CN113454885A

CN113454885A - Motor

Info

Publication number: CN113454885A
Application number: CN202080014017.6A
Authority: CN
Inventors: 石田尚; 藤原英雄; 斋藤裕也; 梅田智之
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2019-03-28
Filing date: 2020-02-20
Publication date: 2021-09-28
Also published as: WO2020195401A1

Abstract

One embodiment of a motor of the present invention includes: a rotor that rotates about a central axis; a stator having an insulator and a plurality of coils attached to the insulator, the stator being radially opposed to the rotor; a housing made of resin and having a stator embedded therein; and a plurality of bus bars located on one axial side of the stator. The motor is a three-phase motor in which a plurality of coils are classified into a 1 st phase coil, a 2 nd phase coil, and a 3 rd phase coil. The coil has a lead wire extending from a lead portion of the coil. The bus bar has lead wire connection portions to which 2 lead wires extending from 2 coils of the same phase are connected. The position of the lead wire connecting portion in the circumferential direction is a midpoint between the lead portions of the 2 lead wires.

Description

Motor

Technical Field

The present invention relates to a motor.

Background

In recent years, for the purpose of simplifying an assembly process and the like, a motor in which a stator is molded with resin has been developed. Patent document 1 discloses a motor in which a resin portion of a molded stator constitutes a housing.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2007-267568

Disclosure of Invention

Problems to be solved by the invention

The motor is connected to the control device via a bus bar connected to a lead wire drawn out from the coil, and electric power is supplied from the control device to the stator. In the case of molding the stator with a resin material, the assembly process can be further simplified by molding the bus bar together with the stator. However, if the length of the lead wire from the coil to the bus bar is not uniform, the resistance of the current path from the bus bar to the coil becomes non-uniform, and there is a possibility that the stability of the rotation of the motor is impaired.

In view of the above circumstances, an object of the present invention is to provide a motor in which the lengths of a plurality of lead wires are made nearly uniform, thereby improving the stability of rotation.

Means for solving the problems

One embodiment of a motor of the present invention includes: a rotor that rotates about a central axis; a stator having an insulator and a plurality of coils attached to the insulator, the stator being radially opposed to the rotor; a housing made of resin and having the stator embedded therein; and a plurality of bus bars located on one axial side of the stator. The motor is a three-phase motor in which a plurality of coils are classified into a 1 st phase coil, a 2 nd phase coil, and a 3 rd phase coil. The coil has a lead wire extending from a lead portion of the coil. The bus bar has a lead wire connection portion to which 2 lead wires extending from 2 coils of the same phase are connected. The position of the lead wire connecting portion in the circumferential direction is a midpoint between the lead portions of the 2 lead wires.

Effects of the invention

According to one embodiment of the present invention, a motor is provided in which the lengths of a plurality of lead wires are made nearly uniform, thereby improving the stability of rotation.

Drawings

Fig. 1 is a sectional view of a motor according to an embodiment.

Fig. 2 is a perspective view of a bus bar and a stator according to an embodiment, and is a view showing a state of being disassembled from each other.

Fig. 3 is a perspective view of a bus bar and a stator according to an embodiment, and is a view showing a state of being assembled with each other.

Fig. 4 is a partial sectional view showing a state of a mold for molding a housing and a stator in the mold according to an embodiment.

Fig. 5 is a schematic plan view of a stator and a bus bar of one embodiment as viewed from the lower side.

Fig. 6 is a partial sectional view of a motor having a bus bar of a modification.

Fig. 7 is a schematic plan view of a stator and bus bars of a modification as viewed from below.

Detailed Description

Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings.

In the following description, a direction parallel to the central axis J (see fig. 1) is simply referred to as an "axial direction" or a "vertical direction", a radial direction about the central axis J is simply referred to as a "radial direction", and a circumferential direction about the central axis J, that is, a direction around the central axis J is simply referred to as a "circumferential direction". In the present specification, one side in the axial direction along the center axis J is simply referred to as "lower side", and the other side is simply referred to as "upper side". The vertical direction in this specification is used for the purpose of explanation only, and is not limited to the posture during use and circulation of the motor.

In the present specification, the side that advances counterclockwise when viewed from below, i.e., the side that advances in the direction of arrow θ, is referred to as the "circumferential side". The side that advances clockwise when viewed from the upper side toward the lower side in the circumferential direction, i.e., the side that advances in the opposite direction to the arrow θ, is referred to as the "other side in the circumferential direction".

Fig. 1 is a sectional view of a motor 1 according to an embodiment. As shown by a phantom line (two-dot chain line) in fig. 1, a control device 9 is attached to a lower side of the motor 1. The control device 9 supplies electric power to the motor 1. The motor 1 of the present embodiment is a three-phase motor. The control device 9 supplies an alternating current to the motor 1.

The motor 1 includes: a rotor 10; a stator 20 surrounding the rotor 10; an upper bearing 15 and a lower bearing (bearing) 16 that hold the rotor 10 to be rotatable with respect to the stator 20; an upper bearing holder 40 for holding the upper bearing 15; a lower bearing holder (bearing holder) 70 that holds the lower bearing 16; a housing 30; and a plurality of bus bars 80.

The rotor 10 rotates about a central axis J extending in the vertical direction. The rotor 10 includes a shaft 11, a rotor core 12, and a rotor magnet 13, wherein the shaft 11 extends along a central axis J.

The shaft 11 is supported by an upper bearing 15 and a lower bearing 16 so as to be rotatable about the center axis J. A rotor core 12 is fixed to an outer peripheral surface of the shaft 11. Further, a rotor magnet 13 is fixed to the outer peripheral surface of the rotor core 12. The plurality of rotor magnets 13 may be embedded in the rotor core 12.

