Motor

Abstract

The present invention addresses the problem of suppressing positional deviation of a coil. A motor (1) comprises a stator core (2), a plurality of coils (4), and a rotor (5). The stator core (2) has a cylindrical base part (20) and a plurality of teeth (21). The coils (4) respectively correspond to the teeth (21) on a one-to-one basis and are wound around the teeth (21). The rotor (5) is disposed so as to face the stator core (2). Each of the coils (4) has a first coil end and a second coil end. The stator core (2) has a protrusion (22) that protrudes along the radial direction from the inner circumferential surface (200) of the base part (20). The protrusion (22) is located between the first coil ends of two of the coils (4) adjacent to each other. The protrusion (22) is in contact with the two adjacent coils (4). The protrusion (22) and the two adjacent coils (4) are electrically insulated from each other.

Description

Motor

[0001] The present disclosure generally relates to motors, and more particularly to a motor including a coil wound around teeth.

[0002] Patent Document 1 discloses a slotless motor including stator protrusions, a cylindrical winding attached to the stator protrusions, and a permanent magnet. The slotless motor has a protrusion at a coil end portion of the winding between adjacent stator protrusions.

[0003] Japanese Unexamined Patent Application Publication No. 2011-24324

[0004] Incidentally, in a slotless motor (motor) like that disclosed in Patent Document 1, positional displacement of the winding (coil) may occur.

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a motor that suppresses positional displacement of coils.

[0006] A motor according to one aspect of the present disclosure includes a stator core, a plurality of coils, and a rotor. The stator core includes a cylindrical base portion, and a plurality of teeth protruding from an inner circumferential surface of the base portion along a radial direction of the base portion. The plurality of coils correspond one-to-one with the plurality of teeth and are wound around the plurality of teeth. The rotor is disposed so as to face the stator core. Each of the plurality of coils has a first coil end and a second coil end. The first coil end and the second coil end protrude in directions opposite to each other in a direction orthogonal to both the circumferential direction of the base portion and the radial direction. The stator core includes a first protrusion and a second protrusion that protrude along the radial direction from the inner circumferential surface of the base portion. The first protrusion is located between the mutually opposing first coil ends of two adjacent coils among the plurality of coils. The first protrusion is in contact with the two coils. The second protrusion is located between the mutually opposing second coil ends of the two coils. The second protrusion is in contact with the two coils. The first protrusion and the second protrusion are electrically insulated from the two coils.

[0007] Figure 1 is a schematic diagram showing the configuration of a motor according to an embodiment. Figure 2 is a schematic cross-sectional view showing the main part of the same motor. Figure 3 is a schematic cross-sectional view showing another main part of the same motor. Figure 4 is a schematic cross-sectional view showing the main part of the motor of Modification 1. Figure 5 is a schematic cross-sectional view showing the main part of the motor of Modification 2. Figure 6 is a schematic cross-sectional view showing the main part of the motor of Modification 3. Figure 7 is a schematic cross-sectional view showing the main part of the motor of Modification 4. Figure 8 is a schematic cross-sectional view showing the main part of the motor of Modification 5.

[0008] Preferred embodiments of this disclosure will be described in detail below with reference to the drawings. Common elements in the embodiments described below are denoted by the same reference numerals, and redundant descriptions of common elements may be omitted. Note that the following embodiments and their variations are only a part of the various embodiments of this disclosure. Furthermore, the following embodiments and their variations can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. It is also possible to combine the configurations of the embodiments and their variations as appropriate.

[0009] The figures described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the arrows indicating directions in the drawings are examples only and are not intended to specify the direction in which the motor 1 is used. Also, the arrows indicating directions in the drawings are for illustrative purposes only and do not represent actual objects.

[0010] (1) Overview First, an overview of the motor 1 according to this embodiment will be described with reference to Figures 1 and 2.

[0011] As shown in Figure 1, the motor 1, which is a permanent magnet synchronous motor of this embodiment, comprises a stator core 2, a plurality of coils 4 (six in the example of Figure 1), and a rotor 5.

[0012] The stator core 2 has a cylindrical base 20 and a plurality of teeth 21 (six in the example of Figure 1) that protrude from the inner circumferential surface 200 of the base 20 along the radial direction of the base 20. Furthermore, the stator core 2 has a plurality of first projections 22 (projections) (six in the example of Figure 1) that protrude from the inner circumferential surface 200 of the base 20 along the radial direction. The "radial direction" in this disclosure is the direction perpendicular to the rotation axis Ax1 of the rotor 5, and is the radial direction centered on the rotation axis Ax1. Note that the rotation axis Ax1 is a virtual axis.

[0013] Multiple coils 4 correspond one-to-one with multiple teeth 21 and are wound around multiple teeth 21. In other words, each of the multiple coils 4 is wound around a corresponding tooth 21 among the multiple teeth 21. Each of the multiple coils 4 has a first coil end 43 (coil end, see Figure 2) and a second coil end 44 (see Figure 2). The first coil end 43 and the second coil end 44 protrude in opposite directions from each other in directions perpendicular to both the circumferential and radial directions of the base 20 of the stator core 2. In this disclosure, "circumferential direction" refers to the circumferential direction of a virtual circle centered on the rotation axis Ax1. The direction perpendicular to both the circumferential and radial directions is the direction parallel to the rotation axis Ax1. In the following description, the direction perpendicular to both the circumferential and radial directions may be referred to as the "up and down direction". In this embodiment, the direction from the second coil end 44 towards the first coil end 43 is defined as upward, and the direction from the first coil end 43 towards the second coil end 44 is defined as downward.

