JP4932310B2 - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor integrated with an ECU in which the reduction of the number of components, the reduction of the number of assembling processes, and cost reduction can be achieved. <P>SOLUTION: This electric motor is configured to have a control board 40 on which a drive circuit for controlling the supply of drive currents to motor coils is formed, a board holding portion 20 that is formed integrally with a housing 10 structuring a motor casing to hold the control board 40, and coil terminals 16 of the motor coils connected and fixed directly to the control board 40. By this configuration, the electric motor integrated with the ECU can be obtained in which the reduction of the number of components, the reduction of the number of assembling processes, and cost cut can be achieved. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an electric motor used for, for example, an electric power steering apparatus.

An electric power steering apparatus includes an electric motor that generates an auxiliary torque for a steering wheel of a vehicle, an electronic control unit (ECU: Electric Control Unit) that controls the driving of the electric motor, a battery that supplies a driving current of the electric motor, a steering It comprises a torque sensor that detects the steering torque of the wheel, a wire harness that electrically connects the electric motor and the ECU, a connector, and the like.
In the electric power steering apparatus as described above, a wire harness, a connector, and the like are necessary, and there is a problem that the number of parts and the number of assembly steps increase.
Various technologies have been proposed in the technical field of electric power steering devices and other fields in which an ECU is integrally provided in an electric motor to reduce the number of parts and assembly steps and to reduce the size of the device. (See, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 10-234158 JP 2000-23408 A

By the way, Patent Document 1 discloses a technique of electrically connecting a substrate on which a power transistor is mounted to a motor coil via a power supply terminal made of a conductive rod-shaped member to make it cordless. Since it is held at the tip, it is difficult to stably support the substrate, and assembly work is not easy.
In the technique disclosed in Patent Document 2, since the case for holding the substrate is formed integrally with the member constituting the motor casing, it is possible to reduce the number of parts, the number of assembly steps, and the like. However, even in the technique disclosed in Patent Document 2, it is necessary to fix the substrate to a power supply bar for electrically connecting the substrate to the brush with solder or the like, and the substrate positioning operation or assembly operation is not easy.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric motor integrated with an ECU capable of reducing the number of parts, the number of assembly steps, and the cost. It is to provide.

An electric motor according to the present invention has a control board on which a drive circuit for controlling the supply of drive current to a motor coil is formed, and a contact portion where a heating element constituting a part of the drive circuit makes surface contact. A board holding part that is integrally formed with the motor casing and holds the control board, and a terminal of the motor coil is directly connected and fixed to the control board, and the contact part is the board. It is characterized by being thicker than the other part of the holding part .
According to this configuration, since the control board is directly connected and fixed to the motor coil terminal, there is no need for a connector or a cable between the motor coil and the control board, reducing the number of parts and the number of assembly steps. The control board is connected to the motor coil terminal while being held by the board holding part formed integrally with the casing, so that the control board can be positioned and assembled. Work becomes easy.

In the above configuration, the motor casing includes a housing that supports one end of the motor rotation shaft and a bracket that supports the other end of the motor rotation shaft, and the bracket is provided at one end of the housing in the axial direction. The bracket may be formed integrally with the substrate holding part .

The said structure WHEREIN : The structure which earth | grounds the said motor casing, the said board | substrate holding | maintenance part, and the said board | substrate for control to a ground level is employable .
According to this configuration, noise can be reduced .

In the above configuration, it is possible to adopt a configuration in which the terminal of the resolver incorporated in the motor casing is directly connected and fixed to the control board.
According to this configuration, connectors and wiring can be omitted for the resolver, and the number of assembly steps can be reduced.

The said structure WHEREIN: The structure which has penetrated the board | substrate for control is employable.
According to this configuration, the terminal can be easily fixed to the control board with solder or the like.

The said structure WHEREIN: The structure which has an electrically insulating support member which supports a terminal in the position which can be directly connected with the board | substrate for control is employable.
According to this configuration, the control board and each terminal can be reliably connected.

In the above configuration, the motor casing and the substrate holding part are fixed to the cover to cover the control substrate, the control substrate has a through hole through which the motor rotation shaft passes, and the cover can freely rotate the motor rotation shaft. The structure which forms a part of casing while supporting it can be adopted.
According to this configuration, the number of parts and the number of assembly steps can be greatly reduced by forming a part of the casing with the cover.

