JP6065436B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

  Conventionally, an electric motor in which a stator is constituted by a plurality of divided stator cores is known, and is applied to, for example, an electric power steering device (EPS). The stator of this electric motor has a structure in which a plurality of stator cores are arranged in an annular shape, and includes an insulator that is an insulator covering the teeth of the stator core, and a coil that is formed by winding a coil wire (conductive wire) around the insulator. In such a motor, it is necessary to improve the efficiency of the motor as the diameter of the coil wire increases, and a method for increasing the space factor of the coil by aligning and winding the coil wires without any gap has been proposed. For example, in Patent Document 1, a guide groove for guiding the coil wire is formed in the teeth of the stator core so as to prevent the displacement of the first-stage (first layer) coil wire on both side surfaces of the teeth. It has become. Moreover, in patent document 2, while providing the guide groove which guides a coil wire to a rotating shaft direction in the side surface near the both ends of an insulator, while winding a coil wire in parallel, the rotating shaft side and the opposite side in both ends of an insulator By providing a protruding portion that contacts the coil wire, the coil wire is prevented from being collapsed.

Japanese Patent Laid-Open No. 11-299132 JP 2004-72970 A

  However, in the stator of the electric motor in which the guide groove for winding is provided in the insulator, the protruding part (side wall) at one end formed integrally at both ends of the insulator has the lead wire at the beginning of winding as the lead wire on the outer diameter side. Interfering and pressing the outer diameter side wall. Also, the conductor on the innermost diameter side of the insulator interferes with the conductor on the inner diameter side and rides on the inner diameter side wall. For this reason, a crack etc. generate | occur | produce by the stress concerning the side wall of an insulator, and an insulator may be damaged. Furthermore, when the guide grooves at both ends in the axial direction of the insulator are formed at right angles to and parallel to the protruding direction of the teeth of the stator core, the conductor is shifted in the inner diameter direction for each turn on one end face. In order to arrange in an inclined manner, it is necessary to wind over the wall of the guide groove. Thereby, the coil wire may collapse on the end face of the insulator, and the coil wire may not be wound smoothly.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric motor that can prevent the coil provided in the stator core from collapsing and increase the coil space factor. .

In order to solve the above-described problem, an electric motor according to a first aspect of the present invention has an arcuate yoke portion and a teeth portion protruding radially inward from the yoke portion, and is arranged annularly around a rotation axis. A stator fixed in a housing, comprising: a plurality of stator cores; an insulator that covers each stator core; and a coil that is provided by winding a conductive wire in multiple layers from above the insulator around the teeth portion of each stator core. An electric motor comprising: a rotor on the rotational axis that is rotatably supported by the housing while facing an inner peripheral surface formed by a magnetic pole portion at an inner tip of the teeth portion of the stator, Insulators are formed on the outer periphery of the side surface in the direction of the rotation axis, and are arranged in parallel at a pitch substantially equal to the diameter of the conducting wire. The guide groove and the both ends in the direction of the rotation axis are integrally formed on the outer diameter side and the inner diameter side of the electric motor, and are provided so as to protrude in the stacking direction of the conductors, and regulate the winding position of the conductors And at least one end portion of the insulator, the leading end portion of the abutting portion of the projecting portion on the outer diameter side inclined so that the lead wire faces the guide groove, and the coil The guide groove has a gap of 1/2 of the pitch between the outer diameter side end of the coil and the conductor in the inner diameter side inner last row of the coil contacts the inner diameter side end of the coil. The gist is that the end portion of the radially outer inclined surface of the projecting portion on the inner diameter side in contact with the inner diameter side end portion of the coil is formed to have substantially the same height in the radial direction .