[0014] Furthermore, the term "orthogonal (perpendicular)" as used in this disclosure includes not only a state where the angle between two objects is exactly 90 degrees, but also a state where the two objects intersect within a certain range of difference. In other words, the angle between two orthogonal objects falls within a certain range of difference from 90 degrees (for example, 5 degrees or less). That is, "orthogonal" as used in this disclosure includes cases where the angle between two objects is between 85 degrees and 95 degrees. Similarly, the term "parallel" as used in this disclosure includes not only a state where two objects do not intersect exactly, but also a state where two objects are aligned within a certain range of difference. For example, "parallel" as used in this disclosure includes cases where the inclination of one object relative to the other is 5 degrees or less. That is, "parallel" as used in this disclosure includes cases where the angle between one object and the other is between -5 degrees and 5 degrees.

[0015] Each of the multiple first projections 22 of the stator core 2 is located between the first coil ends 43 of two adjacent coils 4 among the multiple coils 4. The first projections 22 are in contact with the two adjacent coils 4. In other words, the first projections 22 position the two adjacent coils 4. The first projections 22 are electrically insulated from the two adjacent coils 4.

[0016] If the coil is misaligned, the magnetic flux generated by the coil can be distorted, potentially increasing torque ripple. In the motor 1 of this embodiment, the first projection 22 (projection) positions the coil 4, thus suppressing misalignment of the coil 4 and reducing torque ripple.

[0017] (2) Details The detailed configuration of the motor 1 according to this embodiment will be described below with reference to Figures 1 to 3.

[0018] (2.1) Motor Configuration Motor 1 is, for example, a servo motor, and is an inner rotor type three-phase servo motor. Motor 1 transmits rotational force to industrial machinery such as conveying machines or machine tools, or to loads such as robots, and drives the loads.

[0019] As shown in Figure 1, the motor 1 comprises a stator 3, a rotor 5, and a frame 10. The frame 10 houses the stator 3 and the rotor 5.

[0020] (2.2) Rotor Configuration The rotor 5 has a rotor core 51, a plurality of permanent magnets 52 (four in the example of Figure 1), and a motor shaft 53.

[0021] The rotor core 51 is located inside the stator 3. The rotor core 51 has a cylindrical shape centered on the motor shaft 53. The rotor core 51 is made of, for example, iron. However, the rotor core 51 may be made of silicon steel, permalloy, or ferrite, etc. The rotor core 51 holds a plurality of permanent magnets 52.

[0022] Multiple permanent magnets 52 are arranged on the outer circumference of the rotor core 51. The multiple permanent magnets 52 are arranged so that north poles and south poles alternate in the circumferential direction of the rotor core 51. The multiple permanent magnets 52 are permanent magnets such as neodymium magnets.

[0023] The motor shaft 53 is fixed to the inner circumference of the rotor core 51. The shape of the motor shaft 53 is cylindrical.

[0024] The interaction between the magnetic fields generated by the multiple permanent magnets 52 and the magnetic fields generated by the current flowing through the multiple coils 4 of the stator 3 causes the rotor core 51 and the motor shaft 53 to rotate around the rotation axis Ax1.

[0025] (2.3) Stator Configuration The overall shape of the stator 3 is cylindrical with the motor shaft 53 at its center. The stator 3 has a stator core 2 (magnetic core) and a plurality of coils 4 (six in the example of Figure 1).

[0026] The stator core 2 is a magnetic core formed of, for example, silicon steel. The stator core 2 has a base portion 20, a plurality of teeth 21 (six in the example of Figure 1), a plurality of first projections 22 (projections) (six in the example of Figure 1), a plurality of first insulating members 23 (insulating members) (six in the example of Figure 1), a plurality of second projections 24 (six in this embodiment) (see Figure 2), and a plurality of second insulating members 25 (six in this embodiment) (see Figure 2). However, the first insulating members 23 may be part of the configuration of the first projections 22. Also, the second insulating members 25 may be part of the configuration of the second projections 24.

[0027] The shape of the base portion 20 is cylindrical, with the rotation axis Ax1 of the motor shaft 53 as the center.

[0028] Multiple teeth 31 correspond one-to-one with multiple coils 4. Multiple teeth 31 are arranged at equal intervals (i.e., equal angular intervals) along the circumferential direction of the base 20 (or motor shaft 53). Multiple teeth 21 protrude from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). Each of the multiple teeth 21 is the winding axis of the corresponding coil 4 among the multiple coils 4. In other words, the winding axis direction of the coil 4 is along the radial direction of the base 20.

[0029] The teeth 21 have a tip portion 210. The tip portion 210 is the tip of the teeth 21 in the radial direction and is the portion that faces the rotor 5 in the radial direction. As shown in Figure 3, the amount of protrusion of the teeth 21 in the radial direction is less than or equal to a predetermined length X1. The predetermined length X1 is the distance between the inner circumferential surface 200 (coilback) of the base portion 20 of the stator core 2 and the end portion 40 of the coil 4 in the radial direction. The end portion 40 of the coil 4 is the portion that faces the rotor 5 in the radial direction. In other words, in the radial direction, the tip portion 210 of the teeth 21 is located between the inner circumferential surface 200 of the base portion 20 and the end portion 40 of the coil 4. To put it another way, in the teeth 21 of this embodiment, the distance between the tip portion 210 and the rotor 5 in the radial direction (first distance) is less than or equal to the distance between the end portion 40 of the coil 4 and the rotor 5 in the radial direction (second distance). To put it another way, when viewed from above, the tip 210 of the teeth 21 overlaps with the coil 4. By having a structure in which the tip 210 of the teeth 21 does not protrude radially beyond the coil 4 (hereinafter sometimes referred to as a "quasi-coreless structure"), the generation of torque ripple (or cogging torque) is suppressed while preventing a reduction in the torque generated by the motor 1.

[0030] The configuration of the multiple first protrusions 22, multiple first insulating members 23, multiple second protrusions 24, and multiple second insulating members 25 will be described later.

[0031] As shown in Figure 1, the multiple coils 4 correspond one-to-one with the multiple teeth 21. The coils 4 are wound multiple times around the corresponding teeth 21 along the winding axis. In other words, the multiple coils 4 are arranged at equal intervals (i.e., equal angular intervals) along the circumferential direction of the base 20 of the stator core 2. In this embodiment, the main material of the coils 4 is copper. The conductors forming the coils 4 are covered with an insulating coating material. Furthermore, an insulating material such as electrically insulating paper is interposed between the coils 4 and the inner circumferential surface 200 of the base 20 of the stator core 2.

