Motor and method for producing motor

Abstract

A motor comprising: a stator core including an annular yoke and a plurality of teeth protruding from the yoke in a center direction toward the center of the yoke; a plurality of coils each wound around the corresponding one of the plurality of teeth; and a coupling wedge body, wherein the coupling wedge body includes a plurality of magnetic wedges arranged between adjacent coils at end portions of the respective coils in the center direction, and a coupling part for annularly coupling the plurality of magnetic wedges.

Description

Motor and motor manufacturing method

[0001] This application claims priority to Japanese Patent Application No. 2024-082907, filed May 21, 2024, and incorporates by reference the entire contents of that application.

[0002] Patent Document 1 discloses a cassette coil in which a flange member made of a magnetic material is disposed adjacent to the rotor-side end face of the coil member in the coil side region, and the coil member and flange member are sealed with a molding member. A stator is assembled by fitting the cassette coil disclosed in Patent Document 1 into the teeth of a stator core. When a current is passed through the coil member of the stator, a magnetic current generated by the coil current flows through the flange and the teeth.

[0003] JP 2009-254171 A

[0004] A motor according to one aspect of the present disclosure comprises a stator core including an annular yoke and a plurality of teeth protruding from the yoke in a central direction toward the center of the yoke, a plurality of coils wound around each of the plurality of teeth, and a connecting wedge body, wherein the connecting wedge body includes a plurality of magnetic wedges arranged between adjacent coils at the central end of each of the plurality of coils, and a connecting portion that connects the plurality of magnetic wedges in a circular shape.

[0005] FIG. 1 is a cross-sectional view showing an example of the configuration of a motor according to the first embodiment. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 3 is a perspective view showing an example of the configuration of a stator core according to the first embodiment. FIG. 4 is a perspective view showing an example of a coil according to the first embodiment. FIG. 5 is a perspective view showing an example of a connecting wedge according to the first embodiment. FIG. 6 is an exploded perspective view showing an example of the configuration of a stator core according to the first embodiment. FIG. 7 is a flowchart showing an example of a method of assembling a stator according to the first embodiment. FIG. 8 is a diagram for explaining an example of a method of assembling a stator according to the first embodiment. FIG. 9 is a perspective view showing an example of the configuration of a stator core according to a second embodiment. FIG. 10 is a flowchart showing an example of a method of assembling a stator according to the second embodiment. FIG. 11 is a diagram for explaining an example of a method of assembling a stator according to the second embodiment.

[0006] <Problem to be Solved by the Present Disclosure> The cassette coil disclosed in Patent Document 1 requires two flange members per coil member. In order to manufacture the cassette coil, it is necessary to arrange flange members on the rotor-side end face of the coil member in the coil-side region and then mold the coil member.

[0007] <Advantages of the Present Disclosure> According to the present disclosure, it is possible to improve the manufacturing efficiency of a motor without impairing the magnetic properties of the stator.

[0008] <Outline of Embodiments of the Present Disclosure> Below, an outline of embodiments of the present disclosure will be listed and described.

[0009] (1) A motor according to this embodiment includes a stator core including an annular yoke and a plurality of teeth protruding from the yoke toward the center of the yoke, a plurality of coils wound around each of the plurality of teeth, and a connecting wedge. The connecting wedge includes a plurality of magnetic wedges arranged between adjacent coils at the ends of each of the plurality of coils toward the center, and a connecting portion that connects the plurality of magnetic wedges in an annular shape. Magnetic current generated by coil current flows through the magnetic wedges and the teeth, preventing damage to the magnetic properties of the stator. By attaching the connecting wedge, to which the plurality of magnetic wedges are connected, to a stator core having coils arranged on the teeth, the magnetic wedges can be arranged between adjacent coils, improving motor manufacturing efficiency.

[0010] (2) In the above (1), the connecting portion may be configured in an annular shape, and the plurality of magnetic wedges may protrude from the connecting portion in an axial direction extending along a central axis of the connecting portion. This allows the connecting wedge body to have a simple configuration.

[0011] (3) In the above (2), the connecting wedge may be integrally formed from a magnetic material. This allows the connecting wedge to be integrally formed.

