CN111052557A - Motor with a stator having a stator core - Google Patents

Abstract

In the motor, the stator has a plurality of systems of coil groups, and the bus bar unit has: a plurality of phase bus bars connected to lead wires drawn from the coils of the respective phases; and a bus bar holder that holds a plurality of phase bus bars, the phase bus bars being plate-shaped, at least the bus bar main body portion being arranged with a direction perpendicular to the axial direction as a thickness direction, and a phase bus bar of the plurality of phase bus bars having a maximum length of the bus bar main body portion in the circumferential direction being overlapped with at least a part of the other phase bus bars in the radial direction and passing through a side opposite to a direction in which coil terminals of the other phase bus bar extend in the radial direction.

Description

Motor with a stator having a stator core

Technical Field

The present invention relates to a motor.

Background

As a three-phase motor, a three-phase motor provided with a bus bar connecting coils to each other is known (for example, patent document 1). On the other hand, in recent years, a motor in which a three-phase motor has a wiring structure of a plurality of systems and redundancy is secured has been desired.

Documents of the prior art

Patent document

Patent document 1 Japanese laid-open publication No. 2016-208578

Disclosure of Invention

Problems to be solved by the invention

In a motor having a plurality of systems, the number of bus bars increases, and as a result, the motor becomes large.

In view of the above problem, an object of one embodiment of the present invention is to provide a motor that can be miniaturized by using a plurality of systems.

Means for solving the problems

The motor of the present invention comprises: a rotor that rotates around a central axis extending in the vertical direction; a stator that is radially opposed to the rotor with a gap therebetween; and a bus bar unit provided above the stator, the stator having a plurality of coil groups of one system of a U-phase coil, a V-phase coil, and a W-phase coil, the coil groups of different systems being arranged symmetrically around a central axis, the bus bar unit including: a plurality of phase bus bars connected to lead wires drawn from the coils of the respective phases; and a bus bar holder that holds a plurality of the phase bus bars, the phase bus bar having: a bus bar main body portion extending in a circumferential direction; a coil terminal located at one end of the bus bar main body, extending radially to one side of the bus bar main body, and connected to the lead wire; and an external connection terminal located at the other end of the bus bar main body and extending upward, wherein the phase bus bar is plate-shaped, at least the bus bar main body is arranged with a direction perpendicular to an axial direction as a thickness direction, and at least a part of the phase bus bar having a maximum length of the bus bar main body in a circumferential direction among the plurality of phase bus bars overlaps with at least a part of the other phase bus bars in a radial direction and passes through a side opposite to a direction in which coil terminals of the other phase bus bars extend in the radial direction.

Effects of the invention

According to one embodiment of the present invention, a motor that can be miniaturized using a plurality of systems can be provided.

Drawings

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

Fig. 2 is a top view of an embodiment of a stator.

Fig. 3 is a schematic diagram showing wiring of each coil of the stator according to the embodiment.

Fig. 4 is a schematic diagram showing the Y-wiring of two systems constituted by coils of one embodiment.

Fig. 5 is a perspective view of a bus bar unit of an embodiment.

Fig. 6 is an exploded perspective view of a bus bar unit of an embodiment.

Fig. 7 is a top view of a bus bar unit of an embodiment.

Fig. 8 is a sectional view taken along line VIII-VIII of fig. 7.

Fig. 9 is a bottom view of the bus bar unit of one embodiment.

Fig. 10 is a schematic sectional view taken along line X-X of fig. 9.

Fig. 11 is a schematic diagram showing an electric power steering apparatus according to an embodiment.

Detailed Description

Hereinafter, a motor according to an embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and may be arbitrarily changed within the scope of the technical idea of the present invention. In the drawings below, in order to facilitate understanding of each structure, the actual structure may be different from the scale, the number, and the like of each structure.

In each drawing, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in fig. 1. The X-axis direction is a direction perpendicular to the Z-axis direction and is the left-right direction in fig. 1. The Y-axis direction is a direction perpendicular to both the X-axis direction and the Z-axis direction.

In the following description, the positive side (+ Z side) in the Z-axis direction is referred to as "upper side", and the negative side (-Z side) in the Z-axis direction is referred to as "lower side". The upper and lower sides are directions for explanation only, and the actual positional relationship and directions are not limited. Unless otherwise specified, a direction parallel to the central axis J (Z-axis direction) is simply referred to as "axial direction" or "vertical direction", a radial direction about the central axis J is simply referred to as "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 "circumferential direction". In the following description, the "plan view" refers to a state viewed from the axial direction.

[ Motor ]

Fig. 1 is a sectional view of a motor 1 of the present embodiment. The motor 1 of the present embodiment is a three-phase ac motor. The motor 1 of the present embodiment is an inner rotor type motor.

The motor 1 includes a rotor 20 having a shaft 21, a stator 30, a bus bar unit 60, a housing 40, an upper bearing (bearing) 6A, a lower bearing 6B, and a bearing holder 10. The motor 1 is connected to an external device (control unit) 9 via external connection terminals 71c, 72c, and 73c extending upward from the bus bar unit 60. The motor 1 controls the rotation of the rotor 20 through the external device 9.

[ Shell ]

The housing 40 is cylindrical and open on the upper side (+ Z side). The housing 40 houses the rotor 20 and the stator 30. The housing 40 has a cylindrical portion 45, a bottom portion 49, and a lower bearing holding portion 48.

The cylindrical portion 45 surrounds the stator 30 from the radially outer side. In the present embodiment, the cylindrical portion 45 is cylindrical with the center axis J as the center. The bottom portion 49 is located at the lower end of the cylindrical portion 45. The bottom 49 is located on the underside of the stator 30. The lower bearing holding portion 48 is located at the center of the bottom portion 49 in plan view. The lower bearing holding portion 48 holds the lower bearing 6B. The lower bearing holding portion 48 includes a holding cylinder portion 48a extending in the axial direction about the central axis J, and a lower end projecting portion 48b extending radially inward from the lower end of the holding cylinder portion 48 a. A hole 48c penetrating in the axial direction is provided at the center of the lower end protrusion 48b in a plan view.

[ ROTOR ]

The rotor 20 rotates about the center axis J. The rotor 20 includes a shaft 21, a rotor core 24, and a rotor magnet 23. The shaft 21 is disposed along a central axis J extending in the vertical direction (axial direction) as a center. The shaft 21 is supported by the upper bearing 6A and the lower bearing 6B so as to be rotatable about the center axis J.

The rotor core 24 is fixed to the shaft 21. The rotor core 24 circumferentially surrounds the shaft 21. The rotor magnet 23 is fixed to the rotor core 24. More specifically, the rotor magnet 23 is fixed to an outer surface along the circumferential direction of the rotor core 24. The rotor core 24 and the rotor magnet 23 rotate together with the shaft 21.

[ Upper and lower side Bearings ]

The upper bearing 6A rotatably supports a shaft 21 provided on the rotor 20 above the rotor core 24. The upper bearing 6A is supported by a bearing holder 10. The lower bearing 6B rotatably supports a shaft 21 provided on the rotor 20 below the rotor core 24. The lower bearing 6B is supported by the lower bearing holding portion 48 of the housing 40.

[ Bearings-holder ]

The bearing holder 10 is located on the upper side (+ Z side) of the stator 30. Further, the bearing holder 10 is located on the upper side of the bus bar unit 60 described later. The bearing holder 10 holds the upper bearing 6A. The bearing holder 10 is held by the cylindrical portion 45 of the housing 40. The top view (XY-plane view) of the bearing holder 10 is, for example, a circle concentric with the central axis J.

The bearing holder 10 includes a disc-shaped bearing holder body 16, an upper bearing holding portion 18 located radially inward of the bearing holder body 16, and an engaging cylinder portion 15 located radially outward of the bearing holder body 16. The upper bearing holding portion 18, the bearing holder body portion 16, and the fitting cylinder portion 15 are arranged in this order from the radially inner side toward the radially outer side.

The bearing holder body portion 16 extends along a plane perpendicular to the axial direction. The bearing holder body 16 is provided with through holes 16a through which the external connection terminals 71c, 72c, 73c of the bus bar unit 60 are inserted.

The upper bearing holding portion 18 holds the upper bearing 6A. The upper bearing holding portion 18 is located at the center of the bearing holder 10 in plan view. The upper bearing holding portion 18 includes a cylindrical holding portion 18a extending in the axial direction about the central axis J, and an upper end projecting portion 18b extending radially inward from an upper end of the cylindrical holding portion 18 a. The upper end projection 18b positions the upper bearing 6A in the up-down direction. A hole 18c penetrating in the axial direction is provided at the center of the upper end projection 18b in a plan view. The upper end of the shaft 21 is inserted into the hole 18 c.

The fitting cylinder portion 15 extends downward from the outer edge of the bearing holder main body portion 16. The fitting cylinder portion 15 extends in a cylindrical shape in the circumferential direction. The fitting cylindrical portion 15 is fitted to the inner circumferential surface 45c of the cylindrical portion 45 while facing in the radial direction. Thereby, the bearing holder 10 is fixed to the housing 40.

[ STATOR ]

The stator 30 is annularly arranged around the central axis J. The stator 30 is radially opposed to the rotor 20 with a gap therebetween. The stator 30 surrounds the radially outer side of the rotor 20. The stator 30 is fixed to an inner peripheral surface 45c of the cylindrical portion 45 of the housing 40. The stator 30 includes a stator core 31, an upper insulator (insulator) 35, a lower insulator 34, and a coil 33.

Fig. 2 is a plan view of the stator 30. Fig. 2 shows a part of coil terminals 71a, 72a, 73a, 81a, and 82a of a bus bar unit 60, which will be described later.

The stator core 31 is formed of a plurality of core members 32 arranged annularly in the circumferential direction. In the stator core 31, core members 32 adjacent in the circumferential direction are coupled to each other. That is, the stator core 31 is configured by connecting a plurality of core members 32 in the circumferential direction.

The core member 32 includes a core back portion 32a, a tooth portion 32b, and an umbrella portion 32 c. That is, the stator core 31 has a plurality of core back portions 32a, a plurality of tooth portions 32b, and a plurality of umbrella portions 32 c. The stator core 31 of the present embodiment is configured by 12 core members 32. Therefore, the stator 30 of the present embodiment has 12 teeth 32 b. In addition, the number of the core pieces 32 and the tooth portions 32b is not limited thereto.

