JP5207032B2 - Electric motor and electric power steering device - Google Patents

Description

  The present invention relates to an electric motor and an electric power steering apparatus.

  Conventionally, an electric power steering device for assisting a steering device of a vehicle such as an automobile with the rotational force of an electric motor has been proposed and put into practical use. Such an electric power steering device detects a steering torque generated in the steering column by operating the steering handle, and based on the detection signal, the control unit drives and controls the electric motor to assist the steering force of the steering handle. ing.

An electric motor used in such an electric power steering apparatus includes a stator having a cylindrical stator core and a coil wound around a magnetic pole of the stator core, and a coil of each phase provided on one end side in the axial direction of the stator. A terminal block to be connected (for example, see Patent Document 1).
JP 2006-187175 A

  By the way, in the conventional electric motor as described in the above-mentioned Patent Document 1, since the coil is wound around the stator core via the insulator, when the number of turns of the coil increases due to high output, one end side in the axial direction of the stator The position of the terminal block arranged in the position is separated from the stator along the axial direction. As a result, the overall length of the electric motor becomes long. As described above, in the electric motor, the magnetic circuit portion tends to increase in size as the output increases.

  However, in recent years, it has been required to reduce the overall length of the electric motor of the electric power steering apparatus as much as possible due to the vehicle layout.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an electric motor capable of realizing miniaturization even at high output and an electric power steering device using the same.

  In order to solve the above-described problems, an electric motor according to the present invention connects a stator having a cylindrical stator core provided on the outer periphery of a rotor and a coil wound around a magnetic pole of the stator core, and a coil of each phase. A terminal block, and the terminal block is disposed in a space between the output shaft of the rotor and the coil end portion of the coil.

  By adopting such a configuration, it is possible to arrange the terminal block and the coil end portion so as to overlap in the output shaft direction of the rotor. Thereby, even if the number of coil turns of the electric motor increases (high output), the total length of the electric motor can be shortened, so that the miniaturization of the electric motor can be realized.

  The electric motor may further include a bearing that supports the output shaft of the rotor, and the terminal block may be disposed in a space between the bearing and a coil end portion of the coil.

  When such a configuration is adopted, the bearing, the terminal block, and the coil end portion can be arranged so as to overlap each other in the output shaft direction of the rotor, so that the overall length of the electric motor can be further shortened.

  The electric motor further includes a bottomed cylindrical housing having an opening, the bottom of the housing has a recess recessed toward the opening, and the bearing is disposed in a recess formed by the recess. be able to.

  By adopting such a configuration, the bearing can be assembled from the outside of the housing, and the bearing can be positioned and positioned in accordance with the recess of the recess provided in the housing, so that the assembly work of the motor can be simplified. Can do.

  The electric motor further includes a rotational position detector that detects a rotational position of the rotor, the recess includes a plurality of recesses, and the bearing and the rotation detector are disposed in different recesses, and the bearings are disposed. The recess can be formed closer to the opening than the recess in which the rotational position detector is disposed.

  When such a configuration is adopted, the bearing and the rotational position detector can be assembled from the outside of the housing, respectively, and the bearing and the rotational position detector are respectively positioned and positioned in accordance with a plurality of recesses in the recess provided in the housing. Therefore, the assembly work of the electric motor can be simplified.

  The electric motor may further include a power supply member that supplies power to the coil, and the coil connection member and the power supply member included in the terminal block may be connected through a hole provided in a bottom portion of the housing.

  An electric power steering apparatus according to the present invention is an electric power steering apparatus that applies steering assist torque to a steering system of a vehicle, and includes the electric motor.

  According to such a configuration, it is possible to employ an electric motor that can be miniaturized even at high output, and therefore, the layout (the aesthetic appearance of each component arrangement) can be improved by miniaturizing the electric motor. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the electric motor which can implement | achieve size reduction even if it is high output, and an electric power steering apparatus using the same.

  Hereinafter, with reference to the drawings, an embodiment of an electric motor according to the present invention and an electric power steering apparatus including the electric motor will be described.

  First, an electric power steering apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a column-type electric power steering apparatus according to an embodiment.

  As shown in FIG. 1, the electric power steering apparatus 1 includes a steering system (a structure including a steering shaft 11, a housing 12, a rack and pinion type motion conversion mechanism 20, a worm speed reduction mechanism 30 and the like) and a steering assist to the steering system. A power assist electric motor 13 (electric motor) for applying torque and a torque sensor 40 are provided.

  The steering shaft 11 has a steering input shaft 11a and a steering output shaft 11b. The steering shaft 11 is supported inside the housing 12 so as to be rotatable around an axis. The housing 12 is fixed to a predetermined position in the vehicle interior with the lower portion inclined forward. A steering wheel (not shown) is fixed to the upper end of the steering input shaft 11a, and rotates in synchronization with the steering wheel.