  According to the present invention, an electric motor integrated with an ECU capable of reducing the number of parts, the number of assembly steps, and the cost can be obtained.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 4 are views showing an electric motor according to an embodiment of the present invention, in which FIG. 1 is an external perspective view of the electric motor, and FIG. 2 is an external perspective view of the electric motor with a cover removed. 3 is a perspective view showing the structure of the housing and the substrate holding portion, and FIG. 4 is an exploded perspective view of the electric motor. This electric motor is applied to an electric power steering device. Specifically, a rotating shaft described later is connected to a gear of a vehicle power steering device (not shown) to generate an auxiliary torque of the steering wheel.

As shown in FIGS. 1 to 4, the electric motor 1 includes a housing 10 and a cover 30 that define an outer contour thereof, a rotating shaft 15, a substrate holding portion 20 formed integrally with the housing 10, and the substrate holding portion. 20 includes a control substrate 40 held by 20, a power transistor 60 as a heating element, and the like.
The housing 10 and the cover 30 constitute a casing that houses the stator, rotor, and the like of the electric motor 1 and that rotatably holds the rotary shaft 15. The housing 10 also serves as a yoke (magnetic circuit) of the electric motor 1.

The housing 10 is formed in a substantially cylindrical shape having the axis of the rotating shaft 15 as a central axis, and a motor coil (not shown) that constitutes a stator is provided on the inner periphery thereof, and one end of the rotating shaft 15 is a bearing (not shown). It is supported so that it can rotate freely.
As shown in FIGS. 3, 4, etc., the motor coil terminal 16 is provided so as to protrude from one end side in the axial direction of the housing 10, and is along the circumference of the rotating shaft 15 with a predetermined radius centered on the axis. Are arranged at equal intervals, and are supported by an annular insulating grommet 50 that is formed of an electrically insulating resin and is fitted to the inner periphery of the housing 10. The coil terminal 16 of the motor coil may be one in which a copper wire or the like forming the coil is directly led to the outside, or one in which a copper wire or the like is connected to the coil.

As shown in FIGS. 1 to 4, the substrate holding portion 20 is formed to extend from the side portion of the housing 10 in a direction perpendicular to the axis of the rotary shaft 15. The housing 10 and the substrate holding part 20 are obtained, for example, by die casting or casting.
The substrate holding unit 20 includes a plurality of bosses 21 erected at the four corners of the plate-like base 22 and a part of a drive circuit that controls supply of drive current to a motor coil formed on a part of the base 22. The power transistor 60 is provided with a contact portion 26 in surface contact, a shield wall 24 surrounding the periphery of the base 22, and the like. The drive circuit is composed of, for example, an inverter circuit.

The bosses 21 support the control substrate 40 at their tip portions.
The contact portion 26 is thicker than other portions in order to increase the heat capacity, and absorbs heat from the power transistor 60. A heat dissipating fin (not shown) is formed on the back surface of the contact portion 26 to efficiently release the heat of the power transistor 60 to the outside.
The power transistor 60 is fixed to the contact portion 26 so that the lead terminal 61 protrudes in the direction opposite to the base 22.
The shield wall 24 shields the space on the base 22 from the outside in cooperation with the case 30 described above. The shield wall 24 is formed with notches 24a and 24b into which a control signal connector CN1 and a power connector CN2 described later are fitted.

  As shown in FIGS. 3 and 4, the control board 40 is fixed to the boss 21 of the board holding unit 20 with bolts BT <b> 2. The control board 40 has various large components (capacitor, coil relay) for forming a drive circuit for controlling the supply of drive current to the motor coil on the main surface of the board holding unit 20 facing the base 22. 43) and connectors CN1 and CN2 for receiving connectors (not shown) for supplying control signals and electric power to the drive circuit are fixed. The electric power is supplied from, for example, an in-vehicle battery, and the control signal is supplied from another ECU of the vehicle through a signal cable.