[0012] (4) In any one of (1) to (3) above, the tips of the teeth may protrude toward the center from end faces of the coils wound around the teeth, the end faces facing the center, and the magnetic wedges may be disposed between the tips of adjacent teeth. This allows the magnetic wedges to be located close to the teeth, thereby improving the magnetic properties of the stator.

[0013] (5) In the above (4), the connecting portion may be disposed opposite to the axial ends of the coils arranged in an annular shape, in a direction opposite to the central direction, so that magnetic flux generated from the axial ends of each coil flows through the connecting portion, thereby reducing magnetic flux leakage.

[0014] (6) In the above (5), the connecting portion may be disposed in an annular recess formed by tips of the plurality of teeth and end faces of the plurality of coils toward the center, thereby allowing the connecting portion to be disposed in an annular recess formed at an axial end of the stator core, and preventing the stator from becoming large.

[0015] (7) In any one of the above (1) to (6), the teeth may be convex polyhedrons extending from the yoke toward the center, thereby simplifying the shape of the teeth.

[0016] (8) In the above (7), the teeth may have a shape in which the cross-sectional area perpendicular to the central direction is constant, or a shape in which the cross-sectional area perpendicular to the central direction decreases toward the central direction, thereby allowing the coil to be wound around the teeth by inserting the coil relatively onto the teeth.

[0017] (9) A motor manufacturing method according to this embodiment includes the steps of: forming an assembly in which a coil is disposed on each of a plurality of teeth protruding from an annular yoke of a stator core toward the center of the yoke; and arranging a connecting wedge body in the formed assembly, the connecting wedge body including a plurality of magnetic wedges and a connecting portion that connects the plurality of magnetic wedges in an annular shape. In the step of arranging the connecting wedge body, the magnetic wedges are disposed between adjacent coils at the ends of each of the plurality of coils toward the center. By attaching the connecting wedge body, in which the plurality of magnetic wedges are connected, to the assembly, the magnetic wedges can be disposed between adjacent coils, thereby improving motor manufacturing efficiency. In a motor manufactured in this manner, magnetic current generated by coil current flows through the magnetic wedges and the teeth, preventing impairment of the magnetic properties of the stator.

[0018] (10) In the above (9), in the step of arranging the connecting wedge, the magnetic wedge may be arranged between the two adjacent coils by inserting the magnetic wedge extending from an end face of the annular connecting portion into a groove extending in the axial direction and formed between the tips of the two adjacent teeth. This makes it possible to easily attach the connecting wedge to the assembly.

[0019] (11) In the above (9) or (10), in the step of forming the assembly, the plurality of coils may be inserted in a direction opposite to the central direction for each of the plurality of teeth of the integrally formed stator core. This allows the use of an integrally formed stator core. By inserting a coil into each of the plurality of teeth, the assembly can be easily formed.

[0020] (12) In the above (9) or (10), in the step of forming the assembly, a plurality of split cores obtained by dividing the stator core into a plurality of teeth may be inserted toward the center for each of the plurality of coils arranged in an annular shape. This makes it possible to easily form the assembly by inserting the teeth of the split cores into each of the plurality of coils arranged in an annular shape.

[0021] The present disclosure can be realized not only as a motor having the above-described characteristic configuration and a method for manufacturing a motor including the characteristic steps, but also as a connecting wedge having the characteristic configuration, or as a stator including the connecting wedge.

[0022] <Details of the embodiments of the present disclosure> Hereinafter, the details of the embodiments of the present disclosure will be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any manner.

[0023] 1. First Embodiment 1-1. Motor Configuration Fig. 1 is a cross-sectional view showing an example of the configuration of a motor according to the first embodiment. Fig. 1 shows a cross section perpendicular to the central axis of the motor.

[0024] The motor 10 is a driving motor that generates propulsion power for the electric vehicle. The motor 10 is a three-phase AC motor that is driven by three-phase AC power. An example of the motor 10 is a permanent magnet synchronous motor.

[0025] The motor 10 includes a stator 20 and a rotor 30 .

