Motor stator

Abstract

[Problem] To provide a motor stator having high insulation between a crossover located farthest from a stator core and a housing. [Solution] A plurality of holding grooves (46, 56, 66) of a motor stator (10) include a distal groove (66) that is farthest from a stator core (31) with respect to the axial direction (AX) of the stator core (31). The width (W3) of the distal groove (66) decreases from an opening (67) of the distal groove (66) toward a bottom part (68) of the distal groove (66). The bottom part (68) of the distal groove (66) is positioned biased toward the stator core (31) with respect to the center line (CL3) of the opening (67) of the distal groove (66).

Description

Stator for motor

[0001] The present invention relates to an improved stator for a motor.

[0002] Prior art related to a stator for a motor is disclosed in Patent Document 1.

[0003] This stator is a stator for a three-phase AC motor, and includes a plurality of teeth arranged on the radially inner side of an annular stator core, a plurality of coils formed by winding windings around the teeth, a plurality of connecting wires connecting the coils to each other, and an annular insulator arranged at the end of the stator core.

[0004] Japanese Unexamined Patent Application Publication No. 2024-93314

[0005] When such a stator for a motor is fitted into a metal housing, in order to ensure insulation between the housing and the connecting wires, for example, it is known to attach a cylindrical cover to the outer periphery of the insulator.

[0006] The plurality of connecting wires are held in holding grooves side by side in the axial direction of the stator core and covered with the cover. The connecting wire located farthest from the stator core is located at the end in the entire stator.

[0007] Generally, the connecting wire located farthest is likely to have a shorter creepage distance to the housing than other connecting wires closer to the stator core. It is desirable to enhance the insulation between the connecting wire located farthest and the housing.

[0008] An object of the present invention is to provide a stator for a motor having high insulation between the connecting wire located farthest from the stator core and the housing.

[0009] In the following description, for ease of understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated forms by that.

[0010] This disclosure provides an annular stator core (31) fitted to the inner circumferential surface (21c) of the cylindrical portion (21b) of a metal housing (20) and having a plurality of teeth (33) formed radially inward; an annular insulator (70) provided on the end face of the stator core (31); and a plurality of conductors (40, 50, 60) through which three-phase currents of a three-phase alternating current are carried, each of which conductors (40, 50, 60) is wound around the teeth (33) via the insulator (70) to form a plurality of coils (42, 52, 62), and among the plurality of coils (42, 52, 62) formed on each of the conductors (40, 50, 60), adjacent coils (42, 52, 62) are connected by jumper wires (43, 53, 63). A stator (10) for a three-phase AC motor, wherein each of the plurality of connecting wires (43, 53, 63) is held in retaining grooves (46, 56, 66) formed on the outer circumference of the insulator (70) and runs along the outer circumference of the insulator (70), the stator (10) further comprises an annular cover (90) mounted on the outer circumference of the insulator (70) so as to cover the plurality of retaining grooves (46, 56, 66), the plurality of retaining grooves (46, 56, 66) have distal grooves (66) furthest from the stator core (31) with respect to the axial direction (AX) of the stator core (31), the width (W3) of the distal groove (66) narrows from the opening (67) of the distal groove (66) toward the bottom (68) of the distal groove (66), The bottom portion (68) of the distal groove (66) is positioned biased toward the side closer to the stator core (31) with respect to the center line (CL3) of the opening (67) of the distal groove (66), in the motor stator (10).

[0011] Preferably, the plurality of retaining grooves (46, 56, 66) have a proximal groove (46) closest to the stator core (31) with respect to the axial direction (AX) of the stator core (31), the width (W1) of the proximal groove (46) narrows from the opening (47) of the proximal groove (46) toward the bottom (48) of the proximal groove (46), and the bottom (48) of the proximal groove (46) is positioned biased toward the side closer to the stator core (31) with respect to the center line (CL1) of the opening (47) of the proximal groove (46).

[0012] Preferably, the cover (90) overlaps the outer peripheral surface (74) of the insulator (70) over its entire circumference on the stator core (31) side of the plurality of retaining grooves (46, 56, 66) of the insulator (70).

[0013] This invention provides a motor stator with high insulation between the jumper wires located furthest from the stator core and the housing.