Further, the control substrate 40 is formed with a through hole 41 through which the rotary shaft 15 passes, and through holes (not shown) through which the plurality of coil terminals 16 and the lead terminals 61 of the power transistor 60 pass are formed. Has been.
As shown in FIG. 2, when the control substrate 40 is positioned and installed on the boss 21, the rotating shaft 15, the plurality of coil terminals 16, and the lead terminals 61 of the power transistor 60 penetrate the control substrate 40.
In this state, when the coil terminal 16 and the lead terminal 61 are connected and fixed to a wiring (not shown) formed on the control board 40 by soldering, the control board 40 and a motor coil (not shown) are electrically connected.

The cover 30 is made of, for example, a metal such as an aluminum alloy. As shown in FIGS. 1, 3, and 4, a plurality of projecting pieces 33 are formed on the outer periphery of the cover 30. And a plurality of mounting portions 18 formed at corresponding positions on the outer peripheral portion of the substrate holding portion 20 and fixed by bolts BT1. Thereby, the control board 40 is covered with the cover 30.
The cover 30 includes a support hole 31 on the axis of the rotary shaft 15, and the support hole 31 rotatably supports one end of the rotary shaft 15 via a bearing 32. That is, the cover 30 also functions as a casing for the electric motor 1.

In the electric motor 1 having the above-described configuration, the noise can be reduced by grounding the housing 10, the substrate holding unit 20, and the control substrate 40 to the ground level.
Further, since the control substrate 40 is surrounded by the shield wall 24, noise can be further reduced.
Furthermore, by directly connecting and fixing the control board 40 to the coil terminal 16 of the motor coil without using a connecting member such as a bus bar, the number of parts can be reduced and the cost can be reduced.
Further, since the coil terminal 16 of the motor coil, the lead terminal 61 of the power transistor 60, the rotating shaft 15 and the like face the same axial direction, positioning and the like are very easy when mounting the control board 40, and the number of assembly steps Can also be reduced.

  5 to 8 are views showing an electric motor according to another embodiment of the present invention. FIG. 5 is an external perspective view of the electric motor, FIG. 6 is an external perspective view with the cover removed, and FIG. FIG. 8 is an external perspective view from another direction with the cover removed, and FIG. 8 is an external perspective view showing the structure of the motor casing and the substrate holding part.

As shown in FIGS. 5 to 8, the electric motor 100 includes a housing 101 that defines an outer contour, a bracket 110 and a cover 130, a rotating shaft 115, a board holding unit 120 that is integrally formed with the bracket 110, A control substrate 140 held by the substrate holding unit 120, a power transistor 160 as a heating element, and the like are included.
The housing 101 and the bracket 110 constitute a casing that houses the stator, rotor, and the like of the electric motor 100 and that rotatably holds the rotating shaft 115. The housing 101 also serves as a yoke (magnetic circuit) of the electric motor 100.

  As shown in FIGS. 5 to 8, the housing 101 is formed in a substantially cylindrical shape having the axis of the rotating shaft 115 as a central axis, and a motor coil (not shown) constituting a stator is provided on the inner periphery thereof. One end of the rotating shaft 15 is rotatably supported via a bearing (not shown).

As shown in FIGS. 5 to 8, the bracket 110 is die-cast using an aluminum alloy or the like together with the substrate holding portion 120, and is provided at one end portion in the axial direction of the housing 101, and formed on the outer peripheral portion thereof. The attached mounting portion 128 and the protruding piece 108 formed at a corresponding position of the housing 101 are fastened by a bolt BT4.
The bracket 110 rotatably supports the other end portion of the rotating shaft 115 via a bearing (not shown) and, as shown in FIG. 8, a plurality of penetrating holes formed at equal intervals in the circumferential direction around the rotating axis. A hole 111 is provided. Each through-hole 111 is provided with an insulating grommet 150 formed of an electrically insulating resin.
The insulating grommet 150 supports each coil terminal 116 of the motor coil that passes through each through hole 111 and protrudes in the axial direction.

As shown in FIG. 8, the bracket 110 is provided with a resolver 170 for detecting the amount of rotation of the rotating shaft 115.
A terminal 171 for outputting a detection signal of the resolver 170 is supported by an insulating grommet 172 formed of an electrically insulating resin, and is provided so as to protrude from the insulating grommet 172 in the axial direction of the rotary shaft 115. ing.

