JP2014207860A - Motor, and power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of being miniaturized and of suppressing material cost.SOLUTION: A stator comprises a core and a coil group. The core has a ring part having a ring shape, and a tooth part configured by 12 element tooth parts protruding from the inside of the ring part toward its center. The coil group is configured by 12 coils respectively formed at the element tooth parts. The core is formed by coupling 12 element cores each having one element tooth part. The coil group is configured by six coil pair 40a, 40b and the like each consisting of two coils 4 connected with each other by one conductive wire. When the core is divided into a phase region 27 and a neutral region 28 seen in its axial direction, the one coil 4 in each of the six coil pairs is arranged in the phase region 27, and the other coil 4 is arranged in the neutral region 28.

Description

  The present invention relates to a motor and a power steering apparatus.

  The number of poles (number of magnetic poles of the rotor) and the number of slots (corresponding to the number of magnetic poles on the stator side), which are the basic configuration of the motor, are appropriately determined according to the motor specifications and the like. Usually, the arrangement of each coil is designed for each combination of the number of poles and the number of slots.

  For example, a 14-pole, 12-slot brushless motor that forms a rotating magnetic field by a three-phase coil group including a U phase, a V phase, and a W phase is known (Japanese Patent Laid-Open No. 2006-50690). In the stator of this brushless motor, each phase coil is composed of four divided cores. The divided cores are arranged and fixed in a ring shape so that the coil groups of each phase are in a predetermined arrangement.

The conductive wires derived from these coil groups are generally connected by a bus bar unit provided in the motor.
JP 2006-050690 A

  The configuration of such a bus bar unit is determined by the configuration of the stator, the specifications of the motor, and the like, but is preferably as small and simple as possible.

  The motor of the present invention is a motor having a stator, a rotor, and a bus bar unit. The stator includes a ring-shaped ring portion and twelve element teeth portions projecting from the inside of the ring portion toward the center thereof. A core having a tooth portion, and a coil group composed of 12 coils formed on each of the element tooth portions, each of the cores having one element tooth portion. The coil group is formed of six coil pairs including two coils connected by one conductive wire, and the cores are viewed in the axial direction. When the region and the neutral region are divided into two equal parts, one of the coils in each of the six coil pairs is arranged in the phase region, and the other coil is disposed in the neutral region. The bus bar unit includes a plurality of bus bars and an insulating holder in which the plurality of bus bars are disposed, and the holder has a ring-shaped bus bar support portion, and the bus bar includes: A first semi-circular bus bar and at least second to fourth bus bars in an arcuate shape, the bus bar support portion being viewed in its axial direction and having two phases in the phase side region and the neutral side region When divided, the first bus bar is disposed in the neutral side region, and the at least second to fourth bus bars are disposed in the phase side region so as to overlap.

  According to the present invention, it is possible to reduce the size of a motor or the like and to reduce the material cost.

FIG. 1 is a diagram schematically showing a power steering apparatus according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a configuration of a motor according to a preferred embodiment of the present invention. FIG. 3 is a perspective view schematically showing a stator according to a preferred embodiment of the present invention. FIG. 4 is a schematic diagram for explaining the arrangement of coils according to a preferred embodiment of the present invention. FIG. 5 is a view for explaining a coil pair according to a preferred embodiment of the present invention. FIG. 6 is a wiring diagram of a stator according to a preferred embodiment of the present invention. FIG. 7 is a perspective view schematically showing a bus bar unit according to a preferred embodiment of the present invention. FIG. 8 is a perspective view schematically showing a bus bar according to a preferred embodiment of the present invention. FIG. 9 is a partial cross-sectional view of FIG. (A) is a sectional view taken along line XX, and (b) is a sectional view taken along line YY. FIG. 10 is a schematic diagram for explaining the connection between the stator and the bus bar. FIG. 11 is a partial cross-sectional view of a conventional bus bar unit.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the following description is only illustrations essentially and does not intend restrict | limiting this invention, its application thing, or its use.

  FIG. 1 schematically shows an electric power steering apparatus 100. This power steering device 100 is used to assist the operation of a steering wheel (steering wheel) of a vehicle such as an automobile. The power steering apparatus 100 includes a torque sensor 102 that detects a force applied to the steering wheel via a shaft portion 101 connected to the steering mechanism 200, and a control unit that calculates a necessary assist force based on an output from the torque sensor 102. 103, a motor 50 that generates a rotational force based on an output from the control unit 103, and a speed reduction mechanism 104 that transmits the rotational force of the motor 50 to the steering mechanism 200 while decelerating.