The upper bearing 15 is located at an upper side of the stator 20, and the lower bearing 16 is located at a lower side of the stator 20. The upper bearing 15 supports the upper end of the shaft 11, and the lower bearing 16 supports the lower end of the shaft 11. That is, the upper bearing 15 and the lower bearing 16 rotatably support the rotor 10. The upper bearing 15 and the lower bearing 16 of the present embodiment are ball bearings. The upper bearing 15 and the lower bearing 16 may be other types of bearings such as needle bearings.

The upper bearing holder 40 is located at an upper side of the stator 20. The upper bearing holder 40 is made of metal. The upper bearing holder 40 includes a holder cylindrical portion 41, an upper plate portion 42 extending radially inward from an upper end of the holder cylindrical portion 41, and a holder flange portion 43 extending radially outward from a lower end of the holder cylindrical portion 41.

The holder cylindrical portion 41 is cylindrical with the center axis J as the center. The upper bearing 15 is disposed radially inward of the holder cylindrical portion 41. The upper plate portion 42 covers the upper side of the outer ring of the upper bearing 15. The upper plate portion 42 is provided with a center hole 42a penetrating in the axial direction. The shaft 11 is inserted through the central hole 42 a. The radially outer edge of the retainer flange 43 is embedded in the casing 30. That is, at least a part of the upper bearing holder 40 is embedded in the housing 30.

The lower bearing holder 70 is located at the lower side of the stator 20. The lower bearing holder 70 is made of resin. The lower bearing holder 70 has a disc shape when viewed in the axial direction. The lower bearing holder 70 is fixed to the housing 30 at an outer edge portion.

A center hole 72a is provided in the center of the lower bearing holder 70 as viewed in the axial direction. The lower end of the shaft 11 is inserted through the central hole 72 a. An inner wall surface 71a surrounding the lower bearing 16 from the radially outer side and holding the lower bearing 16 is provided around the center hole 72 a.

The stator 20 surrounds the rotor 10 from the radially outer side. The stator 20 is radially opposed to the rotor 10. The stator 20 includes a stator core 21, a plurality of insulators 22, and a plurality of coils 29 attached to the insulators.

The stator core 21 includes an annular core back 21a centered on the central axis J and a plurality of teeth 21b extending radially inward from the core back 21 a. The plurality of teeth 21b are provided at equal intervals in the circumferential direction around the center axis J.

The coil 29 is attached to the tooth portion 21b via the insulator 22. The end of the coil 29 is connected to a bus bar 80 disposed below the stator 20. The bus bar 80 is connected to a control device not shown. Power is supplied from the control device to the coil 29 via the bus bar 80.

The insulating member 22 is constituted by an insulating member. The insulator 22 is, for example, a resin member. The insulator 22 is attached to the tooth portion 21 b. The insulator 22 is interposed between the tooth portion 21b and the coil 29. The insulator 22 has an upper member 22A and a lower member 22B. The upper member 22A is attached to the stator core 21 from above. The upper member 22A surrounds the upper end surface of the core back 21a and the upper half of the circumferential both end surfaces of the tooth portion 21 b. The lower member 22B is attached to the stator core 21 from below. The lower member 22B surrounds the lower end surface of the core back 21a and the lower half portions of the circumferential both end surfaces of the tooth portion 21B.

In this specification, the circumferential end surfaces of the teeth 21b are surfaces of the teeth 21b that are perpendicular to the radial direction and the axial direction and face in the circumferential direction, and are surfaces of the teeth 21b arranged in the circumferential direction that face each other.

The insulator 22 includes an insulator body 25, an inner wall 23, and an outer wall 24. The insulator main body portion 25 surrounds the entire outer peripheral surface of the tooth portion 21 b. The insulator main body portion 25 is interposed between the outer peripheral surface of the tooth portion 21b and the coil 29.

The inner wall portion 23 is located radially inward of the insulator main body portion 25 and extends in the circumferential direction. The inner wall portion 23 overlaps with the radially inner end portion of the tooth portion 21b as viewed in the axial direction. The inner wall portion 23 is located radially inward of the coil 29. The inner wall portion 23 restricts the coil 29 wound around the tooth portion 21b from moving radially inward.

The inner wall portions 23 are provided on the upper member 22A and the lower member 22B, respectively. In the following description, the inner wall portion 23 of the upper member 22A is referred to as an upper inner wall portion 23A. The inner wall portion 23 of the lower member 22B is referred to as a lower inner wall portion 23B. The upper inner wall portion 23A extends upward relative to the insulator main body portion 25. The lower inner wall portion 23B extends downward relative to the insulator body portion 25.

The outer wall portion 24 is located radially outward of the insulator main body portion 25 and extends in the circumferential direction. The outer wall portion 24 overlaps the core back portion 21a as viewed in the axial direction. The outer wall portion 24 is located radially outward relative to the coil 29. The outer wall portion 24 restricts the coil 29 wound around the tooth portion 21b from moving radially outward.

The outer wall portions 24 are provided to the upper member 22A and the lower member 22B, respectively. In the following description, the outer wall portion 24 of the upper member 22A is referred to as an upper outer wall portion 24A. The outer wall portion 24 of the lower member 22B is referred to as a lower outer wall portion 24B. The upper outer wall portion 24A extends upward relative to the insulator main body portion 25. The lower outer wall portion 24B extends downward relative to the insulator main body portion 25. As will be described later in detail, the lower outer wall portion 24B is provided with a recess 24c into which the bus bar 80 is inserted.

The housing 30 is made of a resin material. In the present specification, the resin material may be a composite material reinforced with a fiber material such as glass fiber or carbon fiber. That is, the housing 30 may be made of a fiber-reinforced resin material. The case 30 may be a thermosetting resin or a thermoplastic resin.

