JP2019170069A - Motor and electric power steering device - Google Patents

Abstract

To provide a motor and an electric power steering device, capable of easily fixing a bus bar to an insulator.SOLUTION: The motor includes: a rotor; a stator (100) including an insulating insulator (120) surrounding radially outer side of the rotor and a coil (130) wound around the insulator (120); and a bus bar (40) electrically connected to the coil (130). The insulator (120) has two snap-fit units (140, 150) that are elastically deformable in a circumferential direction. The two snap-fit units (140, 150) are arranged in the circumferential direction via a slit (S). The bus bar (40) is held by the two snap-fit units (140, 150).SELECTED DRAWING: Figure 2

Description

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

  Conventionally, a motor in which a bus bar is fixed to a stator is known. For example, in Japanese Patent Application Laid-Open No. 2009-247039 (Patent Document 1), a neutral point cable as a bus bar passes through a connection region and a winding portion alternately with a wall portion of an insulator interposed between stator pieces. Is disclosed.

JP 2009-247039 A

  In Patent Document 1, the process of fixing the neutral point cable is complicated. Further, the neutral point cable may rotate in the circumferential direction.

  An object of the present invention is to provide a motor and an electric power steering device that can easily fix a bus bar to an insulator.

  One aspect of the motor of the present invention includes a rotor, a stator that surrounds the outer side in the radial direction of the rotor and includes an insulating insulator, and a coil wound around the insulator, and is electrically connected to the coil. The insulator has two snap-fit portions that can be elastically deformed in the circumferential direction, the two snap-fit portions are arranged through slits in the circumferential direction, and the bus bar has two snap-fit portions. Held in the department.

  According to one aspect of the present invention, it is possible to provide a motor and an electric power steering device that can easily fix a bus bar to an insulator.

FIG. 1 is a cross-sectional view of a motor in the embodiment. FIG. 2 is a perspective view of a stator and a bus bar in the embodiment. FIG. 3 is a perspective view of the insulator in the embodiment. FIG. 4 is a perspective view of a snap fit portion in the embodiment. FIG. 5 is a perspective view of the bus bar in the embodiment. FIG. 6 is an enlarged perspective view of the bus bar in the embodiment. FIG. 7 is an enlarged perspective view of a state in which the bus bar in the embodiment is fixed to the insulator. FIG. 8 is a schematic diagram of the electric power steering apparatus according to the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  In the following description, as shown in FIG. 1, the central axis A of the rotor 30, that is, the axial direction in which the shaft 31 extends is the vertical direction, the opening side of the housing 10 is the upper side, and the bottom 12 side of the housing 10 is the upper side. Lower side. However, the vertical direction in this specification is for use in specifying the positional relationship, and does not limit the actual direction. That is, the downward direction does not necessarily mean the direction of gravity.

  A direction perpendicular to the central axis A of the rotor 30 is a radial direction, and the radial direction is centered on the central axis A. The circumference of the center axis A of the rotor 30 is defined as the circumferential direction.

  Further, in the present specification, “extending in the axial direction” includes a state extending in the axial direction strictly and a state extending in a direction inclined by less than 45 degrees with respect to the axial direction. Similarly, “extending in the radial direction” in the present specification includes a state extending in the radial direction strictly and a state extending in a direction tilted within a range of less than 45 degrees with respect to the radial direction. Similarly, in this specification, “extending in the circumferential direction” includes a state that extends strictly in the circumferential direction and a state that extends in a direction tilted within a range of less than 45 degrees with respect to the circumferential direction.

(motor)
A motor according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the motor 1 mainly includes a housing 10, a bearing holder 21, bearings 22 and 23, a rotor 30, a stator 100, and a bus bar 40.

<Housing>
The housing 10 has a bottomed cylindrical shape. That is, the housing 10 has a cylindrical portion 11 and a bottom portion 12. The upper part of the housing 10 opens. The housing 10 accommodates the rotor 30 and the stator 100 therein.

<Bearing holder>
The bearing holder 21 is disposed on the upper side in the axial direction of the stator 100.