[0014] Figure 1 is a cross-sectional view of an electric compressor with a motor stator built into it, according to an embodiment. Figure 3A is a perspective view of the motor stator built into the electric compressor shown in Figure 1. Figure 3A is a perspective view of a portion of the stator core and insulator. Figure 3B is a plan view of a portion of the stator core. Figure 4A is a perspective view of the stator core and insulator before the wires are wound around them. Figure 4B is a perspective view of the stator core and insulator after the first wire has been wound around it. Figure 4C is a perspective view of the stator core and insulator after the second wire has been wound around it. Figure 4D is a perspective view of the stator core and insulator after the third wire has been wound around it. This figure illustrates the wires held in the retaining grooves of the insulator. This is a cross-sectional view illustrating the shape of the retaining grooves of the insulator.

[0015] <Examples> Examples will be described based on the attached diagrams. Note that the examples described herein are not intended to particularly limit the present invention. Furthermore, the elements constituting each example can be combined as appropriate.

[0016] (Electric compressor 10) Refer to Figure 1. The electric compressor 10 is used, for example, to compress refrigerant in the refrigeration cycle of an automotive air conditioning system. However, the electric compressor 10 is not limited to any particular application.

[0017] This electric compressor 10 includes a motor 11 that serves as a driving source, a compression mechanism 14 driven by the motor 11 that compresses a gas (for example, a gaseous refrigerant), a housing 20 that houses the compression mechanism 14 and the motor 11, a partition member 23 that divides the inside of the housing 20 into a motor 11 side and a compression mechanism 14 side, and a control unit 26 that can control the motor 11.

[0018] (Motor 11) The motor 11 is a three-phase AC motor 11 and comprises an output shaft 12 that penetrates the partition member 23 from the motor 11 side toward the compression mechanism 14 side, a rotor 13 that can rotate together with the output shaft 12, and an annular stator 30 (motor stator) that surrounds the rotor 13 and is capable of generating a force to rotate the rotor 13. The axis AX of the output shaft 12 can also be said to be the axis AX of the stator 30.

[0019] (Compression mechanism 14) The compression mechanism 14 includes a movable scroll 16 rotatably fitted to an eccentric shaft 15 provided on the output shaft 12 of the motor 11, and a fixed scroll 17 that does not rotate relative to the housing 20. The movable scroll 16 and the fixed scroll 17 combine to form a compression chamber 14a inside.

[0020] (Housing 20) The housing 20 comprises a main body member 21 that houses the compression mechanism 14 and the motor 11, and a closing member 22 that closes the opening of the main body member 21. The main body member 21 is formed integrally with a cylindrical portion 21b and a bottom portion 21a that closes the opening on the motor 11 side. The stator core 31 of the stator 30, which will be described later, is fixed to the inner circumferential surface 21c of the cylindrical portion 21b by shrink fitting or the like. The main body member 21 is made of a casting of a metal material such as aluminum (including aluminum alloy).

[0021] (Control Unit 26) The control unit 26 includes an inverter device 27 for supplying drive power to the motor 11, and an inverter housing 28 that houses the inverter device 27 and is fixed to the bottom 21a of the housing 20. The inverter device 27 and the cluster block 34 (see also Figure 2) provided on the stator 30 of the motor 11 are connected by three relay terminals 29.

[0022] (Compression of refrigerant) When the output shaft 12 of the motor 11 rotates, the movable scroll 16 revolves around the axis AX. The refrigerant drawn in from the intake port 21d of the housing 20 is taken into the compression chamber 14a through the gap in the motor 11, the intake hole 23a of the partition member 23, and the refrigerant intake port 17a of the fixed scroll 17.

[0023] As the movable scroll 16 revolves, the compression chamber 14a gradually moves toward the center while its internal volume decreases. As a result, the refrigerant in the compression chamber 14a is compressed. The refrigerant in the compression chamber 14a flows into the discharge chamber 22a through the discharge hole 17b of the fixed scroll 17. The refrigerant in the discharge chamber 22a is discharged outward from a discharge port (not shown).