The stator 20, the bus bar 80, and the upper bearing holder 40 are embedded in the housing 30. Thereby, the case 30 holds the bus bar 80, the stator 20, and the upper bearing holder 40. The housing 30 is insert-molded while the stator 20, the bus bar 80, and the upper bearing holder 40 are held in a mold. That is, since the stator 20, the bus bar 80, and the upper bearing holder 40 can be embedded in the housing 30 at one time, the assembly process of the motor 1 can be simplified.

The housing 30 has: a body 31 that holds the stator 20; an upper annular portion 32 located above the body portion 31; a bus bar holder portion 36 that holds a bus bar 80; a lower tube (tube) 37 extending downward from the lower surface of the body 31; a holding wall portion (wall portion) 39 located below the body portion 31 and to which a lower bearing holder 70 is fixed; and a holder holding portion 38 that holds an upper bearing holder 40.

The stator 20 is embedded in the body 31. The body 31 surrounds the stator 20 at the upper side, the lower side, and the radial outside. The main body portion 31 surrounds the tooth portion 21b and the coil 29 and is also provided between the tooth portion 21b and the coil 29 adjacent to each other in the circumferential direction. The inner peripheral surface of stator core 21 is exposed from case 30.

The upper annular portion 32 extends annularly in the circumferential direction. The upper annular portion 32 has a plurality of ribs 35 extending in the circumferential direction and the radial direction. Thereby, the upper annular portion 32 reinforces the housing 30.

The lower tube portion 37 is cylindrical with the center axis J as the center. The lower tube 37 extends downward from the body 31. The outer peripheral surface 37b of the lower tube portion 37 is continuous with the outer peripheral surface of the body portion 31. The lower cylindrical portion 37 surrounds, from the radially outer side, lower end portions of the plurality of bus bars 80 protruding from the housing 30.

A control device 9 for controlling the motor 1 is attached to the lower cylinder 37. A socket portion 9a is provided on the upper surface of the control device 9. The socket portion 9a is a hole portion extending downward from the upper surface. The bus bar 80 is electrically connected to the control device 9 by being inserted into the socket portion 9 a. Further, the control device 9 has a mounting surface 9b facing radially outward. The mounting surface 9b is a cylindrical surface centered on the central axis J. The mounting surface 9b is fitted to the inner peripheral surface 37a of the lower cylindrical portion 37. Therefore, the inner peripheral surface 37a of the lower tube portion 37 functions as a surface for aligning the motor 1 and the controller 9 with each other.

The holding wall portion 39 protrudes downward from the lower surface of the body portion 31. That is, the holding wall portion 39 is located below the stator 20. The retaining wall portion 39 extends in the circumferential direction. The retaining wall portion 39 is located radially inward of the lower tube portion 37 and the bus bar holder portion 36. A recessed groove 39g is provided between the holding wall portion 39 and the bus bar holder portion 36 on the surface facing downward of the housing 30. Thus, as compared with the case where the holding wall portion 39 and the bus bar holder portion 36 are connected, the thickness of the housing 30 can be suppressed from being locally increased, and sink marks of the housing 30 can be suppressed.

The lower bearing holder 70 is fixed to the holding wall portion 39 by means of thermocompression bonding or the like. A lower bearing holder 70 is fitted to an inner peripheral surface 39a of the holding wall portion 39. Thereby, the lower bearing holder 70 is positioned in the radial direction with respect to the housing 30.

The bus bar holder portion 36 is located on the lower side of the main body portion 31. The bus bar holder portion 36 is located radially inward of the lower cylinder portion 37. 6 bus bars 80 are embedded in the bus bar holder portion 36. The bus bar 80 protrudes downward from the lower surface of the bus bar holder portion 36.

The bus bar 80 is located at the lower side of the stator 20. The bus bar 80 is made of a metal material (e.g., copper alloy) having high conductivity. The bus bar 80 has a plate shape. The bus bar 80 is formed by press working a plate material.

The bus bar 80 is connected to the lead wire 28 extending from the coil 29. The lead wire 28 is a winding start end or a winding end of the coil 29, and in the present embodiment, the lead wire 28 is a winding end of the coil 29. In the present embodiment, the winding start end of the coil 29 is connected to a neutral point bus bar, not shown.

The bus bar 80 has lead wire connection portions 81 connected to the lead wires 28, external connection terminal portions 82 extending downward from the lead wire connection portions 81, and supported portions 83 extending upward from the lead wire connection portions 81.

The lead wire connection portion 81 includes a base portion 81a, a folded portion 81b folded back from an upper end of the base portion 81a, and a bent portion 81c located at a lower end of the folded portion 81 b. The lead wire connecting portion 81 is connected to the external connecting terminal portion 82 and the supported portion 83 at the base portion 81 a.

The base portion 81a and the folded portion 81b extend substantially parallel to each other in the axial direction with the radial direction being the plate thickness direction. The base portion 81a and the folded portion 81b are radially opposed to each other. In the present embodiment, the folded portion 81b is located radially outward of the base portion 81 a. The base 81a and the folded portion 81b sandwich 2 lead wires 28 therebetween.

The bent portion 81c extends downward from the lower end of the folded portion 81 b. The curved portion 81c is inclined toward the base portion 81a side as going toward the lower side. The distance between the lower end of the bent portion 81c and the base portion 81a is smaller than the wire diameter of the lead wire 28. The lower end of the curved portion 81c may contact the base portion 81 a. The bent portion 81c prevents the lead wire 28 from coming off the region sandwiched between the base portion 81a and the folded portion 81 b.

The base portion 81a, the folded portion 81b, and the 2 lead wires 28 are fixed to each other and electrically connected by, for example, soldering. Specifically, in a state where the lead wire 28 is sandwiched between the base portion 81a and the folded portion 81b, the base portion 81a and the folded portion 81b are sandwiched between 2 electrodes, and current is passed through the electrodes, thereby performing welding. However, the connection of the lead wire connection portion 81 and the lead wire 28 is not limited to resistance welding. For example, the fixing may be performed by welding other than resistance welding such as arc welding, soldering, adhesion with a conductive adhesive, or the like.

