WO2020195398A1

WO2020195398A1 - Motor

Info

Publication number: WO2020195398A1
Application number: PCT/JP2020/006705
Authority: WO
Inventors: 尚石田; 梅田　智之; 裕也齋藤; 藤原　英雄
Original assignee: 日本電産株式会社
Priority date: 2019-03-28
Filing date: 2020-02-20
Publication date: 2020-10-01
Also published as: CN113439382A

Abstract

One embodiment of the motor according to the present invention is provided with: a rotor having a shaft extending along the central axis and rotating about the central axis; a stator facing the rotor in the radial direction; and a housing comprising a resin and having the stator embedded thereinto. The stator has a recess portion that is provided in a stator core formed by laminating a plurality of magnetic steel sheets and opens on one side in the axial direction. The housing has an opening portion opening on the one side in the axial direction and exposing at least a part of the inner peripheral surface of the recess portion.

Description

motor

The present invention relates to a motor.

In recent years, motors in which the stator is molded with resin have been developed for the purpose of simplifying the assembly process. Patent Document 1 discloses a motor in which a resin portion for molding a stator constitutes a housing.

Japanese Publication: Japanese Patent Application Laid-Open No. 2007-267568

When molding the stator with a resin material, it was difficult to hold the stator with high position accuracy in the mold for molding the housing. If the positioning accuracy of the stator with respect to the housing is low, the rotational efficiency of the motor may decrease.

One of the objects of the present invention is to provide a motor capable of improving the positioning accuracy of the stator with respect to the housing in view of the above circumstances.

One aspect of the motor of the present invention is a housing having a shaft extending along a central axis and rotating around the central axis, a stator facing the rotor in the radial direction, and a housing in which the stator is embedded. And. The stator has a recess provided in a stator core in which a plurality of electromagnetic steel sheets are laminated and opens on one side in the axial direction, and the housing opens on one side in the axial direction and at least a part of the inner peripheral surface of the recess is formed. Has an opening to expose.

According to one aspect of the present invention, there is provided a motor capable of improving the positioning accuracy of the stator with respect to the housing.

FIG. 1 is a cross-sectional view of the motor of one embodiment. FIG. 2 is a plan view of the motor of one embodiment. FIG. 3 is a bottom view of the motor of one embodiment. FIG. 4 is an exploded perspective view of the split core of one embodiment. FIG. 5 is a partial cross-sectional view showing a holding state of the stator in the mold for molding the housing of one embodiment. FIG. 6 is a cross-sectional view showing a holding state of the stator in the mold for molding the housing of one embodiment. FIG. 7 is a partial perspective view of the stator of one embodiment as viewed from diagonally above. FIG. 8 is a partial perspective view of the stator of one embodiment as viewed from diagonally below. FIG. 9 is a partial perspective view of the stator core of one embodiment as viewed from diagonally below. FIG. 10 is a perspective view of the split core of the modified example.

Hereinafter, embodiments to which the present invention has been applied will be described in detail with reference to the drawings.
In the following description, the direction parallel to the central axis J (see FIG. 1) is simply referred to as "axial direction" or "vertical direction", and the radial direction centered on the central axis J is simply referred to as "radial direction". The circumferential direction around the axis J, that is, the circumference of the central axis J is simply referred to as the "circumferential direction". Further, in the present specification, one side in the axial direction along the central axis J is simply referred to as "lower side", and the other side is simply referred to as "upper side". It should be noted that the vertical direction in the present specification is merely a direction used for explanation, and does not limit the posture during use and distribution of the motor.

FIG. 1 is a cross-sectional view of the motor 1 of one embodiment. FIG. 2 is a plan view of the motor 1. FIG. 3 is a bottom view of the motor 1. Note that the rotor 10 is not shown in FIGS. 2 and 3.

As shown by a virtual line (dashed line) in FIG. 1, the motor 1 is attached to an external device 9 arranged above the motor 1 by using a fixing bolt 9e. The motor 1 transmits power to the external device 9.
The motor 1 includes a rotor 10, a stator 20 that surrounds the rotor 10, an upper bearing 15 and a lower bearing 16 that rotatably hold the rotor 10 with respect to the stator 20, and an upper bearing holder 40 that holds the upper bearing 15. It has a lower bearing holder 70 for holding the lower bearing 16, a housing 30, a plurality of nut members 50, and a plurality of bus bars 80.

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

The shaft 11 is connected to the power transmission mechanism 9d of the external device 9 at the upper end portion (the end portion on the other side in the axial direction). The shaft 11 is rotatably supported around the central axis J by the upper bearing 15 and the lower bearing 16. The rotor core 12 is fixed to the outer peripheral surface of the shaft 11. Further, the rotor magnet 13 is fixed to the outer peripheral surface of the rotor core 12. The plurality of rotor magnets 13 may be embedded inside the rotor core 12.

The upper bearing 15 is located above the stator 20, and the lower bearing 16 is located below the stator 20. The upper bearing 15 supports the upper end of the shaft 11, and the lower bearing 16 supports the lower end of the shaft 11. The upper bearing 15 and the lower bearing 16 of the present embodiment are ball bearings. However, the upper bearing 15 and the lower bearing 16 may be other types of bearings such as needle bearings.

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

The holder cylinder portion 41 has a cylindrical shape centered on the central axis J. The upper bearing 15 is arranged inside the holder cylinder portion 41 in the radial direction. The upper plate portion 42 covers the upper side of the outer ring of the upper bearing 15. The upper plate portion 42 is provided with a central hole 42a penetrating in the axial direction. The shaft 11 is inserted through the central hole 42a. The radial outer edge of the holder flange 43 is embedded in the housing 30. That is, at least a part of the upper bearing holder 40 is embedded in the housing 30.

The lower bearing holder 70 is located below the stator 20. The lower bearing holder 70 is made of resin. The lower bearing holder 70 has a disk shape when viewed from the axial direction. The lower bearing holder 70 is fixed to the housing 30 at the outer edge.

A central hole 72a is provided in the center of the lower bearing holder 70 when viewed from the axial direction. The lower end of the shaft 11 is inserted into the central hole 72a. An inner wall surface 71a that surrounds the lower bearing 16 from the outside in the radial direction and holds the lower bearing 16 is provided around the central hole 72a.

