in Fig. 2, is housed between the lower housing 48 and the upper housing 32. (Heat sink 20)

[0030] The heat sink 20 is made of a metal with good thermal conductivity, such as aluminum or the like, and has a substantially rectangular shape when viewed from the thickness direction of the circuit board 18. Furthermore, a plurality of projections 52 are formed along the longitudinal direction of the heat sink 20 at one end in the direction of the short side of the heat sink 20. The projections 52 are cylindrical and protrude beyond the circuit board 18. Due to this plurality of projections 52, the area of the heat sink 20 is increased, so that the heat dissipation performance of the heat sink 20 is improved. When the circuit board 18, as shown in Fig. 2, is housed between the lower housing 48 and the upper housing 32, the projections 52 are exposed with respect to the upper housing 32.

[0031] As in Fig. 1, the heat sink 20 is designed such that the end portion located on the opposite side of the projections 52 is higher than the circuit board 18 when mounted on the circuit board 18. This end portion of the heat sink 20 is the area facing the upper housing 32 when the end portion, together with the circuit board 18, is held by the upper housing 32 and the lower housing 48 described below. This end portion of the heat sink 20 is thus the area that contributes to the circuit board 18 being held by the upper housing 32 and the lower housing 48 without touching the surface of the upper housing 32.Since the circuit board 18 is held by the heat sink 20 facing the upper case 32, it is not necessary to clamp the circuit board 18 using elements that have the elastic force of a spring, such as clips or the like. Consequently, unnecessary stress on the circuit board 18 is prevented, and thus damage to the circuit board 18 can be prevented.

[0032] As described below, the heat sink 20 is electrically connected to the grounding region of the circuit board 18, and the potential of the heat sink 20 is maintained at the same level as that of the grounding region of the circuit board 18. (Upper housing 32, lower housing 48 and electrically conductive plate 32A)

[0033] The upper housing 32 and the lower housing 48 are components for accommodating the printed circuit board 18 in the space formed by joining the upper housing 32 and the lower housing 48. In the present embodiment, the printed circuit board 18 on which the heat sink 20 is mounted is as shown in Fig. 1 and Fig. 2, is assembled with the upper housing 32 when it is housed in the lower housing 48, the upper housing 32 and the lower housing 48 being connected by means of the Fig. 2 are fastened with the fastening screws 64 shown.

[0034] In consideration of the problem that the surfaces of the upper housing 32 and the lower housing 48 may contact the circuit board 18, these surfaces are integrally formed from an insulating material such as a synthetic resin or the like, or from a core member made of a metal such as an iron alloy such as steel or the like, or a light metal or a copper alloy such as brass, and coated with a synthetic resin or the like. Furthermore, the upper housing 32 has a lower support member holding portion 40 that holds the circuit board 18 on one side and the lower support member 15A at its central portion. The lower support member holding portion 40 is a portion in the shape of a cylindrical tube that projects toward the side of the lower housing 32 to which the motor 12 is mounted.Since an inner wall of the lower bearing member holding portion 40 has a circular opening in which the lower bearing member 15A is housed, the inner wall of the lower bearing member holding portion 40 forms a recess 70 that accommodates the lower bearing member 15A. When the lower bearing member holding portion 40 can hold the lower bearing member 15A, it may be shaped like a polygonal column having a polygonal opening portion, rather than the cylindrical tube having a circular opening.

[0035] As in the Fig. 2 and Fig. 3, according to the present embodiment, on the surface of the upper case 32 from the lower support member 15A to the area where the heat sink 20 faces the upper case 32, an electrically conductive plate 32A formed of a metal plate or by metal plating or the like is arranged.

[0036] As in Fig. 2, the electrically conductive plate 32A is arranged on the underside of the upper housing 32, that is, on the side that forms the space in which the printed circuit board 18 is housed. One end 32A1 of the electrically conductive plate 32A is housed in the recess 70 of the holding portion 40 of the lower bearing member and is in circumferential contact with the side surface of the lower bearing member 15A because it extends to an inner wall 40A of the holding portion 40 of the lower bearing member. The other end 32A2 of the electrically conductive plate 32A is clamped between one end portion 20A of the heat sink 20 and the upper housing 32 when the upper housing 32 and the lower housing 48 are joined by means of the fastening screws 64, with the printed circuit board 18 to which the heat sink 20 is attached being clamped therebetween. As a result, the lower bearing element 15A and the heat sink 20 are electrically connected to each other.The lower bearing member 15A is in contact with the drive shaft 14, which is integrally formed with the rotor 22. Therefore, the rotor 22, the drive shaft 14, the lower bearing member 15A, the electrically conductive plate 32A, and the heat sink 20 are electrically connected according to the present embodiment.