The external connection terminal portions 82 extend in the axial direction with the radial direction as the plate thickness direction. The upper end of the external connection terminal portion 82 is connected to the base portion 81a of the lead wire connection portion 81. The upper end of the external connection terminal portion is embedded in the case 30. The lower end of the external connection terminal 82 is exposed from the case 30.

The supported portion 83 is supported by the insulator 22. Therefore, the bus bar 80 can be temporarily fixed to the stator 20 in a state before the housing 30 is molded. As a result, the work of holding the stator 20 and the bus bar 80 before molding in the mold for molding the housing 30 is facilitated.

Fig. 2 is a perspective view of the bus bar 80 and the stator 20, and is a view showing a state of being exploded from each other. Fig. 3 is a perspective view of the bus bar 80 and the stator 20, and is a view showing a state of mutual assembly.

As shown in fig. 2, the supported portion 83 has a pair of leg portions 83 a. The leg portion 83a extends from the base portion 81a in the axial direction with the radial direction as the plate thickness direction. The pair of leg portions 83a are arranged in the circumferential direction. The pair of legs 83a have outer side surfaces 83ab facing opposite sides to each other.

The insulating member 22 has a recess 24c opened downward. The recess 24c of the present embodiment is a through hole that penetrates the insulator 22 in the axial direction. The recess 24c has a rectangular shape with a long side extending in the circumferential direction and a short side extending in the radial direction, as viewed in the axial direction. The recess 24c has a pair of opposing surfaces 24cb that circumferentially oppose each other. The pair of opposing faces 24cb constitutes a short side of the recess 24c as viewed in the axial direction. The distance dimension between the pair of opposing surfaces 24cb is slightly smaller than the distance dimension between the pair of outer side surfaces 83 ab.

As shown in fig. 3, the pair of leg portions 83a are inserted into the recessed portions 24c of the insulator 22. The pair of opposing surfaces 24cb of the recess 24c are in contact with the outer side surfaces 83ab of the different leg portions 83a, respectively. The pair of legs 83a are pressed by the different facing surfaces 24cb, and elastically deform in the direction of approaching each other. The outer surface 83ab and the opposing surface 24cb are subjected to surface pressure, and the supported portion 83 is stably supported by the insulator 22 in the recess 24c by frictional resistance. Therefore, in the manufacturing process, before the molding process of embedding the bus bar 80 in the housing 30 is performed, the bus bar 80 can be prevented from being detached from the stator 20.

Fig. 4 is a partial sectional view showing a mold 90 for molding the housing 30 and a state of the stator 20 in the mold 90.

A cavity C filled with a resin material constituting the housing 30 is provided inside the mold 90. The mold 90 has a 1 st mold 91 and a 2 nd mold 92 surrounding the cavity C. The 1 st die 91 and the 2 nd die 92 are arranged opposite to each other in the axial direction. The 2 nd die 92 is located on the lower side with respect to the 1 st die 91. The 1 st die 91 and the 2 nd die 92 can be separated relatively vertically at the parting line PL. In the present embodiment, parting line PL is disposed on the same plane as the lower end surface of stator core 21.

The 1 st mold 91 is a region above the parting line PL, and molds the body portion 31, the upper annular portion 32, and the retainer holding portion 38. On the other hand, the 2 nd die 92 is a region below the parting line PL, and molds the bus bar holder portion 36 and the lower tube portion 37.

The 2 nd die 92 has a 1 st annular groove 92a, a 2 nd annular groove 92c, and a holding recess 92b that are open to the upper side. The 2 nd die 92 has an inner block 92h and an outer block 92j which are separable from each other on a separation surface 92p extending downward from the bottom surface of the 1 st annular groove 92 a. The inner block 92h has a circular outer peripheral surface in plan view, and the outer block 92j has a circular inner peripheral surface in plan view. The 2 nd die 92 is configured by fitting the inner peripheral surface of the inner block 92h to the outer peripheral surface of the outer block 92 j. Thus, the inner block 92h and the outer block 92j are accurately aligned with each other.

The 1 st annular groove 92a is recessed downward and extends in the circumferential direction. The resin filled in the 1 st annular groove 92a constitutes the lower cylindrical portion 37 of the housing 30. A 1 st inner wall surface 92aa facing radially outward of the 1 st annular groove 92a is a surface of the inner block 92 h. Further, a 2 nd inner wall surface 92ab of the 1 st annular groove 92a facing radially inward is a surface of the outer block 92 j. The inner block 92h molds the inner peripheral surface 37a of the lower tube portion 37 on the 1 st inner wall surface 92 aa. In addition, the outer block 92j forms the outer peripheral surface 37b of the lower tubular portion 37 of the 2 nd inner wall surface 92 ab.

The holding recess 92b is disposed radially inward of the 1 st annular groove 92 a. The holding recess 92b is provided in the inner block 92 h. The holding recess 92b is recessed downward to hold the bus bar 80. The shape of the holding recess portion 92b substantially matches the cross-sectional shape of the external connection terminal portion 82 of the bus bar 80 as viewed in the axial direction. The housing 30 is molded in a state where the front end of the external connection terminal portion 82 is held by the holding concave portion 92b of the mold 90. This can expose the tip of the bus bar 80 from the housing 30, and can improve the positional accuracy of the bus bar 80 with respect to the housing 30.