The stator 20 surrounds the rotor 10 from the outside in the radial direction. The stator 20 faces the rotor 10 in the radial direction. The stator 20 includes a stator core 21, an insulator 22, and a coil 29.

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

The stator core 21 of this embodiment is divided in the circumferential direction. The stator core 21 is an aggregate of 12 divided cores 21A arranged along the circumferential direction.

FIG. 4 is an exploded perspective view of the split core 21A of the present embodiment.
Each of the divided cores 21A has one tooth portion 21b and a divided core back portion 21d continuous to the radial outer side of the teeth portion 21b. Further, the teeth portion 21b has an umbrella portion 21c at an end portion on the inner side in the radial direction. That is, the split core 21A has an umbrella portion 21c.

The split core back portion 21d has an arc shape extending along the circumferential direction. When a plurality of divided cores 21A are lined up along the circumferential direction, the end faces of the divided core back portions 21d in the circumferential direction face each other and come into contact with each other. The divided core back portions 21d of the plurality of divided cores 21A are connected in the circumferential direction to form an annular core back portion 21a.

The teeth portion 21b extends radially inward from the center of the split core back portion 21d in the circumferential direction. At the tip of the teeth portion 21b, an umbrella portion 21c that is wider than the other portions of the teeth portion 21b is provided.

The split core 21A is configured by laminating a plurality of electromagnetic steel plates 26 along the axial direction. That is, the stator core 21 is configured by laminating a plurality of electromagnetic steel plates 26 along the axial direction. The plurality of electrical steel sheets 26 is a general term including the first electrical steel sheet 26A, the second electrical steel sheet 26B, and the third electrical steel sheet 26C.

The plurality of electrical steel sheets 26 are classified into the first electrical steel sheet 26A, the second electrical steel sheet 26B, and the third electrical steel sheet 26C. That is, the stator core 21 has a first electrical steel sheet 26A, a second electrical steel sheet 26B, and a third electrical steel sheet 26C. The split core 21A of the present embodiment includes two first electrical steel sheets 26A, two third electrical steel sheets 26C, and a large number (two or more) second electrical steel sheets 26B.

The plurality of first electrical steel sheets 26A are laminated on the lower end (one side in the axial direction) of the split core 21A. The plurality of third electromagnetic steel sheets 26C are laminated on the upper end (the other side in the axial direction) in the split core 21A. Further, the plurality of second electrical steel sheets 26B are laminated between the first electrical steel sheet 26A and the third electrical steel sheet 26C. That is, the second electrical steel sheet 26B is laminated on the upper side (the other side in the axial direction) of the first electrical steel sheet 26A. Further, the second electrical steel sheet 26B is laminated on the lower side (one side in the axial direction) of the third electrical steel sheet 26C.

The first electromagnetic steel sheet 26A and the third electrical steel sheet 26C have the same shape. On the other hand, the second electrical steel sheet 26B has a different shape from the first electrical steel sheet 26A and the third electrical steel sheet 26C.

The first electromagnetic steel sheet 26A and the third electrical steel sheet 26C each have two penetrating portions (inner end penetrating portion 27a and outer end penetrating portion 27b) penetrating in the axial direction. In the present embodiment, the two penetrating portions are a notch-shaped inner end penetrating portion 27a that opens at the radial inner end of the electromagnetic steel sheet and a notch-shaped outer end penetrating portion 27b that opens at the radial outer end of the electromagnetic steel sheet. ,are categorized.
The second electromagnetic steel sheet 26B has a shape that does not have the inner end penetrating portion 27a and the outer end penetrating portion 27b as compared with the first electromagnetic steel sheet 26A and the third electromagnetic steel sheet 26C.

The split core 21A has a recess 28E and a sub-recess 28F. That is, the stator 20 has a recess 28E and a sub-recess 28F provided in the stator core 21.

The recess 28E opens to the lower side (one side in the axial direction). The recess 28E is a general term including an inner recess 28a located in the umbrella portion 21c and an outer recess 28b located in the split core back portion 21d.

The inner recess 28a is a portion surrounded by the inner end penetrating portion 27a of the first electrical steel sheet 26A and the lower surface (the surface facing one side in the axial direction) of the second electrical steel sheet 26B on the upper side of the first electrical steel sheet 26A. .. Further, the outer recess 28b is a portion surrounded by the outer end penetrating portion 27b of the first electrical steel sheet 26A and the lower surface (the surface facing one side in the axial direction) of the second electrical steel sheet 26B above the first electrical steel sheet 26A. Is.

The sub-recess 28F opens on the upper side (one side in the axial direction). The sub-recess 28F is a general term including an inner sub-recess 28c located in the umbrella portion 21c and an outer sub-recess 28d located in the split core back portion 21d.

The inner sub-concave 28c is a portion surrounded by the inner end penetrating portion 27a of the third electrical steel sheet 26C and the lower surface (the surface facing the other side in the axial direction) of the second electrical steel sheet 26B below the first electrical steel sheet 26A. Is. Further, the outer sub-concave 28d is surrounded by the outer end penetrating portion 27b of the third electrical steel sheet 26C and the lower surface (the surface facing the other side in the axial direction) of the second electrical steel sheet 26B below the first electrical steel sheet 26A. This is the part to be used.

The inner recess 28a and the inner sub-recess 28c are located at the tip of the tooth portion 21b. The inner recess 28a and the inner sub-recess 28c are located at the center of the umbrella portion 21c in the circumferential direction. That is, the inner recess 28a and the inner sub-recess 28c are located on the teeth center line VL extending in the radial direction through the center of the teeth portion 21b when viewed from the axial direction. The inner recess 28a opens not only on the lower side but also on the inner side in the radial direction. Similarly, the inner sub-recess 28c opens not only on the upper side but also on the inner side in the radial direction.

The outer recess 28b and the outer sub-recess 28d are located at the outer edge of the core back portion 21a. The outer recess 28b and the outer sub-recess 28d are located at the central portion in the circumferential direction of the split core back portion 21d. That is, the outer recess 28b and the outer sub-recess 28d are located on the tooth center line VL. The outer recess 28b opens not only on the lower side but also on the outer side in the radial direction. Similarly, the outer sub-recess 28d opens not only on the upper side but also on the outer side in the radial direction.

The coil 29 is attached to the teeth portion 21b via the insulator 22. The end of the coil 29 is connected to a bus bar 80 located below the stator 20. The bus bar 80 is connected to a control device (not shown). Electric power is supplied to the coil 29 from the control device via the bus bar 80.

