JP2006109666A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrict a movement of electronic parts even when the electronic parts fall off from a fixed position in an electric motor which assists driving operation of a vehicle. <P>SOLUTION: This stator portion 3a of the motor has a bus bar 51 attached to an armature 3, and a substrate 52 attached to the bus bar 51. A first recessed portion 516 facing a portion of the circuit board 52 is formed at a surface of the bus bar 51 on the side of the circuit board 52. All chip parts 524 mounted on a surface on the circuit board 52 are mounted in advance in a recessed portion facing range 523 on the bus bar 51 side of the circuit board 52. By attaching the substrate 52 to the bus bar 51, the chip parts 524 on the circuit board 52 are covered with the first recessed portion 516, therefore the movement in the chip parts 524 can be restricted within the first recessed portion 516 even when the chip parts 524 fall off from the fixed position on the circuit board 52. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric motor that assists driving operation of a vehicle.

  2. Description of the Related Art Conventionally, as a device that assists in driving a vehicle, a hydraulic power steering that assists a steering operation with a hydraulic pressure generated by a pump that operates with engine output has been adopted. In recent years, electric power steering (hereinafter referred to as EPS (Electric Power Steering)), which assists steering operation by rotating a motor with an on-board battery, has been adopted, and hydraulic pressure is generated by engine rotation. It is attracting attention as an efficient system with less engine power loss. In a motor used for such an EPS, various types of electronic components are mounted on a substrate in order to realize highly accurate control.

  Since a vehicle is required to operate accurately for a long period of time in various environments, high reliability is also required for an EPS motor, which is one of its mechanical components. In addition to EPS, there are electric brake systems, electromagnetic suspensions, transmission systems, and the like as devices that assist driving operations in addition to EPS. High reliability is required.

For example, in Patent Document 1, by providing a moisture permeable portion in a housing of an electric motor (motor), dew condensation inside the electric motor is prevented and internal atmospheric pressure is adjusted to prevent occurrence of defects in internal components (electronic components). Technology is disclosed. Patent Document 2 discloses a technique related to grounding of a stator core of a molded electric motor.
JP-A-11-332160 JP-A-7-87696

  By the way, in the motor used for the apparatus for assisting the driving operation of the vehicle described above, even one electronic component is firmly mounted so as not to fall off the substrate. It is necessary to ensure high reliability by taking measures to prevent failure. However, there has been no conventional motor with such countermeasures. For example, in the electric motor disclosed in Patent Document 1, the electronic components in the motor are mounted on the circuit board without being exposed. In addition, the electric motor disclosed in Patent Document 2 has a configuration in which an electronic component is molded together with an armature so that the electronic component does not easily fall off, but it involves an increase in cost due to molding.

  The present invention has been made in view of the above problems, and in an electric motor that assists driving operation of a vehicle, even when the electronic component is out of a fixed position, the movement of the electronic component is limited. This is the main purpose.

  The invention according to claim 1 is an electric motor for assisting a driving operation of the vehicle, and generates a torque centered on a predetermined central axis between the stator portion having the armature and the armature. And a bearing mechanism that rotatably supports the rotor portion with respect to the stator portion about the central axis, the stator portion being related to a direction in which the central axis extends. A bus bar disposed on one side of the armature and provided therein with a wiring for supplying a drive current to the armature; and a circuit board placed on the bus bar, the circuit board side of the bus bar Has a recess covering the electronic component on the circuit board.

  A second aspect of the present invention is the motor according to the first aspect, wherein the electronic component is surface-mounted on the circuit board.

  A third aspect of the present invention is the motor according to the second aspect, wherein all the electronic components that are surface-mounted on the circuit board are covered with the recesses.

  The invention according to claim 4 is the motor according to any one of claims 1 to 3, wherein the circuit board is fixed to the bus bar by heat welding.

  Invention of Claim 5 is the motor of Claim 1, Comprising: The said electronic component by which the terminal was inserted in the hole of the said circuit board is mounted in the surface by the side of the said bus | bath of the said circuit board, The said The bus bar side surface of the electronic component is close to the facing surface on the bus bar.