[0024] (Stator 30) Refer to Figures 2, 3A, and 3B. The stator 30 comprises an annular stator core 31, three wires 40, 50, and 60 for providing a plurality of coils 42, 52, and 62 on the stator core 31, two insulators 70 and 97 for ensuring insulation between the coils 42, 52, and 62 and the stator core 31, and a cover 90 attached to one of the insulators 70.

[0025] (Stator Core 31) The stator core 31 is constructed by laminating ferromagnetic steel plates. The stator core 31 has an annular back yoke 32 and a plurality of teeth 33 that protrude from the back yoke 32 toward the axis AX of the stator core 31. In this example, the stator core 31 has 15 teeth 33.

[0026] (Insulator 70) Insulators 70 and 97 sandwich the stator core 31 in the axial direction AX. Of the insulators 70 and 97, the insulator on the inverter device 27 side is designated as the first insulator 70, and the insulator on the opposite side is designated as the second insulator 97.

[0027] The first insulator 70 has a first annular portion 71 that is superimposed on the back yoke 32, and a plurality of first inward protrusions 72 that protrude radially inward from the first annular portion 71 and are superimposed on a plurality of teeth 33.

[0028] Refer to Figure 1. The second insulator 97 has a second annular portion 98 that is superimposed on the back yoke 32, and a plurality of second inward protrusions 99 that protrude radially inward from the second annular portion 98 and are superimposed on a plurality of teeth 33.

[0029] The teeth 33, the first internal projection 72, and the second internal projection 99, which are superimposed on each other, constitute a winding section 38 around which one of the three conductors 40, 50, or 60 is wound.

[0030] (First conductor 40) Refer to Figures 4A and 4B. The winding of conductors 40, 50, and 60 around the winding section 38 will be described. First, the first conductor 40, through which the U-phase current of the three-phase AC flows, is wound around the first winding section 38. After winding a predetermined number of turns, it is wound around the third adjacent winding section 38 in a clockwise direction. The same winding is repeated to form multiple coils.

[0031] The first conductor 40 includes a first connecting wire 41 that can be connected to the cluster block 34 (see Figure 2), a first coil 42 formed by winding a portion of the first conductor 40 around a winding section 38, a first jumper wire 43 that runs along the outer circumference of the first insulator 70 and connects adjacent first coils 42, and a first end wire 44 on the opposite side of the first connecting wire 41.

[0032] (Second conductor 50) Refer to Figure 4C. Next, the second conductor 50, through which the V-phase current of the three-phase alternating current flows, is wound around the adjacent winding section 38 in a clockwise direction relative to the first coil 42. After winding a predetermined number of turns, it is wound around the winding section 38 three positions away in a clockwise direction. The same winding process is repeated to form multiple coils.

[0033] The second conductor 50 includes a second connecting wire 51 that can be connected to the cluster block 34, a second coil 52 formed by winding a portion of the second conductor 50 around the winding section 38, a second jumper wire 53 that runs along the outer circumference of the first insulator 70 and connects adjacent second coils 52, and a second end wire 54 on the opposite side of the second connecting wire 51.

[0034] (Third conductor 60) Refer to Figure 4D. Finally, the third conductor 60, through which the W-phase current of the three-phase AC flows, is wound around the adjacent winding section 38 in a clockwise direction relative to the second coil 52. After winding a predetermined number of turns, it is wound around the third adjacent winding section 38 in a clockwise direction. The same winding is repeated to form multiple coils.

[0035] The third conductor 60 includes a third connecting wire 61 that can be connected to the cluster block 34, a third coil 62 formed by winding a portion of the third conductor 60 around the winding section 38, a third jumper wire 63 that runs along the outer circumference of the first insulator 70 and connects the third coils 62 to each other, and a third end wire 64 on the opposite side of the third connecting wire 61.

[0036] In this example, the first terminal wire 44, the second terminal wire 54, and the third terminal wire 64 are connected in a star configuration, but a delta configuration may also be used.

[0037] (Holding part 80) Refer to Figures 4A to 5. The first annular part 71 has an annular holding part 80 for holding the first connecting wire 43, the second connecting wire 53, and the third connecting wire 63. Hereinafter, the direction away from the stator core 31 along the axis AX will be referred to as the distal side, and the direction approaching the stator core 31 will be referred to as the proximal side. The connecting wires 43, 53, and 63 held by the holding part 80 are arranged in the order of the first connecting wire 43, the second connecting wire 53, and the third connecting wire 63 from the proximal side to the distal side. The holding part 80 extends distally from the first annular part 71 and is located on the inner circumference side of the first connecting wire 43 to the third connecting wire 63.

