JP2019170013A - 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 and a spacer.SOLUTION: The motor includes: a rotor; a stator; and a bus bar unit. The bus bar unit (100) includes: a plurality of axially overlapping bus bars (120) electrically connected to a coil; an insulating spacer (130) disposed between the bus bars (120); and a bus bar holder (110) holding the bus bars (120) and the spacer (130). The bus bar holder (110) includes: a body (121) that holds the bus bars (120) from a lower side; and a protrusion (122) extending upward from an upper surface of the body (121). The bus bars (120) and the spacer (130) have through holes (124) that allow the protrusions (122) to pass in the vertical direction.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, a motor in which bus bars are stacked in a plurality of layers is known. For example, Japanese Patent Laying-Open No. 2015-76969 (Patent Document 1) discloses a motor in which annular bus bars for U phase, V phase, W phase, and neutral phase are stacked. In Patent Document 1, in a laminating process in which a bus bar and an insulating sheet are sequentially laminated and bonded, an insulating sheet is inserted into an opening formed in a protruding portion protruding in a radial direction in the insulating sheet. A method is disclosed in which the bus bar and the insulating sheet are bonded together in a state where the is positioned.

JP2015-76969A

  In the said patent document 1, the process for fixing a bus-bar and an insulating sheet is complicated.

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

  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 has a coil, and a bus bar unit that is disposed on the upper side in the axial direction of the stator. A plurality of bus bars that are connected to each other in the axial direction, an insulating spacer disposed between the bus bars, and a bus bar holder that holds the bus bar and the spacer. The bus bar holder holds the bus bar from below. And a protrusion extending upward from the upper surface of the main body, and the bus bar and the spacer have a through-hole that passes the protrusion in the vertical direction.

  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 and a spacer.

FIG. 1 is a cross-sectional view of a motor in the embodiment. FIG. 2 is a perspective view of the bus bar unit in the embodiment. FIG. 3 is an exploded perspective view of the bus bar unit in the embodiment. FIG. 4 is a perspective view of the bus bar unit in the embodiment. FIG. 5 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)
With reference to FIGS. 1-4, the motor which is one Embodiment of this invention is demonstrated. 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 40, and a bus bar unit 100.

<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 bearing holder 21, the bearings 22 and 23, the rotor 30, the stator 40, and the bus bar unit 100 therein.

<Bearing holder>
The bearing holder 21 is disposed on the upper side of the stator 40 in the axial direction.

<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>
The stator 40 surrounds the outer side of the rotor 30 in the radial direction. As shown in FIG. 1, the stator 40 includes a stator core 41, an insulator 42, and a coil 43.

  The stator core 41 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. In addition, the stator core 41 may be comprised with one member.

  Stator core 41 includes a core back and teeth. The core back has an annular shape that is concentric with the central axis A. The teeth extend radially inward from the inner side surface of the core back. A plurality of teeth are provided, extend in the radial direction from the core back, and are arranged with a gap in the circumferential direction.

  The insulator 42 covers at least a part of the stator core 41. The insulator 42 is formed of an insulator and is attached to each tooth.

  The coil 43 is configured by exciting the stator core 41 and winding a coil wire around the teeth via the insulator 42. The coil 43 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.

  From each coil 43, two lead lines, that is, a first lead line 43a and a second lead line 43b, are drawn toward the upper side in the axial direction. In the present embodiment, there are four sets of coils, that is, twelve coils 43, each including the U phase, the V phase, and the W phase. Accordingly, there are twelve first and second lead wires 43a and 43b drawn from each coil 43, respectively.

<Bus bar unit>
As shown in FIG. 1, the bus bar unit 100 is disposed on the upper side in the axial direction of the stator 40. As shown in FIGS. 2 to 4, the bus bar unit 100 includes a bus bar holder 110, a plurality of bus bars 120, and a spacer 130. The bus bar holder 110 holds the bus bar 120 and the spacer 130.