  The invention according to claim 6 is an electric motor for assisting in driving operation of the vehicle, and generates a torque centered on a predetermined central axis between a stator portion having an armature and the armature. And a bearing mechanism that rotatably supports the rotor portion with respect to the stator portion about the central axis, the stator portion being related to a direction in which the central axis extends. A bus bar disposed on one side of the armature and provided therein with wiring for supplying a driving current to the armature, a circuit board placed on the bus bar, and disposed on the bus bar side of the circuit board A sensor that detects the position of the field magnet and a sensor holder that is fixed to the bus bar side surface of the circuit board and holds the sensor, and the sensor holder engages with the bus bar. With the engaging portion.

  Invention of Claim 7 is a motor of Claim 6, Comprising: The front end surface on the opposite side to the said circuit board of the said sensor holder opposes a part of said bus bar, The said engaging part is, It has a tip projection protruding from the tip surface toward the bus bar, and the bus bar has a recess into which the tip projection is inserted.

  The invention according to claim 8 is the motor according to claim 6 or 7, wherein the side surface of the sensor holder faces the bus bar, and the engaging portion protrudes from the side surface toward the bus bar. The bus bar further includes a side protrusion protruding toward the opposite side of the circuit board, and the bus bar has a recess into which the side protrusion is inserted.

  The invention according to claim 9 is the motor according to any one of claims 6 to 8, wherein the sensor holder is fixed to the circuit board by thermal welding.

  A tenth aspect of the present invention is the motor according to any one of the sixth to ninth aspects, wherein the bus bar has a substantially cylindrical shape, and an arcuate concave portion is provided on an inner peripheral surface, and the sensor holder is The arc shape is accommodated in the recess.

  In the present invention, even when the electronic component is out of the fixed position, the movement of the electronic component can be restricted, and the reliability of the motor can be improved. According to the invention of claim 3, the reliability of the motor is obtained by covering all the electronic components surface-mounted on the circuit board with the recesses, and in the invention of claim 4 by firmly fixing the circuit board to the bus bar. Can be further improved.

  In the invention of claim 5, it is possible to prevent the electronic component from falling off. In the inventions according to claims 6 to 10, the sensor holder can be prevented from falling off.

  FIG. 1 is a longitudinal sectional view of an electric motor 1 according to an embodiment of the present invention. The motor 1 is a so-called brushless motor and is used, for example, as a drive source for assisting steering in power steering of an automobile. In addition, illustration of the parallel oblique line in the detail of a cross section is abbreviate | omitted. The motor 1 is covered with a cylindrical housing 11 whose upper side is open in FIG. 1 and a cover portion 12 that closes the opening of the housing 11 and has an opening at the center, and the opening of the cover portion 12 and the bottom surface of the housing 11. Are respectively mounted with ball bearings 131 and 132, and the shaft 21 is rotatably supported by the ball bearings 131 and 132.

  A cylindrical rotor yoke 22 is attached to the shaft 21 in the housing 11, and a multi-pole field magnet 23 is fixed to the outer peripheral surface of the rotor yoke 22. As the field magnet 23, for example, a sintered body containing neodymium is used. On the other hand, the armature 3 is attached to the inner peripheral surface of the housing 11 so as to face the field magnet 23. The armature 3 is arranged so that the central axis J1 of the armature 3 coincides with the central axis of the shaft 21. The armature 3 is arranged radially from the inner peripheral surface of the annular portion of the core 30 made of a magnetic material with the tip directed toward the central axis J1 and centering on the central axis J1 (that is, from the inner peripheral surface of the housing 11 to the shaft). 21 and the field magnet 23), a plurality of teeth 31, an insulator 32 covering the plurality of teeth 31, and a coil provided by winding conductive wires around the plurality of teeth 31 in multiple layers from above the insulator 32. 35. The coil 35 is formed by winding a conductive wire around the outer periphery of the tooth 31 and the insulator 32 in the vertical direction (the direction of the central axis J1).