The insulator 22 is made of an insulating member. The insulator 22 is, for example, a resin member. The insulator 22 is attached to the teeth portion 21b. The insulator 22 has an upper piece 22A and a lower piece 22B. The upper piece 22A is attached to the stator core 21 from above. The upper piece 22A surrounds the upper end surface of the core back portion 21a and the upper half region of both end faces in the circumferential direction of the teeth portion 21b. The lower piece 22B is attached to the stator core 21 from below. The lower piece 22B surrounds the lower end surface of the core back portion 21a and the lower half region of both end faces in the circumferential direction of the teeth portion 21b.
In the present specification, the distal end surface of the teeth portion 21b is the surface of the teeth portions 21b that are orthogonal to the radial direction and the axial direction and face the circumferential direction, and the teeth portions 21b arranged along the circumferential direction face each other. It is a face.

The insulator 22 has a base portion 25, an inner wall portion 23, and an outer wall portion 24, respectively. The base portion 25 surrounds the entire outer peripheral surface of the teeth portion 21b. The base portion 25 is interposed between the outer peripheral surface of the teeth portion 21b and the coil 29.

The inner wall portion 23 is located inside the base portion 25 in the radial direction and extends along the circumferential direction. The inner wall portion 23 overlaps with the radial inner end portion of the teeth portion 21b when viewed from the axial direction. The inner wall portion 23 is located radially inside the coil 29. The inner wall portion 23 restricts the coil 29 wound around the teeth portion 21b from moving inward in the radial direction.

The inner wall portion 23 is provided on the upper piece 22A and the lower piece 22B, respectively. In the following description, the inner wall portion 23 of the upper piece 22A is referred to as the upper inner wall portion (first wall portion) 23A. Further, the inner wall portion 23 of the lower piece 22B is referred to as a lower inner wall portion (second wall portion) 23B. The upper inner wall portion 23A extends upward with respect to the base portion 25. The lower inner wall portion 23B extends downward with respect to the base portion 25. As will be described in detail later, the upper inner wall portion 23A and the lower inner wall portion 23B are each provided with an inner wall notch 23c.

The outer wall portion 24 is located on the radial outside of the base portion 25 and extends along the circumferential direction. The outer wall portion 24 overlaps with the core back portion 21a when viewed from the axial direction. The outer wall portion 24 is located radially outside the coil 29. The outer wall portion 24 restricts the coil 29 wound around the teeth portion 21b from moving outward in the radial direction.

The outer wall portion 24 is provided on the upper piece 22A and the lower piece 22B, respectively. In the following description, the outer wall portion 24 of the upper piece 22A will be referred to as the upper outer wall portion 24A. Further, the outer wall portion 24 of the lower piece 22B is referred to as a lower outer wall portion 24B. The upper outer wall portion 24A extends upward with respect to the base portion 25. The lower outer wall portion 24B extends downward with respect to the base portion 25. As will be described in detail later, the lower outer wall portion 24B is provided with an outer wall penetrating portion 24c.

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

A stator 20, a bus bar 80, an upper bearing holder 40, and a nut member 50 are embedded in the housing 30. As a result, the housing 30 holds the bus bar 80, the stator 20, the upper bearing holder 40, and the nut member 50. The housing 30 is insert-molded with the stator 20, the bus bar 80, the upper bearing holder 40, and the nut member 50 held in the mold. That is, since the stator 20, the bus bar 80, the upper bearing holder 40, and the nut member 50 can be embedded in the housing 30 at once, the assembly process of the motor 1 is simplified.

The housing 30 includes a main body 31 that holds the stator 20, a plurality of ribs 3 that project upward from the upper surface of the main body 31, a bus bar holder 36 that holds the bus bar 80, and a lower surface of the main body 31. It has a lower cylinder portion 37 that extends, a plurality of flange portions 39 that project radially outward from the outer peripheral surface of the main body portion 31, and a holder holding portion 38 that holds the upper bearing holder 40. The plurality of ribs 3 are a general term including an annular rib 3A and a radial rib 35. Further, the annular rib 3A is a general term including an inner annular rib 32, an intermediate annular rib 33, and an outer annular rib 34.

The stator 20 is embedded in the main body 31. The main body 31 surrounds the upper side, the lower side, and the radial outer side with respect to the stator 20. The main body 31 surrounds the teeth portion 21b and the coil 29, and is also provided between the teeth portions 21b and the coil 29 that are adjacent to each other in the circumferential direction. The inner peripheral surface of the stator core 21 is exposed from the housing 30.

The main body 31 has a plurality of openings 6. That is, the housing 30 has a plurality of openings 6. As will be described later, the plurality of openings 6 are traces of a support portion that supports the stator 20 in the mold when the housing 30 is molded. The plurality of openings 6 is a general term including a plurality of first openings 61, a plurality of second openings 62, and a plurality of third openings 63.

As shown in FIG. 1, the first opening 61 extends axially from the upper surface of the main body 31 to the stator 20. The first opening 61 opens on the upper side (the other side in the axial direction). The first opening 61 exposes a part of the stator. In the present embodiment, the first opening 61 exposes at least a part of the inner wall surface and the bottom surface of the inner sub-recess 28c provided on the upper end surface of the stator core 21.

As shown in FIG. 2, the housing 30 of the present embodiment is provided with six first openings 61. The distances of the plurality of first openings 61 from the central axis J coincide with each other. That is, the radial positions of the plurality of first openings 61 coincide with each other. The plurality of first openings 61 are arranged at equal intervals along the circumferential direction.

As shown in FIG. 1, the second opening 62 and the third opening 63 extend axially from the lower surface of the main body 31 to the stator 20. The second opening 62 opens downward and radially inward. The third opening 63 opens on the lower side (one side in the axial direction). The second opening 62 and the third opening 63 expose a part of the stator. In the present embodiment, the second opening 62 and the third opening 63 expose at least a part of the inner wall surface and the bottom surface of the recess 28E provided on the lower end surface of the stator core 21. In the present embodiment, the second opening 62 exposes the inner wall surface and the bottom surface of the inner recess 28a. Further, the third opening 63 exposes a part of the inner wall surface and the bottom surface of the outer recess 28b.