[0026] The stator 20 includes a stator core 21. The stator core 21 is made of a soft magnetic material and includes a cylindrical yoke 20Y and a plurality of teeth 20T. Hereinafter, the central axis direction of the yoke 20Y will be referred to as the "Z direction," the direction toward the center O of the yoke 20Y (radial direction) as the "R direction," and the circumferential direction of the center O of the yoke 20Y as the "C direction." Furthermore, the Z direction will also be referred to as the "upward direction," and the direction opposite to the Z direction will also be referred to as the "downward direction." The R direction will also be referred to as the "inward direction," and the direction opposite to the R direction will also be referred to as the "outward direction."

[0027] Each of the multiple teeth 20T is arranged on the inner circumferential surface of the yoke 20Y. Specifically, each of the multiple teeth 20T is a protrusion extending inward from the inner circumferential surface of the yoke 20Y. The multiple teeth 20T are arranged at equal intervals in the C direction.

[0028] For example, each of the multiple teeth 20T corresponds to one of the U-phase, V-phase, and W-phase. A coil 40 is wound around each tooth 20T. In Fig. 1, the double circle mark and the circle mark containing an x ​​indicate the direction of current flowing through the coil 40 (the double circle mark indicates a current flowing from the back of the page to the front, and the circle mark containing an x ​​indicates a current flowing from the front of the page to the back).

[0029] A slot is formed by the coil 40 wound around one tooth 20T. That is, the number of slots is the same as the number of teeth 20T. In the example shown in FIG. 1 , the number of slots is 12. However, the number of slots is not limited to 12. In the case of a three-phase AC motor, the number of slots is a multiple of three.

[0030] For example, the slots for the U, V, and W phases are arranged according to a certain rule. In one example, the slots are arranged counterclockwise in the figure in the order of U, V, and W phases, so that adjacent slots have different phases. That is, the slots are arranged counterclockwise in the order UVWUVWUVWUVWUVWUVW. In another example, the slots are arranged in a concentrated manner for each phase so that the same phases are consecutive. That is, the slots are arranged counterclockwise in the order UUUUVVVVWWWWWW. In yet another example, pairs of slots for the same phase are adjacent to each other, and each pair of slots is arranged counterclockwise in the order of U, V, and W phases. That is, the slots are arranged counterclockwise in the order UUVVWWUUVVWWWW.

[0031] The rotor 30 includes a plurality of permanent magnets 30M. The plurality of permanent magnets 30M are arranged in an annular shape in the circumferential direction of a center O. More specifically, each permanent magnet 30M has a long, thin plate shape. Adjacent pairs of permanent magnets 30M are arranged in a V-shape when viewed in the Z direction, and the permanent magnets 30M of each pair are arranged in an annular shape so that the tip of the V faces the center O. In other words, each permanent magnet 30M is inclined with respect to the R direction so that a first end of the permanent magnet 30M is away from the center O and a second end is closer to the center O.

[0032] For example, the first end of the permanent magnet 30M that is farther from the center O is the south pole, and the second end that is closer to the center O is the north pole. In other words, the ends of adjacent permanent magnets 30M that are close to each other all have the same polarity. The first ends of a pair of adjacent permanent magnets 30M whose first ends are close to each other form the south pole, and the second ends of a pair of adjacent permanent magnets 30M whose second ends are close to each other form the north pole.

[0033] The number of permanent magnets 30M shown in FIG. 1 is 20. Therefore, the 20 permanent magnets 30M form 10 south poles and 10 north poles. In other words, the number of poles of the motor 10 shown in FIG. 1 is 10. Therefore, the motor 10 is a 10-pole, 12-slot three-phase AC permanent magnet synchronous motor. However, the number of poles is not limited to 10. The number of poles is a multiple of 2 (an even number). In the case of a three-phase AC motor, the ratio of the number of poles to the number of slots (number of poles:number of slots) may be 2:3 or may be a ratio other than 2:3.

[0034] FIG. 2 is a partial enlarged view of FIG. 1 . The stator 20 further includes a plurality of magnetic wedges 51. As shown in FIG. 2 , the magnetic wedges 51 have a rectangular cross-sectional shape. Each of the magnetic wedges 51 is disposed between adjacent coils 40 at the R-direction end of each of the plurality of coils 40. More specifically, one coil 40 wound around the tooth 20T is divided into two portions sandwiching the tooth 20T in a cross section perpendicular to the central axis of the yoke 20Y. The magnetic wedges 51 face each of the R-direction end faces 41A, 41A of the adjacent portions 41, 41 of the adjacent coils 40.