  In a vehicle equipped with the power steering apparatus 100, the motor 50 of the power steering apparatus 100 is driven based on the force applied to the steering wheel, and the rotation of the steering wheel is assisted by the rotational force of the motor 50. Handle operation is possible.

  FIG. 2 schematically shows a cross section of the motor 50. The motor 50 is an inner rotor type motor set in a so-called 8-pole 12-slot. The motor 50 includes a shaft 51, a rotor 52, a stator 1, a bus bar unit 30, and a motor housing 5.

  Specifically, a substantially cylindrical stator 1 as shown in FIG. The substantially cylindrical rotor 52 is fixed around a shaft 51 that is rotatably supported by the motor housing 5. The outer peripheral surface of the rotor 52 is opposed to the inner peripheral surface of the stator 1 with a slight gap. On the outer periphery of the rotor 52, eight magnets 54,..., 54 are provided at equal intervals in the circumferential direction so that N poles and S poles are alternately arranged (8 poles).

  The stator 1 includes a core 2, an insulator 3, and a coil 4. The core 2 is formed by laminating steel plates. The core 2 includes a ring-shaped ring portion 21 and a teeth portion 22. The tooth part 22 is composed of twelve element tooth parts 22a,..., 22a protruding from the inside of the ring part 21 toward the center thereof. A conductive wire is wound around each element tooth portion 22a via an insulating insulator 3, and the coil 4 is formed by so-called concentrated winding. That is, a coil group including 12 coils 4,. Conductive wires are accommodated in 12 spaces (slots) 6,..., 6 between the adjacent element tooth portions 22a (12 slots).

  The core 2 is formed by connecting twelve element cores 2a, ..., 2a. Each element core 2a has an external shape extending in the axial direction and having a substantially T-shaped cross section, and each element has one element tooth portion 22a (see FIG. 5). Conductive wires are wound around every two of these element teeth portions 22a to form a total of six coil pairs 40,. Specifically, for two unconnected element cores 2a and 2a, one conductive wire is continuously wound around each element tooth portion 22a and 22a, and two coils 4 and 4 are connected in series. Coil pair 40 is formed.

  As shown in FIG. 4, the winding direction of the two coils 4 and 4 in each coil pair 40 is set in the same direction when viewed from the front end side of the element tooth portion 22a. In the present embodiment, the winding direction of the two coils 4 and 4 in each coil pair 40 is set clockwise, but may be counterclockwise.

  The coil pair 40 includes two types of coil pairs 40a and 40b having different winding directions of the conductive wires. For example, as shown on the left side of FIG. 4, the coil pair 40 a is a first to third coil pair of two coils 4, 4 that starts with the left coil 4 and ends with the right coil 4. 41, 42, 43. Further, as shown on the right side of FIG. 4, the coil pair 40 b is composed of fourth to sixth coil pairs 44, 45, and 46 that start from the right coil 4 and finish winding with the left coil 4. .

  Specifically, the first to third coil pairs 41, 42, and 43 are started to be wound from the left coils 41b, 42b, and 43b, and are finished to be wound by the right coils 41a, 42a, and 43a, respectively. The fourth to sixth coil pairs 44, 45, 46 are respectively started to be wound from the right side coils 44b, 45b, 46b, and are finished to be wound by the left side coils 44a, 45a, 46a. In addition, the white circle in FIG. 4 shows a winding start end, and a black circle shows a winding end end.

  Such two types of coil pairs 40a and 40b having different winding directions of the conductive wire can be easily formed by a method as shown in FIG. 5, for example. That is, one coil pair 40a (40b) bends the coil pair 40 wound in the same direction as the other coil pair 40b (40a) in the direction of the crossover 47 so as to reverse each element core 2a. What is necessary is just to swap left and right. Therefore, any one of the coil pairs 40a (40b) may be formed in advance, and the other coil pair 40b (40a) may be formed by bending as necessary when connecting the element cores 2a. Excellent in properties.

  These coil pairs 40 are assembled in a pre-designed arrangement so that motor performance suitable for the power steering apparatus 100 can be exhibited.

  For example, as shown in FIG. 4, when the core 2 is partitioned into a first region 24 and a second region 25 by a virtual first partition line 23 that bisects the core 2 in the axial direction, the first to third regions The coil pairs 41, 42, 43 are arranged in the first region 24, and the fourth to sixth coil pairs 44, 45, 46 are arranged in the second region 25.