As shown in FIG. 3, the housing 30 of the present embodiment is provided with 12 second openings 62. The plurality of second openings 62 are located on concentric circles centered on the central axis J. Further, the plurality of second openings 62 are arranged at equal intervals along the circumferential direction.

The housing 30 of the present embodiment is provided with six third openings 63. The plurality of third openings 63 are located radially outward of the plurality of second openings 62, and are located on concentric circles centered on the central axis J. Further, the six third openings 63 are divided into two

groups

63A and 63B, with the three as one group. The three third openings 63 included in the group 63A are arranged at equal intervals along the circumferential direction. The three third openings 63 included in the group 63B are arranged at equal intervals along the circumferential direction. When the motor 1 is viewed from the lower side in the axial direction, any one of the three third openings 63 included in the group 63A is arbitrary of the three third openings 63 included in the group 63B. Is located on the opposite side of the central axis J. A plurality of second openings 62 and a plurality of third openings 63 are provided on the lower surface of the housing.

5 and 6 are partial cross-sectional views showing a holding state of the stator 20 in the mold 90 for molding the housing 30. Note that FIG. 5 shows the vicinity of the first opening 61, and FIG. 6 shows the vicinity of the second opening 62 and the third opening 63.

Inside the mold 90, a cavity C filled with a resin material constituting the housing 30 is provided. The mold 90 has a first mold 91 (see FIG. 5) and a second mold 92 (see FIG. 6) surrounding the cavity C. The first type 91 and the second type 92 are arranged so as to face each other in the axial direction. The first type 91 and the second type 92 can be relatively separated vertically, for example, at a parting line (not shown) located in the middle of the main body 31 in the axial direction.

As shown in FIG. 5, the first type 91 has a plurality of first support portions 91a. The first support portion 91a is a prism extending downward from the lower surface of the first type 91 facing the cavity C side. The first support portions 91a are arranged along the circumferential direction. The first support portion 91a is inserted into the inner sub-recess 28c of the stator core 21 and comes into contact with the bottom surface and the inner wall surface of the inner sub-recess 28c.

As shown in FIG. 6, the second type 92 has a plurality of second support portions 92b and a plurality of third support portions 92c. The second support portion 92b has a rib-like shape that projects outward in the radial direction from the surface of the second type 92 that faces the outward direction in the radial direction and extends along the axial direction. The third support portion 92c is a prism extending upward from the upper surface of the second type 92 facing the cavity C side. The third support portion 92c is located radially outward with respect to the second support portion 92b. The second support portion 92b and the third support portion 92c are arranged along the circumferential direction, respectively. The second support portion 92b is inserted into the inner recess 28a of the stator core 21 and comes into contact with the bottom surface and the inner wall surface of the inner recess 28a. The third support portion 92c is inserted into the outer recess 28b of the stator core 21 and comes into contact with the bottom surface and the inner wall surface of the outer recess 28b.

FIG. 7 is a partial perspective view of the stator 20 as viewed from diagonally above. FIG. 7 shows the first support portion 91a by a virtual line (dashed-dotted line). Note that in FIG. 7, the coil 29 is not shown.

As shown in FIG. 7, the upper inner wall portion 23A of the insulator 22 has an inner wall notch portion 23c that exposes the upper surface (end face facing upward) of the stator core 21. The first support portion 91a passes through the inner wall notch portion 23c and comes into contact with the surface of the stator core 21 facing upward.

As described above, an inner sub-recess 28c and an outer sub-recess 28d are provided on the upper surface of the stator core 21. The first support portion 91a is inserted into the inner sub-recess 28c. Further, the first support portion 91a comes into contact with the wall surfaces 28ca and 28cc and the bottom surface 28cc facing the inner side in the radial direction and both sides in the circumferential direction of the inner sub-recess 28c. The portion of each surface constituting the inner sub-recess 28c that comes into contact with the first support portion 91a is exposed from the housing 30 after molding.

According to the present embodiment, the first support portion 91a positions the stator core 21 in the mold 90 in the radial direction by contacting the wall surface 28ca facing the radial inward side of the inner sub-recess 28c. Further, the first support portion 91a positions the stator core 21 in the circumferential direction in the mold 90 by contacting the pair of wall surfaces 28cc facing both sides in the circumferential direction of the inner sub-recess 28c. Further, the first support portion 91a contacts the bottom surface 28cc of the inner sub-recess 28c to position the stator core 21 in the mold 90 in the axial direction.

FIG. 8 is a partial perspective view of the stator 20 as viewed from diagonally below. Further, FIG. 9 is a partial perspective view of the stator core 21 as viewed from diagonally below. 8 and 9 show the second support portion 92b and the third support portion 92c by an alternate long and short dash line (dashed line). Note that in FIG. 8, the coil 29 is not shown.

As shown in FIG. 8, the lower inner wall portion 23B of the insulator 22 has an inner wall notch portion 23c that exposes the lower surface (end surface facing downward) of the stator core 21. The second support portion 92b passes through the inner wall notch portion 23c and comes into contact with the stator core 21.

Similarly, the lower outer wall portion 24B of the insulator 22 has an outer wall penetrating portion 24c that exposes the lower surface (end surface facing downward) of the stator core 21. The outer wall penetrating portion 24c penetrates the lower outer wall portion 24B in the axial direction. The third support portion 92c passes through the outer wall penetrating portion 24c and comes into contact with the surface facing the lower side of the stator core 21.

As shown in FIG. 9, an inner recess 28a and an outer recess 28b are provided on the lower surface of the stator core 21. The second support portion 92b is inserted into the inner recess 28a. The third support portion 92c is inserted into the outer recess 28b.

The second support portion 92b comes into contact with the wall surfaces 28aa and 28ab and the bottom surface 28ac facing the inner side in the radial direction and both sides in the circumferential direction of the inner recess 28a. Similarly, the third support portion 92c comes into contact with the wall surfaces 28ba, 28bb and the bottom surface 28bc facing the radial inside and the circumferential sides of the outer recess 28b. Of the surfaces constituting the inner recess 28a and the outer recess 28b, the portion where the second support portion 92b or the third support portion 92c comes into contact is exposed from the housing 30 after molding.