[0032] As shown in Figure 2, the coil 4 has a first lead portion 41 and a second lead portion 42. The first lead portion 41 and the second lead portion 42 are the ends of the coil 4 in the direction of its length and function as power input and output portions. The first lead portion 41 and the second lead portion 42 protrude upward from the upper end of the stator core 2 (stator 3). The coil 4 has an end portion 40 (see Figure 3) that faces the rotor 5 in the radial direction. The end portion 40 is the inner end in the radial direction. The coil 4 further has a first coil end 43 and a second coil end 44 that protrude in opposite directions from each other in the vertical direction. In this disclosure, "coil end" refers to the portion of the coil 4 that, when viewed from the radial direction, is outside (upper in Figure 2) the first end 211 (upper end) of the teeth 21 of the stator core 2 and outside (lower in Figure 2) the second end 212 (lower end) of the teeth 21. In other words, the first coil end 43 protrudes upward from the first end 211 of the tooth 21, and the second coil end 44 protrudes downward from the second end 212 of the tooth 21.

[0033] Multiple first protrusions 22 are arranged at equal intervals (i.e., equal angular intervals) along the circumferential direction of the base 20 (or motor shaft 53). More specifically, multiple first protrusions 22 are arranged at equal intervals along the circumferential direction of the base 20 and are positioned between two adjacent coils 4. In this embodiment, the first protrusions 22 are provided at the first end (upper end) of the base 20 of the stator core 2 in the vertical direction. Multiple first protrusions 22 project from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the first protrusions 22 is a downwardly convex triangular shape (i.e., an inverted triangular shape) when viewed from the radial direction of the base 20. In other words, the shape of the first protrusions 22 is a downwardly convex polygonal shape when viewed from the radial direction of the base 20. In other words, the first projection 22 is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the second coil end 44 (as it goes downwards). Furthermore, the shape of the first projection 22 is such that, when viewed from the radial direction, it follows the contact portion of the first coil end 43 of the coil 4. This further suppresses displacement of the coil 4. Note that the "polygonal shape" in this disclosure includes not only shapes with sharp angles, such as triangles or rectangles, but also shapes that do not have sharp angles, such as the first projection 22 in this embodiment.

[0034] The first projection 22 is positioned between the first coil ends 43 of two adjacent coils 4. The first projection 22 is in contact with the two adjacent coils 4. In other words, the first projection 22 positions the two adjacent coils 4. In this embodiment, the first projection 22 is in contact with the first coil ends 43 of the two adjacent coils 4 via the first insulating member 23. In other words, in this embodiment, the first projection 22 positions the two adjacent coils 4 via the first insulating member 23.

[0035] Multiple first insulating members 23 correspond one-to-one with multiple first protrusions 22. The first insulating members 23 are positioned to be interposed between a corresponding first protrusion 22 and two coils 4 adjacent to the corresponding first protrusion 22. The first insulating member 23 is a plate-shaped member that covers the periphery of the first protrusion 22, excluding the upper end, when viewed from the radial direction of the base 20. In other words, the first insulating member 23 is a V-shaped plate-shaped member when viewed from the radial direction of the base 20. Furthermore, the shape of the first insulating member 23 is such that, when viewed from the radial direction, it follows the contact portion of the first coil end 43 of the coil 4. This further suppresses displacement of the coil 4. In this embodiment, the first insulating member 23 is integrally molded with the first protrusion 22 by additive manufacturing (AM). However, the first insulating member 23 may be attached to the first protrusion 22.

[0036] The material of the first insulating member 23 includes an electrically insulating material. The material of the first insulating member 23 includes, for example, an electrically insulating magnetic material such as ferrite, or a synthetic resin material such as LCP (Liquid Crystal Polymer) resin. The thickness of the first insulating member 23 is such that an insulation distance conforming to international standards is ensured. In other words, the first insulating member 23 has electrical insulating properties. By arranging the electrically insulating first insulating member 23 between the first projection 22 and the two adjacent coils 4, the first projection 22 and the two adjacent coils 4 are electrically insulated even if the first projection 22 itself does not have electrical insulating properties. As a result, a magnetic material that does not have electrical insulating properties, such as iron, can be used as the material for the first projection 22, increasing the variety of materials that can be used as the material for the first projection 22.

[0037] Multiple second protrusions 24 are arranged at equal intervals (i.e., equal angular intervals) along the circumferential direction of the base 20 (or motor shaft 53). More specifically, multiple second protrusions 24 are arranged at equal intervals along the circumferential direction of the base 20 and are positioned between two adjacent coils 4. In this embodiment, the second protrusions 24 are provided at the second end (lower end) of the base 20 of the stator core 2 in the vertical direction. Multiple second protrusions 24 project from the inner circumferential surface 200 of the base 20 towards the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the second protrusions 24 is a triangular shape that is convex upward when viewed from the radial direction of the base 20. In other words, the shape of the second protrusions 24 is a polygonal shape that is convex upward when viewed from the radial direction of the base 20. In other words, the second projection 24 is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the first coil end 43 (as it goes upward). Furthermore, the shape of the second projection 24 is such that, when viewed from the radial direction, it follows the contact portion of the coil 4 with the second coil end 44. This further suppresses displacement of the coil 4. The shape of the second projection 24 in this embodiment is the same as the first projection 22 but inverted vertically.

[0038] The second projection 24 is positioned between the second coil ends 44 of two adjacent coils 4. The second projection 24 is in contact with the two adjacent coils 4. In other words, the second projection 24 positions the two adjacent coils 4. In this embodiment, the second projection 24 is in contact with the second coil ends 44 of the two adjacent coils 4 via the second insulating member 25. In other words, in this embodiment, the second projection 24 positions the two adjacent coils 4 via the second insulating member 25.