[0038] (Pull-in groove, pull-out groove, column) The holding section 80 has a first pull-in groove 81 for pulling the first jumper wire 43 into the winding section 38, and a first pull-out groove 82 for pulling the first conductor wire 40 out of the first coil 42. These grooves 81 and 82 can be described as grooves that are carved out from the distal side to the proximal side of the holding section 80 (from top to bottom in Figure 5).

[0039] A first column 83 is formed between the first pull-in groove 81 and the first pull-out groove 82. The winding direction of the first conductor 40 to the third conductor 60 is clockwise (see Figures 4A to 4D). Furthermore, the first pull-out groove 82 is located adjacent to the first pull-out groove 82 in a clockwise direction. That is, the first conductor 40 passes radially inside the first column 83. The first column 83 holds only the second jumper wire 53 and the third jumper wire 63. With this configuration, the first jumper wires 43 do not cross each other. The durability of the first jumper wires 43 is increased.

[0040] Furthermore, the holding portion 80 has a second pull-in groove 84 for pulling the second jumper wire 53 into the winding portion 38, and a second pull-out groove 85 for pulling the second conductor wire 50 out from the second coil 52. These grooves 84 and 85 can be described as grooves that are carved out from the distal side to the proximal side (from top to bottom in the figure) of the holding portion 80.

[0041] A second column 86 is formed between the second inlet groove 84 and the second outlet groove 85. The second conductor 50 passes radially inside the second column 86. The second column 86 holds only the third connecting wire 63. With this configuration, the second connecting wires 53 do not cross each other. The durability of the second connecting wires 53 is increased.

[0042] Further, the holding portion 80 has a third drawing-in groove 87 for drawing the third jumper wire 63 into the winding portion 38, and a third drawing-out groove 88 for drawing out the third conductor 60 from the third coil 62. These grooves 87 and 88 can be said to be grooves that are recessed from the distal side to the proximal side (from the top to the bottom in the figure) of the holding portion 80.

[0043] A third pillar 89 is formed between the third drawing-in groove 87 and the first drawing-out groove 82. The third conductor 60 passes through the radially inner side of the third pillar 89. The third pillar 89 does not hold any of the jumper wires 43, 53, 63. With such a configuration, the third jumper wires 63 do not cross each other. The durability of the jumper wire 63 is enhanced.

[0044] (Depth of groove) The second drawing-in groove 84 and the second drawing-out groove 85 are shallower than the first drawing-in groove 81 and the first drawing-out groove 82. In other words, the bottom 84a of the second drawing-in groove 84 and the bottom 85a of the second drawing-out groove 85 are on the distal side of the bottom 81a of the first drawing-in groove 81 and the bottom 84a of the second drawing-in groove 84.

[0045] The third drawing-in groove 87 and the third drawing-out groove 88 are shallower than the second drawing-in groove 84 and the second drawing-out groove 85. In other words, the bottom 87a of the third drawing-in groove 87 and the bottom 88a of the third drawing-out groove 88 are on the distal side of the bottom 84a of the second drawing-in groove 84 and the bottom 85a of the second drawing-out groove 85.

[0046] (Holding grooves 46, 56, 66) Referring to FIGS. 5 and 6. The holding portion 80 has a first holding groove 46 for holding the first jumper wire 43, a second holding groove 56 for holding the second jumper wire 53, and a third holding groove 66 for holding the third jumper wire 63. These grooves 46, 56, 66 are grooves that are recessed from the radially outer side to the inner side (from the right to the left in FIG. 6) of the holding portion 80.

[0047] (Maintaining the shape of the groove) Referring to FIG. 6, the width W1 of the first holding groove 46 decreases as it extends from the opening 47 to the bottom 48a. A line passing through the center of the opening 47 and extending along the radial direction of the axis AX is defined as the center line CL1. The bottom 48a is biased toward the proximal side (the side closer to the stator core 31) with respect to the center line CL1. Note that the shape of the first holding groove 46 is not limited to one in which the width W1 gradually decreases from the opening 47 to the bottom 48a as a whole. As long as a portion where the width W1 becomes narrower is provided in at least a part of the first holding groove 46, it is acceptable. The same applies to the second holding groove 56 and the third holding groove 66 described later.