  A bus bar 51 provided with a wiring board for supplying a driving current to the coil 35 of the armature 3 is attached to the cover 12 side of the armature 3 in the direction in which the central axis J1 extends. Are connected to each coil 35 and wiring 515 extending to the outside. On the cover portion 12 side of the bus bar 51, a detection circuit board 52 on which a Hall element or the like to be described later is mounted is placed and attached.

  In the motor 1, the rotor portion 2 a is configured with the shaft 21, the rotor yoke 22, the field magnet 23 and the like as main parts, and the stator fixed in the housing 11 with the armature 3, the bus bar 51, the circuit board 52 and the like as main parts. The portion 3a is configured, and the ball bearings 131 and 132 serve as a bearing mechanism that supports the rotor portion 2a so as to be rotatable relative to the stator portion 3a around the central axis J1. Then, when a drive current is supplied to the armature 3 via the bus bar 51, a torque around the central axis J1 is generated between the armature 3 and the field magnet 23, and the rotor portion 2a rotates. To do.

  Three hall elements 53 are mounted on the bus bar 51 side of the circuit board 52 so as to protrude downward together with various electronic components, and the hall elements 53 are held by a sensor holder described later. On the other hand, an annular magnet 25 is attached to the shaft 21 on the cover portion 12 side of the field magnet 23 via a flange 25 a made of a magnetic material, and the magnet 25 faces the hall element 53. The magnet 25 is magnetized in the same manner as the field magnet 23, and the position of the field magnet 23 is indirectly detected by the Hall element 53 detecting the position of the magnet 25. Then, the drive current to the armature 3 is controlled based on the detection result.

  FIG. 2 is an exploded perspective view showing the main configuration of the stator portion 3a. In FIG. 2, only the core 30 is shown for the armature 3, but actually, when the bus bar 51 is attached to the armature 3, the teeth 31 of the core 30 are covered with the insulator 32, and the insulator 32 An armature 3 in which a conductive wire is wound from above and a coil 35 is formed is prepared (see FIG. 1).

  In the substantially cylindrical bus bar 51, four arc-shaped wiring boards 518 are stacked at intervals in the direction toward the central axis J1 (see FIG. 4), and only the terminals 513 protruding from the wiring boards 518 are exposed to the outside. The cylindrical part provided at the lower part of the central opening is inserted into the central opening of the core 30 and the lead wire from the coil 35 (not shown) is connected to the outer peripheral terminal 513 by caulking. As a result, the armature 3 is attached. At this time, the plurality of leg portions 514 provided on the outer periphery of the bus bar 51 abut on the upper surface of the core 30, and the tip portions of the leg portions 514 engage with the vertical grooves on the outer peripheral surface of the core 30, The position of the bus bar 51 with respect to the core 30 is determined.

  As shown in FIG. 2, the bus bar 51 has a circuit board 52 side surface on which a first recess 516 facing a part of the circuit board 52 and a connector 55 which is an electronic component connected to an external wiring 552 are accommodated. The second concave portion 517 and the arc-shaped third concave portion 512 which is located on the inner peripheral surface of the bus bar 51 and accommodates the arc-shaped sensor holder 54 made of resin are formed.

  A chip component 524, which is a fine electronic component, is surface-mounted in advance on a region (hereinafter, referred to as “concave confronting region”) 523 that faces the first concave portion 516 on the surface on the bus bar 51 side of the circuit board 52. In the present embodiment, all of the plurality of chip components 524 that are surface-mounted on the circuit board 52 are mounted in the recess facing region 523. The surface mounting means a mounting method in which the terminals of the chip component 524 are fixed to the electrodes on the surface of the circuit board 52, and this mounting method is suitable for reducing the area required for mounting the chip component 524. In the motor 1 that is required to be miniaturized as a driving source for power steering of an automobile, the circuit board 52 can be miniaturized by surface mounting a plurality of chip components 524.