<Bearing>
The bearings 22 and 23 rotatably support the shaft 31 of the rotor 30. The bearing 22 disposed on the upper side in the axial direction is held by the bearing holder 21. The bearing 23 disposed on the lower side in the axial direction is held on the bottom 12 of the housing 10.

<Rotor>
The rotor 30 includes a shaft 31, a rotor core 32, and a magnet 33. The shaft 31 extends in the axial direction along the central axis A. The shaft 31 is supported by the pair of bearings 22 and 23 and rotates around the central axis A.

  The rotor core 32 is a laminated steel plate in which a plurality of electromagnetic steel plates are laminated in the axial direction. The rotor core 32 is fixed to a shaft 31 that passes through the center of the rotor core 32 and rotates together with the shaft 31. The magnet 33 is fixed to the outer surface of the rotor core 32 and rotates together with the rotor core 32 and the shaft 31. Therefore, the rotor 30 in the present embodiment is an SPM (Surface Permanent Magnet) type. Note that the rotor 30 may be an IPM (Interior Permanent Magnet) type in which a magnet 33 is embedded in a rotor core 32.

<Stator>
[Structure of stator]
The stator 100 surrounds the outer side of the rotor 30 in the radial direction. As shown in FIGS. 1 and 2, the stator 100 includes a stator core 110, an insulator 120, and a coil 130.

[Stator core]
As shown in FIG. 2, the stator core 110 has a plurality of electromagnetic steel plates laminated in the axial direction. The plurality of electromagnetic steel plates are fixed by caulking or the like. Note that the stator core 110 may be composed of a single member.

  Moreover, the stator core 110 of this embodiment is comprised by the division | segmentation core divided | segmented into the circumferential direction, as shown in FIG. The configuration of the stator core is not limited to the split core, and may be a straight core, a round core, or the like.

  Stator core 110 includes a core back 111 and teeth. One divided core includes one core back 111 and one tooth.

  The plurality of core backs 111 have an annular shape that is concentric with the central axis A. The core back 111 has a core back groove 111a that is recessed radially inward on the outer surface on the radially outer side. Each core back groove | channel 111a is located in the radial direction outer side of each teeth.

  The teeth extend radially inward from the inner surface of the core back 111. The teeth are arranged at equal intervals in the circumferential direction on the radially inner side surface of the core back 111. The teeth have an umbrella that extends in the circumferential direction at the radially inner end.

[Insulator]
The insulator 120 covers at least a part of the stator core 110. The insulator 120 is attached to each tooth. As shown in FIG. 3, the insulator 120 is constituted by a divided body.

  The insulator 120 has an insulating property, and is formed of an insulator such as an insulating resin.

  The insulator 120 has a main body 121, an inner flange 122, and an outer flange 123. Each of the plurality of divided bodies has one main body 121, one inner flange 122, and one outer flange 123.

  The main body 121 covers the teeth. The inner flange portion 122 projects radially inward from the inner end of the main body portion 121. The inner flange portion 122 extends in the axial direction and the circumferential direction. The inner flange portion 122 covers the umbrella.

  The outer flange portion 123 protrudes radially outward from the outer end of the main body portion 121. The outer flange portion 123 extends in the axial direction and the circumferential direction. The outer flange portion 123 is located on the radially inner end of the core back 111 and protrudes from the core back 111 upward in the axial direction.

  The outer flange portion 123 has two snap fit portions 140 and 150. The outer flange portion 123 of each divided body has two snap fit portions 140 and 150. The two snap fit portions 140 and 150 are arranged via the slits S in the circumferential direction. That is, the two snap fit portions 140 and 150 are two members arranged in the circumferential direction. The shapes of the two snap fit portions 140 and 150 are symmetric with respect to the slit S.

  The snap fit portions 140 and 150 are made of a material that can be elastically deformed in the circumferential direction. In the present embodiment, the snap fit portions 140 and 150 are made of a material that can be elastically deformed in the circumferential direction and the axial direction.

  The distal end portions of the snap fit portions 140 and 150 protrude to one side in the radial direction. In the present embodiment, the snap fit portions 140 and 150 protrude upward in the axial direction on the upper end surface 124, and the tip ends protrude radially outward.