[0048] The side surface 48a from the distal edge 47a of the opening 47 to the bottom 48 is oblique with respect to the radial direction (the left-right direction in FIG. 6). The side surface 48b from the bottom 48 to the proximal edge 47b is along the radial direction. The side surface 48a is longer than the side surface 48b.

[0049] The width W2 of the second holding groove 56 decreases as it extends from the opening 57 to the bottom 58. The bottom 58 is biased toward the proximal side with respect to the center line CL2 of the opening 57. Note that the width W2 is approximately twice the thickness of the second bridging line 53. The second bridging line 53 is contained within the proximal half of the second holding groove 56.

[0050] The side surface 58a from the distal edge 57a of the opening 57 to the bottom 58 is oblique with respect to the radial direction. The side surface 58b from the bottom 58 to the proximal edge 57b is along the radial direction. The side surface 58a is longer than the side surface 58b.

[0051] The width W3 of the third holding groove 66 decreases as it extends from the opening 67 to the bottom 68. The bottom 68 is biased toward the proximal side with respect to the center line CL3 of the opening 67. Note that the width W3 is approximately twice the thickness of the third bridging line 63. The third bridging line 63 is contained within the proximal half of the third holding groove 56.

[0052] The side surface 68a from the distal edge 67a of the opening 67 to the bottom 68 is oblique with respect to the radial direction. The side surface 68b from the bottom 68 to the proximal edge 67b is along the radial direction. The side surface 68a is longer than the side surface 68b.

[0053] (Cover 90) Refer to Figures 2 and 6. The cover 90 is annular in shape and made of insulating resin. The cover 90 has an outer peripheral cover portion 91 that surrounds the outer circumference of the first jumper wire 43 to the third jumper wire 63. Considering the assembly of the cover 90 to the first insulator 70, a gap is provided between the inner peripheral surface 91a of the outer peripheral cover portion 91 and the outer peripheral surface 80b of the retaining portion 80. In other words, the outer peripheral cover portion 91 does not block the openings 47, 57, 67 of the grooves 46, 56, 66.

[0054] Furthermore, the cover 90 has an annular distal cover portion 92 that extends radially inward from the distal end of the outer peripheral cover portion 91 and covers the distal end face 80a of the holding portion 80. The outer peripheral cover portion 91 and the distal cover portion 92 are integrally formed.

[0055] (Proximal Outer Peripheral Surface 74) The first annular portion 71 of the first insulator 70 has an annular proximal outer peripheral surface 74 (outer peripheral surface 74) that is proximal to the proximal edge 47b of the opening 47 of the first retaining groove 46 (the side approaching the stator core 31). The proximal outer peripheral surface 74 is stepped. The proximal outer peripheral surface 74 has a small diameter portion 75 and a large diameter portion 76 with different diameters from each other, and a stepped portion 77 that connects the small diameter portion 75 and the large diameter portion 76. The small diameter portion 75 is located proximal to the large diameter portion 76. The shape of the proximal outer peripheral surface 74 can be changed as appropriate. For example, the direction in which the proximal outer peripheral surface 74 extends may be oblique to the axis AX.

[0056] (Mounting portion 93) The outer peripheral cover portion 91 has a mounting portion 93 that extends from the outer peripheral cover portion 91 toward the proximal side of the first insulator 70 and can be attached to the proximal outer peripheral surface 74. The inner peripheral surface 93a of the mounting portion 93 overlaps the small diameter portion 75 over its entire circumference. The tip surface 93b of the mounting portion 93 is in contact with the stepped portion 77.

[0057] (Securing the cover 90) Refer to Figures 2 and 5. The proximal outer peripheral surface 74 has a projection 74a that protrudes radially outward. The outer peripheral cover portion 91 has a locking hole 95 that can be locked into the projection 74a.