[0035] The tip (end in the R direction) of the tooth 20T protrudes from the coil 40. The magnetic wedge 51 is disposed between the tips of adjacent teeth 20T. That is, the magnetic wedge 51 is disposed between the adjacent side surfaces 22, 22 of the tips (portions protruding from the coil 40) of adjacent teeth 20T. For example, the side surfaces 51A, 51A of the magnetic wedge 51 in the C direction are in contact with the side surfaces 22, 22 of the tips of the adjacent teeth 20T. However, there may be a small gap between the side surfaces 51A, 51A of the magnetic wedge 51 in the C direction and the side surfaces 22, 22 of the tips of the adjacent teeth 20T.

[0036] The arrangement position of the magnetic wedge 51 will be described in more detail. The R-direction end faces 41A, 41A of the adjacent portions 41, 41 of adjacent coils 40, 40 are arranged on the same plane or the same curved surface. The end face 41A of the coil 40 and the side face 22 of the tooth 20T around which the coil 40 is wound are substantially perpendicular to each other. Therefore, the end faces 41A, 41A of the adjacent coils 40, 40 and the side faces 22, 22 of the adjacent teeth 20T, 20T form a rectangular recess with one side open in the R direction. The magnetic wedge 51 with a rectangular cross section is arranged to fit into this rectangular recess.

[0037] The magnetic wedges 51 are made of a soft magnetic material. Therefore, a magnetic current generated by a current flowing through the coil 40 flows through the magnetic wedges 51 and the teeth 20T. This reduces magnetic flux leakage and reduces variations in magnetic flux density.

[0038] [1-2. Configuration of Stator] The detailed configuration of the stator 20 of the motor 10 according to the first embodiment will now be described.

[0039] FIG. 3 is a perspective view illustrating an example of the configuration of the stator core according to the first embodiment.

[0040] As described above, the stator core 21 includes the annular yoke 20Y and the plurality of teeth 20T protruding from the yoke 20Y toward the center of the yoke 20Y.

[0041] Specifically, the yoke 20Y is a circular ring having a uniform length in the Z direction and a uniform length in the R direction. That is, the yoke 20Y is a circular ring having a rectangular cross section.

[0042] The teeth 20T have the same thickness as the yoke 20Y, i.e., the same length in the Z direction. That is, the entire length of the stator core 21 in the Z direction is uniform.

[0043] The teeth 20T are convex polyhedrons extending in the R direction from the yoke 20Y. In a specific example, the teeth 20T are rectangular parallelepipeds (quadrature prisms) protruding from the inner peripheral surface of the yoke 20Y. The teeth 20T have a shape with a constant cross-sectional area perpendicular to the R direction. That is, the width of the teeth 20T is uniform. In other words, the cross section of the teeth 20T is rectangular, and the cross-sectional area is constant in the R direction. The tips of the teeth 20T do not expand in a brim-like shape.

[0044] The shape of the teeth 20T is not limited to a rectangular parallelepiped. For example, the teeth 20T may be polygonal prisms with a uniform cross-sectional shape perpendicular to the R direction. In one specific example, the teeth 20T may be octagonal prisms with chamfered corners of a quadrangular prism.

[0045] In addition, the teeth 20T may be tapered so that the cross-sectional area of ​​the teeth 20T decreases toward the center O of the yoke 20Y, that is, so that at least one of the width and thickness of the teeth 20T decreases toward the center O of the yoke 20Y.

[0046] The stator core 21 is integrally formed from a magnetic material. Specifically, the stator core 21 is made of a soft magnetic material such as ferrite, permalloy, electromagnetic steel sheet, soft magnetic alloy, or amorphous alloy. The stator core 21 may be a powder magnetic core formed by compressing soft magnetic iron powder, or may be a laminate of electromagnetic steel sheets. The stator core 21 is coated with an insulating paint.

[0047] 4 is a perspective view showing an example of a coil according to the first embodiment. The coil 40 is a cassette coil in which a conductor wire is wound in advance. For example, the coil 40 is formed by winding a rectangular wire in a rectangular shape corresponding to the cross-sectional shape of the tooth 20T. The coil 40 may be resin-molded.