  As shown in FIGS. 6 to 8, the coil terminals 116 of the motor coil are provided so as to protrude in the axial direction, and are arranged on the rotating shaft 115 at equal intervals along a circumference of a predetermined radius centered on the axis. ing. The coil terminal 116 of the motor coil is electrically insulated from the bracket 110 by being supported by the insulating grommet 150.

As shown in FIGS. 5 to 8, the substrate holding part 120 is formed in a plate shape extending from the side part of the bracket 110 in a direction perpendicular to the axis of the rotation shaft 115.
The substrate holding part 120 is erected at the end of the base 122 that is farthest from the bracket 110, a plurality of bosses 121 erected at the four corners of the base 122, the contact part 126 where the power transistor 160 comes into surface contact. A shield wall 124 and the like are provided.

The boss 121 supports the control substrate 140 at the tip.
The contact portion 126 is thicker than other portions in order to increase the heat capacity, and absorbs heat from the power transistor 160. A heat radiating fin (not shown) is formed on the back surface of the contact portion 126 to efficiently release the heat of the power transistor 160 to the outside.
The power transistor 160 is fixed to the contact portion 126 with a fastener such as a bolt so that the lead terminal 161 protrudes in the direction opposite to the base 122.
The shield wall 124 shields the space on the base 122 from the outside in cooperation with the cover 130 described above.

  As shown in FIGS. 6 and 7, the control board 140 is fixed to the boss 121 of the board holding unit 120 with bolts BT5. The control board 140 has various large components (capacitors, coil relays) for constituting a drive circuit for controlling the supply of drive current to the motor coil on the main surface of the board holding unit 120 facing the base 122. 143) and connectors CN3 and CN4 for receiving a connector (not shown) for supplying a control signal and power to the drive circuit are fixed to the end on the substrate holding unit 120 side.

In addition, the control substrate 140 is formed with through holes (not shown) through which the plurality of coil terminals 116, the terminals 171 of the resolver 170, and the lead terminals 161 of the power transistor 160 pass.
When the control board 140 is positioned and installed on the boss 121 as shown in FIG. 6 or 7, the plurality of coil terminals 116, the resolver 170 terminal 171 and the power transistor 160 lead terminal 161 are used for control. The substrate 140 is penetrated.
In this state, when the coil terminal 116, the terminal 171 of the resolver 170, and the lead terminal 161 are connected and fixed to the wiring (not shown) formed on the control board 140 by soldering, the control board 140 and the motor coil (not shown) are electrically connected. Connected to.

  The cover 130 is made of, for example, a metal such as an aluminum alloy. As shown in FIGS. 5 and 6, a plurality of protruding pieces 133 are formed on the outer periphery of the cover 130, and the protruding pieces 133 hold the bracket 110 and the substrate. It abuts against a plurality of attachment portions 118 formed at corresponding positions on the outer peripheral portion of the portion 120 and is fixed by a bolt BT3. As a result, the control board 140 is covered with the cover 130.

In the electric motor 100 configured as described above, the noise can be reduced by grounding the bracket 110, the substrate holding unit 120, and the control substrate 140 to the ground level.
In addition, since the coil terminal 116 of the motor coil, the terminal 171 of the resolver 170, the lead terminal 161 of the power transistor 160, and the like face in the same direction, positioning and the like are very easy when attaching the control board 140. Assembly time can also be reduced.

  9 to 12 are views showing an electric motor according to still another embodiment of the present invention. FIG. 9 is an external perspective view of the electric motor, and FIG. 10 is an external perspective view of the electric motor with the cover removed. 11 is an external perspective view from another direction with the electric motor cover removed, and FIG. 12 is an external perspective view showing the structure of the substrate holding part.

As shown in FIGS. 9 to 12, the electric motor 200 includes a housing 201, a bracket 210 and a cover 230, a rotating shaft 215, a substrate holder 220 integrally formed with the bracket 210, A control substrate 240 held by the substrate holding unit 220, a power transistor 260 as a heating element, and the like are included.
The housing 201 and the bracket 210 constitute a casing that houses the stator, the rotor, and the like of the electric motor 200 and that rotatably holds the rotating shaft 215. The housing 201 also serves as a yoke (magnetic circuit) of the electric motor 200.