  For example, the coil 42 a of the second coil pair 42 and the coil 43 a of the third coil pair 43 are disposed between the two coils 41 a and 41 b of the first coil pair 41. In other words, in the first region 24 (or the second region 25), the coils 4 of the other two coil pairs 40 are positioned one by one between the two coils 4 and 4 of the coil pair 40. Be placed.

  The winding direction of each coil pair 40 is set so as to be symmetrical with respect to the first dividing line 23 in the first region 24 and the second region 25.

  Specifically, in the first region 24, the coil 41a, the coil 42a, the coil 43a, the coil 41b, the coil 42b, and the coil 43b are arranged counterclockwise in this order. In the second region 25, the coil 44a, the coil 45a, the coil 46a, the coil 44b, the coil 45b, and the coil 46b are arranged clockwise in this order.

  By arranging in this way, star connection corresponding to the U phase, the V phase, and the W phase as shown in FIG. 6 becomes possible. At that time, when the core 2 is divided into the phase region 27 and the neutral region 28 which are divided into two equal parts by the second comparting line 26 orthogonal to the first comparting line 23 described above when viewed in the axial direction, In the six coil pairs 41, ..., 46, one coil 41a, ..., 46a is arranged in the phase region 27, and the other coil 41b, ..., 46b is arranged in the neutral region 28. . Thereby, all the conductive lines led out from the neutral region 28 can be connected to the neutral point (N).

  By doing so, as will be described next, the connection between the stator 1 and the bus bar unit 30 is simplified and the workability is excellent. Moreover, the bus bar unit 30 and the bus bar 32 can be reduced, and the member cost can be suppressed.

  As shown in FIG. 7, the bus bar unit 30 includes a plurality of bus bars 32 and a holder 31. The holder 31 is an injection-molded product made of an insulating resin such as polybutylene terephthalate (PBT) containing fibers. The holder 31 includes a ring-shaped bus bar support portion 31a, a connector portion 31b provided integrally with the bus bar support portion 31a, and a plurality of support leg portions 31c, ..., 31c for attachment to the motor housing 5.

  The bus bar 32 is a pressed product of a metal plate excellent in conductivity such as copper. Each bus bar 32 is integrally formed with the holder 31 by so-called insert molding. As shown in FIG. 8, the bus bar 32 of the present embodiment extends in a belt shape in the circumferential direction, and has a substantially semicircular first bus bar 32 a and second to fourth subarc arcs having different lengths. Bus bars 32b, 32c, and 32d are provided. A plurality of connection terminals 33, 33,... Protrude from the outer peripheral edge of each bus bar 32. These connection terminals 33, 33,... Are connected to conductive wires led out from the stator 1. Second to fourth connector terminals 34b, 34c, and 34d that rise substantially orthogonally are integrally provided at one end of each of the second to fourth bus bars 32b, 32c, and 32d. The tip ends of the second to fourth connector terminals 34 b, 34 c and 34 d protrude from the connector portion 31 b of the holder 31.

  Each bus bar 32 is embedded in the bus bar support portion 31a so as not to contact each other. Specifically, for example, when the bus bar support portion 31a is divided into two equal parts 35 by dividing the phase side region 37 and the neutral side region 36 when viewed in the axial direction, the first bus bar 32a is neutral. The second to fourth bus bars 32 b, 32 c, and 32 d are disposed in the phase side region 37. As shown to (a) of FIG. 9, in the phase side area | region 37, it arrange | positions so that each of the 2nd-4th bus-bar 32b, 32c, 32d may overlap with a resin layer in between. On the other hand, as shown in FIG. 9B, only the first bus bar 32 a is disposed in the neutral side region 36.

  As shown in FIG. 10, the bus bar unit 30 is connected to the stator 1. That is, the neutral side region 36 of the bus bar unit 30 is arranged corresponding to the neutral region 28 of the stator 1, and the phase side region 37 of the bus bar unit 30 is arranged corresponding to the phase region 27 of the stator 1. The conductive wires derived from the neutral region 28 of the stator 1, specifically, the conductive wires derived from the coil 41b, the coil 42b, the coil 43b, the coil 44b, the coil 45b, and the coil 46b are the first bus bar 32a. Are connected to the connection terminals 33,.

  Conductive wires led out from the phase region 27 of the stator 1 are connected to predetermined connection terminals 33,..., 33 of the second to fourth bus bars 32b, 32c, 32d. Specifically, a conductive wire led out from the coil 43a and the coil 44a is connected to each connection terminal 33, 33 of the second bus bar 32b. Conductive wires derived from the coil 42a and the coil 45a are connected to the connection terminals 33, 33 of the third bus bar 32c. Conductive wires derived from the coil 41a and the coil 46a are connected to the connection terminals 33 and 33 of the fourth bus bar 32d. By doing so, the neutral point (N) is formed by the first bus bar 32a, and the contacts (U, V, W) are formed by the second to fourth bus bars 32b, 32c, and 32d. The star connection is formed.