The core back 32a extends in the circumferential direction. The core back 32a is connected to the core back 32a of the adjacent core member 32 at the end in the circumferential direction. The core back portions 32a adjacent to each other in the circumferential direction are joined to each other by welding or the like. Thereby, the core backs 32a of all the core members 32 are annularly coupled.

The tooth portion 32b extends radially inward from the circumferential center of the core back portion 32 a. The coil 33 is wound around the tooth portion 32b via an upper insulator 35 and a lower insulator 34.

The umbrella portion 32c is located at the tip (radially inner end) of the tooth portion 32 b. The dimension of the umbrella portion 32c in the circumferential direction is larger than the dimension of the tooth portion 32b in the circumferential direction and smaller than the dimension of the core back portion 32a in the circumferential direction. The radially inward surface of the umbrella portion 32c faces the rotor magnet 23 of the rotor 20.

The stator core 31 of the present embodiment is formed of a plurality of core members 32, which are so-called split cores. However, the core member constituting the stator core 31 may be a wound core in which the adjacent core back portions 32a are partially connected to each other and are annularly bent after the coil 33 is wound.

As shown in fig. 1, the upper insulator 35 covers at least the upper sides of the teeth 32b on the upper surface of the stator core 31. Likewise, the lower insulator 34 covers at least the lower sides of the tooth portions 32b on the lower surface of the stator core 31. That is, the upper insulator 35 covers the upper surfaces of the teeth 32b, and the lower insulator 34 covers the lower surfaces of the teeth 32 b. The upper insulator 35 and the lower insulator 34 are made of an insulating material. The upper insulator 35 and the lower insulator 34 have the same configuration except that they are provided on the opposite sides of the stator core 31 in the vertical direction.

As shown in fig. 2, the upper-side insulator 35 has a plurality of insulating sheets 36 on the upper side of each of the core members 32. Although not shown, the lower insulator 34 includes a plurality of insulating sheets 36, similarly to the upper insulator 35.

The insulating sheets 36 of the upper insulator 35 are provided in the same number as the core members 32 (12 in the present embodiment). An insulating sheet 36 is disposed on the upper side of one of the core members 32. The plurality of insulating sheets 36 are annularly arranged in the circumferential direction.

The insulating sheet 36 has a base portion 36b, a first standing wall portion 36a, and a second standing wall portion 36 c. The base 36b is located on the upper side of the tooth portion 32b, covering the upper surface of the tooth portion 32 b. The first standing wall portion 36a protrudes upward from a radially outer end portion of the base portion 36b and extends in the circumferential direction. The first standing wall portion 36a is located on the upper side of the core back portion 32 a. The second standing wall portion 36c protrudes upward from the radially inner end of the base portion 36b and extends in the circumferential direction. The second standing wall portion 36c is located on the upper side of the umbrella portion 32 c.

The coil 33 is wound around the base 36 b. The first standing wall portion 36a and the second standing wall portion 36c are opposed to each other in the radial direction with the base portion 36b interposed therebetween. The first standing wall portion 36a and the second standing wall portion 36c guide the coil 33 wound around the base portion 36b from the radially outer side and the radially inner side, respectively.

The first standing wall portion 36a has a pair of end surfaces 36d facing both sides in the circumferential direction and an outer peripheral surface 36e facing radially outward. End surfaces 36d of adjacent insulating sheets 36 are circumferentially opposed. A chamfer 36f is provided between the first standing wall portion 36a and the outer peripheral surface 36 e. A leg receiving portion 37 having a V-shape when viewed in the axial direction is provided between the chamfers 36f of the adjacent insulating sheets 36. That is, the upper insulator 35 is provided with a leg receiving portion 37.

Conventionally, a structure is known in which a recess provided on an outer peripheral surface of one insulation sheet facing radially outward is used as a leg portion housing portion. In contrast, according to the present embodiment, the leg receiving portions 37 are provided by abutting the chamfers 36f of the pair of insulation sheets 36 arranged in the circumferential direction in the radial direction. Therefore, it is not necessary to provide a recess in one insulating sheet 36, and when the insulating sheet 36 is manufactured by injection molding, the degree of freedom in the direction of mold release of the insulating sheet 36 can be increased. As a result, the insulating sheet 36 can be manufactured at low cost.

The leg receiving portion 37 is formed in a V shape that is open on one side in the radial direction (radially outward in the present embodiment) when viewed from the axial direction and has a width that decreases toward the other side (radially inward in the present embodiment). The leg receiving portion 37 is located above the boundary between adjacent core members 32 when viewed from the axial direction.

The leg portion receiving portion 37 receives a leg portion 65 of a bus bar unit 60 described later. The leg 65 is fitted into the V shape of the leg receiving portion 37. That is, the leg portion 65 has a V-shape that is narrower toward the other side in the radial direction (radially inward in the present embodiment) when viewed from the axial direction.

The coil 33 is formed by winding a coil wire around the tooth portions 32b via an upper insulator 35 and a lower insulator 34. Therefore, the plurality of coils 33 are arranged annularly in the circumferential direction.

In the present embodiment, 12 coils 33 are provided on the stator 30. The 12 coils 33 are formed by winding a pair of coils 33 as 1 set in a continuous arc manner. The two coils 33 wound in a continuous arc are connected via a crossover wire 33 b. The crossover wire 33b passes through the upper side of the coil 33. The crossover wire 33b is insulated from the coil 33 by an insulating tube (not shown).

One lead wire 33a extends upward from each coil 33. The lead wires 33a correspond to the winding start ends and the winding end ends of the two coils 33 wound in a continuous arc. Therefore, one lead wire 33a extends from one coil 33. The lead wires 33a are connected to coil terminals 71a, 72a, 73a, 81a, and 82a described later. The coil terminals 71a, 72a, 73a, 81a, and 82a are classified into the coil terminals 71a, 72a, and 73a of the phase bus bars 71, 72, and 73 and the coil terminals 81a and 82a of the neutral point bus bars 81 and 82.

Fig. 3 is a schematic diagram showing wiring of each coil 33 of the stator 30. The 12 coils 33 of the stator 30 are formed of four U-phase coils U1a, U1b, U2a, U2b, four V-phase coils V1a, V1b, V2a, V2b, and four W-phase coils W1a, W1b, W2a, and W2 b.

Fig. 4 is a schematic diagram showing the Y-wiring of two systems of 12 coils 33. As shown in fig. 4, the stator 30 includes a plurality of (two in the present embodiment) coil groups (the first coil group 7 and the second coil group 8) with the U-phase coil, the V-phase coil, and the W-phase coil as one coil group. That is, the stator 30 has two systems of coil groups 7, 8 classified into a first system of coil groups 7 and a second system of coil groups.

The coil group 7 of the first system includes U-phase coils U1a, U1b, V-phase coils V1a, V1b, and W-phase coils W1a, W1 b. The coil group 8 of the second system includes U-phase coils U2a, U2b, V-phase coils V2a, V2b, and W-phase coils W2a, W2 b. That is, two coils 33 are provided in one phase of each system. The two coils 33 of each phase of each system are connected by a crossover wire 33 b. In other words, in each system, a plurality of U-phase coils, V-phase coils, and W-phase coils are provided, respectively, and are provided across a plurality of teeth 32b via crossover wires 33 b.

In the coil group 7 of the first system, the U-phase coils U1a, U1b, V-phase coils V1a, V1b, and W-phase coils W1a, W1b are wired to each other by Y-wiring. Likewise, in the coil group 8 of the second system, the U-phase coils U2a, U2b, V-phase coils V2a, V2b, and W-phase coils W2a, W2b are wired to each other by Y-wiring.

As shown in fig. 3, one lead wire 33a of the two U-phase coils U1A, U1b of the first system connected via the crossover wire 33b is connected to a U-phase bus bar 71A of a first system-phase bus bar group 70A, which will be described later, and the other lead wire 33a is connected to the first system neutral point bus bar 81.

Similarly, one lead wire 33a of the two V-phase coils V1a and V1b of the first system connected via the crossover wire 33b is connected to the V-phase bus bar 72A of the first system-phase bus bar group 70A, and the other lead wire 33a is connected to the first system neutral point bus bar 81.

Further, one lead wire 33A of the two W-phase coils W1a, W1b of the first system connected via the crossover wire 33b is connected to the W-phase bus bar 73A of the first system-phase bus bar group 70A, and the other lead wire 33A is connected to the first system neutral point bus bar 81.

As described above, one ends of the U-phase coils U1a, U1b, V-phase coils V1a, V1b, W-phase coils W1a, and W1b of the first system are connected to different phase bus bars 71, 72, and 73. That is, the plurality of phase bus bars 71, 72, 73 are connected to lead lines 33a drawn from the coils 33 of the respective phases. The other ends of U-phase coils U1a, U1b, V-phase coils V1a, V1b, W-phase coils W1a, and W1b of the first system are connected to a first system neutral point bus bar 81. That is, one first system neutral point bus bar 81 is connected to the lead line 33a led out from the coil 33 of each phase.

Thus, U-phase coils U1a, U1b, V-phase coils V1a, V1b, and W-phase coils W1a, W1b of the first system constitute a Y-connection.

The wiring structure of the coils 33 of the respective phases of the coil group 8 of the second system is the same as that of the coils of the respective phases of the coil group 7 of the first system. That is, the U-phase coils U2a and U2B of the second system are connected to the U-phase bus bar 71B and the second system neutral point bus bar 82 of the second system. The V-phase coils V2a and V2B of the second system are connected to the V-phase bus bar 72B and the second system neutral point bus bar 82 of the second system. The W-phase coils W2a and W2B of the second system are connected to the W-phase bus bar 73B and the second system neutral point bus bar 82 of the second system. Thus, the U-phase coils U2a, U2b, V-phase coils V2a, V2b, and W-phase coils W2a, W2b of the second system constitute a Y-connection.