  The distal end portion includes an outer peripheral surface opposite to the slit S and a lower surface. The outer peripheral surface and the lower surface are in contact with a bus bar 40 described later.

  As shown in FIG. 4, the outer peripheral surface has tapered surfaces 141 and 151 that are inclined toward the slit S toward the lower side in the axial direction. The tapered surfaces 141 and 151 have first chamfered portions 142 and 152. The first chamfered portions 142 and 152 are provided on the radially outer side.

  The lower surface has second chamfered portions 143 and 153. The second chamfered portions 143 and 153 are provided on the radially outer side of the lower surface.

  Returning to FIG. 3, the outer flange portion 123 has a wall portion 125 extending upward from the radially outer end portion. In the radial direction, a gap is provided between the wall portion 125 and the snap fit portions 140 and 150. A bus bar 40 described later is disposed in the gap. The bus bar 40 is held by two snap fit portions 140 and 150 and a wall portion 125.

[coil]
As shown in FIG. 2, the coil 130 is configured by winding a coil wire around a tooth via an insulator 120. The coil 130 is configured by a coil corresponding to any one of the U phase, the V phase, and the W phase, and is arranged in the circumferential direction in the order of the U phase, the V phase, and the W phase. The number of coils 130 is twelve, which is the same as the number of teeth. Therefore, in the present embodiment, there are four sets of coils each including a U-phase coil, a V-phase coil, and a W-phase coil. The connection method of the coil 130 is a so-called delta connection method.

  From each coil 130, two lead lines, that is, a first lead line 131 and a second lead line 132 are drawn toward the upper side in the axial direction. Accordingly, the total number of first lead lines 131 and second lead lines 132 drawn from each coil 130 is 24.

<Bus bar>
As shown in FIG. 2, the bus bar 40 is electrically connected to the coil 130. The bus bar 40 is conductive. The bus bar 40 of this embodiment is a neutral point bus bar.

  A plurality of bus bars 40 are provided, and four bus bars 40 are provided in the present embodiment. Each bus bar 40 has a plate shape extending along the circumferential direction. The plurality of bus bars 40 are arranged side by side in the circumferential direction.

  As shown in FIG. 5, each bus bar 40 includes first to fifth plate-like portions 41 to 45 that are sequentially positioned from one circumferential side to the other side. The 1st-5th plate-shaped parts 41-45 are formed with one member.

  In FIG. 2, the first, third and fifth plate-like portions 41, 43, 45 of the four bus bars 40 are the three first lead wires 131 drawn from the four coil sets, that is, The ends of the first lead wires 131 of the U phase, V phase, and W phase are electrically connected by welding or the like. Thereby, the neutral point bus bar 40 connects one coil set and constitutes an electrical neutral point. Note that the number of plate-like portions to which the coil wires are connected is the same as the number of first lead wires 131.

  As shown in FIG. 5, the second and fourth plate-like parts 42, 44 are located on the radially outer side than the first, third, and fifth plate-like parts 41, 43, 45. As shown in FIGS. 5 and 6, the second and fourth plate-like portions 42 and 44 are provided with a recess 46.

  The recess 46 has a bottom surface 46a and a side surface 46b. The side surface 46b extends upward from both circumferential ends of the bottom surface 46a. The side surface 46b is a tapered surface that is inclined so that the distance between the side surfaces 46b decreases toward the lower side in the axial direction.

  The recess 46 abuts against the two snap fit portions 140 and 150 of the insulator 120. Specifically, the bottom surface 46 a contacts the lower surfaces of the two snap fit portions 140 and 150. The side surface 46b contacts the outer peripheral surface on the opposite side to the slit S in the two snap fit portions 140 and 150.

  A third chamfered portion 47 is provided outside the concave portion 46 in the circumferential direction. In FIG. 6, the 3rd chamfer part 47 is provided in the upper end part of the both-sides 46b.