  The steering input shaft 11a and the steering output shaft 11b are connected via a torsion bar of the torque sensor 40. The steering torque is transmitted from the steering wheel to the steering output shaft 11b through the steering input shaft 11a. This steering torque is detected by the torque sensor 40. An ECU (Engine Control Unit) (not shown) controls the output of the electric motor 13 based on the detected steering torque.

  The rack and pinion type motion conversion mechanism 20 includes a rack shaft 21, a pinion shaft 22, and a cylindrical case 23 that supports the rack shaft 21 and the pinion shaft 22. The rack shaft 21 is disposed substantially horizontally in the engine room at the front of the vehicle with the longitudinal direction of the rack shaft 21 being the left-right direction of the vehicle. The rack shaft 21 moves freely in the axial direction. The pinion shaft 22 is disposed obliquely with respect to the axis of the rack shaft 21. The pinion shaft 22 has a tooth portion that meshes with a tooth portion of the rack shaft 21. A front wheel is attached to a knuckle (not shown) provided at both ends of the rack shaft 21 of the rack and pinion type motion conversion mechanism 20.

  The pinion shaft 22 and the steering output shaft 11 b are connected by two universal joints 15 and 16 and a connecting member 17. A worm reduction mechanism 30 is disposed at an intermediate position in the axial direction of the steering output shaft 11b. The electric motor 13 applies a steering assist torque to the steering output shaft 11b via the worm reduction mechanism 30.

  Next, the electric motor in the embodiment will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the electric motor in the embodiment, FIG. 3 is an external configuration diagram when the electric motor is viewed from the bottom side, and FIG. 4 is an exploded cross-sectional view of the electric motor in the embodiment. .

  The electric motor 13 (brushless motor) corresponds to the electric motor according to the present invention. The electric motor 13 includes a substantially bottomed cylindrical housing 50 and a substantially annular flange 51 attached to the opening side of the housing 50.

  The housing 50 includes a cylindrical body portion 53 along the motor shaft direction, and a bottom portion 54 that closes one end side of the body portion 53 in the motor shaft direction. A concave portion 55 that is recessed in two steps toward the opening side of the housing 50 is formed at the center position of the bottom portion 54 of the housing 50. A rear bearing 60 (bearing) is arranged in the recess formed by the recess 55a having a small diameter formed on the opening side of the housing 50, and the recess formed by the recess 55b having a large diameter is provided in the recess 55b. A resolver rotor 61 and a resolver stator 62 that constitute a resolver (rotational position detector) are disposed. With this configuration, the rear bearing 60 and the resolver can be assembled from the outside of the housing 50, and the rear bearing 60 and the resolver can be positioned by being aligned with the recess of the recess 55, so that the electric motor can be assembled. Work can be simplified.

  The resolver rotor 61 is fastened to the output shaft 81 of the rotor 80 together with the rear bearing 60 with a nut N2. The resolver stator 62 is fixed to the resolver holder 63, a part of the resolver holder 63 is inserted into the recess 55b, and the resolver holder 63 is fixed to the bottom 54 of the housing 50 using screws S1 and nuts N1. A sensor grommet 68 is provided on the outer side of the resolver holder 63, and the resolver and the sensor harness 69 are connected via the sensor grommet 68. The resolver stator 62 included in the resolver detects the rotational position of the rotor 80 by detecting the rotational position of the resolver rotor 61.

  A cylindrical stator core 71 is fixed to the inner peripheral surface of the body portion 53 of the housing 50, and a coil 73 is wound around the magnetic pole of the stator core 71 via an insulator 72. Stator 70 is constituted by stator core 71, insulator 72, and coil 73. Here, a portion of the coil 73 wound around the stator core 71 that protrudes axially outward from both axial end portions of the stator core 71 is referred to as a coil end portion 73a.

  The flange 51 is fitted to the opening side of the housing 50. A concave portion 51 a that is recessed toward the bottom 54 side of the housing 50 is formed at the center position of the flange 51. A front bearing 85 (bearing) is held in the recess formed by the recess 51a. The output shaft 81 of the rotor 80 is rotatably supported by the front bearing 85 and the rear bearing 60 described above.

  Of the end portions of the output shaft 81 of the rotor 80, the end portion located on the opening side of the housing 50 protrudes outward from the flange 51, and the protruding portion is splined. On the other hand, a connecting member 82 is integrally coupled to the worm of the worm reduction mechanism 30 shown in FIG. A connecting member 82 is splined to the protruding portion of the output shaft 81. That is, the worm is splined to the protruding portion of the output shaft 81 (via the connecting member 82).