According to the present embodiment, the stator 30 has a plurality of systems of coil groups (the coil group 7 of the first system and the coil group 8 of the second system). In the stator 30, the coil groups 7 and 8 of different systems are arranged symmetrically around the central axis J. This ensures redundancy of the motor 1. That is, even when a failure occurs in any one of the coil groups 7 and 8 of the plurality of systems, the motor 1 can be smoothly driven using the coil group of the other system.

[ busbar Unit ]

The bus bar unit 60 is provided to the motor 1. The bus bar unit 60 is located between the stator 30 and the bearing holder 10 in the axial direction. That is, the bus bar unit 60 is provided above the stator 30 and below the bearing holder 10.

Fig. 5 is a perspective view of the bus bar unit 60. Fig. 6 is an exploded perspective view of the bus bar unit 60. Fig. 7 is a plan view of the bus bar unit 60.

The bus bar unit 60 has a bus bar holder 61, a pair of terminal holders (external connection terminal holders) 66, a first system phase bus bar group 70A, a second system phase bus bar group 70B, a first system neutral point bus bar 81, and a second system neutral point bus bar 82.

The first-system-phase bus bar group 70A and the first-system neutral point bus bar 81 are connected to the coil group 7 of the first system. In addition, the second system-dedicated bus bar group 70B and the second system neutral point bus bar 82 are connected to the coil group 8 of the second system.

The first system-phase bus bar group 70A and the second system-phase bus bar group 70B are fixed to one axial side (upper side in the present embodiment) of the bus bar holder 61, and the first system neutral point bus bar 81 and the second system neutral point bus bar 82 are fixed to the other axial side (lower side in the present embodiment) of the bus bar holder 61. In addition, in the present specification, "one side" and "the other side" do not indicate a specific direction. That is, the above description may be said as follows. The first system neutral point bus bar 81 and the second system neutral point bus bar 82 are fixed to one axial side of the bus bar holder 61, and the first system phase bus bar group 70A and the second system phase bus bar group 70B are fixed to the other axial side of the bus bar holder 61.

The first system-phase bus bar group 70A includes a U-phase bus bar 71A, V-phase bus bar 72A and a W-phase bus bar 73A. Similarly, the second system phase bus bar group 70B includes a U-phase bus bar 71B, V phase bus bar 72B and a W-phase bus bar 73B.

In the following description, the U-phase bus bars 71A and 71B are simply referred to as U-phase bus bars 71 when the U-phase bus bars are not distinguished from each other. Note that, when the V- phase bus bars 72A and 72B of different systems are not distinguished, they are simply referred to as V-phase bus bars 72. When the W- phase bus bars 73A and 73B of different systems are not distinguished, they are simply referred to as W-phase bus bars 73. When the U-phase bus bar 71, the V-phase bus bar 72, and the W-phase bus bar 73 are not distinguished from each other, they are simply referred to as phase bus bars 71, 72, and 73. Likewise, in the case where the first system neutral point bus bar 81 and the second system neutral point bus bar 82 are not distinguished, they are simply referred to as neutral point bus bars 81, 82.

The U-phase bus bars 71A and 71B, V and the W- phase bus bars 73A and 73B are phase bus bars (first bus bars). That is, the plurality of phase busbars 71, 72, and 73 include phase busbars connected to U-phase coils U1a, U1b, U2a, U2b, V-phase coils V1a, V1b, V2a, V2b, and W-phase coils W1a, W1b, W2a, and W2b of the first-system coil group 7 and the second-system coil group 8, respectively.

(busbar holder)

As shown in fig. 1, the bus bar holder 61 is provided on the upper side of the stator 30. The bus bar holder 61 holds the opposing bus bars 71, 72, 73 and the neutral point bus bars 81, 82. The bus bar holder 61 is made of a resin material.

As shown in fig. 6, the bus bar holder 61 has a holder main body portion (bus bar holder main body) 62, a pair of base portions 63, a plurality of (6 in the present embodiment) clamping portions 64, and a plurality of (6 in the present embodiment) leg portions 65.

The cage body portion 62 has an annular shape centered on the central axis J when viewed in the axial direction. The cage main body portion 62 is located between the phase bus bars 71, 72, 73 and the neutral point bus bars 81, 82 in the axial direction. The holder body 62 has an upper surface 62a facing upward and a lower surface 62b facing downward. A plurality of phase bus bars 71, 72, 73 are arranged on the upper surface 62a of the holder main body 62. A plurality of neutral point bus bars 81 and 82 are arranged on the lower surface 62b of the holder main body portion 62.

As shown in fig. 1, a first wall portion 62c and a second wall portion 62d are provided on a lower surface 62b of the holder main body portion 62. That is, the bus bar holder 61 has a first wall portion 62c and a second wall portion 62 d. The first wall portion 62c and the second wall portion 62d project from the lower surface 62b in the axial direction. Further, the first wall portion 62c and the second wall portion 62d extend in the circumferential direction, respectively. The first wall portion 62c is located radially outward with respect to the neutral point bus bars 81, 82. The second wall portion 62d is located radially inward with respect to the neutral point bus bars 81, 82. Therefore, the neutral point bus bars 81, 82 are located between the first wall portion 62c and the second wall portion 62d in the radial direction and extend in the circumferential direction.

The lower surface 62b of the holder main body portion 62 is provided with a plurality of shaft portions 67a, 68a, 69a and a plurality of fusion-bonded portions 67b, 68b, 69b located at the tips of the shaft portions 67a, 68a, 69 a. That is, the bus bar holder 61 has a plurality of shaft portions 67a, 68a, 69a and a plurality of fusion portions 67b, 68b, 69 b. As will be described later with reference to fig. 10, the plurality of fusion portions 67b, 68b, 69b fix the neutral point bus bars 81, 82 to the bus bar holder 61.

As shown in fig. 6, the base portion 63 protrudes upward from the upper surface 62a of the holder body portion 62. The pair of base portions 63 are located on opposite sides with respect to the center axis J. One of the pair of base portions 63 holds the external connection terminals 71c, 72c, and 73c of the first system phase bus bar group 70A, and the other holds the external connection terminals 71c, 72c, and 73c of the second system phase bus bar group 70B.

The base portion 63 has an upper surface 63a facing upward. A terminal support 66 is mounted on an upper surface 63a of the base portion 63. Four grooves (recesses) 63d are provided on the upper surface 63 a. That is, the bus bar holder 61 is provided with a groove 63 d. A part of the V-phase bus bar 72, a part of the W-phase bus bar 73, and parts of two U-phase bus bars 71 of different systems (a U-phase bus bar 71A of the first system and a U-phase bus bar 71B of the second system) are inserted into the four grooves 63 d. Thereby, the base portion 63 holds the plurality of phase bus bars 71, 72, 73.

As shown in fig. 1, a shaft portion 63b extending upward and a fusion portion 63c positioned at the upper end of the shaft portion 63b are provided on the upper surface 63a of the base portion 63. That is, the bus bar holder 61 has the shaft portion 63b and the welded portion 63 c.

The shaft portion 63b passes through a fixing hole 66h provided in the terminal support 66. The fusion-bonded portion 63c is expanded to the outside of the fixing hole 66h when viewed from the axial direction on the upper side of the fixing hole 66h of the terminal support 66. The welded portion 63c is hemispherical and convex upward. The welded portion 63c is formed by melting the upper end portion of the shaft portion 63b by heat. The welded portion 63c suppresses the terminal support 66 from being pulled out from the shaft portion 63 b. By providing the welding portion 63c, the terminal holder 66 is fixed to the bus bar holder 61.

As shown in fig. 7, the clip portion 64 is provided on the upper surface 62a of the holder body portion 62. The clamping portion 64 has a pair of claw portions 64a extending upward from the upper surface 62 a. The pair of claw portions 64a hold the phase bus bars 71, 72, 73 therebetween in the thickness direction. That is, the clamping portion 64 holds the plurality of phase bus bars 71, 72, 73 from the thickness direction. In the present embodiment, the clamping portion 64 is provided with the same number (6) of the bus bars 71, 72, 73 for the phases provided on the upper side of the bus bar holder 61. Therefore, one phase bus bar 71, 72, 73 is held by one clip portion 64. In addition, the number of the clamping portions 64 may be more than 6.

A plurality of (6 in the present embodiment) leg portions 65 are provided in the bus bar holder 61. The plurality of leg portions 65 are arranged at equal intervals around the central axis. The bus bar holder 61 is supported by the stator 30 by the leg portion 65.

As shown in fig. 6, the leg portion 65 includes a radially extending portion 65a extending radially outward from the outer edge of the holder body portion 62, and a lower extending portion 65b extending downward from the radially outer front end of the radially extending portion 65 a. That is, the leg portion 65 extends downward relative to the holder body portion 62.

As shown in fig. 9, the lower end portion 65c of the leg portion 65 has a V-shape whose width becomes narrower toward the radially inner side when viewed from the axial direction. As shown in fig. 2, the V-shaped lower end portion 65c is housed in the leg housing portion 37 provided in the upper insulator 35. In addition, the leg portion 65 contacts the upper surface of the stator 30 on the lower end surface. As described above, the leg receiving portion 37 has a V-shape having the same shape or a similar shape to the lower end portion 65c of the leg 65 when viewed from the axial direction. When the leg portion 65 is received in the leg portion receiving portion 37, the bus bar holder 61 is positioned with respect to the stator 30 in a plane perpendicular to the axial direction.

The leg receiving portions 37 are provided above the boundary portions between the core members 32 adjacent in the circumferential direction. The leg portions 65 housed in the leg housing portions 37 are provided above the boundary portions between the core members 32 adjacent in the circumferential direction. That is, the leg portions 65 are arranged so as to overlap with the boundaries between the core members 32 adjacent in the circumferential direction when viewed from the axial direction.

According to the present embodiment, the lower end portion 65c of the leg portion 65 and the leg portion housing portion 37 are V-shaped with a width that becomes narrower toward the radial direction side, whereby the leg portion 65 can be easily inserted into the leg portion housing portion 37. Each leg portion 65 is in contact with the V-shaped wall portion when viewed in the axial direction from one side and the other side in the circumferential direction of the leg portion housing portion 37. Therefore, the positioning accuracy of the bus bar holder 61 in the circumferential direction can be improved. The leg receiving portion 37 may have a shape other than a V-shape. For example, the same effect can be obtained even in the trapezoidal or semicircular arc shape.