[0039] Multiple second insulating members 25 correspond one-to-one with multiple second protrusions 24. The second insulating members 25 are positioned to be interposed between a corresponding second protrusion 24 and two adjacent coils 4. The second insulating member 25 is a plate-shaped member that covers the periphery of the second protrusion 24, excluding the lower end, when viewed from the radial direction of the base 20. In other words, the second insulating member 25 is an inverted V-shaped plate-shaped member when viewed from the radial direction of the base 20. Furthermore, the shape of the second insulating member 25 is such that it follows the contact portion of the second coil end 44 of the coil 4 when viewed from the radial direction. This further suppresses displacement of the coil 4. The shape of the second insulating member 25 in this embodiment is the same as the first insulating member 23 but inverted vertically. The second insulating member 25 in this embodiment is integrally molded with the second protrusion 24 by additive manufacturing. However, the structure may be such that the second insulating member 25 is attached to the second projection 24.

[0040] The material of the second insulating member 25 includes an electrically insulating material. The material of the second insulating member 25 includes, for example, an electrically insulating magnetic material such as ferrite, or a synthetic resin material such as LCP resin. The thickness of the first insulating member 23 is such that an insulation distance conforming to international standards can be secured. In other words, the second insulating member 25 has electrical insulating properties. By arranging the electrically insulating second insulating member 25 between the second projection 24 and the two adjacent coils 4, the second projection 24 and the two adjacent coils 4 are electrically insulated even if the second projection 24 itself does not have electrical insulating properties.

[0041] According to the motor 1 of the present embodiment, the first coil end 43 of the coil 4 is positioned by the first protrusion 22, and the second coil end 44 of the coil 4 is positioned by the second protrusion 24. This further suppresses positional displacement of the coil 4. Further, in the present embodiment, two adjacent first protrusions 22 position the coil 4 by sandwiching the first coil end 43 of the coil 4 in the circumferential direction of the base portion 20. Similarly, two adjacent second protrusions 24 position the coil 4 by sandwiching the second coil end 44 of the coil 4 in the circumferential direction of the base portion 20. This further suppresses positional displacement of the coil 4. As described above, according to the motor 1 of the present embodiment, the quasi-coreless structure suppresses the generation of torque ripple, while also suppressing reduction in the torque generated by the motor 1, and further can suppress positional displacement of the coil 4.

[0042] (3) Method for manufacturing the motor Next, a method for manufacturing the motor 1 of the present embodiment will be described.

[0043] In the method for manufacturing the motor 1 of the present embodiment, the stator core 2 included in the motor 1 is formed by additive manufacturing. In the method for manufacturing the motor 1, the coil 4 may further be formed by additive manufacturing so as to be wound around each of the plurality of teeth 21 of the stator core 2.

[0044] Accordingly, according to this aspect, the motor 1 capable of suppressing positional displacement of the coil 4 can be manufactured more easily.

[0045] (4) Modifications Modifications of the above embodiment will be listed below.

[0046] (4.1) Modification 1 As shown in FIG. 4, the stator core 2 of the motor 1 according to Modification 1 includes a first protrusion 22A in place of the first protrusion 22, includes a second protrusion 24A in place of the second protrusion 24, includes a first insulating member 23A in place of the first insulating member 23, and includes a second insulating member 25A in place of the second insulating member 25.

[0047] The first protrusion 22A of Modification 1 differs in shape from the first protrusion 22 of the above embodiment. The first protrusion 22A protrudes toward the rotor 5 from the inner circumferential surface 200 of the base portion 20 along the radial direction of the base portion 20 (or the motor shaft 53). When viewed from the radial direction of the base portion 20, the first protrusion 22A has a downwardly convex semicircular shape (lower semicircular shape). That is, when viewed from the radial direction of the base portion 20, the first protrusion 22A has a downwardly convex semicircular shape. By forming the first protrusion 22A into a simple shape, the manufacturing of the first protrusion 22A, that is, the manufacturing of the motor 1, is facilitated. In addition, the first protrusion 22A has a tapered shape that becomes narrower as it approaches the second coil end 44 (as it goes downward) in a direction orthogonal to both the circumferential direction and the radial direction.

[0048] The first protrusion 22A is disposed between the respective first coil ends 43 of two adjacent coils 4. The first protrusion 22A is in contact with the two adjacent coils 4. That is, the first protrusion 22A positions the two adjacent coils 4. In Modification 1, the first protrusion 22A is in contact with the first coil ends 43 of the two adjacent coils 4 via the first insulating member 23A. That is, the first protrusion 22A of the present embodiment positions the two adjacent coils 4 via the first insulating member 23A.

[0049] The first insulating member 23A of Modification 1 differs in shape from the first insulating member 23 of the above embodiment. The first insulating member 23A is disposed so as to be interposed between the corresponding first protrusion 22A and the two coils 4 adjacent to the corresponding first protrusion 22A. When viewed from the radial direction of the base portion 20, the first insulating member 23A is a plate-shaped member that covers the periphery of the first protrusion 22A excluding the upper end thereof. That is, when viewed from the radial direction of the base portion 20, the first insulating member 23A is a downwardly convex semicircular arc-shaped plate-shaped member. By forming the first insulating member 23A into a simple shape, the manufacturing of the first insulating member 23A, that is, the manufacturing of the motor 1, is facilitated. The first insulating member 23A of Modification 1 is integrally molded with the first protrusion 22A by additive manufacturing. However, a structure in which the first insulating member 23A is attached to the first protrusion 22A is also possible.

[0050] The second projection 24A in Modification 1 differs from the second projection 24 in the above embodiment only in shape. Furthermore, since the shape of the second projection 24A is the same as the first projection 22A inverted vertically, a detailed explanation is omitted.

[0051] The second insulating member 25A in Modification 1 differs from the second insulating member 25 in the above embodiment only in shape. Furthermore, since the shape of the second insulating member 25A is the same as the first insulating member 23A inverted vertically, a detailed explanation is omitted.