The 2 nd die has a tapered surface 92ba located at the opening of the holding recess 92 b. The tapered surface 92ba surrounds the opening of the holding recess 92b when viewed in the axial direction. The tapered surface 92ba is inclined downward as it approaches the opening of the holding recess 92 b. The tapered surfaces 92ba lead the external connection terminal portions 82 into the holding recessed portions 92b in the process of inserting and holding the bus bars 80 into the holding recessed portions 92 b. Therefore, by providing the tapered surface 92ba, the external connection terminal portion 82 can be inserted into the holding recessed portion 92b without being damaged.

As shown in fig. 1, the bus bar holder portion 36 of the housing 30 has a raised portion 36a that protrudes downward (one side in the axial direction). The ridge portion 36a is a region formed by the tapered surface 92 ba. Therefore, the external connection terminal portions 82 protrude downward from the bus bar holder portion 36 at the bulging portions 36 a. In the present embodiment, the external connection terminal portion 82 protrudes downward from the bus bar holder portion 36 at the top of the raised portion 36 a.

According to the present embodiment, the bus bar 80 has the external connection terminal portion 82 exposed from the housing 30. Further, the lower cylindrical portion 37 surrounds the external connection terminal portion 82 from the radially outer side. The inner peripheral surface 37a of the lower tube portion 37 contacts the mounting surface 9b of the control device 9, and functions as a surface for positioning the control device 9 with respect to the motor 1. According to the present embodiment, since the lower cylindrical portion 37 surrounds the external connection terminal portion 82 from the radially outer side, the lower cylindrical portion 37 can be molded by 1 mold (2 nd mold 92) and the external connection terminal portion 82 can be held. In particular, in the present embodiment, the inner peripheral surface 37a of the lower tube portion 37 is molded by the same block (inner block 92h) and the external connection terminal portion 82 is held. As a result, the positional accuracy of the external connection terminal portion 82 with respect to the inner peripheral surface 37a of the lower tube portion 37 can be improved, and the bus bar 80 can be smoothly inserted into the socket portion 9a of the control device 9.

The 2 nd annular groove 92c is disposed radially inward of the 1 st annular groove 92a and the retaining recess 92 b. The 2 nd annular groove 92c is recessed downward and extends in the circumferential direction. The 2 nd annular groove 92c is provided in the inner block 92 h. The resin filled in the 2 nd annular groove 92c constitutes the holding wall portion 39 of the case 30.

As described above, the lower bearing holder 70 is fitted to the inner peripheral surface 39a of the holding wall portion 39. Therefore, the holding wall portion 39 supports the shaft 11 via the lower bearing holder 70 and the lower bearing 16. According to the present embodiment, the inner peripheral surface of the holding wall portion 39 and the inner peripheral surface 37a of the lower cylindrical portion 37 can be molded by the same block (inner block 92 h). Therefore, the positional accuracy of the inner peripheral surface 37a of the lower tube portion 37 with respect to the inner peripheral surface 37a of the lower tube portion 37 can be improved. As a result, the positional accuracy of the shaft 11 with respect to the control device 9 attached to the lower cylinder 37 can be improved.

Next, a state in which the lead wires 28 are arranged in the stator 20 of the present embodiment will be described in detail.

Fig. 5 is a schematic plan view of the stator 20 and the bus bar 80 as viewed from below. The stator 20 of the present embodiment has a 4-system three-phase circuit. Each three-phase circuit is formed by a star connection. The winding start ends of all the coils 29 are connected to a neutral point bus bar (not shown) as a neutral point of a three-phase circuit of 4 systems, and have the same potential.

In the present embodiment, the stator 20 has 12 coils 29. The 12 coils 29 are classified into 4U-phase coils (phase 1 coils) 29U, 4V-phase coils (phase 2 coils) 29V, and 4W-phase coils (phase 3 coils) 29W. U-phase coil 29U, V phase coil 29V and W-phase coil 29W are arranged in this order toward the other circumferential side (clockwise in fig. 1) around center axis J.

Each of the plurality of coils 29 has a lead wire 28 extending from the lead portion 27 of the coil 29. In the present embodiment, the lead portions 27 of all the coils 29 (U-phase coil 29U, V-phase coil 29V and W-phase coil 29W) are located on the one circumferential side with respect to the coil 29.

According to the present embodiment, the lead portions 27 of all the coils 29 are located on one side in the circumferential direction with respect to the coils 29. The lead wire 28 drawn out from the lead portions 27 is a terminal end at which the winding of the coil 29 is completed. Therefore, the winding direction, the winding end position, and the like of all the coils 29 can be made the same. As a result, the winding can be performed without dividing the plurality of coils 29, and the manufacturing process can be simplified.

In the present embodiment, 6 bus bars 80 are attached to the stator 20. The 6 bus bars 80 are classified into 2U-phase bus bars (1 st-phase bus bars) 80U, 2V-phase bus bars (2 nd-phase bus bars) 80V, and 2W-phase bus bars (3 rd-phase bus bars) 80W. The U-phase bus bar 80U, V-phase bus bar 80V and the W-phase bus bar 80W are arranged in the following order toward the other side in the circumferential direction about the center axis J.

The bus bar 80 has 2 lead wires 28 connected to the lead wire connection portion 81, the lead wires being in the same phase with each other. That is, 2 lead wires 28 extending from 2 coils 29 of the same phase are connected to the lead wire connection portion 81 of 1 bus bar 80.

The U-phase bus bar 80U, V phase bus bar 80V and the W-phase bus bar 80W are phase bus bars. The control device 9 supplies an ac current to each bus bar 80. The phases of the ac currents supplied to the bus bars 80 are shifted by 120 °.

The 2 three-phase circuits are connected in parallel by a bus bar 80. Therefore, the group of bus bars 80 consisting of 1U-phase bus bar 80U, 1V-phase bus bar 80V, and 1W-phase bus bar 80W simultaneously supplies electric power to 2 three-phase circuits. In addition, the group of bus bars 80 composed of 1U-phase bus bar 80U, 1V-phase bus bar 80V, and 1W-phase bus bar 80W constitutes 1 input system. Therefore, the motor 1 of the present embodiment has 2 input systems.