  As shown in FIGS. 9 to 12, the housing 201 is formed in a substantially cylindrical shape having the axis of the rotating shaft 115 as a central axis, and a motor coil (not shown) is provided therein, and the rotating shaft 215 One end is rotatably supported through a bearing (not shown).

  As shown in FIGS. 9 to 12, the bracket 210 is formed in a plate shape having a circular outer shape, covers one end of the housing 201 in the axial direction, and at the center of the rotary shaft 215 via a bearing (not shown). The other end is rotatably supported. The bracket 210 is die-cast using an aluminum alloy or the like together with the substrate holding portion 220, and is provided at one end portion in the axial direction of the housing 201. The mounting portion 228 and the housing 201 formed on the outer peripheral portion thereof. The projecting piece 208 formed at the corresponding position is fastened by a bolt BT7.

As shown in FIG. 12, the bracket 210 is provided with a resolver 270 for detecting the amount of rotation of the rotating shaft 215.
A terminal 271 that outputs a detection signal of the resolver 270 is supported by an insulating grommet 272 formed of an electrically insulating resin, and is provided so as to protrude from the insulating grommet 272 in the axial direction of the rotary shaft 215. ing.

  As shown in FIGS. 9 to 12, the substrate holding part 220 is formed in a plate shape having a rectangular outer shape and is integrally formed so as to overlap the bracket 210 in the axial direction. Note that the outer shape of the substrate holding part 220 is slightly larger than the outer shape of the bracket 210. Further, as shown in FIGS. 10 to 12, the substrate holding part 220 is formed on a plurality of bosses 221 erected so as to extend in the axial direction at the four corners of the base 222 and a part of the base 222. A contact portion 226 where the transistor 260 is in surface contact, a lead-out hole 225 for leading out the coil terminal 216 of the motor coil, and the like are provided.

As shown in FIGS. 10 and 12, the boss 221 supports the control substrate 240 at the tip.
The contact portion 226 is thicker than other portions in order to increase the heat capacity, and absorbs heat from the power transistor 260.
The power transistor 260 is fixed to the contact portion 226 with a fastener such as a bolt so that the lead terminal 261 protrudes in the direction opposite to the base 222.

  As shown in FIG. 12, the coil terminal 216 of the motor coil is supported by an insulating grommet 250 formed of an electrically insulating resin and protrudes in the axial direction of the rotary shaft 215 from a lead-out hole 225 formed in the base 222. It is provided to do. The coil terminal 216 is supported by the insulating grommet 250 so as to be fixed at a predetermined position and electrically insulated from the bracket 210 and the substrate holding part 220.

  As shown in FIGS. 10 and 11, the control board 240 is fixed to the boss 221 of the board holding part 220 with bolts. The control board 240 has various large components (capacitors, coil relays) for forming a drive circuit for controlling the supply of drive current to the motor coil on the main surface of the board holding unit 220 facing the base 222. Etc.) 243 is mounted, and connectors CN5 and CN6 for receiving connectors (not shown) for supplying control signals and power to the drive circuit are fixed to one end.

The control board 240 is formed with through holes (not shown) through which the plurality of coil terminals 216, the terminals 271 of the resolver 270, and the lead terminals 261 of the power transistor 260 pass.
When the control board 240 is positioned and installed on the boss 221 as shown in FIG. 10 or FIG. 11, the plurality of coil terminals 216, the resolver 270 terminal 271 and the power transistor 260 lead terminal 261 are used for control. The substrate 240 is penetrated.
In this state, when the coil terminal 216, the terminal 271 of the resolver 270, and the lead terminal 261 are connected and fixed to the wiring (not shown) formed on the control board 240 by soldering, the control board 240 and the motor coil (not shown) are electrically connected. Connected to.

  The cover 230 is made of, for example, a metal such as an aluminum alloy. As shown in FIGS. 9 and 10, a plurality of projecting pieces 233 are formed on the outer periphery of the cover 230, and the projecting pieces 233 are formed on the substrate holding unit 220. It abuts against a plurality of mounting portions 218 formed at corresponding positions on the outer peripheral portion and is fixed by bolts BT6. As a result, the control board 240 is covered with the cover 230.