As shown in fig. 2, when viewed from the axial direction, a straight line connecting the lead line 33a drawn from each coil 33 and the center axis J is set as a virtual line VL. The leg portion 65 is located between the imaginary lines VL of the lead lines 33a of the pair of coils 33 adjacent in the circumferential direction when viewed from the axial direction. The lead wire 33a is connected to any one of the coil terminals 71a, 72a, 73a, 81a, and 82a provided on the plurality of phase bus bars 71, 72, and 73 and the plurality of neutral bus bars 81 and 82, respectively.

According to the present embodiment, the leg portion 65 is disposed between the pair of virtual lines VL arranged in the circumferential direction, and thus the leg portion 65 and the coil terminals 71a, 72a, 73a, 81a, and 82a can be disposed with a shift in the circumferential direction. This can suppress interference between the leg portion 65 and the coil terminals 71a, 72a, 73a, 81a, 82a and the lead wire 33 a. In addition, the leg portion 65 does not easily obstruct the soldering process of the coil terminals 71a, 72a, 73a, 81a, 82a and the lead wire 33 a.

In the present embodiment, the plurality of coil terminals 71a, 72a, 73a, 81a, 82a are alternately arranged at first intervals and second intervals narrower than the first intervals in the circumferential direction, and therefore, the plurality of virtual lines VL extending radially from the central axis J alternately extend at the first angle α and the second angle β smaller than the first angle α in the circumferential direction, the leg portion 65 of the present embodiment is positioned between the pair of virtual lines VL at the first angle α, a certain effect of suppressing interference between the leg portion 65 and the lead wire 33a can be obtained even when the leg portion 65 is arranged at any one of the pair of virtual lines VL at the first angle α and the pair of virtual lines VL at the second angle β, and the effect of suppressing interference between the leg portion 65 and the lead wire 33a can be further improved by arranging the leg portion 65 between the pair of virtual lines VL at the first angle α as shown in the present embodiment.

The leg portion 65 is located between a pair of coil terminals (for example, a pair of coil terminals 81a and 73a) connected to the lead lines 33a of the pair of coils 33 adjacent in the circumferential direction when viewed from the axial direction. According to the present embodiment, even when the radial positions of the leg portion 65 and the coil terminals 81a, 73a are matched, the leg portion 65 and the coil terminals 81a, 73a are arranged offset in the circumferential direction, and therefore interference between the leg portion 65 and the coil terminals 81a, 73a can be suppressed.

According to the present embodiment, since the interference between the leg portion 65 and the coil terminals 71a, 72a, 73a, 81a, and 82a is suppressed by the above arrangement, it is not necessary to arrange the leg portion 65 and the coil terminals 71a, 72a, 73a, 81a, and 82a so as to be shifted in the axial direction. More specifically, as shown in fig. 5, a part of the leg portion 65 may be disposed so as to overlap a part of the coil terminal 82a in the axial direction. By disposing at least a part of the leg portion 65 so as to overlap the coil terminal 82a in the axial direction, the bus bar unit 60 can be downsized in the axial direction.

(phase bus bar (first bus bar, bus bar))

The plurality of phase bus bars 71, 72, 73 are fixed to the upper side of the bus bar holder 61. The plurality of phase busbars 71, 72, 73 are classified into a first system phase busbar group 70A and a second system phase busbar group 70B. As described above, the first system-phase bus bar group 70A and the second system-phase bus bar group 70B have the U-phase bus bar 71, the V-phase bus bar 72, and the W-phase bus bar 73, respectively.

The U-phase bus bars 71 of the first system-phase bus bar group 70A and the second system-phase bus bar group 70B have the same shape, the V-phase bus bars 72 of the first system-phase bus bar group 70A and the second system-phase bus bar group 70B have the same shape, and the W-phase bus bars 73 of the first system-phase bus bar group 70A and the second system-phase bus bar group 70B have the same shape.

As shown in fig. 6, the U-phase bus bar 71 includes a bus bar main body portion 71b, a coil terminal 71a, an external connection terminal 71c, and a protruding portion 71 e. Similarly, the V-phase bus bar 72 includes a bus bar body 72b, a coil terminal 72a, an external connection terminal 72c, and a protrusion 72 e. The W-phase bus bar 73 includes a bus bar main body 73b, a coil terminal 73a, an external connection terminal 73c, and a protrusion 73 e.

The bus bar main bodies 71b, 72b, 73b extend along a plane perpendicular to the axial direction. The bus bar main bodies 71b, 72b, and 73b extend in the circumferential direction. The bus bar main bodies 71b, 72b, and 73b are arranged with a direction perpendicular to the axial direction as a thickness direction.

The coil terminals 71a, 72a, and 73a are located at one ends of the bus bar main bodies 71b, 72b, and 73b, respectively. The coil terminals 71a, 72a, and 73a extend radially outward from the bus bar main bodies 71b, 72b, and 73 b. The coil terminals 71a, 72a, and 73a may extend radially inward with respect to the bus bar main bodies 71b, 72b, and 73 b. That is, the coil terminals 71a, 72a, 73a may extend radially to one side with respect to the bus bar main bodies 71b, 72b, 73 b.

The coil terminals 71a, 72a, and 73a are connected to the lead wires 33 a. The coil terminals 71a, 72a, and 73a hold the lead wires 33 a. The coil terminals 71a, 72a, and 73a have a substantially U-shape in plan view, which is open radially inward. The coil terminals 71a, 72a, and 73a are arranged in a direction perpendicular to the axial direction as a thickness direction.

The external connection terminals 71c, 72c, and 73c are located at the opposite end portions (the other ends) of the bus bar main bodies 71b, 72b, and 73b from the coil terminals 71a, 72a, and 73a, respectively. The external connection terminals 71c, 72c, 73c extend upward from the bus bar main body portions 71b, 72b, 73 b.

The three external connection terminals 71c, 72c, 73c are provided in the first system phase bus bar group 70A and the second system phase bus bar group 70B, respectively. The external connection terminals 71c, 72c, and 73c of the first system phase bus bar group 70A and the external connection terminals 71c, 72c, and 73c of the second system phase bus bar group 70B are arranged on opposite sides with respect to the center axis J.

The external connection terminals 71c, 72c, and 73c are arranged in a direction perpendicular to the axial direction as a thickness direction. The external connection terminals 71c of the U-phase bus bar 71 are arranged in a direction perpendicular to the radial direction as the plate width direction. On the other hand, the external connection terminals 72c and 73c of the V-phase bus bar 72 and the W-phase bus bar 73 are arranged with the direction perpendicular to the plate width direction of the external connection terminal 71c of the U-phase bus bar 71 as the plate width direction.

As shown in fig. 6, the protruding portions 71e, 72e, 73e extend from the connection portions of the bus bar main body portions 71b, 72b, 73b and the external connection terminals 71c, 72c, 73c to the opposite side of the bus bar main body portion 71 b. The projections 71e, 72e, and 73e are arranged with a direction perpendicular to the axial direction as a thickness direction.

The bus bars 71, 72, 73 for phase are inserted into the concave grooves (concave portions) 63d provided in the bus bar holder 61 in the connection portions between the bus bar main body portions 71b, 72b, 73b and the external connection terminals 71c, 72c, 73c and the protruding portions 71e, 72e, 73 e. Therefore, the phase bus bars 71, 72, 73 are held by the bus bar holder 61 at the root portions of the external connection terminals 71c, 72c, 73 c. Therefore, the stress applied when the external connection terminals 71c, 72c, and 73c are inserted into the sockets of the external device can be stably supported by the bus bar holder 61.

According to the present embodiment, the bus bar main bodies 71b, 72b, 73b and the protruding portions 71e, 72e, 73e extend to both sides in the board width direction of the external connection terminals 71c, 72c, 73c at the root portions of the external connection terminals 71c, 72c, 73 c. The bus bar main bodies 71b, 72b, and 73b and the protrusions 71e, 72e, and 73e suppress the external connection terminals 71c, 72c, and 73c from wobbling in the board width direction inside the concave groove 63 d. This can improve the stability of insertion of the external connection terminals 71c, 72c, 73c into the sockets of the external device.

The entire width of the bus bar main bodies 71b, 72b, 73b of the common bus bars 71, 72, 73 is equal to the entire width of the protruding portions 71e, 72e, 73 e. Therefore, the stability of the external connection terminals 71c, 72c, 73c can be improved, and the effect of suppressing the rattling of the external connection terminals 71c, 72c, 73c on both sides in the width direction can be improved.

As shown in fig. 7, the U-phase bus bar 71 is the phase bus bar having the largest length in the circumferential direction of the bus bar main body portion among the three types of phase bus bars 71, 72, 73. The bus bar main body 71b of the U-phase bus bar 71 is located radially inward of the bus bar main bodies 72b, 73b of the other phase bus bars (the V-phase bus bar 72 and the W-phase bus bar 73). More specifically, the bus bar main body portion 71b of the U-phase bus bar 71 is located radially inward of the V-phase bus bar 72 belonging to the bus bar group of the same system and the W-phase bus bar 73 belonging to the bus bar group of another system.

The bus bars 71, 72, 73 for phase in the present embodiment are arranged to overlap in the radial direction in the bus bar main bodies 71b, 72b, 73 b. Therefore, by arranging the bus bar main bodies 71b, 72b, 73b so that the thickness direction thereof is perpendicular to the axial direction, the bus bars 71, 72, 73 can be arranged compactly in the radial direction. As a result, the radial dimension of the bus bar unit 60 can be reduced.

According to the present embodiment, the U-phase bus bar 71 having the largest length in the circumferential direction of the bus bar main body portion 71b among the plurality of phase bus bars 71, 72, 73 overlaps at least a part of the other phase bus bars (i.e., the V-phase bus bar 72 and the W-phase bus bar 73) in the radial direction. The bus bar main body portion 71b of the U-phase bus bar 71 is located on the opposite side in the radial direction from the direction in which the coil terminals 72a and 73a of the other phase bus bar extend. Therefore, the bus bar main body portion 71b of the U-phase bus bar 71 can be arranged at a sufficient distance in the radial direction from the lead wires 33a connected to the coil terminals 72a and 73a of the V-phase bus bar 72 and the W-phase bus bar 73. As a result, insulation can be ensured without the bus bar main body portion 71b of the U-phase bus bar 71 and the lead wire 33a being separated by a wall or the like.