According to the present embodiment, the second support portion 92b contacts the wall surface 28aa facing the radial inward side of the inner recess 28a to position the stator core 21 in the mold 90 in the radial direction. Further, the second support portion 92b contacts the pair of wall surfaces 28ab facing both sides in the circumferential direction of the inner recess 28a to position the stator core 21 in the circumferential direction in the mold 90. Further, the second support portion 92b contacts the bottom surface 28ac of the inner recess 28a to axially position the stator core 21 in the mold 90.

Similarly, according to the present embodiment, the third support portion 92c positions the stator core 21 in the mold 90 in the radial direction by contacting the wall surface 28ba facing the radial inward side of the outer concave portion 28b. Further, the third support portion 92c contacts the pair of wall surfaces 28bb facing both sides in the circumferential direction of the outer concave portion 28b, thereby positioning the stator core 21 in the circumferential direction in the mold 90. Further, the third support portion 92c contacts the bottom surface 28bc of the outer concave portion 28b to axially position the stator core 21 in the mold 90.

As shown in FIGS. 4 and 5, the housing 30 is formed by curing the resin material filled in the cavity C. After the resin material is cured, the housing 30 is separated from the mold 90 by separating the first mold 91 and the second mold 92 from each other along the axial direction. Along with this, the first support portion 91a is pulled out upward with respect to the housing 30. Further, the second support portion 92b and the third support portion 92c come out downward with respect to the housing 30.

In the housing 30, a first opening 61 is formed in a portion where the first support portion 91a is removed. Since the first support portion 91a passes through the inner wall notch 23c and the inner sub-recess 28c, the inner wall notch 23c and the inner sub-recess 28c are arranged coaxially with the first opening 61.
In the housing 30, a second opening 62 is formed in a portion where the second support portion 92b is removed. Since the second support portion 92b passes through the inner wall notch 23c and the inner recess 28a, the inner wall notch 23c and the inner recess 28a are arranged coaxially with the second opening 62.
In the housing 30, a third opening 63 is formed in a portion where the third support portion 92c is removed. Since the third support portion 92c passes through the outer wall penetrating portion 24c and the outer recess 28b, the outer wall penetrating portion 24c and the outer recess 28b are arranged coaxially with the third opening 63.

According to the present embodiment, in the housing 30, the first opening 61 opens upward, and the second opening 62 and the third opening 63 open downward. Therefore, the first support portion 91a supports the stator 20 from above, and the second support portion 92b and the third support portion 92c support the stator from below. The stator 20 can be sandwiched and supported in the mold 90 by the second support portion 92b, the third support portion 92c, and the first support portion 91a. Therefore, the position accuracy of the stator 20 in the mold 90 can be improved. In addition, the holding strength of the stator 20 in the mold 90 is increased, and the displacement of the stator 20 due to the injection pressure of the resin during molding can be suppressed.

According to the present embodiment, the stator core 21 is provided with an inner sub-recess 28c, an inner recess 28a, and an outer recess, which are connected to the first opening 61, the second opening 62, and the third opening 63, respectively, to expose the bottom surface. Will be done. Therefore, the first opening 61, the second opening 62, and the third opening 63 are traces of the first support portion 91a, the second support portion 92b, and the third support portion 92c that support the respective stators 20. Therefore, the first support portion 91a, the second support portion 92b, and the third support portion 92c can be brought into contact with the bottom surface and the wall surface of the inner sub-recess 28c, the inner recess 28a, and the outer recess, and the stator 20 in the mold 90. Positioning accuracy can be improved.

According to the stator core 21 of the present embodiment, as shown in FIG. 4, the recess 28E is formed by providing the inner end penetrating portion 27a and the outer end penetrating portion 27b on the first electromagnetic steel plate 26A laminated on the upper end portion. Will be done. Further, the sub-concave 28F is formed by providing the inner end penetrating portion 27a and the outer end penetrating portion 27b on the third electromagnetic steel plate 26C laminated on the lower end portion. Therefore, by preparing two types of electrical steel sheets having different shapes, the recess 28E and the sub-concave 28F can be easily provided. Therefore, it is not necessary to post-process the stator core 21 in order to provide the recess 28E and the sub-recess 28F. Therefore, the manufacturing process of the stator core 21 can be performed at low cost. In addition, it is possible to suppress the generation of residual stress due to post-processing in the stator core 21, and it is possible to suppress an increase in the magnetic resistance of the stator core 21.

According to the present embodiment, the outer recess 28b is located at the outer edge of the core back portion 21a of the stator core 21. The magnetic flux density of the magnetic field generated by the coil 29 and passing through the core back portion 21a is the smallest at the outer edge portion. By locating the outer recess 28b at the outer edge of the core back portion 21a, it is possible to prevent the outer recess 28b from increasing the magnetic resistance of the core back portion 21a.

According to this embodiment, the outer recess 28b is located at the center of the split core back portion 21d in the circumferential direction. A part of the magnetic field passing through the split core back portion 21d is curved toward the teeth portion 21b. Therefore, the magnetic flux density of the magnetic field passing through the split core back portion 21d is the smallest in the circumferential central portion of the split core back portion 21d, which is the radial outside of the teeth portion 21b. Since the outer recess 28b is located at the center of the split core back portion 21d in the circumferential direction, it is possible to prevent the outer recess 28b from increasing the magnetic resistance of the core back portion 21a.
The outer sub-recess 28d is also arranged at the same position as the outer recess 28b to prevent the core back portion 21a from increasing the magnetic resistance.

According to the present embodiment, the inner recess 28a is located at the umbrella portion 21c at the tip of the teeth portion 21b of the stator core 21. Further, the inner recess 28a is located at the center of the umbrella portion 21c in the circumferential direction. The magnetic field passing through the teeth portion 21b is emitted to the outside of the stator core 21 at the inner edge of the umbrella portion 21c. Since the inner recess 28a is located at the center of the umbrella portion 21c in the circumferential direction, the magnetic field passing through the teeth portion 21b is emitted from the umbrella portion 21c in a well-balanced manner in the circumferential direction, and a decrease in the rotational efficiency of the motor 1 can be suppressed.
By arranging the inner sub-recess 28c at the same position as the inner recess 28a, the magnetic field passing through the teeth portion 21b can be discharged from the umbrella portion 21c in a well-balanced manner in the circumferential direction.