The U-phase bus bar 80U is supported by the insulator 22 to which the V-phase coil 29V is attached. The U-phase bus bar 80U is connected to 2 lead wires 28, i.e., a 1 st lead wire 28Ua extending from one circumferential side and a 2 nd lead wire 28Ub extending from the other circumferential side.

The 1 st lead wire 28Ua is led out from the U-phase coil 29U located on the circumferential direction side with respect to the connected U-phase bus bar 80U. The 1 st lead wire 28Ua is led from the lead portion 27 to the other side in the circumferential direction and connected to the U-phase bus bar 80U. The 1 st lead wire 28Ua is led to the radially outer side of the V-phase coil 29V through the lower side of the led U-phase coil 29U, and is connected to the U-phase bus bar 80U. Therefore, the length of the 1 st lead-out wire 28Ua extending in the circumferential direction is an amount of 1.5 of the length (coil width) of the coil 29 in the circumferential direction.

The 2 nd lead wire 28Ub is led out from the U-phase coil 29U located on the other circumferential side with respect to the connected U-phase bus bar 80U. The 2 nd lead wire 28Ub is led from the lead portion 27 toward the circumferential side and connected to the U-phase bus bar 80U. The 2 nd lead wire 28Ub is led radially outward of the V-phase coil 29V through the led W-phase coil 29W, and is connected to the U-phase bus bar 80U. Therefore, the length of the 2 nd lead wire 28Ub extending in the circumferential direction is an amount of 1.5 of the length (coil width) of the coil 29 in the circumferential direction.

The position of the lead wire connecting portion 81 of the U-phase bus bar 80U in the circumferential direction is the midpoint between the lead portions 27 of the 2 lead wires (the 1 st lead wire 28Ua and the 2 nd lead wire 28 Ub). Therefore, the distances from the lead wire connection part 81 to the 2 lead-out parts 27 are the same as each other. As a result, the lengths of the 1 st lead wire 28Ua and the 2 nd lead wire 28Ub can be made substantially the same.

The V-phase bus bar 80V is supported by the insulator 22 to which the W-phase coil 29W is attached. The lead wire 28 connected to the V-phase bus bar 80V has the same configuration as the lead wire 28 connected to the U-phase bus bar 80U described above.

The V-phase bus bar 80V is connected with 2 lead wires 28, i.e., a 1 st lead wire 28Va extending from one circumferential side and a 2 nd lead wire 28Vb extending from the other circumferential side. The 1 st lead wire 28Va is led out from the V-phase coil 29V located on one side in the circumferential direction with respect to the connected V-phase bus bar 80V. The 1 st lead wire 28Va is connected to the V-phase bus bar 80V through the lower side of the V-phase coil 29V. The 2 nd lead wire 28Vb is led out from the V-phase coil 29V located on the other side in the circumferential direction with respect to the connected V-phase bus bar 80V. The 2 nd lead wire 28Vb is connected to the V-phase bus bar 80V through the radially outer side of the U-phase coil 29U. The lead wire connecting portion 81 of the V-phase bus bar 80V is located at a position in the circumferential direction that is a midpoint between the lead portions 27 of the 2 lead wires (the 1 st lead wire 28Va and the 2 nd lead wire 28 Vb). Therefore, the lengths of the 1 st lead wire 28Va and the 2 nd lead wire 28Vb can be made substantially the same.

W-phase bus bar 80W is supported by insulator 22 to which U-phase coil 29U is attached. The lead wire 28 connected to the W-phase bus bar 80W has the same configuration as the lead wire 28 connected to the U-phase bus bar 80U described above.

The W-phase bus bar 80W is connected to 2 lead wires 28, i.e., a 1 st lead wire 28Wa extending from one circumferential side and a 2 nd lead wire 28Wb extending from the other circumferential side. The 1 st lead wire 28Wa is led from the W-phase coil 29W located on one circumferential side with respect to the connected W-phase bus bar 80W. The 1 st lead wire 28Wa passes under the W-phase coil 29W and is connected to the W-phase bus bar 80W. The 2 nd lead wire 28Wb is led out from the W-phase coil 29W located on the other circumferential side with respect to the connected W-phase bus bar 80W. The 2 nd lead wire 28Wb is connected to the W-phase bus bar 80W through the radially outer side of the V-phase coil 29V. The lead wire connecting portion 81 of the W-phase bus bar 80W is located at a position in the circumferential direction that is a midpoint between the lead portions 27 of the 2 lead wires (the 1 st lead wire 28Wa and the 2 nd lead wire 28 Wb). Therefore, the 1 st lead wire 28Wa and the 2 nd lead wire 28Wb can be made substantially the same in length.

According to the present embodiment, the lengths of the lead wires 28 connected to the bus bars 80 of different phases are the same as each other. Since the resistance of the lead wire 28 is proportional to the length, the amplitudes of the magnetic fields of the coils 29 that are out of phase from each other can be made close to each other. As a result, the rotation of the motor 1 can be stabilized.

According to the present embodiment, the lengths of the 2 lead wires 28 connected to the bus bar 80 of the same phase can be made equal to each other. Therefore, the amplitudes of the magnetic fields of the coils 29 of the same phase can be made close to each other, and the rotation of the motor 1 can be stabilized.

The lead wires 28 are embedded in the case 30 together with the stator 20 and the bus bar 80. Therefore, if the route of the lead wires 28 becomes complicated, the resin cannot be sufficiently wound between the lead wires 28, and there is a possibility that the fixing of the lead wires 28 by the housing 30 becomes insufficient. According to the present embodiment, by connecting the coils 29 of the same phase in parallel, the path of the lead wire 28 can be shortened as compared with the case of connecting them in series, and the path of the lead wire 28 can be simplified. As a result, the resin can be sufficiently wound around the lead wires 28.