[0037] The lower bearing member 15A is, for example, a radial ball bearing or the like and is made of an iron alloy except for the seal that prevents the grease, ie the encapsulated lubricant, from flowing out, and is electrically conductive from its central portion, which is fixed to the drive shaft 14, to a side surface in the circumferential direction.

[0038] Fig. 3 is a view (a bottom view) in which the upper case 32 is seen from a side on which a printed circuit board 18 is mounted. As in Fig. 3, the portion of the electrically conductive plate 32A that is clamped by and in contact with the heat sink 20 is as large as the dimensions of the upper case 32 and the heat sink 20 allow, while being reliably in electrical contact with the heat sink 20.

[0039] It should be noted that if the Fig. 2 has contact with a location other than the grounding area of the circuit board 18, the circuit on the circuit board 18 will short-circuit, therefore the electrically conductive plate 32A must be mounted so that it does not directly touch the circuit board 18. In the Fig. 2, the electrically conductive plate 32A is mounted with a gap that ensures the insulation between the electrically conductive plate 32A and the circuit board 18. However, if it is difficult to establish the gap between the electrically conductive plate 32A and the circuit board 18 as shown in Fig. 2, which ensures the insulation capacity, can be used at the points shown in Fig. 3, where there is a possibility of contact with the circuit board 18, a resin or paint which is insulating may be provided.

[0040] Since the upper bearing element 15B is located near the windings 26 of the stator 24 to which voltage is applied, it may be covered by a cylindrical sleeve 15C made by plastic technology or the like, which is insulating and stable, in order to ensure insulation between the upper bearing element 15B and the windings 26.

[0041] As in Fig. 2, the electrically conductive plate 32A is arranged on the underside of the upper housing 32, that is, on the side that forms the space in which the printed circuit board 18 is housed. However, the electrically conductive plate 32A may be arranged on the top side of the upper housing 32, wherein one end 32A1 of the electrically conductive plate 32A may be in contact with the lower support member 15A and the other end 32A2 of the electrically conductive plate 32A may be in contact with the heat sink 20. When the other end of the electrically conductive plate 32A extends so as to be bent back from the top side to the bottom side of the upper housing 32, this other end 32A2 is clamped between the upper housing 32 and the end portion of the heat sink 20 that is opposite to the upper housing 32. (Grounding area 54A of the circuit board 18 and heat sink 20)

[0042] Fig. Figure 4 is a drawing of an example of a grounding region 54A, which is a ground potential on the circuit board 18 according to the present embodiment. Fig. 4, the grounding portion 54A is arranged on the rear side, on the side where the FET and the like, which generate considerable heat, are mounted. The grounding portion 54A is connected to a grounding terminal 38N of the connector 38 by means of a clamp terminal 54N and a connecting terminal 38N1. The grounding terminal 38N of the connector 38 is grounded to the vehicle main body through a wire harness. The clamp terminal 54N may be a via or a connecting member such as a rivet, screw, or the like, which electrically and mechanically connects the grounding portion 54 to the connecting terminal 38N.

[0043] As in Fig. As shown in Figure 4, by making the grounding portion 54A flat, the surface area of the portion for the heat sink 20 to make surface contact with the circuit board 18 can be increased, allowing the heat sink 20 to be stably mounted on the circuit board 18. Near a central portion of the circuit board 18, a drive shaft connecting portion 14A is provided, to which the drive shaft 14 is connected. Power supply terminals 36A, 36B, 36C, which supply power to the respective U-phase, V-phase, and W-phase windings 26 of the stator 24, are arranged at the outer periphery of the drive shaft connecting portion 14A.

[0044] Fig. Figure 5 is a schematic diagram of the connection of the circuit board 18 and the heat sink 20. The heat sink 20 has projections 56 and 58 that protrude further on the side mounted on the circuit board 18 than the other portions of the heat sink 20.

[0045] The protrusions 56 and 58 abut flatly against the grounding region 54A of the circuit board 18. The heat sink 20 is fixed to the circuit board 18 by means of a fastening screw 50 in a state in which the protrusions 56 and 58 abut against the grounding region 54A of the circuit board 18. It is desirable that the tip portions of the protrusions 56 and 58, particularly the tip portion of the protrusion 56, which has a large surface area, be flat so that they abut parallel and flat against the grounding region 54A of the circuit board 18.