[Bus bar holder]
As shown in FIGS. 2 and 3, the bus bar holder 110 includes a main body 111 and a protrusion 112. The main body portion 111 and the protruding portion 112 are constituted by one member. The bus bar holder 110 is made of an insulating material such as resin.

  The main body 111 holds the bus bar 120 from below. The main body 111 is annular. Specifically, when viewed from the upper side in the axial direction, the main body 111 has an annular shape.

  The main body 111 has an upper surface 113 located on the upper side in the axial direction. The upper surface 113 is composed of a plurality of surfaces positioned at different heights in the axial direction. As shown in FIGS. 3 and 4, the upper surface 113 of the present embodiment includes a first surface 113a, a second surface 113b, and a third surface 113c in order from the lower side in the axial direction. The first surface 113a is a surface located at the lowest level. The third surface 113c is a surface located at the uppermost stage. The second surface 113b is a surface located between the first surface 113a and the third surface 113c in the axial direction. The first to third surfaces 113a to 113c extend in the circumferential direction.

  As shown in FIGS. 2 and 3, a step 113 d is provided between the lower surface and the upper surface of the upper surface 113 of the main body 111. 113 d of step parts are comprised by the surface located below, the surface located above, and the surface extended in the axial direction which connects these surfaces. In FIG. 3, the step part 113d is provided in four places, and has two steps of axial height.

  The protrusion 112 extends upward from the upper surface 113 of the main body 111. The protruding portion 112 is provided at the central portion in the radial direction of the main body portion 111. The protrusion 112 is a member for positioning the bus bar 120 and the spacer 130 by being passed through a through hole 124 of the bus bar 120 and a through hole 134 of the spacer 130 described later.

  The number of the protrusions 112 is not limited, but a plurality of protrusions 112 are provided, and in this embodiment, 12 are provided. When a plurality of protrusions 112 are provided, the protrusions 112 are arranged at equal intervals in the circumferential direction. Thereby, the freedom degree of arrangement | positioning of the bus-bar 120 and the spacer 130 can be raised.

  The upper surfaces of the plurality of protrusions 112 have the same axial height and are located on the same plane. For this reason, the axial length of the protrusion 112 extending from the first surface 113a is larger than the axial length of the protrusion 112 extending from the second surface 113b and the third surface 113c. The length in the axial direction of the protrusion 112 extending from the second surface 113b is larger than the length in the axial direction of the protrusion 112 extending from the third surface 113c.

  The plurality of protrusions 112 include a protrusion that passes through the through holes 124 and 134 of the bus bar 120 and the spacer 130, and a protrusion that passes only the through hole 124 of the bus bar 120.

  The protrusion 112 has a cylindrical shape. The size of the protrusion 112 is the same as or slightly smaller than the through holes 124 and 134 of the bus bar 120 and the spacer 130.

[Bus bar]
The plurality of bus bars 120 are electrically connected to the coil 43. The plurality of bus bars 120 overlap in the axial direction.

  The plurality of bus bars 120 are a plurality of phase bus bars. In the present embodiment, as shown in FIGS. 2 to 4, six bus bars 120 are provided. The first to sixth bus bars 120a to 120f correspond to any of the U phase, the V phase, and the W phase, and two bus bars corresponding to each phase are provided. The first to sixth bus bars 120a to 120f are electrically connected to the respective coil wires provided at intervals in the circumferential direction.

  In the present embodiment, the first to sixth bus bars 120a to 120f are three layers. Specifically, the first and second bus bars 120a and 120b are located on the lower side in the axial direction, that is, at the lowest level. The fifth and sixth bus bars 120e and 120f are located on the upper side in the axial direction, that is, on the uppermost stage. The third and fourth bus bars 120c and 120d are located between the first and second bus bars 120a and 120b and the fifth and sixth bus bars 120e and 120f.