[0052] (4.2) Modified Example 2 As shown in Figure 4, the stator core 2 of the motor 1 in Modified Example 2 has a first projection 22B instead of the first projection 22, a second projection 24B instead of the second projection 24, a first insulating member 23B instead of the first insulating member 23, and a second insulating member 25B instead of the second insulating member 25.

[0053] The first projection 22B of Modification 1 differs in shape from the first projection 22 of the above embodiment. The first projection 22B protrudes from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the first projection 22B is a polygonal shape that is convex downward when viewed from the radial direction of the base 20. In other words, the first projection 22B is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the second coil end 44 (as it goes downward). Also, the shape of the first projection 22B is such that, when viewed from the radial direction, it follows the contact portion of the first coil end 43 of the coil 4.

[0054] The first projection 22B is positioned between the first coil ends 43 of two adjacent coils 4. The first projection 22B is in contact with the two adjacent coils 4. In other words, the first projection 22B positions the two adjacent coils 4. In the modified example 2, the first projection 22B is in contact with the first coil ends 43 of the two adjacent coils 4 via the first insulating member 23B. In other words, in this embodiment, the first projection 22B positions the two adjacent coils 4 via the first insulating member 23B.

[0055] The first insulating member 23B in Modification 1 differs in shape from the first insulating member 23 in the above embodiment. The first insulating member 23B is positioned between the corresponding first projection 22B and two coils 4 adjacent to the corresponding first projection 22B. The first insulating member 23B is a plate-shaped member that covers the periphery of the first projection 22B, excluding the upper end, when viewed from the radial direction of the base 20. In other words, the first insulating member 23B is a V-shaped plate-shaped member that protrudes downward when viewed from the radial direction of the base 20. Furthermore, the shape of the first insulating member 23B is such that it follows the contact portion of the first coil end 43 of the coil 4 when viewed from the radial direction. In Modification 2, the first insulating member 23B is integrally molded with the first projection 22A by additive manufacturing. However, the structure may also be such that the first insulating member 23B is attached to the first projection 22B.

[0056] The second projection 24B in Modification 1 has a different shape from the second projection 24 in the above embodiment. Furthermore, the second projection 24B also has a different shape from the first projection 22B. In other words, in Modification 2, the shape of the first projection 22B and the shape of the second projection 24B are different. The statement in this disclosure that "the shape of the first projection 22B and the shape of the second projection 24B are different" means that even if the first projection 22B is inverted vertically, it will not have the same shape as the second projection 24B. The second projection 24B protrudes from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the second projection 24B is a polygonal shape that is convex upward when viewed from the radial direction of the base 20. In other words, the second projection 24B is tapered in a direction perpendicular to both the circumferential and radial directions, becoming narrower as it approaches the first coil end 43 (as it goes upwards). Furthermore, the shape of the second projection 24B is such that, when viewed from the radial direction, it follows the contact portion of the second coil end 44 of the coil 4.

[0057] Here, the maximum width of the second projection 24B in the circumferential direction (the width of the lower end in the example of Figure 5) is wider than the maximum width of the first projection 22B in the circumferential direction (the width of the upper end in the example of Figure 5). As a result, in the case of the first projection 22B located near the first lead portion 41 or the second lead portion 42 of the coil 4, by making the width of the first projection 22B narrower than the width of the second projection 24B, space can be secured for the first lead portion 41 or the second lead portion 42 to be pulled upward. Furthermore, by making the width of the second projection 24B wider than the width of the first projection 22B, the displacement of the coil 4 can be further suppressed.

[0058] The second projection 24B is positioned between the second coil ends 44 of two adjacent coils 4. The second projection 24B is in contact with the two adjacent coils 4. In other words, the second projection 24B positions the two adjacent coils 4. In the modified example 2, the second projection 24B is in contact with the first coil ends 43 of the two adjacent coils 4 via the second insulating member 25B. In other words, in this embodiment, the second projection 24B positions the two adjacent coils 4 via the second insulating member 25B.

[0059] The second insulating member 25B in Modification 1 has a different shape from the second insulating member 25 in the above embodiment. Furthermore, the second insulating member 25B also has a different shape from the first insulating member 23B. In other words, in Modification 2, the shape of the first insulating member 23B and the shape of the second insulating member 25B are different. The second insulating member 25B is positioned to be interposed between the corresponding second projection 24B and the two coils 4 adjacent to the corresponding second projection 24B. The second insulating member 25B is a plate-shaped member that covers the periphery of the second projection 24B, excluding the lower end, when viewed from the radial direction of the base 20. In other words, the second insulating member 25B is an inverted V-shaped plate-shaped member that is convex upward when viewed from the radial direction of the base 20. Also, the shape of the second insulating member 25B is such that, when viewed from the radial direction, it follows the contact portion of the second coil end 44 of the coil 4. In the modified example 2, the second insulating member 25B is integrally molded with the second projection 24B by additive manufacturing. However, the second insulating member 25B may be attached to the second projection 24B.

[0060] (4.3) Modified Example 3 As shown in Figure 6, the stator core 2 of the motor 1 in Modified Example 3 has a first projection 22C instead of the first projection 22, a second projection 24C instead of the second projection 24, a first insulating member 23C instead of the first insulating member 23, and a second insulating member 25C instead of the second insulating member 25.

[0061] The first projection 22C of Modification 1 differs in shape from the first projection 22 of the above embodiment. The first projection 22C protrudes from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the first projection 22C is a polygonal shape that is convex downward when viewed from the radial direction of the base 20. Also, the shape of the first projection 22C is such that it follows the contact portion of the first coil end 43 of the coil 4 when viewed from the radial direction. Furthermore, the first projection 22C is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the second coil end 44 (as it goes downward).