In the electric motor 200 having the above configuration, the bracket 210 and the substrate holding portion 220 formed integrally with the bracket 210 are formed to have substantially the same size and are overlapped with each other, so that the outer dimension of the motor is further reduced. Can do.
Further, the noise can be reduced by grounding the bracket 210, the substrate holding unit 220, and the control substrate 240 to the ground level.
Furthermore, since the coil terminal 216 of the motor coil, the terminal 271 of the resolver 270, the lead terminal 261 of the power transistor 260 and the like are oriented in the same direction, positioning and the like are very easy when attaching the control board 240, Assembly time can also be reduced.

  In the above embodiment, the case where the electric motor is used in the electric power steering apparatus has been described. However, the present invention is not limited to this, and the present invention can be applied to other electrical components in the vehicle and electric devices other than the vehicle.

1 is an external perspective view of an electric motor according to an embodiment of the present invention. It is an external appearance perspective view of the electric motor of the state which removed the cover. It is a perspective view which shows the structure of a housing and a board | substrate holding part. It is a disassembled perspective view of an electric motor. It is an external appearance perspective view of the electric motor which concerns on other embodiment of this invention. It is an external appearance perspective view of the state which removed the cover of the electric motor. It is an external appearance perspective view from the other direction of the state which removed the cover of the electric motor. It is an external appearance perspective view which shows the structure of a motor casing and a board | substrate holding part. It is an external appearance perspective view of the electric motor which concerns on other embodiment of this invention. It is an external appearance perspective view of the state which removed the cover of the electric motor. It is an external appearance perspective view from the other direction of the state which removed the cover of the electric motor. It is an external appearance perspective view which shows the structure of a board | substrate holding part.

Explanation of symbols

1, 100, 200 ... Electric motor 10 ... Housing (motor casing)
15, 115, 215 ... rotating shafts 16, 116, 216 ... coil terminals 18, 118, 218 ... cover mounting parts 20, 120, 220 ... substrate holding parts 21, 121, 221 ... bosses 22, 122, 222 ... base 24, 124: shield walls 26, 126, 226 ... element contact portions 30, 130, 230 ... cover 31 ... support holes 32 ... bearings 33, 133, 233 ... projecting pieces 40, 140, 240 ... control board 41 ... through holes 43, 143, 243 ... Large parts 50, 150, 250 ... Insulating grommets (support members)
60, 160, 260 ... power transistors 61, 161, 261 ... lead terminals 101, 201 ... housing (motor casing)
170,270 ... Resolvers 171,271 ... Resolver terminals 172,272 ... Insulating grommets CN1-CN6 ... Connectors BT1-BT7 ... Bolts

Claims (7)

A control board on which a drive circuit for controlling the supply of drive current to the motor coil is formed;
A heating element that forms part of the drive circuit has a contact portion that makes surface contact , and a substrate holding portion that is formed integrally with the motor casing and holds the control substrate;
The electric motor is characterized in that a terminal of the motor coil is directly connected and fixed to the control board, and the contact portion is thicker than other portions of the board holding portion . The motor casing includes a housing that supports one end of a motor rotation shaft, and a bracket that supports the other end of the motor rotation shaft, and the bracket is provided at one end of the housing in the axial direction. The electric motor according to claim 1, wherein the electric motor is formed integrally with the substrate holding portion . The electric motor according to claim 1 , wherein the motor casing, the substrate holding unit, and the control substrate are grounded to a ground level .   The electric motor according to any one of claims 1 to 3, wherein a terminal of a resolver incorporated in a motor casing is directly connected and fixed to the control board.   The electric motor according to claim 1, wherein the terminal penetrates the control board.   6. The electric motor according to claim 1, further comprising an electrically insulating support member that supports the terminal at a position where it can be directly connected to the control board. A cover fixed to the motor casing and the substrate holding part and covering the control substrate;
The control board has a through hole through which the motor rotation shaft passes,
The electric motor according to claim 1, wherein the cover rotatably supports the motor rotation shaft and forms a part of the casing.

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