  The bus bar 120 is conductive. When viewed from the upper side in the axial direction, each of the bus bars 120 has an arc shape. When the whole of the plurality of bus bars 120 is viewed from the upper side in the axial direction, it has an annular shape. The first to sixth bus bars 120a to 120f partially overlap in the circumferential direction. The axial thicknesses of the first to sixth bus bars 120a to 120f are the same.

  As shown in FIGS. 2 and 3, each of the plurality of bus bars 120 includes a main body portion 121, a coil connection portion 122, and a terminal portion 123. The main body part 121, the coil connection part 122, and the terminal part 123 may be configured by a single member, or a plurality of members may be coupled.

  The main body 121 has an arc shape. The main body 121 has a through hole 124 through which the protrusion 112 of the bus bar holder 110 passes in the vertical direction. The through hole 124 is provided in the central portion of the main body 121 in the radial direction.

  A plurality of through holes 124 are provided. The through holes 124 are arranged at equal intervals in the circumferential direction. In the present embodiment, there are five through holes 124 provided in one bus bar 120. The through hole 124 is circular when viewed from the upper side in the axial direction.

  The coil connection part 122 is connected to the coil 43. The coil connection part 122 extends upward from the radially inner end of the main body part 121. In FIG. 2 to FIG. 4, the coil connection portion 122 is L-shaped and stands up from the radially inner end of the main body portion 121. Specifically, the coil connecting portion 122 is electrically connected to the end portion of the second lead wire 43b of each of the U-phase, V-phase, and W-phase coils 43 by welding or the like. One bus bar 120 has two coil connections 122.

  The terminal portion 123 extends upward from the radially inner side of the main body portion 121. Terminal portion 123 is connected to an external device.

  One bus bar 120 has one terminal portion 123. The axial height of the terminal portion 123 is higher than the axial height of the coil connecting portion 122.

[Spacer]
The spacer 130 is disposed between the bus bars 120. The spacer 130 is insulative. The spacers 130 are located between the bus bars 120 that overlap in the axial direction, and prevent current flow between the bus bars 120.

  A plurality of spacers 130 are provided, and four spacers 130 are provided in this embodiment. The first and second spacers 130a and 130b are located on the lower side in the axial direction. The third and fourth spacers 130c and 130d are positioned on the upper side in the axial direction. The thicknesses of the first to fourth spacers 130a to 130d are the same.

  Each of the plurality of spacers 130 has a through-hole 134 that allows the protrusion 112 of the bus bar holder 110 to pass in the vertical direction. The through hole 134 is provided in the central portion in the radial direction. One spacer 130 is provided with a plurality of through holes 134. The plurality of through holes 134 are arranged at equal intervals in the circumferential direction. In the present embodiment, there are three through holes 134 provided in one spacer 130. The through hole 134 is circular when viewed from the upper side in the axial direction. The through hole 134 of the spacer 130 and the through hole 124 of the bus bar 120 have the same shape.

  Each spacer 130 has an arc shape. The width in the radial direction of the spacer 130 is larger than the width in the radial direction of the main body 121 of the bus bar 120.

[Fastening of bus bar holder, bus bar and spacer]
The bus bar 120 and the spacer 130 penetrate the protrusion 112 of the bus bar holder 110 in the vertical direction. Specifically, as illustrated in FIG. 4, the protrusion 112 extending from the first surface 113 a is provided with the through holes 124 of the first or second bus bars 120 a and 120 b in order from the bottom in the axial direction, the first or second. Through holes 124 in the spacers 130a and 130b, through holes 124 in the third or fourth bus bars 120c and 120d, through holes 124 in the third or fourth spacers 130c and 130d, and fifth or sixth bus bars 120e, A through hole 124 of 120f is located. In the protrusion 112 extending from the second surface 113b, the through holes 124 of the third or fourth bus bars 120c, 120d, the through holes 124 of the third or fourth spacers 130c, 130d, The through holes 124 of the fifth or sixth bus bars 120e and 120f are located. The through hole 124 of the fifth or sixth bus bar 120e, 120f is located in the protrusion 112 extending from the third surface 113c.