[0062] The first projection 22C is positioned between the first coil ends 43 of two adjacent coils 4. The first projection 22C is in contact with the two adjacent coils 4. In other words, the first projection 22C positions the two adjacent coils 4. In the modified example 3, the first projection 22C is in contact with the first coil ends 43 of the two adjacent coils 4 via the first insulating member 23C. In other words, in this embodiment, the first projection 22C positions the two adjacent coils 4 via the first insulating member 23C.

[0063] The first projection 22C has a plurality of (two in the example of Figure 6) first connecting portions 221. The first connecting portion 221 is a downwardly recessed recess formed at the upper end of the first projection 22C. The first projection 22C engages with the second connecting portion 231 of the first insulating member 23C, which will be described later.

[0064] The first insulating member 23C in Modification 1 differs in shape from the first insulating member 23 in the above embodiment. The first insulating member 23C is positioned between the corresponding first projection 22C and the two coils 4 adjacent to the corresponding first projection 22C. The first insulating member 23C is a plate-shaped member that covers the periphery of the first projection 22C, excluding a part of the upper end, when viewed from the radial direction of the base 20. In other words, the first insulating member 23C is a V-shaped plate-shaped member that protrudes downward when viewed from the radial direction of the base 20. Furthermore, the shape of the first insulating member 23C is such that, when viewed from the radial direction, it follows the contact portion of the first coil end 43 of the coil 4.

[0065] The first insulating member 23C is attached to the first projection 22C. Furthermore, the first insulating member 23C is detachable from the first projection 22C. This allows the first insulating member 23C, which is molded separately from the first projection 22C, to be attached to the first projection 22C after the first projection 22C has been molded by a method such as additive manufacturing, making it easy to interpose the first insulating member 23C between the first projection 22C and the coil 4.

[0066] The first insulating member 23C has a plurality of (two in the example of Figure 6) second connecting portions 231. The second connecting portions 231 are formed at positions corresponding to the first connecting portions 221 of the first projection 22C. The second connecting portions 231 are protrusions that project downward. When the first insulating member 23C is attached to the first projection 22C, the second connecting portions 231 of the first insulating member 23C interlock with the first connecting portions 221 of the first projection 22C. This allows the first insulating member 23C to be attached to the first projection 22C more firmly.

[0067] The shape of the second projection 24C is the same as the first projection 22C but inverted vertically, so a detailed explanation is omitted.

[0068] Since the shape of the second insulating member 25C is the same as the first insulating member 23C but inverted, a detailed explanation will be omitted.

[0069] (4.4) Modification 4 As shown in Figure 7, the stator core 2 of the motor 1 of Modification 4 has a first projection 22D instead of the first projection 22, a second projection 24D instead of the second projection 24, and an insulating member 6 instead of the first insulating member 23 and the second insulating member 25. The motor 1 of Modification 4 differs from the motor 1 of the above embodiment in that the periphery of the multiple coils 4 is covered with insulating member 6.

[0070] The first projection 22D of Modification 1 differs in shape from the first projection 22 of the above embodiment. The first projection 22D protrudes from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the first projection 22D is a polygonal shape that is convex downward when viewed from the radial direction of the base 20. Also, the shape of the first projection 22D is such that it follows the contact portion of the first coil end 43 of the coil 4 when viewed from the radial direction. Furthermore, the first projection 22D is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the second coil end 44 (as it goes downward).

[0071] The first projection 22D is positioned between the first coil ends 43 of two adjacent coils 4. The first projection 22D is in contact with the two adjacent coils 4. In other words, the first projection 22D positions the two adjacent coils 4. In modified example 4, the first projection 22D is in contact with the first coil ends 43 of the two adjacent coils 4 via the insulating member 6. In other words, in this embodiment, the first projection 22D positions the two adjacent coils 4 via the insulating member 6.

[0072] Since the shape of the second projection 24D is the same as the first projection 22D but inverted vertically, a detailed explanation will be omitted.

[0073] The insulating member 6 surrounds the multiple coils 4. In other words, the insulating member 6 is interposed between two adjacent coils 4. The material of the insulating member 6 includes an electrically insulating material. For example, the material of the insulating member 6 includes an electrically insulating magnetic material such as ferrite, or a synthetic resin material such as LCP resin. The thickness of the insulating member 6 is such that an insulation distance conforming to international standards is ensured. In other words, the insulating member 6 has electrical insulating properties. By covering the multiple coils 4 with an electrically insulating insulating member 6, the first projection 22D is electrically insulated from the two adjacent coils 4, even if the first projection 22D itself does not have electrical insulating properties. As a result, a magnetic material that does not have electrical insulating properties, such as iron, can be used as the material for the first projection 22D, increasing the variety of materials that can be used for the first projection 22D. Furthermore, by having the insulating member 6 surround multiple coils 4, the distance between adjacent coils 4 can be shortened. This makes it possible to increase the size of the coils 4 and thus increase the cross-sectional area of ​​the coils 4.

[0074] In Modified Example 4, the insulating member 6 is formed by additive manufacturing so as to cover the periphery of the multiple coils 4. Note that the motor 1 in Modified Example 4 does not necessarily have insulating paper, such as insulating paper, interposed between the inner circumferential surface 200 of the base 20 of the stator core 2 and the coils 4.

[0075] (4.5) Modified Example 5 As shown in Figure 8, the stator core 2 of the motor 1 in Modified Example 5 has a first projection 22E instead of the first projection 22, a second projection 24E instead of the second projection 24, and does not have a first insulating member 23 and a second insulating member 25.

[0076] The first projection 22E protrudes from the inner circumferential surface 200 of the base 20 toward the rotor 5 along the radial direction of the base 20 (or motor shaft 53). The shape of the first projection 22E is a polygonal shape that is convex downward when viewed from the radial direction of the base 20. The shape of the first projection 22E is such that it follows the contact portion of the first coil end 43 of the coil 4 when viewed from the radial direction. Furthermore, the first projection 22E is tapered in a direction perpendicular to both the circumferential and radial directions, becoming thinner as it approaches the second coil end 44 (as it goes downward).