According to the above configuration, the protrusion of the insulator that covers the teeth portion of the stator core of the electric motor has a 1/2 pitch between the distal end of the outer diameter side protrusion and the outer diameter side end of the coil in the radial direction of the rotating shaft. The end of the radially outer inclined surface of the inner diameter side protruding portion and the inner diameter side end of the coil are formed to have substantially the same height in the radial direction. The interference of the conducting wire at the beginning of winding and the running of the conducting wire on the inner diameter side protruding portion on the inner diameter side are suppressed. As a result, the stress applied to the protruding portion of the insulator is reduced, and damage to the insulator can be prevented.

  According to a second aspect of the present invention, in the electric motor according to the first aspect of the invention, the insulator engages with the conductive wire that is inclined at each end and wound in parallel at the pitch at the one end. The gist is that the engaging portion is formed in a planar shape.

  According to the above configuration, since the engaging portion with the conducting wire that inclines the conducting wire in the inner diameter direction for each turn at the one end portion of the insulator of the electric motor is formed in a flat shape, the winding of the conducting wire is suppressed and aligned and wound. I can turn. As a result, the space factor of the coil is improved, and the electric motor can be reduced in size.

  ADVANTAGE OF THE INVENTION According to this invention, the electric motor which can prevent the coil collapse provided in a stator core and can raise the space factor of a coil can be provided.

1 is a longitudinal sectional view showing a schematic configuration of an electric motor according to an embodiment of the present invention. The top view which shows schematic structure of the stator of FIG. The top view which shows an insulator. The side view which shows an insulator.

Hereinafter , as an example of an embodiment of the present invention, an electric motor used in an electric power steering apparatus will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an electric motor according to an embodiment of the present invention. An electric motor (hereinafter, referred to as a brushless motor) 1 is a inner over-rotor brushless motor. As shown in FIG. 1, the brushless motor 1 includes an annular rotor 3 that is connected to a rotating shaft 2 so as to be able to rotate together, an annular stator 4 that surrounds the periphery of the rotor 3, and a first housing that accommodates the rotor 3 and the stator 4. A cylindrical housing (hereinafter referred to as a motor housing) 5 including a single housing 16 and a second housing 17 is provided. For example, in the case of a column assist type EPS motor, a worm speed reducer (not shown) is arranged on the right side in the axial direction of the brushless motor 1 in FIG.

  The rotor 3 includes an annular rotor core 6 coaxially connected to the rotating shaft 2 and a plurality of permanent magnets 7 fixed to the outer periphery of the rotor core 6. The permanent magnet 7 is a multipolar magnet having a plurality of segment magnetic poles. The magnetic poles on the outer peripheral surface of the permanent magnet 7 have N and S poles alternately switched in the circumferential direction of the permanent magnet 7. The permanent magnet 7 has, for example, 10 segment magnetic poles.

The stator 4 includes an annular stator core 8 and a plurality of coils 9 wound around the stator core 8. The stator core 8 is a laminated body in which a plurality of thin plates formed by punching electromagnetic steel plates into a predetermined shape are laminated and fixed in the axial direction of the rotating shaft 2 of the rotor 3 . That is, the stator core 8 is made of a material containing iron. As the electromagnetic steel plate, for example, a silicon steel plate whose surface is subjected to insulation treatment can be used.

  Referring to FIG. 1, the motor housing 5 includes a cylindrical first housing 16 having one end opened, and a cylindrical second housing 17 fitted to the first housing 16. The first housing 16 and the second housing 17 are each formed of a material containing, for example, iron such as carbon steel or aluminum.

  The first housing 16 includes a first tubular portion 19, a first flange portion 20 that protrudes radially outward from the first tubular portion 19 from one end of the first tubular portion 19, and An annular portion 22a having a first insertion hole 21a extending from the other end of the first tubular portion 19 inward in the radial direction of the first tubular portion 19 and through which the rotary shaft 2 is inserted. . A bearing holding portion 23 holding a bearing 37 is formed on the inner peripheral portion of the annular portion 22a.

  The first cylindrical portion 19 of the first housing 16 is longer than the stator core 8 in the axial direction. The stator core 8 is fixed to the inner periphery of the first cylindrical portion 19 by shrink fitting or press fitting. That is, the first housing 16 and the stator core 8 are joined by fitting.