  At least the lower end of the protrusion 112 is fixed to the bus bar 120 and the spacer 130. The upper end portion of the protrusion 112 protrudes upward from the through holes 124 and 134 of the bus bar 120 and the spacer 130.

  The protrusion 112 of the bus bar holder 110 is fixed in a state of being passed through the through hole 124 of the bus bar 120 and the through hole 134 of the spacer 130 in the vertical direction. By passing the protrusion 112 of the bus bar holder 110 through the through holes 124 and 134 of the bus bar 120 and the spacer 130, the bus bar 120 and the spacer 130 can be positioned. By fixing in such a positioned state, the bus bar 120 and the spacer 130 can be easily fixed to the bus bar holder 110.

  The method for fixing the protruding portion 112 to the bus bar 120 and the spacer 130 is not particularly limited, but is fixed by, for example, heat welding. That is, the protrusion 112 has a heat welding part for heat-welding the bus bar 120 and the spacer 130. Note that, by thermally welding the protrusion 112 from the uppermost bus bar 120, the lower bus bar 120 and the spacer 130 can all be fixed. In this case, the protrusion 112 and at least a part of the bus bar 120 and the spacer 130 are in contact with each other. In addition, you may fix the projection part 112, the bus-bar 120, and the spacer 130 using a connection member.

  In the step of fixing the bus bar 120 and the spacer 130 to the bus bar holder 110, the bus bar 120 and the spacer 130 may be press-fitted into the protrusion 112, but are preferably inserted. The bus bar 120 and the spacer 130 are preferably heat-welded after being inserted into the protrusion 112.

[Positional relationship of bus bar holder, bus bar and spacer]
The first and second bus bars 120a and 120b are disposed on the first surface 113a located at the lowest level of the bus bar holder 110. First and second spacers 130a and 130b are disposed on the first and second bus bars 120a and 120b. Third and fourth bus bars 120c and 120d are disposed on the first and second spacers 130a and 130b and the second surface 113b. Third and fourth spacers 130c and 130d are disposed on the third and fourth bus bars 120c and 120d. The fifth and sixth bus bars 120e and 120f are disposed on the third and fourth spacers 130c and 130d and the third surface 113c. In this way, the lower bus bar 120 is disposed on the lower surface of the bus bar holder 110.

  The fifth and sixth bus bars 120e and 120f located at the uppermost stage are disposed on the third surface 113c located at the uppermost stage of the bus bar holder 110. Thereby, the connection between the bus bar 120 and the coil 43 is easy.

  Further, the upper surfaces of the fifth and sixth bus bars 120e and 120f arranged on the third surface 113c located at the uppermost stage are positioned at the same height in the axial direction.

  The upper surfaces of the first and second spacers 130a and 130b and the second surface 113b of the bus bar holder 110 are positioned at the same height in the axial direction. Further, the upper surfaces of the third and fourth spacers 130c and 130d and the third surface 113c of the bus bar holder 110 are located at the same height in the axial direction.

  In the present embodiment, since the bus bar holder 110 is provided with the step 113d, the upper surface of the spacer 130 disposed on the upper side of the bus bar 120 disposed on the lower surface of the bus bar holder 110 and the upper surface of the bus bar holder 110 are , Located at the same height in the axial direction. That is, when the spacer 130 is disposed on the lower bus bar 120, the upper surface of the spacer 130 is the same height as the upper surface 113 of the bus bar holder 110. With such a configuration, the bus bar unit 100 can be prevented from becoming larger in the axial direction. Moreover, the external appearance of the bus bar unit 100 is good.