  A fourth chamfered portion 48 is provided on the other radial side of the bottom surface 46 a of the recess 46. The radial position of the fourth chamfered portion 48 is opposite to the direction in which the tip ends of the snap fit portions 140 and 150 protrude in the radial direction. In the present embodiment, the fourth chamfered portion 48 is provided on the radially inner side of the bottom surface 46 a of the recess 46.

  The bus bar 40 further includes bent portions 49 that are provided on both sides in the circumferential direction of the recess 46 and project toward one radial side. The bent portion 49 constitutes a step in the radial direction. The direction in which the bent portion 49 protrudes in the radial direction is the same as the direction in which the tip ends of the snap fit portions 140 and 150 protrude in the radial direction. In the present embodiment, the bent portion 49 protrudes outward in the radial direction. In this case, the 1st, 3rd and 5th plate-shaped parts 41, 43, and 45 which connect the 2nd and 4th plate-shaped parts 42 and 44 which have the recessed part 46 can be made into plate shape.

  In one bus bar 40, four bent portions 49 are provided. The four bent portions 49 include the vicinity of the boundary between the first and third plate-like portions 41 and 43 in the second plate-like portion 42 and the third and fifth plate-like portions 43 and 45 in the fourth plate-like portion 44. And near the boundary. By positioning the bent portion 49 with the insulator 120, the bus bar 40 can be positioned in the circumferential direction. Moreover, since the notch part containing the recessed part 46 can be plate-shaped by the bending part 49, the yield of the bus-bar 40 can be improved.

  The bent portion 49 may further be provided with a step where the concave portion 46 side is located on the lower side in the axial direction. In this case, since the snap fit portion can be disposed in the axially lower direction, interference with other members can be suppressed.

<Fixing between insulator and bus bar>
As shown in FIGS. 2 and 7, the bus bar 40 is held by the two snap fit portions 140 and 150. Since the slit S is provided between the two snap fit portions 140 and 150, the two snap fit portions 140 and 150 can be deformed in the circumferential direction. By inserting the bus bar 40 into the snap fit portions 140 and 150 in the deformed state, the bus bar 40 is held using the elastic deformation force of the snap fit portions 140 and 150. For this reason, it can prevent that the bus-bar 40 rotates in the circumferential direction. Therefore, the bus bar 40 can be easily fixed to the insulator 120.

  In addition, when the snap fit portions 140 and 150 are made of a material that can be elastically deformed in the axial direction, the bus bar 40 can be held in the axial direction by using a force that elastically deforms the snap fit portions 140 and 150 in the axial direction. .

  In the present embodiment, the snap fit portions 140 and 150 press the bus bar 40 located on the outer periphery of the snap fit portions 140 and 150 toward the outer side in the circumferential direction. That is, the two snap fit portions 140 and 150 are contracted in the circumferential direction by receiving a force from the bus bar 40 in the circumferential direction. Thereby, the bus-bar 40 located in an outer periphery can be hold | maintained using the force which the snap fit parts 140 and 150 spread in the circumferential direction.

  In FIG. 7, the tapered surfaces 141 and 151 that incline toward the slit S toward the lower side in the axial direction abut against the recess 46 of the bus bar 40 and receive force from the bus bar 40 in the circumferential direction. That is, the two snap fit portions 140 and 150 receive a force in the circumferential direction from the side surface 46 b which is a tapered surface of the bus bar 40. By the tapered surfaces 141 and 151, the recess 46 of the bus bar 40 can be easily inserted into the two snap-fit portions 140 and 150 contracted in the circumferential direction.

  In order to more easily insert the bus bar 40 into the snap fit portions 140 and 150, in this embodiment, chamfered portions are provided on the contact surfaces of the snap fit portions 140 and 150 and the bus bar 40. Specifically, as shown in FIG. 4, the tapered surfaces 141 and 151 of the snap fit portions 140 and 150 have first chamfered portions 142 and 152. The lower surfaces of the snap fit portions 140 and 150 have second chamfered portions 143 and 153. Furthermore, as shown in FIG. 6, the bus bar 40 includes a third chamfered portion 47 and a fourth chamfered portion 48 provided on the contact surface with the snap fit portions 140 and 150. The third chamfered portion 47 is provided on the outer side in the circumferential direction of the recess 46. The fourth chamfered portion 48 is provided on the other radial side of the bottom surface 46 a of the recess 46.