  The second housing 17 includes a second cylindrical portion 24 connected along the outer peripheral portion of the first cylindrical portion 19 of the first housing 16, and a rear end portion of the second cylindrical portion 24. A second annular portion 22b having a second insertion hole 21b extending inward in the radial direction of the second cylindrical portion 24 and through which the rotary shaft 2 is inserted is formed at the center, and the second cylindrical portion 24 And a second flange portion 25 protruding outward in the radial direction of the second cylindrical portion 24 from the outer peripheral surface. A bearing holding portion 29 that holds the bearing 38 is formed at the center portion of the annular portion 22b of the second housing 17 on the stator core 8 side. A resolver 32 attached to the rotary shaft 2 is disposed on the opposite side of the annular portion 22b as a rotation angle sensor that detects the rotational position of the rotor 3. The rotating shaft 2 is rotatably held by the motor housing 5 via a bearing 37 held by the bearing holding portion 23 and a bearing 38 held by the bearing holding portion 29.

  The second flange portion 25 is overlapped with the first flange portion 20. The first flange portion 20 and the second flange portion 25 are constituted by a plurality of bolts (not shown) as fixing means (for example, three locations in the present embodiment) and screw portions provided on the second flange portion 25. Fastened and fixed.

  Thereby, one end of the first housing 16 and one end of the second housing 17 are fixed, and the rotation of the second housing 17 with respect to the first housing 16 is prevented. That is, the plurality of bolts and nuts, and the first flange portion 20 and the second flange portion 25 function as rotation preventing means for preventing the rotation of the second housing 17 with respect to the first housing 16.

  An ECU (not shown) for controlling the brushless motor 1 is attached to the rear end surface (left side in FIG. 1) of the annular portion 22b of the second housing 17 and fixed to the second flange portion 25 with screws. A metal bus bar 30 that is an output terminal of each phase of the brushless motor 1 that is connected to each coil 9 and insulated and supported by the insulator 31 is inserted into the board of the ECU and screwed to the inverter circuit section on the board. Has been. With the above configuration, the drive current controlled by the ECU is supplied to each coil 9 of the brushless motor 1. Thereby, a rotating magnetic field is generated in the coil 9, torque is generated in the permanent magnet 7, and the rotor 3 is rotationally driven. Similarly, the resolver 32 is connected to the ECU board by soldering lead wires as signal input / output terminals.

The brushless motor 1 includes, for example, column assist by a third flange portion 28 that protrudes radially outward of the first tubular portion 19 from the left end in the axial direction of the first tubular portion 19 of the first housing 16 . In this type of electric power steering apparatus, the worm shaft rotating shaft is coupled to a worm shaft rotating shaft 2 via a boss 33 that is fixedly attached to a worm speed reducer (not shown) and that transmits torque.

Next, the figure of the stator 4 before the coil 9 (refer FIG. 1) is provided is shown. FIG. 2 is a plan view showing a schematic configuration of the stator of FIG. In stator 4, a plurality (in this embodiment, twelve) teeth 11 of the stator core 8 is provided to protrude ring shaped outer diameter portion from (yoke) 10 toward the rotating shaft 2 (see Fig. 1) in which, on the inner side tips of the teeth 11, magnetic pole portion 1 2 that spread on both sides is provided in the circumferential direction around the rotation shaft 2. The length in the axial direction of the rotating shaft 2 of each of the tooth portions 11 stacked is larger than the width in the circumferential direction of the tooth portion 11, and both side surfaces of each tooth portion 11 in the circumferential direction are the axes of the rotating shaft 2. Parallel to the direction.

  As shown in FIG. 2, each tooth portion 11 is covered with an insulator 31. In addition, a part of the end surface in the axial direction of the yoke portion 10 and almost the entire end surface in the axial direction of the magnetic pole portion 12 are covered with an insulator 31. The yoke portion 10, the teeth portion 11, and the magnetic pole portion 12 are formed by laminating a plurality of silicon steel plates having shapes corresponding to these in the axial direction. The insulators 31 are provided in order to electrically insulate each tooth portion 11 and its peripheral portion from the coil 9, and are attached to both axial ends of the stator core 8. The insulator 31 is made of a resin material (for example, glass fiber reinforced PPS).