[0077] The first projection 22E is positioned between the first coil ends 43 of two adjacent coils 4. The first projection 22E is in contact with the two adjacent coils 4. In other words, the first projection 22E positions the two adjacent coils 4. In modified example 5, the first projection 22E is in direct contact with the first coil ends 43 of the two adjacent coils 4.

[0078] The material of the first projection 22E includes an electrically insulating magnetic material. In Modification 5, the material of the first projection 22E includes an electrically insulating magnetic material such as ferrite. As a result, the first projection 22E is electrically insulated from two adjacent coils. The motor 1 of Modification 5 can reduce the number of parts of the motor 1 compared to the case in which an insulating member (for example, a first insulating member 23) is interposed between the projection (for example, the first projection 22) and the coil 4.

[0079] The material of the second projection 24E includes an electrically insulating magnetic material. In modified example 5, the material of the second projection 24E includes an electrically insulating magnetic material such as ferrite. As a result, the second projection 24E is electrically insulated from two adjacent coils. The shape of the second projection 24E is the same as the first projection 22E inverted vertically, so a detailed explanation is omitted.

[0080] (4.6) Other Modifications In the above embodiment, the case in which motor 1 is a servo motor was illustrated, but motor 1 may be a motor other than a servo motor.

[0081] In the above embodiment, an example is shown in which a plurality of (six in the above embodiment) first protrusions 22 and a plurality of (six in the above embodiment) second protrusions 24 are arranged in a vertical direction. However, it is not essential that the stator core 2 has a plurality of first protrusions 22 and a plurality of second protrusions 24; the stator core 2 may have any of the plurality of first protrusions 22 and a plurality of second protrusions 24.

[0082] In the above embodiment, an example is shown in which the stator core 2 has the same number of first protrusions 22 and second protrusions 24 as there are coils 4 (six in the above embodiment). However, the number of first protrusions 22 and second protrusions 24 may be less than the number of coils 4. For example, the stator core 2 may have half (three) of the number of coils 4 (six) as first protrusions 22 and second protrusions 24. For example, three first protrusions 22 are arranged at equal intervals (i.e., equal angular intervals) along the circumferential direction of the base 20 (or motor shaft 53), and three second protrusions 24 are arranged at equal intervals along the circumferential direction of the base 20 (or motor shaft 53). Furthermore, the three first protrusions 22 and three second protrusions 24 may be arranged so that they do not align with each other in the vertical direction, and so that when viewed from the vertical direction, the first protrusions 22 and second protrusions 24 are arranged alternately.

[0083] (Modes) As is clear from the embodiments and modifications described above, the motor (1) according to the first mode comprises a stator core (2), a plurality of coils (4), and a rotor (5). The stator core (2) has a cylindrical base (20) and a plurality of teeth (21) protruding from the inner circumferential surface (200) of the base (20) along the radial direction of the base (20). The plurality of coils (4) correspond one-to-one with the plurality of teeth (21) and are wound around the plurality of teeth (21). The rotor (5) is arranged to face the stator core (2). Each of the plurality of coils (4) has a first coil end (43) and a second coil end (44). The first coil end (43) and the second coil end (44) protrude in opposite directions from each other in directions perpendicular to both the circumferential and radial directions of the base (20). The stator core (2) has first projections (22; 22A; 22B; 22C; 22D; 22E) and second projections (24, 24A, 24B, 24C, 24D, 24E) projecting radially from the inner circumferential surface (200) of the base (20). The first projections (22; 22A; 22B; 22C; 22D; 22E) are located between the first coil ends (43) of two adjacent coils (4) among the plurality of coils (4). The first projections (22; 22A; 22B; 22C; 22D; 22E) are in contact with two adjacent coils (4). The second projections (24, 24A, 24B, 24C, 24D, 24E) are located between the second coil ends (44) of two coils (4). The first protrusions (22; 22A; 22B; 22C; 22D; 22E) and the second protrusions (24, 24A, 24B, 24C, 24D, 24E) are electrically insulated from two adjacent coils (4).

[0084] According to this embodiment, displacement of the coil (4) can be suppressed.

[0085] In the motor (1) according to the second embodiment, in the first embodiment, the material of the first projection (22E) includes an electrically insulating magnetic material.

[0086] According to this embodiment, the number of parts of the motor (1) can be reduced compared to the case in which an insulating member is interposed between the first projection (22E) and the coil (4).

[0087] A motor (1) according to a third embodiment further comprises an insulating member (first insulating member 23; 23A; 23B; 23C) in the first embodiment. The insulating member is interposed between the first projection (22; 22A; 22B; 22C) and the two coils (4). The insulating member has electrical insulating properties. The first projection (22; 22A; 22B; 22C) is in contact with the two coils (4) via the insulating member.

[0088] According to this embodiment, the first projections (22; 22A; 22B; 22C) themselves do not need to have electrical insulating properties, thus increasing the variety of materials that can be used as the material for the first projections (22; 22A; 22B; 22C).

[0089] In the motor (1) according to the fourth embodiment, the insulating member (first insulating member 23C) is attached to the first projection (22C) in the first or third embodiment.

[0090] According to this embodiment, it becomes easy to interpose an insulating member between the first projection (22C) and the coil (4).

[0091] In the motor (1) according to the fifth embodiment, the shape of the first projection (22B) and the shape of the second projection (24B) are different in any of the first to fourth embodiments.

[0092] According to this embodiment, for example, by making the width of the first projection (22B) narrower than the width of the second projection (24B), space can be secured for the lead-out portion of the coil (4) to be pulled out.

[0093] In the motor (1) according to the sixth embodiment, in any of the first to fifth embodiments, the shape of the first projection (22; 22A; 22B; 22C; 22D; 22E) is tapered, becoming narrower as it approaches the second coil end (44) in the orthogonal direction.

[0094] In the motor (1) according to the seventh embodiment, the shape of 2 (22A) is semicircular when viewed from the radial direction, as in the sixth embodiment.