  In the circuit board 52, a connector 55 is mounted on the surface of the circuit board 52 on the bus bar 51 side. A terminal 551 of the connector 55 is inserted into a hole 525 formed in a land on the circuit board 52 and fixed to the circuit board 52 by soldering. In addition, the Hall element 53 is inserted and held in each recess 54 a of the arc-shaped sensor holder 54, and the terminals of the Hall element 53 are inserted into holes formed in lands on the circuit board 52, and then the sensor holder 54. Is fixed to the surface of the circuit board 52 on the bus bar 51 side. The terminals of the Hall element 53 protruding from the surface of the circuit board 52 opposite to the bus bar 51 are fixed to the circuit board 52 by soldering, and the Hall element 53 is provided to protrude from the mounting surface of the circuit board 52. . Although the chip component 524, the connector 55, and the Hall element 53 are mounted on one surface of the circuit board 52, the solder portions are surfaces opposite to each other depending on the mounting method. As a result, when the connector 55 and the hall element 53 are soldered to the circuit board 52 on which the chip component 524 is mounted, the soldering operation can be performed without harming the mounted chip component 524. Two resin projections 541 are provided on the circuit board 52 side of the sensor holder 54, and holes 521 are provided at corresponding positions on the circuit board 52. The sensor holder 54 is attached to the projection 541. The sensor holder 54 is firmly fixed to the circuit board 52 by thermal welding which is inserted into the hole 521 and heat-melts and crushes the protrusion 541.

  FIG. 3 is an enlarged plan view showing a part of the sensor holder 54 in which the Hall element 53 is inserted. As shown in FIG. 3, a recess 54 a that covers the Hall element 53 of the sensor holder 54 has a shape in which both side surfaces of the Hall element 53 are fitted without gaps. The Hall element 53 has a sensor surface that is centered on the sensor holder 54. The sensor holder 54 is held in a non-movable state while substantially matching a surface (hereinafter referred to as a “holder inner surface”) 546 facing the J1 (see FIG. 2) side. Accordingly, the relative arrangement of the plurality of Hall elements 53, that is, the pitch angle between the Hall elements with the central axis J1 as the center, and the relative arrangement of the Hall elements 53 and the magnet 25 are easily and accurately matched. Furthermore, the mounting of the plurality of Hall elements 53 on the circuit board 52 can be easily performed collectively. Further, even if any obstacle comes into contact with the mounted hall element 53, the position of the hall element 53 is prevented from being shifted.

  When the connector 55 and the sensor holder 54 are attached to the circuit board 52, as shown in FIG. 2, two resin protrusions 511 provided on the upper surface of the bus bar 51 are inserted into the holes 522 of the circuit board 52, and the core After the sensor holder 54 is positioned with respect to 30, the circuit board 52 is firmly fixed to the bus bar 51 by heat welding that melts and crushes the protrusion 511.

  FIG. 4 is a cross-sectional view of the bus bar 51 and the circuit board 52 at the position of the first recess 516 of the bus bar 51, and shows only a part of the bus bar 51 (the same applies to FIGS. 5, 7, and 8). In the stator portion 3 a, the circuit board 52 is attached to the bus bar 51, so that it is surface-mounted on the chip component 524 mounted on the recess facing region 523 of the circuit board 52, that is, the circuit board 52, as shown in FIG. 4. All the chip components 524 are covered by the first recesses 516 of the bus bar 51.