In the present embodiment, the V-phase bus bar 72 and the W-phase bus bar 73 are held by the clip portion 64 in a region where the coil terminals 72a, 73a extend in the radial direction. On the other hand, the U-phase bus bar 71 is held by the clip portion 64 in the bus bar main body portion 71 b. The clip portion 64 holding the U-phase bus bar 71 does not radially overlap the V-phase bus bar 72 and the W-phase bus bar 73. That is, among the plurality of phase bus bars 71, 72, 73, the U-phase bus bar 71 having the largest length in the circumferential direction of the bus bar main body portion 71b is held by the clamp portion 64 in a region not overlapping with other phase bus bars in the radial direction. In other words, the bus bar main body portion 71b of the U-phase bus bar 71 radially overlaps the V-phase bus bar 72 and the W-phase bus bar 73 in the region not held by the clip portion 64. Therefore, the U-phase bus bar 71 can be arranged close to the V-phase bus bar 72 and the W-phase bus bar 73 in the radial direction.

The bus bar main body portion 71b of the U-phase bus bar 71 extends 180 ° in the circumferential direction around the center axis J. Therefore, the external connection terminal 71c located at one end of the bus bar main body portion 71b and the coil terminal 71a located at the other end of the bus bar main body portion 71b are disposed on opposite sides with respect to the central axis J. This makes it possible to arrange the external connection terminals 71c, 72c, 73c of one system while reducing the size of the main bodies 72b, 73b of the other phase bus bars (the V-phase bus bar 72 and the W-phase bus bar 73) in the circumferential direction. In the present embodiment, a case where the bus bar for the phase having the largest length in the circumferential direction of the bus bar main body portion among the plurality of bus bars 71, 72, 73 for the phase is the bus bar 71 for the U phase is described. However, when the bus bar main bodies 72b, 73b of the V-phase bus bar 72 or the W-phase bus bar 73 are longer than those of the other phase bus bars, the bus bar main bodies 72b, 73b of the phase bus bars 72, 73 may extend 180 ° around the central axis J.

In the present embodiment, the external connection terminals 71c, 72c, 73c of the same-phase bus bars 71, 72, 73 of different systems and the same phase are located on opposite sides with respect to the central axis J. That is, the external connection terminals 71c, 72c, 73c of the pair of phase bus bars 71, 72, 73 connected to the coils 33 of the first system coil group 7 and the second system coil group 8 which are in the same phase as each other are arranged on the opposite side with respect to the center axis J. Thus, the three external connection terminals 71c, 72c, and 73c of the first system and the second system can be arranged symmetrically about the central axis J. As a result, even if the circumferential position of the motor 1 is rotated by 180 °, the motor 1 can be connected to an external device, and the connection process of the motor 1 to the external device can be simplified.

When viewed from the axial direction, the external connection terminal 71c of one of the U-phase bus bar 71A of the first system and the U-phase bus bar 71B of the second system and the coil terminal 71A of the other partially overlap each other when viewed from the axial direction. The bus bar main body portion 71b of the U-phase bus bar 71A has a crank portion 71d extending in the axial direction near the root of the external connection terminal 71 c. By providing the crank portion 71d on the bus bar main body portion 71b, the external connection terminal 71c is offset upward, and interference with the coil terminal 71a is suppressed.

As shown in fig. 6, the bus bar main bodies 72b, 73b of the V-phase bus bar 72 and the W-phase bus bar 73 do not have a portion corresponding to the crank portion 71d of the U-phase bus bar 71. Therefore, the bus bar main bodies 72b and 73b of the V-phase bus bar 72 and the W-phase bus bar 73 extend only in a plane perpendicular to the axial direction.

In the phase bus bars 71, 72, 73, the bus bar main bodies 71b, 72b, 73b and the coil terminals 71a, 72a, 73a are formed by bending a plate material extending in one direction. The entire widths of the bus bar main bodies 72b and 73b of the V-phase bus bar 72 and the W-phase bus bar 73 are equal to the entire widths of the coil terminals 72a and 73 a. Therefore, in the case where the V-phase bus bar 72 and the W-phase bus bar 73 are manufactured by press working, the number of V-phase bus bars 72 and W-phase bus bars 73 obtained from the plate material can be increased as compared with the case where the coil terminal extends upward or downward with respect to the bus bar main body.

(terminal holder (external connection terminal holder))

The terminal support 66 is fixed to the upper side of the bus bar holder 61. The terminal support 66 covers the upper surface 63a of the base portion 63 of the bus bar holder 61. The terminal support 66 is made of a resin material.

The terminal support 66 includes a terminal support body 66a, three support portions 66b extending in a columnar shape upward from the terminal support body 66a, and a projection 66d projecting downward from the terminal support body 66 a. Support portion 66b has a cylindrical shape. The three support portions 66b are arranged in the circumferential direction.

As shown in fig. 1, the terminal support body 66a is provided with a fixing hole 66h penetrating in the axial direction. The shaft portion 63b of the bus bar holder 61 is inserted into the fixing hole 66 h.

The three support portions 66b are provided with holding holes 66c that penetrate in the axial direction. That is, three holding holes 66c are provided in the terminal support 66. The external connection terminals 71c, 72c, and 73c of the U-phase busbar 71, the V-phase busbar 72, and the W-phase busbar 73 are inserted into the three holding holes 66c, respectively. Thereby, the three holding holes 66c hold the external connection terminals 71c, 72c, 73 c.

The external connection terminals 71c, 72c, and 73c are inserted from the lower side of the holding hole 66c and protrude to the upper side of the support portion 66 b. The external connection terminals 71c, 72c, 73c pass through the through-holes 16a of the bearing holder 10 in the region surrounded by the support portion 66 b.

According to the present embodiment, the external connection terminals 71c, 72c, 73c are held by the holding holes 66c of the terminal holder 66. This improves the stability of the external connection terminals 71c, 72c, 73c when inserted into the socket of the external device.

According to the present embodiment, the external connection terminals 71c, 72c, 73c are surrounded by the support portion 66b of the terminal support 66. Therefore, when the bus bar unit 60 is disposed below the bearing holder 10 and the external connection terminals 71c, 72c, and 73c are inserted into the through-holes 16a of the bearing holder 10, the support portions 66b can be interposed between the external connection terminals 71c, 72c, and 73c and the inner peripheral surfaces of the through-holes 16 a. As a result, insulation between the external connection terminals 71c, 72c, 73c and the bearing holder 10 can be ensured.

As shown in fig. 6, the projection 66d extends in a plate shape from the terminal holder body portion 66a toward the lower side. The projection 66d is fitted into the groove 63d of the bus bar holder 61. This can improve the reliability of holding the terminal holder 66 by the bus bar holder 61. As a result, the reliability of holding the external connection terminals 71c, 72c, 73c held by the terminal holder 66 can be improved.

As described above, the groove 63d is inserted with the bus bar main body portions 71b, 72b, 73b of the phase bus bars 71, 72, 73. The convex portion 66d is fitted into the concave groove 63d from the upper side of the bus bar main bodies 71b, 72b, 73 b. Thereby, the phase bus bars 71, 72, 73 are pressed into the groove 63d from the upper side, and the holding of the phase bus bars 71, 72, 73 in the bus bar unit 60 can be stabilized.

Of the three convex portions 66d, two convex portions 66d that press the bus bar main bodies 72b, 73b of the V-phase bus bar 72 and the W-phase bus bar 73 from above extend downward along the external connection terminals 72c, 73c, respectively, and are fitted into the concave groove 63 d. Therefore, the two convex portions 66d can press the vicinity of the root portions of the external connection terminals 72c and 73c from above, and the effect of stabilizing the external connection terminals 72c and 73c can be improved.

Fig. 8 is a sectional view taken along line VIII-VIII of fig. 7.

Fig. 8 illustrates a fixing structure of the V-phase bus bar 72 inserted into the groove 63 d. Here, although the description is omitted, the same fixing structure is adopted for the U-phase bus bar 71 and the W-phase bus bar 73 inserted into the other grooves 63 d.

The opening on the upper side of the groove 63d is provided with a tapered portion 63e whose groove width becomes wider toward the upper side. By providing the tapered portion 63e, the insertion process of the phase junction 72 and the protrusion 66d into the groove 63d is facilitated.

The front end surface 66f of the projection 66d contacts the surface of the phase bus bar 72 facing upward. A welded portion 66e that is joined to the inner surface of the recess 63d is provided at the tip end of the projection 66 d. The welded portion 66e is formed by melting and solidifying the tip of the projection 66 d. The weld 66e engages the walls of the recess 63d and the mating bus bar 72 during curing. This enables the terminal holder 66 to be firmly fixed to the bus bar holder 61. Further, the phase bus bar 72 can be effectively suppressed from being pulled out from the groove 63 d. In the present embodiment, a case where the welded portion 66e is provided at the tip end of the projection 66d is exemplified. The weld 66e may be provided at least in a part of the projection 66 d.

The terminal support 66 is made of a resin material including a first resin portion 66A and a second resin portion 66B which are integrally molded. That is, the terminal holder 66 is molded by two-color molding. That is, the terminal holder 66 is molded by two-color molding the first resin portion 66A and the second resin portion 66B.

The second resin portion 66B is a thermoplastic resin material having a lower melting point than the first resin portion 66A. The terminal support body portion 66A and the support portion 66b are constituted by the first resin portion 66A. On the other hand, the convex portion 66d is formed of the second resin portion 66B.

According to the present embodiment, the welded portion 66e is formed of the second resin portion 66B having a low melting point. Therefore, the welded portion 66e can be easily formed by heating the terminal support 66 in a state where the convex portion 66d is inserted into the concave groove 63 d. In the present embodiment, the case where the entire projection 66d is formed of the second resin portion 66B is exemplified. However, it is sufficient if a part of the portion fitted into the groove 63d of the projection 66d is constituted by the second resin portion 66B.