According to the present embodiment, 2 coils 29 of the same phase are connected in parallel by 1 bus bar 80. Therefore, compared to the case where 1 bus bar 80 is connected to 1 coil 29, the number of bus bars 80 can be reduced, and the number of components of the motor 1 can be reduced.

According to the present embodiment, one of the 2 lead wires 28 connected to the bus bar 80, which extends from one side in the circumferential direction, passes below the coils 29 of the same phase, and the other of the lead wires extends from the other side in the circumferential direction, passes radially outward of the coils 29 of the plurality of phases. In this regard, the detailed description will be given with a focus on the 1 st lead wire 28Va and the 2 nd lead wire 28Vb connected to the V-phase bus bar 80V.

The 1 st lead wire 28Va passes under the V-phase coil 29V of the same phase. That is, the 1 st lead wire 28Va and the V-phase coil 29V overlap as viewed in the axial direction. Since the 1 st lead wire 28Va and the V-phase coil 29V are V-phase, the arrangement close to the V-phase coil 29V does not cause an electrical problem even if a short circuit occurs. On the other hand, the lead wire 28 of the other phase is disposed sufficiently apart from the V-phase coil 29V in order to suppress a short circuit with the V-phase coil 29V. Therefore, according to the present embodiment, the distance between the 1 st lead wire 28Va and the lead wire 28 of the other phase can be ensured. Therefore, not only short-circuiting with other phases can be suppressed, but also the lead wires 28 can be suppressed from being dense, and the filling rate of the resin can be increased in the molding step of the case 30.

The 2 nd lead wire 28Vb passes through the radially outer side of the U-phase coil 29U of the other phase. That is, the 2 nd lead wire 28Vb passes through a position different from the position of the coil 29 of the other phase when viewed from the axial direction. This can suppress the 2 nd lead wire 28Vb from short-circuiting with the coil 29 of the other phase.

As shown in fig. 3, 2 lead wires 28 connected to the bus bar 80 extend in the circumferential direction and are arranged in the axial direction. According to the present embodiment, the lead wire 28 led in the circumferential direction can be smoothly connected to the bus bar 80, and the route of the lead wire 28 can be simplified. Further, since the 2 lead wires 28 are arranged in the axial direction, the lead wire connection portion 81 of the bus bar 80 can be prevented from becoming large in the radial direction, and a distance from the lead wire 28 of another phase can be easily secured.

As shown in fig. 1, the bus bar 80 is located outside the radially outer end of the coil 29. The rotor 10 is disposed radially inward of the stator 20. Therefore, if the bus bar 80 is disposed radially inward of the coil 29, a structure is required to suppress the lead wire 28 from protruding toward the rotor 10 side. According to the present embodiment, the bus bar 80 is disposed radially outward of the coil 29, so that interference between the lead wire 28 and the rotor 10 can be easily suppressed.

According to the present embodiment, the folded-back portion 81b of the bus bar 80 is located radially outward with respect to the base portion 81 a. Therefore, the distance between the bus bar 80 and the coil 29 located radially inward of the bus bar can be secured at the folded-back portion, and mutual short-circuiting can be suppressed.

Next, a modified example of the above embodiment will be described. The same reference numerals are given to the same constituent elements as those of the above-described embodiment, and the description thereof will be omitted.

< modification of bus bar >

Fig. 6 is a partial sectional view of a motor having a bus bar 180 of a modification.

The bus bar 180 of the present modification is different from the above-described embodiment mainly in the structure of the lead wire connection portion 181.

As in the above-described embodiment, the bus bar 180 of the present modification includes the lead wire connection portion 181 connected to the lead wire 28, the external connection terminal portion 82 extending downward from the lead wire connection portion 181, and the supported portion 83 extending upward from the lead wire connection portion 181.

The lead wire connection portion 181 has a base portion 181a, a folded portion 181b folded back from an upper end of the base portion 181a, and a bent portion 181c located at a lower end of the folded portion 181 b. The base portion 181a and the folded portion 181b extend substantially parallel to each other in the axial direction in the radial direction as the plate thickness direction. The folded back portion 181b is located radially inward of the base portion 181 a. The 2 lead wires 28 are sandwiched between the base portion 181a and the folded portion 181 b. The bent portion 181c prevents the lead wire 28 from coming off the region sandwiched between the base portion 181a and the folded portion 181 b.

According to the present modification, the folded portion 181b is located radially inward of the base portion 181 a. Therefore, the lead wire connection portion 181 can be brought close to the coil 29 in the radial direction, and the lead wire 28 extending from the coil 29 can be shortened.

< modification of stator >

Fig. 7 is a schematic plan view of a stator 220 and a bus bar 80 of a modification example viewed from below.

The stator 220 of the present modification differs from the above-described embodiment mainly in the state where the lead wires 28 are arranged.

As in the above embodiment, the stator 220 has 12 coils 29. The 12 coils 29 are classified into 4U-phase coils (phase 1 coils) 29U, 4V-phase coils (phase 2 coils) 29V, and 4W-phase coils (phase 3 coils) 29W. Of the 4 coils 29 of the same phase, 2 coils 29 of the same phase are arranged adjacent to each other in the circumferential direction. Each of the plurality of coils 29 has a lead wire 28 extending from a lead portion 227 of the coil 29.

The stator 220 is provided with 6 bus bars 80. In the present modification, 6 bus bars 80 are arranged at equal intervals in the circumferential direction. The 6 bus bars 80 are classified into 2U-phase bus bars (1 st-phase bus bars) 80U, 2V-phase bus bars (2 nd-phase bus bars) 80V, and 2W-phase bus bars (3 rd-phase bus bars) 80W.