As shown in FIG. 2, the insulators 31 are arranged in parallel at a pitch substantially equal to the diameter of a coil wire (conductive wire, which will be described later) forming the coil 9 in the yoke portion 10 covering the upper end of the tooth portion 11. A plurality of guide grooves 14 for restricting the winding position of the coil wire are provided. The plurality of guide grooves 14 are provided in parallel to a plane that is parallel to the rotation axis 2 and perpendicular to the rotation axis center J1 of the tooth portion 11. One guide groove 14 is continuously formed in the axial direction over one end face and both side faces of the tooth portion 11. Moreover, the guide groove 14 is continuously formed also on the opposite end surface and both side surfaces (not shown) of the tooth portion 11.

Next, FIGS. 3 and 4 are enlarged views showing the vicinity of the insulator 31 located on the uppermost side in FIG. FIG. 3 is a plan view showing the insulator, and FIG. 4 is a side view showing the insulator. The insulator 31 reverses the first insulator 31a and the first insulator 31a which are resin molded products provided with a plurality of guide grooves 14 covering one side (left side in FIG. 1) from the center in the axial direction of the tooth portion 11. The second insulator 31b that covers the other side (the right side in FIG. 1) that is disposed in the direction is formed, and the divided first and second insulators 31a and 31b are fitted into the tooth portion 11 (see FIG. 2) from both sides in the axial direction . Has been. Here, the first insulator 31 a is an insulator on the winding start and winding end side of the coil wire 13.

When the coil 9 is formed, the first stage coil wire 13 is wound around the first insulator 31a along the guide groove 14 from the left side to the right side at the end of the first insulator 31a shown in FIG. In FIG. 3, it is indicated by a one-dot chain line). Here, each coil wire 13 is wound in parallel with an inclination equal to the pitch d of the guide groove 14 and shifted toward the inner diameter side. As a result, each coil wire 13 is wound so as to move in the inner diameter direction by one pitch each time it goes around the outer periphery of the first insulator 31a. Subsequently, the second stage coil wire 13 is wound around the first stage coil wire 13. Each coil wire 13 is wound in the horizontal direction along the guide groove 14 at the end of the second insulator 31b opposite to the first insulator 31a.

As shown in FIGS. 3 and 4, at the end of the first insulator 31a, two side walls ( for preventing the coil wire 13 laminated in the axial direction on the plurality of guide grooves 14 from collapsing to the side ) (Protrusions) 26 and 27 are provided. Hereinafter, the side wall provided on the outer diameter side of the insulator 31 is referred to as the outer diameter side wall 26, and the side wall provided on the inner diameter side is referred to as the inner diameter side wall 27. The side walls 26 and 27 extend in the axial direction Z , which is the stacking direction of the coil wires 13.

As shown in FIG. 3, the outer diameter side wall 26 of the first insulator 31a includes contact portions 34 and 35 that are inclined radially inward. As shown by the alternate long and short dash line in FIG. 3, at the beginning of winding, the contact portion 34 is inclined so that the coil wire 13 faces the guide groove 14. The contact portion 35 is inclined at the same angle in the opposite direction, and guides the coil wire 13 at the end of winding. The apexes (tip portions P) of the contact portions 34 and 35 on the inner surface have a gap of approximately ½ of the pitch d of the guide groove 14 between the outer diameter side end portion B of the coil 9. The inner diameter side wall 27 is formed such that the horizontal end D of the radially outer inclined surface C perpendicular to the rotation axis center J1 has a height h substantially the same as the inner diameter side end A of the coil 9. ing. The first stage of the coil 9 is guided in the winding direction (right direction in FIG. 3) with the coil wire 13 at the start of winding in contact with the contact part 34 and the coil wire 13 in the last row in contact with the contact part 36. The In the fourth stage, the coil wire 13 at the end of winding is guided by being brought into contact with the contact portion 35 and taken out.