[0095] According to this embodiment, the manufacturing of the first projection (22A), that is, the manufacturing of the motor (1), becomes easier.

[0096] In the motor (1) according to the eighth embodiment, in the sixth embodiment, the shape of the first projection (22; 22A; 22B; 22C; 22D; 22E) is polygonal when viewed from the radial direction.

[0097] According to this embodiment, displacement of the coil (4) can be further suppressed.

[0098] In the motor (1) according to the ninth embodiment, in any of the first to eighth embodiments, each of the plurality of teeth (21) has a tip (210). The tip (210) faces the rotor (5) in the radial direction of the base (20). Each of the plurality of coils (4) has an end (40) that faces the rotor (5) in the radial direction of the base 20. In the radial direction of the base (20), the tip (210) is located between the inner circumferential surface (200) of the base (20) and the end (40).

[0099] According to this embodiment, the generation of torque ripple (or cogging torque) is suppressed while preventing a reduction in the torque generated by the motor (1).

[0100] Configurations other than those in the first embodiment are not essential to the motor (1) and can be omitted as appropriate.

[0101] The manufacturing method for the motor (1) according to the tenth embodiment involves forming the stator core (2) of the motor (1) according to any of the first to ninth embodiments by additive manufacturing.

[0102] According to this embodiment, a motor (1) capable of suppressing coil misalignment can be manufactured more easily.

[0103] As is clear from the embodiments and modifications described above, the motor (1) according to the eleventh embodiment comprises a stator core (2), a plurality of coils (4), and a rotor (5). The stator core (2) has a cylindrical base (20) and a plurality of teeth (21) protruding from the inner circumferential surface (200) of the base (20) along the radial direction of the base (20). The plurality of coils (4) correspond one-to-one with the plurality of teeth (21) and are wound around the plurality of teeth (21). The rotor (5) is arranged to face the stator core (2). Each of the plurality of coils (4) has a first coil end (43) and a second coil end (44). The first coil end (43) and the second coil end (44) protrude in opposite directions from each other in directions perpendicular to both the circumferential and radial directions of the base (20). The stator core (2) has projections (first projections 22; 22A; 22B; 22C; 22D; 22E) that protrude radially from the inner circumferential surface (200) of the base (20). The projections are located between the first coil ends (43) of two adjacent coils (4) among the plurality of coils (4). The projections are in contact with the two adjacent coils (4). The projections are electrically insulated from the two adjacent coils (4).

[0104] According to this embodiment, displacement of the coil (4) can be suppressed.

[0105] In the motor (1) according to the twelfth embodiment, as in the eleventh embodiment, the projection is a first projection (22; 22A; 22B; 22C; 22D; 22E). The stator core (2) further has second projections (24, 24A, 24B, 24C, 24D, 24E) projecting radially from the inner circumferential surface (200) of the base (20). The second projections (24, 24A, 24B, 24C, 24D, 24E) are located between the second coil ends (44) of two adjacent coils (4). The second projections (24, 24A, 24B, 24C, 24D, 24E) are in contact with the two coils (4). The second protrusions (24, 24A, 24B, 24C, 24D, 24E) and the two coils (4) are electrically insulated from each other.

[0106] According to this embodiment, displacement of the coil (4) can be further suppressed.

[0107] A motor (1) according to the 13th embodiment further comprises an insulating member (6) in the 11th or 12th embodiment. The insulating member (6) is interposed between two coils (4). The insulating member (6) has electrical insulating properties. The protrusions (first protrusions 22; 22A; 22B; 22C; 22D; 22E) are in contact with the two coils (4) via the insulating member (6).

[0108] The manufacturing method for the motor (1) according to the 14th embodiment involves forming the stator core (2) of the motor (1) according to any of the 11th to 13th embodiments by additive manufacturing.

[0109] 1 Motor 2 Stator core 20 Base 200 Inner surface 21 Teeth 22, 22A, 22B, 22C, 22D, 22E First projection 23, 23A, 23B, 23C First insulating member (insulating member) 24, 24A, 24B, 24C, 24D, 24E Second projection 4 Coil 43 First coil end (coil end) 44 Second coil end 5 Rotor 6 Insulating member

Claims

1. A motor comprising: a stator core having a cylindrical base and a plurality of teeth projecting from the inner circumferential surface of the base along the radial direction of the base; a plurality of coils corresponding one-to-one with the plurality of teeth and wound around the plurality of teeth; and a rotor positioned opposite the stator core, wherein each of the plurality of coils has a first coil end and a second coil end projecting in opposite directions to each other in directions perpendicular to both the circumferential and radial directions of the base; the stator core has a first projection and a second projection projecting from the inner circumferential surface of the base along the radial direction; the first projection is located between the first coil ends of two adjacent coils among the plurality of coils and is in contact with the two coils; the second projection is located between the second coil ends of the two coils and is in contact with the two coils; and the first projection and the second projection are electrically insulated from the two coils.

2. The motor according to claim 1, wherein the material of the first projection includes an electrically insulating magnetic material.

3. The motor according to claim 1, further comprising an insulating member interposed between the first projection and the two coils, wherein the insulating member has electrical insulating properties, and the first projection is in contact with the two coils via the insulating member.

4. The motor according to claim 3, wherein the insulating member is attached to the first projection.

5. The motor according to claim 1, wherein the shape of the first projection and the shape of the second projection are different.

6. The motor according to any one of claims 1 to 5, wherein the shape of the first projection is tapered, becoming narrower as it approaches the second coil end in the orthogonal direction.

7. The motor according to any one of claims 1 to 5, wherein the shape of the first projection is semicircular when viewed from the radial direction.

8. The motor according to any one of claims 1 to 5, wherein the shape of the first projection is polygonal when viewed from the radial direction.

9. The motor according to any one of claims 1 to 5, wherein each of the plurality of teeth has a tip facing the rotor in the radial direction, each of the plurality of coils has an end facing the rotor in the radial direction, and the tip is located between the inner circumferential surface of the base and the end in the radial direction.

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