[0048] The coil 40 is configured in a substantially rectangular ring shape. That is, the coil 40 includes two side portions 41, 41 extending in the up-down direction and an upper portion 42 and a lower portion 43 extending in the C direction. The inner peripheral shape of the coil 40 is rectangular corresponding to the outer circumferential cross-sectional shape of the tooth 20T.

[0049] In a more specific example, the coil 40 has a trapezoid shape when viewed in the Z direction. The internal holes of the coil 40 (holes for inserting the teeth 20T) have a rectangular parallelepiped shape corresponding to the teeth 20T. That is, the width of the side portions 41 gradually increases from the upper base (narrower side) of the trapezoid of the coil 40 to the lower base (wider side). The coil 40 is disposed such that the upper base of the trapezoid is close to the center O and the lower base is away from the center O.

[0050] The coil 40 is inserted into each tooth 20T of the stator core 21. As a result, the coil 40 is wound around the teeth 20T.

[0051] The stator 20 further includes a connecting wedge 50. The connecting wedge 50 includes the above-described plurality of magnetic wedges 51. Fig. 5 is a perspective view showing an example of a connecting wedge according to the first embodiment. The connecting wedge 50 includes the plurality of magnetic wedges 51 and a connecting portion 52 that connects the plurality of magnetic wedges 51 in an annular shape.

[0052] The connecting portion 52 is configured in a circular ring shape. The multiple magnetic wedges 51 protrude downward from the connecting portion 52. More specifically, the magnetic wedges 51 are square bars with a rectangular cross-sectional shape. The connecting portion 52 is a circular ring with a rectangular cross-sectional shape. The multiple magnetic wedges 51 extend downward from the underside of the connecting portion 52.

[0053] The connecting wedge body 50 includes the same number of magnetic wedges 51 as the number of slots. That is, in the example of Fig. 5, the number of magnetic wedges 51 is 12. The connecting portion 52 has 12 magnetic wedges 51 arranged at equal intervals in the C direction.

[0054] FIG. 6 is an exploded perspective view showing an example of the configuration of the stator core according to the first embodiment.

[0055] Coils 40 are fitted onto each tooth 20T of the stator core 21 to form an assembly 60. The length of the teeth 20T in the R direction is longer than the length of the coils 40 in the R direction. Therefore, in the assembly 60, the tips of the teeth 20T are exposed from the coils 40.

[0056] Between the tips of adjacent teeth 20T, 20T, a long groove 61 is formed in the vertical direction by the side surfaces 22, 22 of the tips of the teeth 20T, 20T and the end faces 41A, 41A of the adjacent side portions 41, 41 of the coils 40, 40 fitted to the teeth 20T, 20T. Each magnetic wedge 51 fits into the corresponding groove 61.

[0057] For example, the Z-direction length of the connecting wedge body 50 is the same as the Z-direction length of the coil 40. That is, the Z-direction length of each magnetic wedge 51 is the same as the Z-direction length of the coil 40 minus the Z-direction length of the connecting portion 52. The Z-direction length of the magnetic wedge 51 is the same as the Z-direction length of the groove 61.

[0058] For example, the inner diameter of the connecting wedge 50 is the same as the diameter of the annulus (see FIG. 3) formed by connecting the tip surfaces of the teeth 20T of the stator core 21. For example, the thickness (thickness in the R direction) of the connecting wedge 50 is the same as the protrusion length of the tip of the tooth 20T from the coil 40 when the coil 40 is fitted to the tooth 20T.

[0059] The connecting portion 52 is disposed opposite the upper portions 42 of the plurality of coils 40 arranged in an annular shape in the opposite direction of the R direction. Explaining in more detail, the length (height) of the connecting portion 52 in the Z direction is the same as the length (height) of the upper portions 42 of the coils 40 in the Z direction. An annular recess 62 is formed by the tip upper surfaces of the plurality of teeth 20T exposed from the coils 40 and the R-direction end surfaces 42A of the upper portions 42 of the plurality of coils 40. The connecting portion 52 fits into the annular recess 62.

[0060] The connecting wedge 50 is integrally formed from a magnetic material. Specifically, the connecting wedge 50 is made of a soft magnetic material such as ferrite, permalloy, electromagnetic steel sheet, soft magnetic alloy, amorphous alloy, etc. The connecting wedge 50 is a powder magnetic core obtained by compressing and molding soft magnetic iron powder.