  FIG. 5 is a cross-sectional view of the bus bar 51 and the circuit board 52 at the position of the second recess 517. As shown in FIG. 5, in the connector 55 connected to the external wiring 552, the terminal 551 is inserted into the hole 525 of the circuit board 52, and the surface on the circuit board 52 side is brought into contact with the surface on the bus bar 51 side of the circuit board 52. It is mounted on the circuit board 52 in contact therewith. The second recess 517 of the bus bar 51 is formed so that the depth is slightly larger (or equal) than the thickness of the connector 55. The depth of the second recess 517 has a dimensional relationship such that the terminal 551 is still inserted into the hole 525 of the circuit board 52 even if the solder of the terminal 551 of the connector 55 is removed. This is to prevent the connector 55 from protruding in the depth direction of the second recess 517 due to a molding error of the second recess 517, a shift in the mounting position of the connector 55, and the like, and not immediately coming off the second recess 517. . In addition, each wiring board 518 is arranged so as to be shifted in the circumferential direction so as not to be exposed from the first recess 516 and the second recess 517. In the stator portion 3a, the circuit board 52 is attached to the bus bar 51, so that the connector 55 is accommodated in the second recess 517, and the surface of the connector 55 on the bus bar 51 side is the opposite surface on the bus bar 51 (that is, the bus bar 51 It approaches (or abuts) the bottom surface of the second recess 517 that is a part of the surface on the circuit board 52 side. In other words, the connector 55 mounted on the circuit board 52 is covered with the second recess 517 of the bus bar 51 except for the outer surface.

  FIG. 6 is a bottom view of the sensor holder 54. As shown in FIG. 6, the arc-shaped sensor holder 54 has an outer peripheral side (that is, a central axis J1) of a front end surface (hereinafter referred to as “holder bottom surface”) 542 opposite to the circuit board 52 (see FIG. 2). Three tip projections 543 are provided in a portion far from (see FIG. 2). Further, the sensor holder 54 further includes two L-shaped side protrusions 544 on the circuit board 52 (see FIG. 2) side of the holder outer surface 545 that is a side surface far from the central axis J1. FIG. 7 is a cross-sectional view of the bus bar 51 and the circuit board 52 at the position of the tip protrusion 543, and FIG. 8 is a cross-sectional view of the bus bar 51 and the circuit board 52 at the position of the side protrusion 544.

  When the circuit board 52 is attached to the bus bar 51 and the sensor holder 54 is fitted into the third recess 512, the holder bottom surface 542 of the sensor holder 54 that holds the Hall element 53 is connected to the bus bar 51 as shown in FIG. A tip protrusion 543 that faces the bottom of the third recess 512 and protrudes from the holder bottom 542 toward the bus bar 51 is inserted into a small recess 5121 formed on the bottom of the third recess 512. Further, as shown in FIG. 8, the holder outer surface 545 is also opposed to the side surface of the third recess 512, and once protrudes from the holder outer surface 545 toward the side of the third recess 512, and further on the side opposite to the circuit board 52. An L-shaped side protrusion 544 protruding toward the bottom is inserted into a small recess 5122 provided on the bus bar 51. As described above, the sensor holder 54 is fixed to the bus bar 51 with high reliability by the tip protrusions 543 and the side protrusions 544 which are engaging portions that engage with the bus bars 51.

  As shown in FIGS. 7 and 8, the sensor holder 54 is accommodated in the third recess 512 so that the holder inner side surface 546 coincides with the inner peripheral surface of the bus bar 51. Further, as shown in FIG. The sensor surface of the element 53 substantially coincides with the holder inner surface 546. As a result, the Hall element 53 can be disposed close to the annular magnet 25 (see FIG. 1) while minimizing the bus bar 51 by minimizing the inner diameter of the bus bar 51, and the field magnet by the Hall element 53. The position 23 can be detected with higher accuracy.

  As described above, in the motor 1, since the chip component 524 on the circuit board 52 is covered with the first recess 516, even if the chip component 524 is out of the fixed position on the circuit board 52, The movement of the chip component 524 can be limited to the inside of the first recess 516. By adopting such a structure, when the chip component 524 is mounted by surface mounting, the removed chip component 524 enters the rotor portion 2a side and affects the rotational characteristics of the motor 1. Therefore, the reliability of the motor 1 can be improved. Further, since the chip component 524 is accommodated in the first recess 516, the reliability of the motor 1 can be improved by preventing the occurrence of a short circuit due to adhesion of foreign matter or the like generated inside the motor 1 to the chip component 524. Realized. In the motor 1, since all the chip components 524 on the circuit board 52 are covered with the first recesses 516, the reliability of the motor 1 can be further improved.