In the method of manufacturing the bus bar unit 60, a process of fixing the terminal holder 66 to the bus bar holder 61 will be described. First, a bus bar mounting step of mounting the bus bars 71, 72, and 73 for use to the bus bar holder 61 is performed. In the phase bus bar mounting process, the phase bus bars 71, 72, 73 are inserted into the grooves 63d provided in the bus bar holder 61.

Next, a terminal holder mounting step (external connection terminal holder mounting step) of mounting the terminal holder 66 to the bus bar holder 61 is performed. In the terminal holder mounting step, first, the external connection terminals 71c, 72c, 73c are inserted into the holding holes 66c of the terminal holder 66. Next, the convex portion 66d of the terminal holder 66 is fitted into the concave groove 63d from the upper side of the phase bus bars 71, 72, 73. Then, the terminal support 66 is heated to melt and solidify a part of the projection 66d, and a welded portion 66e joined to the inner surface of the groove 63d is formed.

In the process of forming the welded portion 66e, a current may be passed through the phase bus bars 71, 72, and 73 to melt a part of the projection 66 d. When a current is passed through the phase bus bars 71, 72, 73, the phase bus bars 71, 72, 73 generate heat by joule heat. The heat is transferred to the projection 66d to melt a part of the projection 66 d. When the welded portion 66e is formed by passing a current through the phase bus bars 71, 72, 73, only the tip end portion of the projection 66d can be locally heated. Therefore, the welded portion 66e can be molded without affecting other portions of the terminal support 66. When the welded portion 66e is formed by joule heating, the current value flowing through the phase bus bars 71, 72, and 73 is sufficiently larger than the current value when the motor 1 is driven.

(neutral point bus bar (second bus bar, bus bar))

As described above, the stator 30 of the present embodiment includes two coil groups 7 and 8 (see fig. 4). The plurality of neutral point bus bars 81, 82 are provided in the same number as the number of coil groups (i.e., the number of systems). Therefore, the bus bar unit 60 of the present embodiment has two neutral point bus bars 81, 82.

Fig. 9 is a bottom view of the bus bar unit 60. As shown in fig. 9, the neutral point bus bars 81, 82 have bus bar main body portions 81b, 82b and three coil terminals 81a, 82 a. The neutral point bus bars 81 and 82 have a plate shape. At least the bus bar main bodies 81b and 82b of the neutral point bus bars 81 and 82 are arranged with the axial direction as the thickness direction.

The bus bar main body portions 81b, 82b extend along a plane perpendicular to the axial direction. The bus bar main body portions 81b, 82b extend in the circumferential direction in a region of 240 ° around the central axis J, respectively. At least a part of the bus bar main body portions 81b, 82b is exposed from the bus bar holder 61. That is, the neutral point bus bars 81 and 82 are not insert-molded with resin to the bus bar holder 61.

The coil terminals 81a and 82a are connected to the lead wire 33 a. The coil terminals 81a and 82a include portions for gripping the lead wires 33 a. The coil terminals 81a and 82a have a substantially U-shape in plan view, which is open radially inward. The coil terminals 81a and 82a are arranged with a direction perpendicular to the axial direction as a thickness direction.

The three coil terminals 81a and 82a are arranged at equal intervals in the longitudinal direction (i.e., the circumferential direction) of the bus bar main bodies 81b and 82b, respectively. Two coil terminals 81a, 82a of the three coil terminals 81a, 82a are located at both ends of the bus bar main bodies 81b, 82b, and the remaining one coil terminal 81a, 82a is located between the two coil terminals 81a, 82 a.

The coil terminals 81a and 82a extend in a direction away from the bus bar main bodies 81b and 82b in the radial direction. More specifically, the coil terminals 81a and 82a extend radially outward from the bus bar main bodies 81b and 82 b.

The coil terminals 81a and 82a may extend radially inward with respect to the bus bar main bodies 81b and 82 b. That is, the coil terminals 81a and 82a may extend radially to one side with respect to the bus bar main bodies 81b and 82 b.

The coil terminals 81a, 82a of the neutral point bus bars 81, 82 and the coil terminals 71a, 72a, 73a of the phase bus bars 71, 72, 73 extend in the same radial direction with respect to the bus bar main bodies 81b, 82b, 71b, 72b, 73b, respectively. With this arrangement, the neutral point bus bars 81 and 82 and the coil terminals 81a, 82a, 71a, 72a, and 73a of the phase bus bars 71, 72, and 73 can be aligned in the radial direction in which the bus bar holder 61 protrudes. Therefore, the positions of the lead wires 33a extending from the stator 30 and connected to the coil terminals 81a, 82a, 71a, 72a, 73a in the radial direction can be uniformly arranged. Thus, the structure of the bus bar holder 61 (the first wall portion 62c and the like in the present embodiment) that insulates the neutral point bus bars 81, 82 and the phase bus bars 71, 72, 73 from the lead wires 33a is not easily complicated. Further, with this arrangement, the coil terminals 71a, 72a, 73a of the plurality of phase busbars 71, 72, 73 and the coil terminals 81a, 82a of the plurality of neutral point busbars 81, 82 are arranged on a single imaginary circle VC around the central axis J when viewed from the axial direction. Therefore, in the welding step, by rotating the bus bar unit 60 and the stator 30 about the center axis J, the lead wires 33a and the coil terminals 81a, 82a, 71a, 72a, 73a can be welded and connected without moving the welding jig in the radial direction. This can simplify the welding process.

The coil terminals 81a and 82a extend downward from the bus bar main bodies 81b and 82 b. That is, the coil terminals 81a and 82a extend in the axial direction away from the phase bus bars 71, 72, and 73. Thus, the coil terminals 81a and 82a can be arranged so as to be axially apart from the coil terminals 71a, 72a, and 73a of the phase bus bars 71, 72, and 73, and interference therebetween can be suppressed. In addition, in the welding step of the lead wire 33a and one of the coil terminals of the neutral point bus bars 81 and 82 and the phase bus bars 71, 72, and 73, deterioration of the workability of welding by the other coil terminal can be suppressed.

The plurality of neutral point bus bars 81, 82 are classified into a first system neutral point bus bar 81 and a second system neutral point bus bar 82. The first system neutral point bus bar 81 is connected to the lead wires 33a of the coils 33 of the respective phases (U-phase, V-phase, W-phase) of the coil group of one system (the coil group 7 of the first system). Similarly, the second system neutral point bus bar 82 is connected to the lead wires 33a of the coils 33 of the respective phases (U-phase, V-phase, W-phase) of the coil group of one system (the coil group 8 of the second system). The coil terminals 71a, 72a, 73a of the phase bus bars 71, 72, 73 and the coil terminals 81a, 82a of the neutral point bus bars 81, 82 are alternately arranged in the circumferential direction.

As shown in fig. 6, a plurality of neutral point bus bars 81, 82 are fixed to the lower side of the bus bar holder 61. At least a part of the plurality of neutral point bus bars 81, 82 overlap each other when viewed from the axial direction.

The neutral point bus bars 81 and 82 are plate materials in which at least the bus bar main bodies 81b and 82b are arranged with the axial direction as the thickness direction. That is, the neutral point bus bars 81 and 82 of the present embodiment are of a so-called flat type. Therefore, even when the plurality of neutral point bus bars 81 and 82 are arranged to overlap in the axial direction, the dimension in the axial direction is not easily increased.

According to the present embodiment, the neutral point bus bars 81, 82 among the phase bus bars 71, 72, 73 and the neutral point bus bars 81, 82 are of a flat type. On the other hand, the phase bus bars 71, 72, 73 are of a so-called vertical type in which the bus bar main bodies 71b, 72b, 73b are arranged with the axial direction as the thickness direction. Generally, at least three phase bus bars 71, 72, 73 are required corresponding to the U-phase, V-phase, and W-phase coils 33. Therefore, when the phase bus bars 71, 72, and 73 are arranged in a flat manner and overlapped in the axial direction, 3 or more layers need to be stacked and arranged corresponding to the bus bars of the respective phases. Further, an insulating layer is provided between the laminated bus bars. Therefore, when 3 or more layers need to be stacked, the axial dimension is the sum of the thicknesses of the three bus bars and the thicknesses of the insulating layers therebetween, and the effect of axial miniaturization due to the stacked arrangement is reduced. According to the present embodiment, the two neutral point bus bars 81 and 82 are stacked in a flat type, whereby the effect of suppressing the dimension in the axial direction can be enhanced. In addition, the insulating layer provided between the bus bars overlapping in the axial direction is an air layer in the present embodiment.

As shown in fig. 9, the plurality of neutral point bus bars 81 and 82 are disposed between the first wall portion 62c and the second wall portion 62d provided in the holder main body portion 62, and extend in the circumferential direction. The first wall portion 62c and the second wall portion 62d are arranged in the radial direction so as to sandwich the bus bar main body portions 81b and 82b of the neutral point bus bars 81 and 82.

According to the present embodiment, the first wall portion 62c is located between the bus bar main body portions 81b, 82b of the neutral point bus bars 81, 82 and the lead wire 33a when viewed from the axial direction. This can easily insulate the neutral point bus bars 81 and 82 and the lead wire 33 a.

According to the present embodiment, the neutral point bus bars 81, 82 are sandwiched between the first wall portion 62c and the second wall portion 62d from the inside and the outside in the radial direction. Therefore, the neutral point bus bars 81 and 82 can be easily positioned in the radial direction.

According to the present embodiment, the rigidity of the holder main body portion 62 can be improved by providing the first wall portion 62c and the second wall portion 62d in the holder main body portion 62.

The first wall 62c is provided with a first notch 62ca and a second notch 62 cb. In addition, only the second cutout portion 62db is provided in the second wall portion 62 d. The neutral point bus bars 81, 82 are exposed in the radial direction in the first cutout portion 62ca or the second cutout portions 62cb, 62 db.

The first cutout portion 62ca allows the coil terminals 81a and 82a of the neutral point bus bars 81 and 82 to pass therethrough. The first cut-out portion 62ca can be provided to directly extend the coil terminals 81a and 82a radially outward from the bus bar main bodies 81b and 82 b. That is, the neutral point bus bars 81 and 82 can be manufactured at low cost without providing the coil terminals 81a and 82a with portions extending downward and beyond the first wall portion 62 c.