[0058] (Preventing rattling of the cover 90) Refer to Figures 2 and 6. Multiple U-shaped holes are formed in the distal cover portion 92. The area surrounded by these holes is an elastically deformable portion 94 that can be elastically deformed when pressed by the holding portion 80 when the cover 90 is locked to the first insulator 70. Due to the elastic deformation of this elastically deformable portion 94, the cover 90 is pressed distally and fixed, thus preventing rattling.

[0059] (Effects of the embodiment) The first motor stator 10 is fitted into the inner circumferential surface 21c of the cylindrical portion 21b of a metal housing 20 and has an annular stator core 31 with a plurality of teeth 33 formed on the radially inward side, an annular insulator 70 provided on the end face of the stator core 31 and a plurality of conductors 40, 50, 60 through which the three phases of three-phase alternating current are carried, each of the conductors 40, 50, 60 being wound around the teeth 33 via the insulator 70 to form a plurality of coils 42, 52, 62, and among the plurality of coils 42, 52, 62 formed on each of the conductors 40, 50, 60, adjacent coils 42, 52, 62 are connected by jumper wires 43, 53, 63. A stator 10 for a three-phase AC motor, wherein each of the multiple jumper wires 43, 53, 63 is held in retaining grooves 46, 56, 66 formed on the outer circumference of the insulator 70 and runs along the outer circumference of the insulator 70, the stator 10 further comprises an annular cover 90 mounted on the outer circumference of the insulator 70 so as to cover the multiple retaining grooves 46, 56, 66, the multiple retaining grooves 46, 56, 66 have a distal groove 66 (third retaining groove 66) that is furthest from the stator core 31 with respect to the axial direction AX of the stator core 31, the width W3 of the distal groove 66 narrows from the opening 67 of the distal groove 66 toward the bottom 68 of the distal groove 66, and the bottom 68 of the distal groove 66 is positioned biased toward the stator core 31 with respect to the center line CL3 of the opening 67 of the distal groove 66.

[0060] The conductor 60, including the connecting wire 63, is wound while being pulled with sufficient tension to prevent it from loosening. Due to the shape of the distal groove 66 as described above, the connecting wire 64 is guided by the sides 68a and 68b of the distal groove 66, and the connecting wire 64 is moved proximal to a position where it abuts the proximal side 68b.

[0061] In general, electric equipment used at high voltages must ensure insulation from conductor to conductor. In the electric compressor 10, insulation between the jumper wires 43, 53, and 63 routed around the outer circumference of the stator 30's insulator 70 and the housing 20 to which the stator 30 is fixed must be considered. Even if a cylindrical cover 90 is provided between the jumper wires 43, 53, and 63 and the housing to ensure spatial insulation, there is still a risk of surface discharge from the jumper wire 63, in particular, through the distal opening of the cover 90, to the housing 20.

[0062] In this embodiment, the bottom 68 of the distal groove 66 is positioned biased toward the side closer to the stator core 12. Therefore, the distal side surface 68a of the distal groove 66 is longer than the proximal side surface 68b. The creepage distance from the third connecting wire 63 to the housing 20, which includes the distal side surface 68a in its path, is increased. This improves the insulation between the connecting wire 63 held in the distal groove 66 and the housing 20.

[0063] Furthermore, since the width W3 of the distal groove 66 (third retaining groove) is sufficiently larger than the thickness of each connecting wire 63, the connecting wires 63 can be reliably positioned inside the groove 66 without contacting or interfering with the opening 67 of the groove 66. The width W1 is approximately twice the thickness of the first connecting wire 43. The first connecting wire 43 is contained within the proximal half of the first retaining groove 46. This effect is also achieved in the other grooves 46 and 56.

[0064] Secondly, in the first motor stator 10, the plurality of retaining grooves 46, 56, 66 have a proximal groove 46 that is closest to the stator core 31 with respect to the axial direction AX of the stator core 31, the width W1 of the proximal groove 46 narrows from the opening 47 of the proximal groove 46 toward the bottom 48 of the proximal groove 46, and the bottom 48 of the proximal groove 46 is positioned biased toward the side closer to the stator core 31 with respect to the center line CL1 of the opening 47 of the proximal groove 46.

[0065] Similar to the distal groove 66, the bottoms 48 and 58 of the proximal grooves 46 and 56 are also positioned biased toward the side closer to the stator core 31. This allows the connecting wires 43, 53, and 63 to be further apart, and contact between the connecting wires 43, 53, and 63 can be avoided.