<Other configurations>
The motor 1 may further include a neutral point bus bar. The neutral point bus bar is electrically connected to the end portion of the first lead wire 43a drawn from the coil. The neutral point bus bar is disposed between the phase bus bar and the stator 40. The neutral point bus bar may be held by a bus bar holder 110 that holds a phase bus bar. In addition, the motor 1 may further include a bus bar holder that holds the neutral point bus bar separately from the bus bar holder 110.

<Modification>
In the above-described embodiment, the structure in which the phase bus bar has the through-hole 124 that passes the protrusion 112 of the bus bar holder 110 in the vertical direction has been described as an example. The bus bar 120 having the holes 124 may be a neutral point bus bar.

  In the above-described embodiment, the upper surface 113 of the bus bar holder 110 has been described as an example of a structure including a plurality of surfaces positioned at three different heights in the axial direction. There is no limit. The upper surface 113 of the bus bar holder 110 of the present invention may be composed of a plurality of surfaces located at two different heights, or may be composed of a plurality of surfaces located at four or more different heights.

  Moreover, if the bus-bar unit of this invention is provided with the some bus bar from which an axial direction position differs, the number of bus bars, a shape, etc. will not be limited. Moreover, if the spacer of this invention is arrange | positioned between bus bars, a number, a shape, etc. will not be limited.

(Electric power steering device)
With reference to FIG. 5, 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 and the spacer 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 Stator, 41 Stator core, 42 Insulator, 43 Coil, 43a first lead wire, 43b second lead wire, 100 bus bar unit, 110 bus bar holder, 111, 121 main body, 112 protrusion, 113 upper surface, 113a first surface, 113b second surface, 113c third surface, 113d Step part, 120, 120a to 120f Bus bar, 122 Coil connection part, 123 Terminal part, 124, 134 Through hole, 130, 130a to 130d Spacer, 911 Steering, 912 Wheel, 913 Axle, 914 Steering shaft .

Claims (11)

The rotor,
A stator surrounding a radially outer side of the rotor and having a coil;
A bus bar unit disposed on the axially upper side of the stator;
With
The bus bar unit is
A plurality of bus bars electrically connected to the coil and overlapping in the axial direction;
An insulating spacer disposed between the bus bars;
A bus bar holder for holding the bus bar and the spacer;
Including
The bus bar holder is
A main body for holding the bus bar from below;
A protrusion extending upward from the upper surface of the main body,
Have
The bus bar and the spacer have a through hole through which the protruding portion passes in the vertical direction.   The motor according to claim 1, wherein the protrusions are arranged at equal intervals in the circumferential direction. The upper surface of the main body has a plurality of surfaces positioned at different heights in the axial direction, and a stepped portion is provided between the lower surface and the upper surface,
The motor according to claim 1, wherein the bus bar located on the lower side is disposed on the lower surface. The spacer is disposed on the upper side of the bus bar disposed on the lower surface,
The motor according to claim 3, wherein the upper surface of the spacer and the upper surface of the bus bar holder are located at the same height in the axial direction. The first bus bar is disposed on the lower surface, the first spacer is disposed on the first bus bar,
A second bus bar is disposed on the upper surface;
5. The motor according to claim 3, wherein the upper surface of the first spacer and the upper surface are positioned at the same height in the axial direction.   The motor according to any one of claims 3 to 5, wherein the bus bar located at the uppermost stage is arranged on a surface located at the uppermost stage of the bus bar holder.   The motor according to claim 1, wherein the bus bar has a terminal portion connected to an external device. The bus bar
A bus bar body extending in the circumferential direction;
A coil connecting portion that extends upward from the radially inner end of the bus bar main body and is connected to the coil;
The motor according to claim 1, further comprising:   The motor according to claim 1, wherein the plurality of bus bars are phase bus bars for a plurality of systems.   The motor according to any one of claims 1 to 9, wherein each of the bus bars has an arc shape when viewed from the upper side in the axial direction.   An electric power steering apparatus comprising the motor according to claim 1.