[0046] An insulating member 62 is provided between the heat sink 20 and the area of the circuit board 18, except where the projections 56 and 58 abut. This insulating member 62 may be, for example, an insulating silicone grease or silicone resin that is gel-like at normal temperature and hardens due to the heat generation by components such as the FET and the like, or a rigid insulating material made of rubber or resin or the like that is flexible.

[0047] The circuit board 18 has a grounding region 54B on one side, namely the back of the side on which the FET and the like, ie the heat sink 20 and the grounding region 54A, are arranged. As shown in Fig. 5, the grounding portion 54B is electrically connected to the heat sink 20 and the grounding portion 54A by a metal fastening screw 50. The grounding portion 54B may be electrically connected to the grounding terminal 38N of the connector 38 by means of the clamping terminal 54N and the connecting terminal 38N1, or a component similar to the clamping terminal 54N and the connecting terminal 38N1. The grounding portion 54B is electrically connected to the grounding terminal 38N through the heat sink 20 and the grounding portion 54A, or through the clamping terminal 54N and the connecting terminal 38N1, or a component similar to the clamping terminal 54N and the connecting terminal 38N1. The grounding portion 54B is connected to the vehicle main body via a wire harness connected to the grounding terminal 38N.

[0048] Fig. 6 is a schematic diagram of an example of the side of the heat sink 20 mounted on the circuit board 18. The projections 56 and 58 are formed at locations corresponding to the four corners of the substantially rectangular surface and abut the grounding region 54A of the circuit board 18.

[0049] In Fig. 6, the hatched area is the area where the insulating element 62 is provided. When the heat sink 20 is mounted at a predetermined position on the circuit board 18, the Fig. 6 hatched area sections corresponding to the locations where the FETs 41A and 41B and the like are mounted (see Fig. 5), which form the inverter circuit, on the back, ie the side where the FETs 41A and 41B and the like are mounted.

[0050] In order to achieve both insulation and heat dissipation between the circuit board 18 and the heat sink 20, in the present embodiment the dimension A of the space into which the insulating element 62 is filled (see Fig. 5), ie the thickness of the insulating element 62, is optimized.

[0051] The thickness of the insulating member 62 depends on factors such as the height of the protrusions 56 and 58, the curvature of the circuit board 18, the thermal deformation of the circuit board 18, the flatness of the protrusions 56 and 58, and the like. According to the present embodiment, the thickness of the insulating member 62 should preferably be such that reliable heat dissipation is achieved while ensuring insulation. (Functionality and effects of the present design)

[0052] The functionality and effects of this design are described below.

[0053] As in Fig. 2 and Fig. 3, in the motor drive controller 10 for a vehicle according to the present embodiment, the electrically conductive plate 32A is disposed on the surface of the upper case 32, and the lower bearing member 15A disposed on the drive shaft 14 and the heat sink 20 are electrically connected to each other through the electrically conductive plate 32A. The lower bearing member 15A, the drive shaft 14, and the rotor 22 are each made of metal, the lower bearing member 15A is disposed on the drive shaft 14, and the drive shaft 14 is integrally formed with the rotor 22. Accordingly, the rotor 22, the drive shaft 14, and the lower bearing member 15A are electrically connected to each other in the present embodiment.

[0054] The heat sink 20 is connected to the grounding area 54A and 54B provided on the circuit board 18 ( Fig. 5) are electrically connected. The grounding portions 54A and 54B of the circuit board 18 are electrically connected to the grounding terminal 38N of the connector 38 through the circuit pattern on the circuit board 18, the terminal block 54N, and the connecting terminal 38N1. Furthermore, the grounding terminal 38N of the connector is grounded to the vehicle body via the wire harness.

[0055] Accordingly, the electrical connection of the rotor 22, the drive shaft 14, the lower bearing member 15A, the electrically conductive plate 32A, the heat sink 20, the grounding portion 54A and 54B, and the grounding terminal 38N of the connector 38 is possible according to the present embodiment. For example, the potential accumulated on the rotor 22 can be grounded from the grounding terminal 38N of the connector 38 via the wire harness to the vehicle main body. Consequently, according to the present embodiment, a potential difference occurring on the rotor 22 or the drive shaft 14 with respect to the circuit board 18 is eliminated by the current 60 flowing in Fig. 2 is marked by the arrows, and an equalization of the potentials of the respective areas of the device can be achieved.

[0056] According to the present embodiment, the electrical connection from the rotor 22 to the ground terminal of the connector 38, as described above, is made possible by disposing the electrically conductive plate 32A, which is a thin metal plate or a metal plating, on the surface of the upper housing 32 made of insulating material.