[0061] [1-3. Motor Manufacturing Method] A manufacturing method for the motor 10 according to the first embodiment will now be described. Here, a method for assembling the stator, which is part of the manufacturing method for the motor 10, will be described. Fig. 7 is a flowchart showing an example of the stator assembling method according to the first embodiment, and Fig. 8 is a diagram for explaining an example of the stator assembling method according to the first embodiment.

[0062] In the method of assembling the stator 20, first, the assembly 60 is formed (step S101). In this step, each coil 40 is inserted into each tooth 20T of the stator core 21 in the direction opposite to the R direction (see FIG. 8).

[0063] Next, the connecting wedge 50 is placed on the assembly 60 (step S102). In this step, the connecting wedge 50 is placed above the assembly 60, and the central axis of the assembly 60 is aligned with the central axis of the connecting wedge 50. At this time, the connecting wedge 50 is oriented such that the magnetic wedges 51 are close to the assembly 60 and the connecting portions 52 are away from the assembly 60. The connecting wedge 50 and the assembly 60 are moved vertically relative to each other so that the connecting wedge 50 and the assembly 60 are close to each other, and the magnetic wedges 51 are inserted into the grooves 61 of the assembly 60. That is, with the lower end of the magnetic wedge 51 engaged with the upper end of the groove 61, the magnetic wedge 51 is slid downward within the groove 61. The connecting wedge 50 and the assembly 60 are moved relative to each other until the connecting portions 52 are engaged with the annular recess 62 (see FIG. 8 ). With the above steps, the stator 20 is completed.

[0064] 2. Second Embodiment 2-1. Configuration of Stator FIG. 9 is a perspective view showing an example of the configuration of a stator core according to a second embodiment.

[0065] The stator core 21A according to the second embodiment is composed of a plurality of split cores 21P. Each split core 21P includes one tooth 20T. More specifically, the split core 21P includes a split yoke 20YP and a tooth 20T protruding from one surface of the split yoke 20YP. The plurality of split yokes 20YP can be connected in an annular shape. The stator core 21A is constructed by arranging the plurality of split cores 21P so that the plurality of split yokes 20YP form an annular ring. In other words, the stator core 21A is divided into individual teeth 20T.

[0066] The other configuration of the stator according to the second embodiment is the same as the configuration of the stator according to the first embodiment, so the same components are given the same reference numerals and descriptions thereof will be omitted.

[0067] [2-2. Motor Manufacturing Method] A method for manufacturing the motor 10 according to the second embodiment will now be described. Here, a method for assembling the stator, which is part of the method for manufacturing the motor 10, will be described. Fig. 10 is a flowchart illustrating an example of the stator assembling method according to the second embodiment, and Fig. 11 is a diagram for explaining an example of the stator assembling method according to the second embodiment.

[0068] In the method of assembling the stator 20, first, a plurality of (12) coils 40 are arranged in a ring shape (step S201). That is, the sides 41 of adjacent coils 40 are butted together so that the upper bases of the coils 40 are close to the center and the lower bases are far from the center (see FIG. 11). For example, the coils 40 can be arranged in a ring shape by using a jig that determines the arrangement positions of the plurality of coils 40.

[0069] Next, the assembly 60A is formed (step S202). In this step, the teeth 20T of the split core 21P are inserted into each coil 40 in the R direction (see FIG. 11).

[0070] Next, the connecting wedge 50 is placed on the assembly 60A (step S203). In this step, the connecting wedge 50 is placed above the assembly 60A, and the central axis of the assembly 60A is aligned with the central axis of the connecting wedge 50. At this time, the connecting wedge 50 is positioned so that the magnetic wedges 51 are close to the assembly 60A and the connecting portion 52 is away from the assembly 60A. The connecting wedge 50 and the assembly 60A are moved vertically relative to each other so that the connecting wedge 50 and the assembly 60A are close to each other, and the magnetic wedges 51 are inserted into the grooves 61 of the assembly 60A. That is, with the lower end of the magnetic wedge 51 fitted into the upper end of the groove 61, the magnetic wedge 51 is slid downward within the groove 61. The connecting wedge 50 and the assembly 60A are moved relative to each other until the connecting portion 52 fits into the annular recess 62 (see FIG. 11). With the above steps, the stator 20 is completed.