  A terminal block 65 fitted and fixed to the insulator 72 is provided in a space formed between the stator 70 and the rotor 80 and the bottom portion 54 of the housing 50. Specifically, the terminal block 65 is disposed in a space formed between the wall surface portion of the recess 55b where the rear bearing 60 is disposed and the coil end portion 73a. By arranging the terminal block 65 in this way, the rear bearing 60, the terminal block 65, and the coil end portion 73a can be arranged so as to overlap in the direction of the output shaft 81 of the rotor 80. In this case, at least a part of the terminal block 65 and a part of the coil end part 73a may overlap, but the greater the degree of the overlap between the terminal block 65 and the coil end part 73a, the greater the total length of the electric motor. There is a merit that it becomes possible to shorten.

  On the terminal block 65, a plurality of bus bars 65a (coil connection members) for connecting the coils 73 of the respective phases are stacked along the motor axial direction. The bus bar 65a and the coil 73 are connected by, for example, welding or TIG (Tungsten Inert Gas) welding. The bus bar 65a is incorporated into the terminal block 65 by, for example, insert molding or insertion.

  An end portion of the bus bar 65 a is drawn out of the housing 50 from a hole portion 56 provided in the bottom portion 54 of the housing 50. The spacer 66 is provided to position and insulate the drawn bus bar 65a. The end of the bus bar 65a drawn out of the housing 50 is connected (connected) to a power harness 64 (power supply member) for power supply by welding or screwing. The terminal cover 67 is attached to cover the connection portion between the end portion of the bus bar 65a and the power harness 64.

  As described above, according to the electric motor 13 of the present embodiment, the terminal block 65 is disposed in a space formed between the wall surface portion of the recess 55b where the rear bearing 60 is disposed and the coil end portion 73a. Therefore, in the direction of the output shaft 81 of the rotor 80, the rear bearing 60, the terminal block 65, and the coil end portion 73a can be arranged to overlap each other. Thereby, even if the number of turns of the coil 73 of the electric motor 13 increases (high output), the entire length of the electric motor 13 can be shortened, so that the electric motor 13 can be downsized.

  Further, in the electric motor 13 according to the present embodiment, the rear bearing 60 can be assembled in the recess of the recess 55a formed in the bottom of the housing 50 so that the electric motor 13 can be assembled. The rear bearing 60 can be easily positioned. Therefore, the assembly work of the electric motor 13 can be simplified.

  Further, in the electric motor 13 according to the present embodiment, the resolver holder 63 to which the resolver stator 62 is fixed can be arranged in the recess of the recess 55b formed in the bottom of the housing 50, so that the electric motor 13 can be assembled. The stator 62 can be assembled from the outside of the housing 50, and the resolver stator 62 can be easily positioned. Therefore, the assembly of the electric motor 13 can be simplified.

  In addition, since the electric power steering apparatus 1 according to the present embodiment employs the electric motor 13 that can achieve downsizing even at high output, the layout can be improved by downsizing the electric motor 13. It becomes possible.

1 is a schematic configuration diagram of a column-type electric power steering device in an embodiment. It is sectional drawing of the electric motor shown in FIG. It is an external appearance block diagram when seeing an electric motor from the bottom side. It is an exploded sectional view of an electric motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus, 13 ... Electric motor, 50 ... Housing, 54 ... Bottom part, 55, 55a, 55b ... Recessed part, 56 ... Hole part, 60 ... Rear bearing, 61 ... Resolver rotor, 62 ... Resolver stator, 64 ... Power harness, 65 ... terminal block, 65a ... bus bar, 70 ... stator, 71 ... stator core, 73 ... coil, 73a ... coil end, 80 ... rotor, 81 ... output shaft, 85 ... front bearing.

Claims (4)

A stator having a cylindrical stator core provided on the outer periphery of the rotor and a coil wound around the magnetic pole of the stator core;
A terminal block for connecting the coils of each phase;
A bearing for supporting the output shaft of the rotor;
A bottomed cylindrical housing having an opening , and
The terminal block is disposed in a space between the coil end portion of the coil and the bearing , and the coil end portion of the coil, the terminal block, and the bearing overlap in the output shaft direction of the rotor. Placed in
The bottom of the housing has a recess that is recessed toward the opening,
The electric motor according to claim 1, wherein the bearing is disposed in a recess formed by the recess . A rotation position detector for detecting the rotation position of the rotor;
The recess is formed with a plurality of recesses,
The bearing and the rotation detector are arranged in different indentations,
Said recesses bearing is disposed, the electric motor according to claim 1, characterized in that it is formed on the opening side than the recess the rotation position detecting section is disposed. A power supply member for supplying power to the coil;
3. The electric motor according to claim 1, wherein the coil connection member and the power supply member included in the terminal block are connected through a hole provided in a bottom portion of the housing. An electric power steering device that applies steering assist torque to a steering system of a vehicle,
An electric power steering device characterized by comprising a motor according to any one of claims 1 to 3.

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