  The connector 55 has the terminal 551 inserted into the hole 525 of the circuit board 52, soldered on the surface of the circuit board 52 opposite to the side where the connector 55 is located, and the surface on the bus bar 51 side is further soldered to the second recess 517. Is accommodated in the second recess 517 in a state of being close to (or in contact with) the bottom surface of the first recess. Therefore, even when the connector 55 is pulled away from the bus bar 51 by the external wiring 552, the terminal 551 is always held by the circuit board 52 without coming out of the hole 525, The connector 55 can be prevented from falling off, and the reliability of the motor 1 can be further improved. In addition, even if the connector 55 is removed, it is covered with the second recess 517, so that a secondary failure such that the detached connector 55 enters the rotor portion 2a side and affects the rotational characteristics of the motor 1 is prevented. can do. Furthermore, since the connector 55 is accommodated in the second recess 517, foreign matter or the like generated inside the motor 1 is less likely to adhere to the connector 55 body, and a short circuit can be prevented.

  In the motor 1, since the sensor holder 54 is fixed to the circuit board 52 by heat welding, the sensor holder 54 can be prevented from falling off with higher reliability than other fastening methods (adhesion, screwing, etc.). . Even if the heat-welded part (the projection 541 of the sensor holder 54 or the like) is damaged, the tip projection 543 is inserted into the recess 5121 and the sensor holder 54 is engaged with the bus bar 51. Therefore, it is possible to reliably prevent the sensor holder 54 from falling off the circuit board 52. Furthermore, the side protrusion 544 is inserted into the recess 5122, so that the sensor holder 54 can be more reliably prevented from falling off. In other words, even if a primary failure occurs due to breakage of the heat-welded portion of the sensor holder 54, the sensor holder 54 may drop and cause the mounting failure of the Hall element 53, or the sensor holder 54 and the Hall element 53 This prevents the occurrence of secondary problems such as contact with the rotor portion 2a and causing rotation failure, so that the motor 1 achieves high reliability.

  Further, when the sensor holder 54 is inserted into the sub of the bus bar 51, the tip protrusion 543 is engaged with the recess 5121, and the side protrusion 544 is engaged with the recess 5122, so that the sensor holder 54 is third. It is possible to reliably prevent a mounting failure such as being fixed while being tilted with respect to the recess 512. Either one of the tip protrusion 543 and the side protrusion 544 functions, but it is desirable that both protrusions are present.

  Thus, the motor 1 is suitable for a power steering drive source for automobiles that require high reliability.

  The electronic components (chip component 524, connector 55, and hall element 53) on the circuit board 52 are all mounted on the surface on the bus bar 51 side, and the thickness direction of the bus bar 51 (that is, the central axis J1 faces) by a predetermined recess. Therefore, the dimension in the direction in which the central axis J1 of the motor 1 faces is smaller than in the case where the electronic component is mounted on the surface of the circuit board 52 opposite to the bus bar 51. Therefore, it contributes to miniaturization of the motor 1.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, the chip component 524 may be mounted on the circuit board 52 by various methods other than surface mounting. In addition, from the viewpoint of restricting movement when the chip component 524 is removed, it is preferable that all the chip components 524 are covered with the first recesses 516. The chip component to be surface-mounted may be mounted in a region (for example, on the main surface opposite to the bus bar 51) other than the recess facing region 523 of the circuit board 52.

  In the motor 1, the shape of the engaging portion that engages with the bus bar 51 of the sensor holder 54 may be various shapes other than the tip protruding portion 543 and the side protruding portion 544, and the position and number of the engaging portions are also different. The sensor holder 54 may be appropriately changed according to the shape and size of the sensor holder 54. For example, the sensor holder 54 may be fixed to the bus bar 51 by providing a protrusion on the bottom surface of the third recess 512 and inserting the protrusion into the recess provided on the holder bottom surface 542.