Further, as shown in FIG. 4, at the end of the first insulator 31 a, the coil wire 13 is wound around the inner diameter direction by moving to the next row every turn, and the engaging portion 15 with which the coil wire 13 is engaged. Is formed in a planar shape without the guide groove 14. Each coil wire 13 in the first stage is in contact with the planar engaging portion 15 at the end of the first insulator 31a for each turn, and is arranged in parallel with an inclination at the pitch d of the guide groove 14, and adjacent coils. The wire 13 is wound with no gap so as to be in contact with each other (indicated by a one-dot chain line in FIG. 4). Coil wire 13 guided in the winding direction, in FIG. 4 along the guide groove 14 provided in parallel to the axial direction to the first insulator 31a side is wound to extend to the right. 3 is wound around the stator core 8 (see FIG. 2) so as to form a position E where the one-dot chain line at the start of winding and the one-dot chain line at the end of winding intersect in the vicinity of the tip portion P.

  Next, operations and effects of the brushless motor 1 according to the present embodiment configured as described above will be described.

According to the above configuration, the outer diameter side wall 26 of the first insulator 31 a includes the contact portions 34 and 35 that are inclined inward in the radial direction, and at the beginning of winding, the contact portion 34 has the coil wire 13 in the guide groove 14. The contact portion 35 is inclined at the same angle in the opposite direction, and guides the coil wire 13 at the end of winding. Between the tip portions P of the contact portions 34, 35 on the inner surface and the outer diameter side end portion B of the coil 9, there is a gap of approximately ½ of the pitch d of the guide groove 14. The inner diameter side wall 27 is formed so that the horizontal end D of the inclined surface C on the outer side in the radial direction has substantially the same height h as the inner diameter side end A of the coil 9. Further, at the end portion of the first insulator 31a, the coil wire 13 is wound in the inner diameter direction by moving to the next row every turn, and the engaging portion 15 with which the coil wire 13 is engaged does not have the guide groove 14. It is formed in a planar shape. Each coil wire 13 in the first stage is in contact with the planar engaging portion 15 at the end of the first insulator 31a for each turn, and is arranged in parallel with an inclination at the pitch d of the guide groove 14, and adjacent coils. The wire 13 is wound with no gap so as to be in contact with each other. The coil wire 13 guided in the winding direction is wound along a guide groove 14 provided on the side surface of the first insulator 31a in parallel with the axial direction. Then, the coil wire 14 at the start of winding and the coil wire 14 at the end of winding are wound around the stator core 8 so as to form a position E that intersects in the vicinity of the front end portion P.

As a result, the coil wire 13 at the beginning of winding on the outer diameter side interferes with the first-stage coil wire 13 and the last row of coil wires 13 on the inner diameter side is prevented from riding on the inner diameter side wall 27. As a result, the stress applied to the outer diameter side wall 26 and the inner diameter side wall 27 of the first insulator 31a is reduced, and damage to the insulator 31a can be prevented. Further, the coil wire 13 can be wound in an aligned manner while preventing the coil wire 13 from collapsing. As a result, improved space factor of coils 9, it is possible to reduce the size of the brushless motor 1, leading to improved performance of the brushless motor 1.

  Furthermore, by making the first and second insulators 31a and 31b in common or by reducing the amount of glass filler or the like that affects the resin strength of the insulator 31, it is possible to select a low-cost member. Manufacturing costs can be reduced.

  As described above, according to the present embodiment, it is possible to provide a brushless motor that can prevent the coil provided on the stator core from collapsing and increase the coil space factor.

As mentioned above, although embodiment which concerns on this invention was described, this invention can also be implemented with another form.
In the above embodiment, parts having the same shape are used for the first and second insulators 31a and 31b. However, the present invention is not limited to this, and a guide groove 14 is provided in parallel at the end of the second insulator 31b. The inner surface side of the inner diameter side walls 26 and 27 may be formed horizontally.