FIG. 3 shows the first opening 61 with a broken line. As shown in FIG. 3, the first opening 61 overlaps the second opening 62 when viewed from the axial direction. Therefore, the first support portion 91a and the second support portion 92b can support the stator 20 at the same position when viewed from the axial direction in the mold, and the stator 20 can be stabilized in the mold 90. ..

According to the present embodiment, the plurality of first openings 61 are arranged at equal intervals along the circumferential direction. That is, the plurality of first support portions 91a are arranged at equal intervals along the circumferential direction to support the stator 20 from above. Therefore, the first support portion 91a can stably support the stator 20 in the mold 90. Similarly, since the plurality of second openings 62 are arranged at equal intervals along the circumferential direction, the plurality of second support portions 92b are arranged at equal intervals along the circumferential direction to support the stator 20 from below. To do. Therefore, the second support portion 92b can stably support the stator 20 in the mold 90.

According to the present embodiment, the insulator 22 is provided with an inner wall notch 23c through which the first support 91a passes, an inner wall notch 23c through which the second support 92b passes, and an outer wall penetration 24c through which the third support 92c passes. Be done. The first support portion 91a passes through the inside of the inner wall notch portion 23c and directly supports the stator core 21. The second support portion 92b passes through the inside of the inner wall notch portion 23c and directly supports the stator core 21. The third support portion 92c passes through the inside of the outer wall penetrating portion 24c on the outside of the second support portion 92b and directly supports the stator core 21. The insulator 22 is generally made of a resin material. On the other hand, since the stator core 21 is made of a metal material, it has higher rigidity than the insulator 22. By supporting the stator core 21 by the first support portion 91a, the second support portion 92b, and the third support portion 92c, the holding of the stator 20 in the mold 90 can be stabilized, and the position of the stator 20 with respect to the housing 30 can be stabilized. The accuracy can be improved.

As shown in FIG. 2, the rib 3 projects upward from the upper surface of the main body 31. The rib 3 is located above the stator 20. The rib 3 has a plurality of annular ribs 3A extending along the circumferential direction and a plurality of radial ribs 35 extending along the radial direction and connecting to the annular rib 3A. Since the housing 30 has an annular rib 3A and a radial rib 35 that are connected to each other, the strength in the radial direction and the circumferential direction is enhanced in a well-balanced manner.

Each of the plurality of annular ribs 3A has a cylindrical shape centered on the central axis J. The plurality of annular ribs 3A include an inner annular rib 32 having the smallest diameter, an intermediate annular rib 33 located between the inner annular rib 32 and the outer annular rib 34 in the radial direction, and an outer annular rib 34 having the largest diameter. , Have. The inner annular rib 32, the intermediate annular rib 33, and the outer annular rib 34 are provided concentrically with the central axis J as the center.

The outer annular rib 34 is located radially outside the inner annular rib 32 and the intermediate annular rib 33. The intermediate annular rib 33 is located radially outward of the inner annular rib 32. The outer peripheral surface of the outer annular rib 34 is continuous with the outer peripheral surface of the main body 31. A flange portion 39 is provided on the outer peripheral surface of the outer annular rib 34.

The plurality of radial ribs 35 extend radially with respect to the central axis J. The plurality of radial ribs 35 are arranged at equal intervals along the circumferential direction. The housing 30 of the present embodiment is provided with six radial ribs 35. The plurality of radial ribs 35 connect the inner annular rib 32, the intermediate annular rib 33, and the outer annular rib 34, respectively. Further, the plurality of radial ribs 35 intersect and connect with the intermediate annular rib 33. By connecting the plurality of concentric annular ribs 3A to each other by the plurality of radial ribs 35, the strength in the circumferential direction and the radial direction of the housing 30 can be increased.

As shown in FIG. 1, the inner annular rib 32 has an annular portion 32a attached to the external device 9. The annular portion 32a is located at the upper end of the inner annular rib 32. The annular portion 32a is a portion of the inner annular rib 32 located above the upper end surface of the other ribs (intermediate annular rib 33, outer annular rib 34, and radial rib 35). In the axial direction, the positions of the upper end surfaces of the other ribs (that is, the intermediate annular rib 33, the outer annular rib 34, and the radial rib 35) coincide with each other. The annular portion 32a has a cylindrical shape extending upward from the upward facing surface of the housing 30.

The annular portion 32a is located on the radial outside of the first opening 61. The annular portion 32a is located radially inside the outer peripheral surface of the housing 30. The annular portion 32a is attached to the external device 9 and plays a part of the sealing function of the motor 1.

The external device 9 has a cylindrical holding cylinder portion 9a centered on the central axis J. The holding cylinder portion 9a surrounds the annular portion 32a from the outside in the radial direction. The inner diameter of the holding cylinder portion 9a is slightly larger than the outer diameter of the annular portion 32a. The tip surface of the holding cylinder portion 9a comes into contact with the upper end surface of the radial rib 35.

A concave groove 9b extending along the circumferential direction is provided on the inner peripheral surface of the holding cylinder portion 9a. The sealing member 9c is housed in the groove 9b. The sealing member 9c is made of an elastic material such as rubber. The seal member 9c extends along the circumferential direction. In this embodiment, the seal member 9c is an O-ring. The seal member 9c is not limited to a member having a circular cross-sectional shape as long as it functions as a gasket.

The seal member 9c is sandwiched between the outer peripheral surface 32d of the annular portion 32a facing outward in the radial direction and the bottom surface of the concave groove 9b facing outward in the radial direction. As a result, the seal member 9c is compressed, and moisture is prevented from entering the inside of the holding cylinder portion 9a.

According to this embodiment, the seal member 9c comes into contact with the outer peripheral surface 32d of the annular portion 32a. Further, the annular portion 32a surrounds the plurality of first openings 61 from the outside in the radial direction. Since the sealing member 9c suppresses the infiltration of water into the annular portion 32a, it is possible to prevent the moisture from reaching the first opening 61 arranged inside the annular portion 32a. The motor 1 of the present embodiment has an effect that it is easy to suppress the infiltration of liquid into the inside of the stator 20.

In the present embodiment, the annular portion 32a is in contact with the seal member 9c on the outer peripheral surface 32d to form a seal structure. However, the annular portion 32a may be in contact with the sealing member on the inner peripheral surface of the annular portion 32a, for example, as long as it bears a part of the sealing function.