The bus bar 80 is disposed radially outward of the plurality of coils 29 and between the coils 29 that are circumferentially in phase. More specifically, the U-phase bus bar 80U is disposed between the U-phase coils 29U adjacent to each other in the circumferential direction. The V-phase bus bar 80V is disposed between the adjacent V-phase coils 29V in the circumferential direction. The W-phase bus bar 80W is disposed between the adjacent W-phase coils 29W in the circumferential direction.

Lead wires 28 drawn from 2 coils 29 of the same phase adjacent in the circumferential direction among the plurality of coils 29 are connected to the lead wire connection portion 81 of the bus bar 80. Of the 2 coils 29 of the same phase adjacent in the circumferential direction, the lead portion 227 of the coil 29 on one side in the circumferential direction is located on one side in the circumferential direction with respect to the coil 29. In addition, the lead portion 227 of the coil 29 on the other side in the circumferential direction among the 2 coils 29 of the same phase adjacent in the circumferential direction is located on the other side in the circumferential direction with respect to the coil 29. Therefore, the position of the lead wire connection portion 81 in the circumferential direction is the midpoint between the lead portions 227 of the 2 lead wires 28 connected to the lead wire connection portion 81. Therefore, the lengths of the 2 lead wires 28 connected to the 1 lead wire connection portion 81 can be made the same.

According to the present modification, the lengths of the lead wires 28 connected to the bus bars 80 of different phases are the same as each other. Therefore, the amplitudes of the magnetic fields of the coils 29 that are out of phase from each other can be made close to each other. As a result, the rotation of the motor can be stabilized.

According to this modification, the lengths of the 2 lead wires 28 connected to the bus bar 80 of the same phase can be made equal to each other. Therefore, the amplitudes of the magnetic fields of the coils 29 of the same phase can be made close to each other, and the rotation of the motor 1 can be stabilized.

While one embodiment of the present invention and its modified examples have been described above, the configurations of the embodiment and modified examples and combinations thereof are examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The present invention is not limited to the embodiments.

For example, the use of the motor unit of the above-described embodiment and its modified examples is not particularly limited. The motor unit according to the above-described embodiment and the modifications thereof is mounted on, for example, an electric pump and an electric power steering apparatus.

Description of the reference symbols

1: a motor; 10: a rotor; 20. 220, and (2) a step of: a stator; 22: an insulating member; 27. 227: a lead-out section; 28: an outgoing line; 29: a coil; 29U: a U-phase coil (phase 1 coil); 29V: a V-phase coil (phase 2 coil); 29W: a W-phase coil (phase 3 coil); 30: a housing; 80. 180: a bus bar; 80U: a U-phase bus bar (1 st-phase bus bar); 80V: a V-phase bus bar (2 nd-phase bus bar); 80W: a W-phase bus bar (3 rd phase bus bar); 81. 181: a lead wire connection part; 81a, 181 a: a base; 81b, 181 b: a fold-back portion; j: a central axis.

Claims

1. A motor, comprising:

a rotor that rotates about a central axis;

a stator having an insulator and a plurality of coils attached to the insulator, the stator being radially opposed to the rotor;

a housing made of resin and having the stator embedded therein; and

a plurality of bus bars located on one axial side of the stator,

the motor is a three-phase motor in which a plurality of the coils are classified into a 1 st phase coil, a 2 nd phase coil, and a 3 rd phase coil, wherein,

the coil has a lead wire extending from a lead portion of the coil,

the bus bar has a lead wire connection part to which 2 lead wires extending from 2 coils of the same phase are connected,

the position of the lead wire connecting portion in the circumferential direction is a midpoint between the lead portions of the 2 lead wires.

2. The motor of claim 1,

the 1 st phase coil, the 2 nd phase coil and the 3 rd phase coil are arranged in order toward the other side in the circumferential direction around the central axis.

3. The motor of claim 2,

the lead-out portion of the coil is located on one side in the circumferential direction with respect to the coil,

the plurality of bus bars are classified into:

a phase 1 bus bar connected to a lead line of the phase 1 coil;

a 2 nd phase bus bar connected to an outgoing line of the 2 nd phase coil; and

a 3 rd phase bus bar connected to an outgoing line of the 3 rd phase coil,

the phase 1 bus bar is supported by the insulator to which the phase 2 coil is attached,

the 2 nd phase bus bar is supported by the insulator to which the 3 rd phase coil is attached,

the 3 rd phase bus bar is supported by the insulator to which the 1 st phase coil is attached.

4. The motor of claim 1,

the coils of 2 of the same phase are arranged adjacent to each other in the circumferential direction.

5. The motor of claim 4,

the lead wire connection portion is connected with the lead wires led out from 2 coils of the same phase adjacent in the circumferential direction among the plurality of coils,

the lead-out portion of one of the 2 coils of the same phase adjacent in the circumferential direction is located on one side in the circumferential direction with respect to the coil, and the lead-out portion of the other coil is located on the other side in the circumferential direction with respect to the coil.

6. The motor according to any one of claims 1 to 5,

the bus bar is located further to the outside than the radially outer end of the coil.

7. The motor according to any one of claims 1 to 6,

the bus bar is in the shape of a plate,

the lead wire connecting portion has a base portion and a folded-back portion folded back from an end portion of the base portion,

the lead wire is sandwiched by the base portion and the folded-back portion.

8. The motor of claim 7,

the fold back is located radially outward relative to the base.

9. The motor of claim 7,

the folded back portion is located radially inward with respect to the base portion.

10. The motor according to any one of claims 1 to 9,

the lead wire is a terminal end of the coil at which winding is completed.

11. The motor according to any one of claims 1 to 10,

when n is set to be a natural number,

the motor is a three-phase motor having n input systems, the motor having 6 × n coils arranged in a circumferential direction.