The second notch portions 62cb, 62db radially overlap wide portions 81s, 82s of neutral point bus bars 81, 82 described later. By providing the second notch portions 62cb, 62db, interference between the wide portions 81s, 82s and the bus bar holder 61 can be suppressed.

In the present embodiment, the coil terminal 81a passes through a part of the second notch 62 cb. That is, a part of the second notch 62cb also functions as a notch through which the coil terminal 81a passes.

The second notch 62cb provided in at least a part of the plurality of second notches 62cb of the first wall 62c is arranged to be radially offset from the lead line 33 a. Since the second notch 62cb is arranged to be radially offset from the lead wire 33a, insulation between the bus bar main bodies 81b and 82b exposed from the second notch 62cb and the lead wire 33a is easily secured. All the second notches 62cb may be arranged to be radially offset from the lead lines 33 a.

In the following description, one of the neutral point bus bars 81 and 82 located on the holder main body portion 62 side (i.e., on the bus bar holder 61 side) is referred to as a first-layer bus bar 81. The other of the neutral point bus bars 81 and 82 located outside the holder main body 62 (on the bus bar holder 61 side) from the first-layer bus bar 81 is defined as a second-layer bus bar 82. In the following description, the first-layer bus bar 81 and the second-layer bus bar 82 are collectively referred to as neutral point bus bars 81 and 82. The first-layer bus bar 81 is a first-system neutral point bus bar 81 connected to the first-system coil group 7, and the second-layer bus bar 82 connected to the second-system coil group 8 is a second-system neutral point bus bar 82.

Fig. 10 is a schematic sectional view taken along line X-X of fig. 9. The bus bar main body 81b of the first-layer bus bar 81 is provided with a fixing hole (through hole) 81h and a through hole (through hole) 81i that penetrate in the axial direction. The bus bar main body portion 82b of the second-layer bus bar 82 is provided with a fixing hole (through hole) 82h and a relief hole (through hole) 82i that penetrate in the axial direction.

In the present embodiment, the fixing holes 81h and 82h, the through hole 81i, and the relief hole 82i are surrounded by the bus bar main bodies 81b and 82b in four directions. However, the fixing holes 81h and 82h, the passing hole 81i, and the escape hole 82i may be cut-out shapes as long as they penetrate in the axial direction. That is, as long as the internal regions of the fixing holes 81h and 82h, the through hole 81i, and the escape hole 82i are surrounded by the bus bar main bodies 81b and 82b from three sides, the internal regions may not be surrounded by the bus bar main bodies 81b and 82 b.

The lower surface 62b of the holder main body portion 62 is provided with a plurality of shaft portions 67a, 68a, 69a and a plurality of fusion-bonded portions 67b, 68b, 69b located at the tips of the shaft portions 67a, 68a, 69 a. The fusion-bonded portions 67b, 68b, and 69b are hemispherical and convex downward. The welded portions 67b, 68b, 69b are formed by melting the distal end portions of the shaft portions 67a, 68a, 69a with heat.

As shown in fig. 9, the plurality of shaft portions 67a, 68a, 69a includes three first shaft portions 67a, two second shaft portions 68a, and one third shaft portion 69 a. The plurality of fusion-bonded portions 67b, 68b, and 69b include a first fusion-bonded portion 67b located at the tip of the first shaft portion 67a, a second fusion-bonded portion 68b located at the tip of the second shaft portion 68a, and a third fusion-bonded portion 69b located at the tip of the third shaft portion 69 a.

The first shaft portion 67a and the first welding portion 67b are provided for fixing the first-layer bus bar 81. The second shaft portion 68a, the third shaft portion 69a, the second fusion portion 68b, and the third fusion portion 69b are provided for fixing the second-layer bus bar 82. Therefore, the first-layer bus bar 81 and the second-layer bus bar 82 are fixed by three fusion portions, respectively.

The first weld portion 67b, the second weld portion 68b, and the third weld portion 69b are aligned on a single imaginary circle about the central axis J. Therefore, in the thermocompression bonding step of molding the first, second, and third fusion bonding portions 67b, 68b, and 69b, the busbar unit 60 is rotated around the central axis J, so that it is not necessary to move the thermocompression bonding jig in the radial direction. This can simplify the thermocompression bonding process. In fig. 9, the imaginary circle in which the first fusion-bonded part 67b, the second fusion-bonded part 68b, and the third fusion-bonded part 69b are arranged is not shown. The virtual circle is a circle including an arc-shaped X-X line shown in fig. 9.

As shown in fig. 10, the first shaft portion 67a passes through the fixing hole 81h of the first-layer bus bar 81. The first fusion portion 67b is located on the lower side of the first-layer bus bar 81. The first fusion portion 67b extends to the outside of the fixing hole 81h of the first-layer bus bar 81 when viewed from the axial direction. The first fusion-bonded portion 67b has a first fixing surface 67d facing upward at a portion extending outward from the first shaft portion 67 a. The first fixing surface 67d is in contact with the lower surface 81p of the first-layer bus bar 81. In addition, the upper surface 81q of the first-layer bus bar 81 is in contact with the lower surface 62b of the holder main body portion 62. That is, the first-layer bus bar 81 is sandwiched between the holder main body portion 62 and the first fusion portion 67 b. Thereby, the first welding portion 67b fixes the first-layer bus bar 81.

The escape hole 82i of the second-layer bus bar 82 is located in a region where the first-layer bus bar 81 and the second-layer bus bar 82 overlap when viewed from the axial direction and is located below the first welding portion 67b to which the first-layer bus bar 81 is fixed. That is, the escape hole 82i overlaps the first fusion-bonded portion 67b when viewed from the axial direction. As shown in fig. 9, the first fusion-bonded portion 67b is located inward of the inner peripheral surface of the escape hole 82i when viewed in the axial direction. That is, the first fusion-bonded portion 67b is disposed in the hole of the escape hole 82i when viewed from the axial direction.

According to the present embodiment, by providing the relief hole 82i in the second-layer bus bar 82, when the first-layer bus bar 81 is fixed in the region where the first-layer bus bar 81 and the second-layer bus bar 82 overlap, even if the first-layer bus bar 81 and the second-layer bus bar 82 are arranged so as to be close to each other in the axial direction, interference between the first fusion portion 67b and the second-layer bus bar 82 can be suppressed.

That is, according to the present embodiment, the first-layer bus bar 81 can be fixed in the region where the first-layer bus bar 81 and the second-layer bus bar 82 overlap. Therefore, the welding portions 67b to which the first-layer bus bars 81 are fixed can be evenly arranged in the longitudinal direction of the bus bar main body portion 81b of the first-layer bus bar 81. Further, since the first-layer bus bar 81 and the second-layer bus bar 82 can be disposed close to each other, the bus bar unit 60 can be downsized in the axial direction.

As shown in fig. 10, the second shaft portion 68a is provided with a stepped surface 68c facing the opposite side of the holder main body portion 62 (i.e., the opposite side and the lower side of the bus bar holder 61). The diameter of the second shaft portion 68a on the base end side (upper side) of the stepped surface 68c is larger than the diameter of the stepped surface 68c on the tip end side (lower side).

The second shaft portion 68a passes through the passing hole 81i of the first-layer bus bar 81 and the fixing hole 82h of the second-layer bus bar 82. The lower surface 81p of the first-layer bus bar 81 is located above the step surface 68 c. Therefore, the passage hole 81i of the first-layer bus bar 81 is inserted through the second shaft portion 68a at a position closer to the base end side than the stepped surface 68 c.

On the other hand, the second-layer bus bar 82 is positioned below the step surface 68 c. The upper surface 82q of the second-layer bus bar 82 contacts the step surface 68 c. Therefore, the fixing hole 82h of the second-layer bus bar 82 is inserted through the second shaft portion 68a at a position closer to the tip end side than the stepped surface 68 c.

The second fusion 68b is located on the lower side of the second layer of bus bars 82. The second fusion portion 68b extends to the outside of the fixing hole 82h of the second-layer bus bar 82 when viewed from the axial direction. The second fusion-bonded portion 68b has a second fixing surface 68d facing upward at a portion extending outward from the second shaft portion 68 a. The second fixing surface 68d is in contact with the lower surface 82p of the second-layer bus bar 82. Since the upper surface 82q of the second-layer bus bar 82 is in contact with the step surface 68c, the second-layer bus bar 82 is sandwiched between the step surface 68c and the second fusion portion 68 b. Thereby, the second fusion portion 68b fixes the second-layer bus bar 82.

According to the present embodiment, the second-layer bus bar 82 can be fixed in the region where the first-layer bus bar 81 overlaps the second-layer bus bar 82. In addition, since the second shaft portion 68a passes through the passage hole 81i of the first-layer bus bar 81, the first-layer bus bar 81 can be positioned in a plane perpendicular to the axial direction. At least a part of the outer peripheral surface of the second shaft portion 68a may be in contact with the inner peripheral surface of the through hole 81i in a region on the base end side (upper side) of the stepped surface 68 c. In this case, the accuracy of positioning the first-layer bus bar 81 via the second shaft portion 68a can be improved.

As shown in fig. 10, a stepped portion 62e protruding downward is provided on the lower surface 62b of the holder main body portion 62. The step portion 62e has a step portion lower surface 62f facing downward. The third shaft portion 69a protrudes downward from the step portion lower surface 62 f. The stepped portion lower surface 62f is disposed in a region where only the second-layer bus bar 82 is provided on the lower surface 62b of the holder main body portion 62. The upper surface 82q of the second-layer bus bar 82 contacts the step lower surface 62 f.

The third shaft portion 69a passes through the fixing hole 82h of the second-layer bus bar 82 in a region where the first-layer bus bar 81 and the second-layer bus bar 82 do not overlap. The third fusion 69b is located on the lower side of the second-layer bus bar 82. The third weld 69b extends outside the fixing hole 82h of the second-layer bus bar 82 when viewed from the axial direction. The third fusion-bonded portion 69b has a third fixing surface 69d facing upward at a portion extending outward from the third shaft portion 69 a. The third fixing face 69d is in contact with the lower surface 82p of the second-layer bus bar 82. That is, the second-layer bus bar 82 is sandwiched between the step portion 62e of the holder main body portion 62 and the third weld portion 69 b. Thereby, the third fusion portion 69b fixes the second-layer bus bar 82.