According to the present embodiment, the upper end portion of the shaft 11 is connected to the external device 9 inside the annular portion 32a and transmits power to the external device 9. That is, the motor 1 of the present embodiment has an effect that it is easy to suppress the infiltration of liquid into the inside of the stator 20 from the output side to the external device 9.

As shown in FIG. 1, the upper end surface (end surface on the other side in the axial direction) 32b of the annular portion 32a is located on the upper side (the other side in the axial direction) with respect to the opening of the first opening 61. Further, according to the present embodiment, the annular portion 32a comes into contact with the seal member 9c on the outer peripheral surface 32d. Therefore, the route from the seal portion to the opening of the first opening 61 can be complicated. As a result, even when a small amount of water passes through the seal portion due to an unexpected impact or the like, it is possible to prevent the water content from reaching the first opening 61. As described above, the motor 1 has high reliability with respect to the infiltration of the liquid into the stator 20.

A chamfered inclined surface 32c is provided on the outer edge of the upper end surface 32b of the annular portion 32a. That is, in the annular portion 32a, the boundary portion between the upper end surface 32b and the outer peripheral surface 32d is an inclined surface 32c that inclines outward in the radial direction toward the lower side (one side in the axial direction). Therefore, when the annular portion 32a is inserted inside the holding cylinder portion 9a, it is possible to prevent the seal member 9c held on the inner peripheral surface of the holding cylinder portion 9a from being caught on the outer edge of the annular portion 32a. As a result, when the motor 1 is attached to the external device 9, it is possible to prevent the seal member 9c from being twisted or damaged.

As shown in FIG. 2, a gate mark G is provided on the outer surface of the housing 30. In the present embodiment, the gate mark G is provided on the upper end surface (the surface on the other side in the axial direction) of the housing 30. As shown in FIG. 5, the gate mark G is a mark of the gate 99 formed when the cavity C of the mold 90 for molding the housing 30 is filled with the resin material. The gate mark G is a portion where the cured resin is cut in the gate 99.

According to the housing 30 of the present embodiment, the gate mark G is provided on the upper surface, and the second opening 62 and the third opening 63 are provided on the lower surface. As shown in FIGS. 5 and 6, the gate 99 of the mold 90 and the second support portion 92b and the third support portion 92c are arranged on surfaces facing each other. Therefore, the injection pressure of the resin flowing from the gate 99 into the cavity C at the time of molding the housing 30 can be received by the second support portion 92b and the third support portion 92c. As a result, it is possible to prevent the stator 20 from being displaced in the mold 90 due to the injection pressure of the resin.

FIG. 3 shows the gate mark G with a broken line. As shown in FIG. 3, the gate mark G is located between the second opening 62 and the third opening 63 in the radial direction when viewed from the axial direction. That is, as shown in FIGS. 5 and 6, the gate 99 is located between the second support portion 92b and the third support portion 92c in the radial direction when viewed from the axial direction. Therefore, the injection pressure of the resin flowing from the gate 99 into the mold 90 can be received by the second support portion 92b and the third support portion 92c in a well-balanced manner. As a result, it is possible to effectively prevent the stator 20 from being displaced in the mold 90 due to the injection pressure of the resin.

As shown in FIG. 3, the circumferential positions of some of the gate marks G among the plurality of gate marks G overlap with the circumferential positions of the second opening 62 and the third opening 63. That is, in the radial direction, the second opening 62, the gate mark G, and the third opening 63 are arranged side by side. By arranging in this way, the injection pressure of the resin flowing from the gate 99 into the mold 90 can be received by the second support portion 92b and the third support portion 92c in a more balanced manner.
In this embodiment, the case where the circumferential position of a part of the gate marks G overlaps with the circumferential position of the second opening 62 and the third opening 63 has been illustrated. However, it is more preferable to satisfy the above-mentioned relationship with respect to the positional relationship of all the gate marks G, the second opening 62, and the third opening 63.

As shown in FIG. 2, a plurality of gate marks G (6 in this embodiment) are provided in the housing 30. The distances of the plurality of gate marks G from the central axis J coincide with each other. That is, the radial positions of the plurality of gate marks G coincide with each other. The plurality of gate marks G are arranged at equal intervals along the circumferential direction. Therefore, in the molding process of the housing 30, the resin material can be injected into the mold 90 from the gates 99 arranged at equal intervals along the circumferential direction in a well-balanced manner, and the molding accuracy of the housing 30 can be improved.

The gate mark G is located on the rib. More specifically, the gate mark G is located at the intersection of the radial rib 35 and the intermediate annular rib 33. That is, the gate mark G is located at the intersection of the ribs extending in the radial direction and the circumferential direction. Therefore, the resin injected from the gate 99 can be efficiently distributed to the intermediate annular rib 33 and the radial rib 35. Further, the resin injected from the gate 99 can be efficiently distributed to the inner annular rib 32 and the outer annular rib 34 via the radial rib 35.

As shown in FIG. 1, the holder holding portion 38 is located above the main body portion 31 and extends radially inward from the inner end of the main body portion 31. Further, the holder holding portion 38 is located inside the inner annular rib 32 in the radial direction. The holder flange portion 43 of the upper bearing holder 40 is embedded in the holder holding portion 38. As a result, the holder holding portion 38 holds the upper bearing holder 40.

The holder holding portion 38 is located inside the first opening 61 provided in the main body portion 31 in the radial direction. Therefore, the holder flange portion 43 embedded in the holder holding portion 38 is located inside the first opening 61 in the radial direction. That is, the first opening 61 is located inside the upper bearing holder 40 in the radial direction.

The flange portion 39 is provided on the outer peripheral surface of the outer annular rib 34 and the outer peripheral surface of the main body portion 31. The upper end surface of the flange portion 39 is continuous with the upper end surface of the outer annular rib 34. A nut member 50 is embedded in each of the plurality of flange portions 39. As a result, the housing 30 holds the nut member 50.

As shown in FIG. 2, the housing 30 of the present embodiment is provided with three flange portions 39. The three flange portions 39 are arranged at equal intervals along the circumferential direction. One nut member 50 is embedded in each of the three flange portions 39.

As shown in FIG. 1, the nut member 50 is a columnar shape extending along the axial direction. The upper end surface of the nut member 50 is arranged on the same plane as the upper end surface of the flange portion 39. The lower end surface of the nut member 50 is arranged on the same plane as the lower end surface of the flange portion 39.