  In the motor 1, various types of electronic components other than the Hall element 53 and the connector 55 may be mounted on the circuit board 52.

  The motor 1 may be used for an electric brake system, an electromagnetic suspension, and a transmission system in addition to the electric power steering of the automobile, and may be used for various systems that assist driving operation of a vehicle other than the automobile.

It is a longitudinal cross-sectional view of a motor. It is a disassembled perspective view of a stator part. It is a top view which expands and shows a part of sensor holder. It is sectional drawing of a bus bar and a circuit board. It is sectional drawing of a bus bar and a circuit board. It is a bottom view of a sensor holder. It is sectional drawing of a bus bar and a circuit board. It is sectional drawing of a bus bar and a circuit board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2a Rotor part 3 Armature 3a Stator part 21 Shaft 23 Field magnet 51 Bus bar 52 Circuit board 53 Hall element 54 Sensor holder 55 Connector 131,132 Ball bearing 512 3rd recessed part 516 1st recessed part 518 Wiring board 524 Chip components 525 hole 542 holder bottom surface 543 tip protrusion 544 side protrusion 545 holder outer surface 546 holder inner surface 551 terminal 552 wiring 5121, 5122 recess J1 central axis

Claims (10)

An electric motor that assists in driving the vehicle,
A stator portion having an armature;
A rotor portion having a field magnet that generates torque centered on a predetermined central axis with the armature;
A bearing mechanism that rotatably supports the rotor portion with respect to the stator portion around the central axis;
With
The stator portion is
A bus bar disposed on one side of the armature with respect to the direction in which the central axis extends, and a wiring for supplying a drive current to the armature is provided inside;
A circuit board placed on the bus bar;
With
A surface of the bus bar on the circuit board side has a recess that covers an electronic component on the circuit board. The motor according to claim 1,
A motor characterized in that the electronic component is surface-mounted on the circuit board. The motor according to claim 2,
All the electronic components surface-mounted on the said circuit board are covered with the said recessed part, The motor characterized by the above-mentioned. The motor according to any one of claims 1 to 3,
The motor, wherein the circuit board is fixed to the bus bar by heat welding. The motor according to claim 1,
The electronic component having a terminal inserted into the hole of the circuit board is mounted on the bus bar side surface of the circuit board, and the bus bar side surface of the electronic component is close to a facing surface on the bus bar. A motor characterized by An electric motor that assists in driving the vehicle,
A stator portion having an armature;
A rotor portion having a field magnet that generates torque centered on a predetermined central axis with the armature;
A bearing mechanism that rotatably supports the rotor portion with respect to the stator portion around the central axis;
With
The stator portion is
A bus bar disposed on one side of the armature with respect to the direction in which the central axis extends, and a wiring for supplying a drive current to the armature is provided inside;
A circuit board placed on the bus bar;
A sensor that is disposed on the bus bar side of the circuit board and detects the position of the field magnet;
A sensor holder that holds the sensor by being fixed to the bus bar side surface of the circuit board;
With
The motor, wherein the sensor holder has an engaging portion that engages with the bus bar. The motor according to claim 6,
The front end surface of the sensor holder opposite to the circuit board faces a part of the bus bar,
The engaging portion includes a tip protrusion protruding from the tip surface toward the bus bar,
The motor, wherein the bus bar has a recess into which the tip protrusion is inserted. The motor according to claim 6 or 7,
The side surface of the sensor holder faces the bus bar,
The engaging portion includes a side protrusion that protrudes once from the side surface toward the bus bar and further protrudes toward the opposite side of the circuit board,
The bus bar has a recess into which the side protrusion is inserted. The motor according to any one of claims 6 to 8,
The motor, wherein the sensor holder is fixed to the circuit board by thermal welding. The motor according to any one of claims 6 to 9,
The bus bar is substantially cylindrical, and has an arc-shaped recess on the inner peripheral surface,
The motor, wherein the sensor holder has an arc shape that is received in the recess.

Images