As shown by imaginary lines (two-dot chain lines) in fig. 10, an insulating sheet (insulating member) 4 may be interposed between the first-layer bus bar 81 and the second-layer bus bar 82. That is, the bus bar unit 60 may have the insulating sheet 4 sandwiched between the plurality of neutral point bus bars 81 and 82. The insulating sheet 4 is provided with a hole portion 4h for avoiding interference between the first welded portion 67b and the second shaft portion 68 a. By providing the insulating sheet 4 between the first-layer bus bar 81 and the second-layer bus bar 82, the reliability of insulation between the first-layer bus bar 81 and the second-layer bus bar 82 can be improved.

In fig. 9, the phase bus bars 71, 72, 73 arranged above the bus bar holder 61 are shown as hidden lines (broken lines). As shown in fig. 9, the neutral point bus bars 81, 82 and the phase bus bars 71, 72, 73 overlap each other at least partially when viewed from the axial direction. This enables the bus bar unit 60 to be reduced in size in the radial direction. Further, the holder main body portion 62 of the bus bar holder 61 is interposed between the phase bus bars 71, 72, 73 and the neutral point bus bars 81, 82 in the axial direction. Accordingly, even when the phase bus bars 71, 72, 73 and the neutral point bus bars 81, 82 are overlapped with each other when viewed from the axial direction, insulation between the phase bus bars 71, 72, 73 and the neutral point bus bars 81, 82 is easily ensured.

The welded portions 67b, 68b, and 69b are arranged to be shifted from the bus bars 71, 72, and 73 when viewed from the axial direction. As described above, the welded portions 67b, 68b, 69b are formed by melting resin at the distal ends of the shaft portions 67a, 68a, 69 a. Therefore, the bus bar holder 61 is heated to mold the welded portions 67b, 68b, and 69 b. The portions of the holder main body portion 62 that overlap the fusion-bonded portions 67b, 68b, and 69b when viewed axially may be slightly deformed by heat generated during molding of the fusion-bonded portions 67b, 68b, and 69 b. When viewed from the axial direction, the welding portions 67b, 68b, and 69b are arranged offset from the phase bus bars 71, 72, and 73, and thus deformation of the welding portions 67b, 68b, and 69b when they are melted can be prevented from affecting the positional accuracy of the phase bus bars 71, 72, and 73. This can improve the positional accuracy of the phase bus bars 71, 72, 73.

In the present embodiment, the U-phase bus bar 71 having the largest length in the circumferential direction of the bus bar main bodies 71b, 72b, 73b of the plurality of phase bus bars 71, 72, 73 passes through the radially inner side of the welded portions 67b, 68 b. The U-phase bus bar 71 extends in the circumferential direction through a position radially inward of the welded portions 67b and 68b, and thus the U-phase bus bar 71 can be shortened. As a result, the weight of the motor 1 can be reduced and the material cost of the U-phase bus bar 71 can be saved.

In the present embodiment, the plurality of phase busbars 71, 72, and 73 are plate-shaped, and the busbar main bodies 71b, 72b, and 73b are of a vertical type arranged with a direction perpendicular to the axial direction as a thickness direction. By using the vertical bus bars 71, 72, 73, the bus bar unit 60 is less likely to increase in size in the radial direction even when the bus bars 71, 72, 73 and the welding portions 67b, 68b, 69b are arranged so as not to overlap when viewed from the axial direction.

In the present embodiment, one welded portion 67b of the six welded portions 67b, 68b, 69b is located at the root portion of the coil terminal 81a of the first-layer bus bar 81. That is, one welded portion 67b overlaps the coil terminal 81a in the radial direction. With this arrangement, it is possible to secure positional accuracy of the coil terminals 81a and easily suppress vibration of the coil terminals 81 a. In the present embodiment, a case where only one fusion-bonded portion 67b is located at the root portion of the coil terminal 81a is described. However, all the fusion-bonded portions 67b, 68b, and 69b may be located at the root of the coil terminal 81 a.

The bus bar main body portion 81b of the first-layer bus bar 81 has a wide portion 81s provided around the passage hole 81 i. Similarly, the bus bar main body portion 82b of the second-layer bus bar 82 has a wide portion 82s provided around the escape hole 82 i. The wide portions 81s and 82s extend outward in the width direction in a circular shape having a center coincident with the center of the through hole 81i or the escape hole 82 i.

According to the present embodiment, by providing the wide portions 81s and 82s, even if the through holes 81i or the escape holes 82i are provided in the neutral point bus bars 81 and 82, the sectional areas of the bus bar main bodies 81b and 82b are not reduced. The increase in the resistance of the neutral point bus bars 81 and 82 can be suppressed.

In the present embodiment, the description has been given of the motor 1 in which the stator 30 includes two coil groups (the first coil group 7 and the second coil group 8), and the bus bar unit 60 includes six phase bus bars 71, 72, 73 corresponding to the two coil groups, and two neutral point bus bars 81, 82 corresponding to the two coil groups. However, the number of systems is not limited. For example, the stator 30 may have only three or more coil groups, and the bus bar unit 60 may have three or more systems of phase bus bars and neutral point bus bars corresponding to the coil groups.

Next, an embodiment of a device on which the motor 1 of the present embodiment is mounted will be described. Fig. 11 is a schematic diagram of an electric power steering apparatus equipped with the motor 1 of the present embodiment. The electric power steering apparatus 2 is mounted on a steering mechanism of a wheel of an automobile. The electric power steering apparatus 2 is an apparatus that reduces a steering force by hydraulic pressure. The electric power steering apparatus 2 includes a motor 1, a steering shaft 214, an oil pump 216, and a control valve 217.

The steering shaft 214 transmits an input from the steering device 211 to an axle 213 having wheels 212. The oil pump 216 generates hydraulic pressure in a cylinder 215 that transmits driving force based on the hydraulic pressure to the axle 213. The control valve 217 controls oil of the oil pump 216. In the electric power steering apparatus 2, the motor 1 is mounted as a drive source of the oil pump 216. The motor 1 of the present embodiment is not limited to the electric power steering apparatus, and may be mounted on any apparatus.

While the embodiment and the modification of the present invention have been described above, the configurations and combinations thereof in the embodiment and the modification are examples, and addition, omission, replacement, and other modifications of the configurations may be made without departing from the scope of the present invention. The present invention is not limited to the embodiments.

Claims (11)

1. A motor is provided with:

a rotor that rotates around a central axis extending in the vertical direction;

a stator that is radially opposed to the rotor with a gap therebetween; and

a bus bar unit disposed at an upper side of the stator,

the stator has a plurality of systems of the coil groups with a U-phase coil, a V-phase coil, and a W-phase coil as the coil groups of one system,

the coil groups of systems different from each other are arranged symmetrically around the central axis with respect to each other,

the bus bar unit has:

a plurality of phase bus bars connected to lead wires drawn from the coils of the respective phases; and

a bus bar holder that holds a plurality of the phase bus bars,

the phase bus bar has:

a bus bar main body portion extending in a circumferential direction;

a coil terminal located at one end of the bus bar main body, extending radially to one side of the bus bar main body, and connected to the lead wire; and

an external connection terminal located at the other end of the bus bar main body portion and extending upward,

the phase bus bar has a plate shape, at least the bus bar main body portion is arranged with a direction perpendicular to an axial direction as a thickness direction,

the phase bus bar having the largest length of the bus bar main body portion in the circumferential direction among the plurality of phase bus bars overlaps at least a part of the other phase bus bars in the radial direction, and passes through a side opposite to a direction in which coil terminals of the other phase bus bars extend in the radial direction.

2. The motor of claim 1,

the stator has the coil groups of two systems classified into a first system of coil groups and a second system of coil groups,

the plurality of phase bus bars include the phase bus bars connected to the U-phase coil, the V-phase coil, and the W-phase coil of the coil group of the first system and the coil group of the second system, respectively.

3. The motor of claim 2,

the pair of external connection terminals of the phase bus bar connected to coils of the same phase of the coil group of the first system and the coil group of the second system are disposed on opposite sides with respect to the central axis.

4. The motor according to any one of claims 1 to 3,

among the plurality of phase bus bars, the phase bus bar having the largest length of the bus bar main body portion in the circumferential direction is arranged such that the coil terminal and the external connection terminal are on opposite sides with respect to a central axis.

5. The motor according to any one of claims 1 to 4,

the bus bar holder has a clamping portion that holds the plurality of phase bus bars from a thickness direction,

the bus bar main body portion is held by the clamping portion in a region where the phase bus bar having the largest length of the bus bar main body portion in the circumferential direction does not overlap with other phase bus bars in the radial direction, among the plurality of phase bus bars.

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

in the plurality of phase bus bars, the coil terminal extends radially outward with respect to the bus bar main body,

the phase bus bar having the largest length of the bus bar main body portion in the circumferential direction among the plurality of phase bus bars is radially overlapped with at least a part of the other phase bus bars and is located radially inward of the phase bus bar.

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

the bus bar unit has the same number of neutral point bus bars as the number of systems of the coil groups held by the bus bar holder,

the neutral point bus bar is connected to the lead-out wires of the coils of the phases of the coil group of one system,

the neutral point bus bar has:

a bus bar main body portion extending along a plane perpendicular to the axial direction; and

a plurality of coil terminals extending radially to one side with respect to the bus bar main body and connected to the lead wires,

the coil terminal of the neutral point bus bar and the coil terminal of the phase bus bar extend in the same radial direction with respect to the bus bar body portion.

8. The motor of claim 7,

the neutral bus bar and the phase bus bar overlap each other at least in part when viewed from the axial direction.

9. The motor according to claim 7 or 8,

the neutral point bus bar has a plate shape, and at least the bus bar main body portion is arranged with an axial direction as a thickness direction.

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

the stator has a plurality of teeth portions around which coils are wound,

in each system, a plurality of U-phase coils, V-phase coils, and W-phase coils are provided, respectively, and are provided across the plurality of teeth via crossover wires.

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

the stator has 12 teeth portions around which coils are wound.

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