The nut member 50 has a screw hole 51 that opens in the upper end surface of the nut member 50 and extends downward, and a positioning hole 52 that opens in the lower end surface of the nut member 50 and extends upward. In the present embodiment, the screw hole 51 and the positioning hole 52 are arranged coaxially.

A fixing bolt 9e for fixing the motor 1 to the external device 9 is fastened to the screw hole 51. A positioning pin (not shown) provided in the mold 90 is inserted into the positioning hole 52 in the molding process of the housing 30. That is, the positioning hole 52 is used for positioning the nut member 50 in the mold 90.

The bus bar holder portion 36 is located on the lower surface of the main body portion 31. As shown in FIG. 3, the housing 30 of the present embodiment is provided with two bus bar holder portions 36. Three bus bars 80 are embedded inside each bus bar holder portion 36. The bus bar 80 projects downward from the lower surface of the bus bar holder portion 36.

The lower cylinder portion 37 has a cylindrical shape centered on the central axis J. The outer peripheral surface of the lower cylinder portion 37 is continuous with the outer peripheral surface of the main body portion 31. The lower cylinder portion 37 surrounds the lower end portions of the plurality of bus bars 80 protruding from the housing 30 from the outside in the radial direction. Further, the lower cylinder portion 37 surrounds the plurality of second openings 62 and the plurality of third openings 63 from the outside in the radial direction.

A control device (not shown) for controlling the motor 1 is attached to the lower cylinder portion 37. Further, the bus bar 80 is connected to a socket portion (not shown) provided in the control device. The inner peripheral surface of the lower cylinder portion 37 and the control device are sealed by a seal structure (not shown). According to the present embodiment, the lower cylinder portion 37 having a sealing function surrounds the plurality of second openings 62 and the plurality of third openings 63 from the outside in the radial direction. Therefore, it is possible to prevent water from reaching the second opening 62 and the third opening 63.

<Modification example>
FIG. 10 is a perspective view of the split core 121A of the modified example. The split core 121A of this modified example has a different recess configuration as compared with the above-described embodiment. The components having the same aspects as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The split core 121A is configured by laminating a plurality of electromagnetic steel plates 126 along the axial direction. That is, the stator core 21 is configured by laminating a plurality of electromagnetic steel plates 126 along the axial direction.

An inner recess (recess) 102a and an outer recess (recess) 102b are provided on the upper surface of the split core 121A. The inner recess 102a and the outer recess 102b are recessed downward. The inner recess 102a corresponds to the inner recess 28a in the above embodiment. The outer recess 102b corresponds to the outer recess 28b in the above embodiment. The bottom surface of each of the inner recess 102a and the outer recess 102b is exposed by the opening of the housing 30. The second support portion 92b and the third support portion 92c are inserted into the inner recess 102a and the outer recess 102b when the housing 30 is molded. As a result, the second support portion 92b and the third support portion 92c position the stator core 21 in the mold 90. According to this modification, the stator core 21 can be positioned in the mold 90 by using the hole-shaped inner recess 102a and the outer recess 102b.

Although one embodiment of the present invention and a modification thereof have been described above, each configuration and a combination thereof in the embodiment and the modified example are examples, and the configuration is added within a range not deviating from the gist of the present invention. , Omission, replacement and other changes are possible. Moreover, the present invention is not limited to the embodiments.

For example, the use of the motor unit of the above-described embodiment and its modified example is not particularly limited. The motor unit of the above-described embodiment and its modification is mounted on, for example, an electric pump, an electric power steering, and the like.

1 ... motor, 10 ... rotor, 11 ... shaft, 20 ... stator, 21 ... stator core, 21a ... core back part, 21b ... teeth part, 21c ... umbrella part, 21d ... split core back part, 21A, 121A ... split core, 26a, 26A ... 1st electrical steel sheet, 26A, 126 ... Electrical steel sheet, 26B ... 2nd electrical steel sheet, 27a ... Penetration, 28a ... Inner recess (recess), 28ac, 28bc, 28cc ... Bottom, 28b ... Outer recess (recess ), 28c ... Sub-concave, 29 ... Coil, 30 ... Housing, 61, 62 ... Opening, 61 ... First opening, 62 ... Second opening, 99 ... Gate, 102a ... Inner recess (recess), 102b ... Outer recess (recess), G ... Gate mark, J ... Central axis

Claims

A rotor having a shaft extending along a central axis and rotating around the central axis,
A stator facing the rotor in the radial direction and
A housing made of resin and into which the stator is embedded is provided.
The stator has a recess provided in a stator core in which a plurality of electromagnetic steel plates are laminated and opens on one side in the axial direction.
The housing has an opening that opens on one side in the axial direction to expose the bottom surface of the recess.
motor.
The stator core
It has a first electrical steel sheet and a second electrical steel sheet laminated on the other side in the axial direction from the first electrical steel sheet.
The first electrical steel sheet has a penetrating portion that penetrates in the axial direction.
The motor according to claim 1, wherein the recess is a portion surrounded by the penetrating portion of the first electrical steel sheet and a surface of the second electrical steel sheet facing one side in the axial direction.
The motor according to claim 1 or 2, wherein the recess has an outer recess located at the outer edge of the core back portion of the stator core.
The stator core is an aggregate of a plurality of divided cores which are divided in the circumferential direction and have a teeth portion on which a coil is mounted and a divided core back portion which is continuous on the radial outer side of the teeth portion.
The motor according to claim 3, wherein the outer recess is located at the center of the divided core back portion in the circumferential direction.
The motor according to any one of claims 1 to 4, wherein the recess has an inner recess located at the tip of a tooth portion of the stator core.
The stator core is an aggregate of a plurality of divided cores which are divided in the circumferential direction and have a teeth portion on which a coil is mounted and an umbrella portion which is continuous in the radial direction of the teeth portions.
The motor according to claim 5, wherein the inner recess is located at the center of the umbrella portion in the circumferential direction.
The stator core has a sub-recess that opens on the other side in the axial direction.
The motor according to any one of claims 1 to 6, wherein the housing has a sub-opening that opens on the other side in the axial direction to expose at least a part of the inner peripheral surface of the sub-recess.
The motor according to claim 7, wherein the first opening overlaps with the second opening when viewed from the axial direction.
The motor according to any one of claims 1 to 8, wherein the housing has a gate mark on the surface on the other side in the axial direction.