[0071] For example, the shape of the stator 20 can be maintained by winding an annular holding member around the outer periphery of the stator 20. The holding member may be made of carbon steel, and the stator 20 may be fitted to the holding member by shrink fitting.

[0072] In the second embodiment, the assembly 60A is formed by inserting the teeth 20T of the split core 21P into each of the multiple coils 40 arranged in a ring shape, but this is not limiting. For example, the assembly 60A may be formed by attaching a coil 40 to each tooth 20T of the multiple split cores 21P and arranging the multiple split cores 21P to which the coils 40 are attached in a ring shape.

[0073] [4. Supplementary Note] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, not the above-described embodiments, and includes meanings equivalent to the claims and all modifications within the scope thereof.

[0074] REFERENCE SIGNS LIST 10 Motor 20 Stator 20Y Yoke 20T Teeth 21, 21A Stator core 21P Split core 22 Side surface 30 Rotor 30M Permanent magnet 40 Coil 41 Side portion 41A End surface 42 Upper portion 42A End surface 43 Lower portion 50 Connecting wedge body 51 Magnetic wedge 51A, 51A Side surface 52 Connecting portion 60, 60A Assembly 61 Groove 62 Annular recess

Claims

1. A motor comprising: a stator core including an annular yoke and a plurality of teeth protruding from the yoke in a central direction toward the center of the yoke; a plurality of coils wound around each of the plurality of teeth; and a connecting wedge body, wherein the connecting wedge body includes a plurality of magnetic wedges arranged between adjacent coils at the end of each of the plurality of coils in the central direction; and a connecting portion that connects the plurality of magnetic wedges in an annular shape.

2. The motor according to claim 1, wherein the connecting portion is configured in an annular shape, and the plurality of magnetic wedges protrude from the connecting portion in an axial direction extending along a central axis of the connecting portion.

3. The motor according to claim 2, wherein the connecting wedge is integrally formed from a magnetic material.

4. A motor according to any one of claims 1 to 3, wherein the tips of the teeth protrude towards the centre from the end faces of the coils wound around the teeth that face towards the centre, and the magnetic wedges are arranged between the tips of adjacent teeth.

5. The motor according to claim 4, wherein the connecting portion is disposed opposite the axial end of the plurality of coils arranged in an annular shape, in a direction opposite to the center direction.

6. The motor according to claim 5, wherein the connecting portion is disposed in an annular recess formed by the tips of the plurality of teeth and the end faces of the plurality of coils in the center direction.

7. The motor according to any one of claims 1 to 6, wherein the teeth are convex polyhedrons extending from the yoke toward the center.

8. The motor according to claim 7, wherein the teeth have a shape in which the cross-sectional area perpendicular to the central direction is constant, or a shape in which the cross-sectional area perpendicular to the central direction decreases toward the central direction.

9. A method for manufacturing a motor, comprising the steps of: forming an assembly in which a coil is arranged on each of a plurality of teeth that protrude from an annular yoke of a stator core in a central direction toward the center of the yoke; and arranging a connecting wedge body in the formed assembly, the connecting wedge body including a plurality of magnetic wedges and a connecting portion that connects the plurality of magnetic wedges in a circular shape; wherein in the step of arranging the connecting wedge body, the magnetic wedges are arranged between adjacent coils at the end of each of the plurality of coils in the central direction.

10. A method for manufacturing a motor as described in claim 9, wherein in the step of arranging the connecting wedge body, the magnetic wedge extending from the end face of the annular connecting portion is inserted into an axially extending groove formed between the tips of two adjacent teeth, thereby arranging the magnetic wedge between the two adjacent coils.

11. A method for manufacturing a motor according to claim 9 or 10, wherein in the step of forming the assembly, each of the plurality of coils is inserted in a direction opposite to the central direction onto each of the plurality of teeth of the integrally formed stator core.

12. A method for manufacturing a motor as described in claim 9 or claim 10, wherein in the step of forming the assembly, a plurality of split cores obtained by dividing the stator core for each of the plurality of teeth are inserted toward the center for each of the plurality of coils arranged in an annular shape.

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