[0066] Thirdly, in the first or second motor stator 10, the cover 90 overlaps the proximal outer peripheral surface 74 (outer peripheral surface 74) of the insulator 70 over its entire circumference, on the stator core 31 side of the multiple retaining grooves 46, 56, 66 of the insulator 70.

[0067] In other words, there is no gap between the proximal outer surface 74 (outer surface 74) and the cover 90. Since the path from the jumper wire 43 held in the most proximal groove 46 (first retaining groove 46) to the housing 20 is blocked by the cover 90, the insulation between the jumper wire 43 and the housing 20 can be improved.

[0068] In this embodiment, the small-diameter portion 75 of the proximal outer peripheral surface 74 and the cover 90 overlap, but the portion of the cover 90 that overlaps can be changed as appropriate.

[0069] Refer to Figure 5. Within the first annular portion, the circumferential position of the protrusion 74a can be changed as appropriate. For example, it may be provided on the proximal side of the first column 83 (below the first column 83 in Figure 5).

[0070] 20...Housing 21b...Cylindrical section 21c...Inner surface of cylindrical section 30...Stator (Motor stator) 31...Stator core 40...First conductor 42...First coil 43...First jumper wire 46...First retaining groove (proximal groove) 47...Opening of first retaining groove (opening of proximal groove) 48...Bottom of first retaining groove (bottom of proximal groove) 50...Second conductor 52...Second coil 53...Second jumper wire 56...Second retaining groove 60...Third conductor 62...Third coil 63...Third jumper wire 66...Third retaining groove (distal groove) 67...Opening of third retaining groove (opening of distal groove) 68...Bottom of third retaining groove (bottom of distal groove) 70...First insulator (insulator) 74...Proximal outer surface (outer surface of the insulator) 90...Cover

Claims

1. The starter has an annular stator core (31) fitted into the inner circumferential surface (21c) of the cylindrical portion (21b) of a metal housing (20) and having a plurality of teeth (33) formed radially inward; an annular insulator (70) provided on the end face of the starter core (31); and a plurality of conductors (40, 50, 60) through which the three phases of a three-phase alternating current are carried, each of which conductors (40, 50, 60) is wound around the teeth (33) via the insulator (70) to form a plurality of coils (42, 52, 62); and among the plurality of coils (42, 52, 62) formed on each of the conductors (40, 50, 60), adjacent coils (42, 52, 62) are connected by jumper wires (43, 53, 63). A stator (10) for a three-phase AC motor, wherein each of the plurality of connecting wires (43, 53, 63) is held in retaining grooves (46, 56, 66) formed on the outer circumference of the insulator (70) and runs along the outer circumference of the insulator (70), the stator (10) further comprises an annular cover (90) mounted on the outer circumference of the insulator (70) so as to cover the plurality of retaining grooves (46, 56, 66), the plurality of retaining grooves (46, 56, 66) have distal grooves (66) furthest from the stator core (31) with respect to the axial direction (AX) of the stator core (31), the width (W3) of the distal groove (66) narrows from the opening (67) of the distal groove (66) toward the bottom (68) of the distal groove (66), The bottom portion (68) of the distal groove (66) is positioned biased toward the side closer to the stator core (31) with respect to the center line (CL3) of the opening (67) of the distal groove (66), in the motor stator (10).

2. The motor stator (10) according to claim 1, wherein the plurality of retaining grooves (46, 56, 66) have a proximal groove (46) closest to the stator core (31) with respect to the axial direction (AX) of the stator core (31), the width (W1) of the proximal groove (46) narrows from the opening (47) of the proximal groove (46) toward the bottom (48) of the proximal groove (46), and the bottom (48) of the proximal groove (46) is positioned biased toward the side closer to the stator core (31) with respect to the center line (CL1) of the opening (47) of the proximal groove (46).

3. The motor stator (10) according to claim 1 or claim 2, wherein the cover (90) overlaps the outer peripheral surface (74) of the insulator (70) over its entire circumference on the stator core (31) side of the plurality of retaining grooves (46, 56, 66) of the insulator (70).

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