  A method for fixing the bus bar 40 to the insulator 120 is, for example, as follows. The two snap fit portions 140 and 150 of the insulator 120 are gripped in a state of being contracted in the circumferential direction so that the interval between the slits S becomes small. In this state, the bus bar is arranged so that the bottom surface 46a of the recess 46 of the bus bar 40 comes into contact with the lower surfaces of the snap fit portions 140 and 150. Thereafter, by releasing the snap fit portions 140 and 150, the outer peripheral surfaces of the snap fit portions 140 and 150 abut on the side surfaces 46b of the recesses 46 of the bus bar. The bus bar 40 is fitted into the snap fit portions 140 and 150, and the position of the bus bar 40 is held by the restoring force directed to the outer side in the circumferential direction of the snap fit portion.

  As described above, the bus bar 40 is fixed to the insulator 120 by being fitted and hooked into the recess 46 of the bus bar 40 using the elastic force of the snap fit portions 140 and 150. In this state, the bus bar 40 and the first lead wire 131 of the coil can be connected by resistance welding or the like. In the connecting step, the positions of the coil 130 and the bus bar 40 are stabilized, so that the quality can be improved.

<Other configurations>
The motor 1 may further include a phase bus bar and a bus bar holder. The bus bar holder is disposed on the upper side of the insulator 120. Specifically, the bus bar holder is disposed on the upper side of the neutral point bus bar 40. The bus bar holder holds the phase bus bar. The phase bus bar is electrically connected to the end of the second lead wire 132 drawn from the coil 130.

<Modification>
In the embodiment described above, the structure in which the snap fit portions 140 and 150 press the bus bar 40 positioned on the outer periphery of the snap fit portions 140 and 150 toward the outer side in the circumferential direction has been described as an example. The motor of the present invention includes a structure in which the snap fit portions 140 and 150 press the bus bar 40 located on the inner periphery of the snap fit portions 140 and 150 toward the inner side in the circumferential direction. That is, when the bus bar 40 is inserted into the insulator 120, the snap fit portions 140, 150 are configured to spread in the circumferential direction, and the bus bar 40 positioned in the slit S is held by the snap fit portions 140, 150. As such a structure, for example, the bus bar has a protrusion, the two snap fit portions sandwich the protrusion, and the protrusion is held using a force that the snap fit portion contracts in the circumferential direction.

  Further, the snap fit portions 140 and 150 of the embodiment are provided at the radially outer end portion of the insulator. If the snap fit part of this invention is provided in the insulator, the position will not be specifically limited.

  Moreover, the front-end | tip part of the snap fit parts 140 and 150 of embodiment protrudes on the radial direction outer side. The shape of the front-end | tip part of the snap fit part of this invention is not specifically limited, You may protrude in radial direction inner side. In the present invention, the taper surfaces 141 and 151 of the snap fit portion may be omitted. In the present invention, the chamfered portions 142, 143, 152, and 153 of the snap fit portion may be omitted.

  Further, the chamfered portion of the bus bar of the embodiment is provided on the outer side in the circumferential direction of the recess and on the inner side in the radial direction of the bottom surface of the recess. The position of the chamfered portion of the bus bar of the present invention is not limited as long as it is provided on the contact surface with the snap fit portion. Further, the chamfered portion of the bus bar may be omitted.

  Moreover, although the bending part 49 of the bus-bar 40 of embodiment protrudes toward a radial direction outer side, the bending part 49 may protrude toward an inner side. Further, the bent portion may be omitted.

  In addition, the bus bar 40 of the embodiment is held by the two snap-fit portions 140 and 150 and the wall portion 125. As long as the bus bar of the present invention is held by the two snap fit portions 140 and 150, the wall portion 125 may be omitted or may be held by a member different from the wall portion 125.

(Electric power steering device)
With reference to FIG. 8, one Embodiment of an apparatus provided with the motor 1 mentioned above is described. In the present embodiment, an example in which the motor 1 is mounted on an electric power steering device will be described.