  FIG. 11 shows an example of a conventional bus bar unit. When conductive wires connected to the neutral point are widely distributed around the entire circumference of the stator, in general, the bus bar for the neutral point should be formed in an annular shape or a dominant arc shape to avoid twisting the conductive wire. There are many. However, if so, the four bus bars 320a, 320b, 320c, and 320d overlap each other as in the bus bar unit of the same figure, thereby increasing the thickness of the bus bar support portion 310a. On the other hand, in the bus bar unit 30 of the present embodiment, the first bus bar 32a for the neutral point is formed in a substantially semicircular shape, and the second to fourth bus bars 32b, 32c, 32d for the contacts of each phase are formed. By forming them in an inferior arc shape and disposing them in the neutral side region 36 and the phase side region 37 of the bus bar unit 30 respectively, the thickness of the bus bar support portion can be reduced and the bus bar unit 30 can be downsized. Connection work with the stator 1 is also facilitated, and workability is improved.

DESCRIPTION OF SYMBOLS 1 Stator 2 Core 2a Element core 4 Coil 21 Ring part 22 Teeth part 22a Element tooth part 27 Phase area 28 Neutral area 40 Coil pair

Claims (9)

In a motor having a stator, a rotor, and a bus bar unit,
The stator is
A core having a ring portion having a ring shape, and a tooth portion composed of twelve element teeth portions protruding from the inside of the ring portion toward the center thereof;
A coil group consisting of twelve coils formed on each of the element teeth portions;
Including
The core is formed by connecting twelve element cores, each having one element tooth portion,
The coil group is composed of six coil pairs composed of two coils connected by one conductive wire,
When the core is bisected into a phase region and a neutral region when viewed in the axial direction, one of the coils in each of the six coil pairs is disposed in the phase region, and the other coil is Arranged in the neutral region,
The bus bar unit is
Multiple busbars,
An insulating holder in which the plurality of bus bars are disposed;
Including
The holder has a ring-shaped bus bar support;
The bus bar
A first semi-circular first bus bar;
At least second to fourth busbars in a subarc shape;
Including
When the bus bar support portion is divided into two equal parts when viewed in the axial direction into the phase side region and the neutral side region, the first bus bar is disposed in the neutral side region, and the at least second to fourth A motor disposed in the phase-side region so that the bus bars overlap. The motor according to claim 1,
The winding direction of the two coils in each coil pair is set in the same direction when viewed from the tip side of the element teeth portion,
Each coil pair is
Of the two coils, first to third coil pairs that start from one of the coils and finish winding on the other coil;
Of the two coils, the fourth to sixth coil pairs that start from the other coil and finish winding with the one coil;
Consisting of
When the core is partitioned into a first region and a second region by dividing the core into two equal parts when viewed in the axial direction, the first to third coil pairs are disposed in the first region, The fourth to sixth coil pairs are disposed in the second region,
When the core is partitioned into the phase region and the neutral region that are equally divided by a second partition line orthogonal to the first partition line when viewed in the axial direction, the first to sixth coil pairs In each, one of the coils is disposed in the phase region, the other coil is disposed in the neutral region, and each coil pair is star-connected,
A stator in which all of the conductive wires derived from the neutral region are connected to a neutral point;
A rotor with 8 magnetic poles,
Including motor. The motor according to claim 1,
Each of the coil pairs is star-connected,
A motor in which all conductive wires derived from the neutral region are connected to a neutral point. The motor according to claim 1,
Furthermore, a motor including a rotor in which the number of magnetic poles is set to eight. In the motor of Claims 1-4,
The motor disposed in the phase-side region so that at least the second to fourth bus bars overlap in the axial direction. The motor according to claim 5, wherein
The motor disposed in the phase-side region so that at least the second to fourth bus bars overlap in the axial direction. The motor according to claim 5 or 6,
Each one end of the second to fourth bus bars is integrally provided with second to fourth connector terminals that rise substantially orthogonally,
The second to fourth connector terminals are arranged to overlap in the circumferential direction,
The second to fourth connector terminals are motors having tips protruding from a connector portion of the holder. The motor according to claim 5,
The motors in which the second to fourth connector terminals are arranged closer to the phase region than the equipartition line. A power steering apparatus including the motor according to claim 1.