[0057] When the upper case 32 and the lower case 48 are joined together, the circuit board 18 is fixed at a predetermined location within the space formed inside the upper case 32 and the lower case 48. Since the circuit board 18 is not fixed by means of members such as clip members that stress the circuit board 18, damage to the circuit board 18 can be prevented.

[0058] The electrically conductive plate 32A, which ensures the electrical connection between the lower support member 15A and the heat sink 20, is a simple structure made of a thin metal plate or formed by metal plating and arranged along the surface of the upper case 32. When the upper case 32 and the lower case 48 are fastened by the fastening screws 64, with the circuit board 18 on which the heat sink 20 is mounted sandwiched between the upper case 32 and the lower case 48, the electrically conductive plate 32A is electrically connected by being sandwiched between the heat sink 20 and the upper case 32. Therefore, the electrically conductive plate 32A can be used inexpensively and easily for the motor drive controller 10 for a vehicle according to the present embodiment.

[0059] As in the Fig. 2 and Fig.3, the location of the electrically conductive plate 32A that is clamped by and in contact with the heat sink 20 is as large as the dimensions of the upper housing 32 and the heat sink 20 allow. According to the shape of the surface of the upper housing 32, one end of the electrically conductive plate 32A that is in contact with the lower bearing element 15A extends to the inner wall of the opening-shaped holding portion 40 of the lower bearing element, in which the lower bearing element 15A is housed. Consequently, it is ensured that the contact area of the heat sink 20 and the electrically conductive plate 32A, as well as the contact area of the electrically conductive plate 32A and the lower bearing element 15A, are sufficiently large, and that the electrical connection from the rotor 22 via the drive shaft 14, the lower bearing element 15A, and the electrically conductive plate 32A to the heat sink 20 is reliable.The electrical connection from the heat sink 20 via the circuit board 18 to the ground terminal 38N is also reliable.

[0060] As described above, according to the present embodiment, a motor drive controller for a vehicle can be provided that achieves equalization of the potentials of the respective regions by a simple structure.

[0061] Note that the rotor 22 of the present embodiment corresponds to the rotating body of the claims. Furthermore, the lower bearing member 15A corresponds to the bearing member, the heat sink 20 corresponds to the heat dissipating member, the upper housing 32 corresponds to the support member, the electrically conductive plate 32A corresponds to the electrically conductive member, and the holding portion 40 of the lower bearing member corresponds to the holding portion of the bearing member.

Claims

[1] A motor drive control (10) for a vehicle, comprising: a motor (12) having a rotary body (22) which rotates due to an applied magnetic field generated by the voltage applied to the windings (26), a drive shaft (14) formed integrally with the rotary body, and a bearing member (15A) which holds the drive shaft so that the drive shaft rotates freely; a circuit board (18) on which a circuit is mounted which generates the voltage applied to the windings, the circuit board having a ground region (54); a heat dissipating element (20) which dissipates the heat of the circuit board and is electrically connected to the grounding region of the circuit board; a support member (32) holding the circuit board and the bearing member and having an insulating surface; and an electrically conductive member (32A) disposed on the surface of the support member, which grounds the rotating body, the drive shaft, and the bearing member by electrically connecting the bearing member and the heat-dissipating member. [2] A motor drive control system for a vehicle according to claim 1, wherein the Support element has a holding section (4) for the bearing element, which holds the bearing element, and a first end of the electrically conductive element extends to an inner wall of the holding portion of the bearing element and has surface contact with the side surface of the bearing element in the circumferential direction, wherein a second end of the electrically conductive element has contact with the heat-dissipating element when the circuit board on which the heat-dissipating element is mounted is held by the support element. [3] A motor drive control system for a vehicle according to claim 2, wherein: the inner wall of the holding section of the bearing element has a recess (70) in which the bearing element is accommodated, wherein the first end of the electrically conductive element is accommodated in the recess of the holding portion of the bearing element. [4] A motor drive control for a vehicle according to claim 2 or claim 3, wherein: the heat-dissipating element has a region which is opposite to the support member when the circuit board on which the heat-dissipating element is mounted is held by the support member, and when the circuit board on which the heat-dissipating element is mounted is held by the support member, the second end of the electrically conductive element is clamped between the support member and the portion of the heat-dissipating element opposite the support member. [5] A motor drive controller for a vehicle according to any one of claims 1 to 4, wherein a potential of the grounding portion (18) of the circuit board is a ground potential since a connector member is electrically connected to the grounding portion (18).

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