  The electric power steering device 2 is mounted on a steering mechanism of a vehicle wheel. The electric power steering device 2 of the present embodiment is a column type power steering device that directly reduces the steering force by the power of the motor 1. The electric power steering device 2 includes a motor 1, a steering shaft 914, and an axle 913.

  The steering shaft 914 transmits the input from the steering 911 to the axle 913 having the wheels 912. The power of the motor 1 is transmitted to the axle 913 via a ball screw. The motor 1 employed in the column type electric power steering device 2 is provided inside the engine room. The electric power steering device of the present invention is not limited to the column type, and may be a rack type or the like.

  The electric power steering device 2 includes the motor 1 of the present embodiment. For this reason, the electric power steering apparatus 2 with the same effect as the motor 1 is obtained. That is, since the motor 1 is provided, the electric power steering device 2 that can easily fix the bus bar to the insulator can be realized.

  In addition, although the electric power steering apparatus 2 was mentioned here as an example of the usage method of the motor 1 of embodiment, the usage method of the motor 1 is not limited and can be used widely, such as a pump and a compressor.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above-described embodiments but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Motor, 2 Electric power steering apparatus, 10 Housing, 11 Cylindrical part, 12 Bottom part, 21 Bearing holder, 22, 23 Bearing, 30 Rotor, 31 Shaft, 32 Rotor core, 33 Magnet, 40 Bus bar, 41-45 Plate-shaped part, 46 concave portion, 46a bottom surface, 46b side surface, 47, 48, 142, 143, 152, 153 chamfered portion, 49 bent portion, 100 stator, 110 stator core, 111 core back, 111a core back groove, 120 insulator, 121 main body portion, 122 inner flange portion, 123 outer flange portion, 124 upper end surface, 125 wall portion, 130 coil, 131 first lead wire, 132 second lead wire, 140, 150 snap fit portion, 141, 151 taper surface, 911 steering, 12 wheels, 913 axle 914 steering axis, A central axis, S slit.

Claims (12)

The rotor,
A stator that surrounds a radially outer side of the rotor and includes an insulating insulator and a coil wound around the insulator;
A bus bar electrically connected to the coil;
With
The insulator has two snap-fit portions that are elastically deformable in the circumferential direction,
The two snap-fit portions are arranged via slits in the circumferential direction,
The bus bar is a motor that is held by the two snap-fit portions.   The motor according to claim 1, wherein the snap-fit portion presses the bus bar located on the outer periphery of the snap-fit portion toward the outer side in the circumferential direction. The two snap-fit portions protrude upward in the axial direction,
The bus bar includes a recess,
3. The motor according to claim 2, wherein an outer peripheral surface opposite to the slit in the two snap-fit portions has a tapered surface that abuts the concave portion and is inclined toward the slit side toward the lower side in the axial direction. .   The motor according to claim 3, wherein the tapered surface has a chamfered portion. The front end portion of the snap fit portion has a lower surface that protrudes to one side in the radial direction and abuts against the concave portion,
The motor according to claim 3 or 4, wherein the lower surface has a chamfered portion.   The motor according to any one of claims 3 to 5, wherein the bus bar has a chamfered portion provided on a contact surface with the snap fit portion.   The motor according to claim 6, wherein the chamfered portion of the bus bar is provided on the outer side in the circumferential direction of the concave portion.   The motor according to claim 6 or 7, wherein the chamfered portion of the bus bar is provided on the other radial side of the bottom surface of the concave portion. The bus bar is a plate extending along the circumferential direction,
9. The motor according to claim 3, wherein the bus bar further includes a bent portion that is provided on both sides in the circumferential direction of the recess and protrudes toward one radial side.   The motor according to claim 9, wherein the bent portion is provided with a step where the concave portion is positioned on the lower side in the axial direction. The insulator further includes a wall portion facing the two snap-fit portions and the bus bar,
The said bus-bar is a motor of any one of Claims 1-10 hold | maintained by the two said snap-fit parts and the said wall part.   An electric power steering apparatus comprising the motor according to claim 1.

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