  Moreover, in the said embodiment, although the insulator 31 with which the some tooth | gear part 11 was mounted | worn showed the division | segmentation shape, it is not only this but it is connected or integrated like the 1st insulator 31a connected or formed integrally in the annular | circular shape. You may be comprised by the shape | molded 2nd insulator 31b. The insulator 31 may be formed by resin molding on the stator core 8.

  In the above embodiment, the stator 4 is a split core, but is not limited thereto, and may be an integral core. The brushless motor 1 provided with the stator 4 is not limited to the inner rotor type, and may be an outer rotor type.

  In the above embodiment, the brushless motor 1 is applied to a so-called column assist type of an electric power steering apparatus (EPS). However, the present invention is not limited to this, and the present invention is not limited to a pinion assist type or rack assist type electric power steering apparatus. You may apply. Moreover, you may apply to other apparatuses (for example, electric oil pump apparatus etc.) using the same brushless motor.

1: brushless motor (electric motor), 2: rotating shaft, 3: rotor, 4: stator,
5: motor housing, 6: rotor core, 7: permanent magnet, 8: stator core,
9: Coil, 10: Yoke part, 11: Teeth part, 12: Magnetic pole part,
13: Coil wire (conductive wire), 14: Guide groove, 15: Engaging portion, 16: First housing,
17: 2nd housing, 19: 1st cylindrical part, 20, 25, 28: Flange part,
21a, 21b: insertion hole, 22a, 22b: annular part, 23, 29: bearing holding part,
24: 2nd cylindrical part, 26: Outer diameter side wall (protrusion part), 27: Inner diameter side wall (protrusion part),
30: Bus bar, 31: Insulator, 31a, 31b: First and second insulators, 32: Resolver, 33: Boss, 34, 35: Abutting portion of outer diameter side wall,
36: contact part of inner diameter side wall, 37, 38: bearing, J1: center of rotation axis,
d: pitch, A: a coil inner diameter side end portion, B: coil outer diameter end, C: inner diameter side wall inclined surface,
D: horizontal edge of the inner diameter side wall inclined surface, E: winding start and winding the intersection of end, P: tip,
Z: Axial direction which is the lamination direction of coils

Claims (2)

A plurality of stator cores each having an arcuate yoke portion and a teeth portion projecting radially inward from the yoke portion, and arranged annularly around a rotation axis;
An insulator covering each stator core;
A coil provided by winding a conductive wire in multiple layers from the insulator on the teeth portion of each stator core; and a stator fixed in a housing;
An electric motor comprising: a rotor on the rotational axis that is rotatably supported by the housing while facing an inner peripheral surface formed by a magnetic pole portion at an inner tip of the teeth portion of the stator.
The insulator is formed on the outer periphery of the side surface in the direction of the rotation axis, and is arranged in parallel at a pitch substantially equal to the diameter of the conducting wire to guide the coil, and
At both ends in the direction of the rotation axis, the electric motor is integrally formed on the outer diameter side and the inner diameter side, and is provided so as to protrude in the laminating direction of the conductive wire, and regulates the winding position of the conductive wire and contacts the coil. A protrusion, and
In at least one end of the insulator, the guide groove is formed between the tip of the contact portion of the protruding portion on the outer diameter side and the outer diameter side end of the coil inclined so that the lead wire faces the guide groove. An end of the radially outer inclined surface of the projecting portion on the inner diameter side , which has a gap of 1/2 of the pitch, and contacts the inner diameter side inner last row of the coil toward the inner diameter side end of the coil The electric motor is characterized in that the portion is formed to have substantially the same height in the radial direction as the inner diameter side end of the coil. The electric motor according to claim 1,
The electric motor according to claim 1, wherein an engaging portion is formed in a planar shape at the one end portion to engage with the conducting wire that is inclined at each turn and wound in parallel at the pitch.

Images