Coil for an electric motor, method for manufacturing the coil for an electric motor, and electric motor

Abstract

To provide a miniaturized electric motor coil that can be easily manufactured, a manufacturing method of the electric motor coil, and an electric motor.SOLUTION: An electric motor coil includes a coil made of a conductor wound around an axis, and a plurality of cooling units provided corresponding to different winding layers in the conductor, and each of the cooling units includes a first portion protruding radially outward from each winding layer, and a second portion extending from the tip of the first portion toward one side in the axial direction, and the first portion located on the other side in the axial direction has a longer projecting length, and the second portion is located radially outward in relation to the first portion located on the other side in the axial direction, and the plurality of second portions are radially spaced apart and overlapped.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a coil for an electric motor, a method for manufacturing the coil for an electric motor, and an electric motor.

Background Art

[0002] A wire rod forming a coil of an electric motor (motor) is generally covered with an insulating film such as resin. When the coil is energized, the coil generates heat, and the insulating film may deteriorate. Therefore, as exemplified in Patent Document 1 below, a configuration has been proposed in which a part of the winding of the coil is extended to form an overhanging portion and functions as a cooling fin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it is very difficult to stably wind the wire so as to form the above-described cooling fins. In addition, since the cooling fins protrude greatly, there is also a problem that the size and dimensions of the electric motor increase.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a coil for an electric motor, a method for manufacturing the coil for an electric motor, and an electric motor that can be easily manufactured and are miniaturized.

Means for Solving the Problems

[0006] In order to solve the above problems, the coil for an electric motor according to the present disclosure includes a coil composed of a conductor wound around an axis, and a plurality of cooling portions provided corresponding to different winding layers in the conductor. Each of the cooling portions includes a first portion protruding radially outward from each of the winding layers, and a second portion extending from the tip of the first portion toward one side in the axial direction. The first portion has a greater protruding length as it is located on the other side in the axial direction. The second portion is located more radially outward as it corresponds to the first portion located on the other side in the axial direction. At least a part of the second portion is arranged so as to overlap with a radial interval. They are provided at intervals so as to be adjacent to each other, and more in the one axial direction than the first part located on one side in the axial direction The first portion located on the other side in the axial direction has a greater protruding length, and the second portion than the second part corresponding to the first part located on one side in the axial direction is located more radially outward as it corresponds to the first portion located on the other side in the axial direction. corresponding to the first parts adjacent to each other in the axial direction The second portion each other are is arranged such that at least a part thereof overlaps with a radial interval.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to provide a coil for an electric motor that can be easily manufactured and is miniaturized, a method for manufacturing the coil for an electric motor, and an electric motor.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] (Configuration of Electric Motor) Hereinafter, the electric motor 100 according to the embodiment of the present disclosure will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the electric motor 100 includes a rotor 1, a stator 2, and a housing 3. The rotor 1 has a columnar shape extending along the main axis O1. Although not shown in detail, a plurality of permanent magnets are arranged inside the rotor 1 in the circumferential direction. Alternatively, a configuration in which a cylindrical magnet is attached to the outer peripheral surface of the rotor 1 can also be adopted. The rotor 1 is rotatably supported around the main axis O1.

[0010] The stator 2 covers the rotor 1 from the outer peripheral side. The stator 2 has an annular shape centered on the main axis O1. The stator 2 is configured by connecting a plurality of stator cores 26 (described later) in the circumferential direction. The configurations of the stator core 26 and the coil 20 for the electric motor will be described later. The housing 3 covers the stator 2 from the outer peripheral side. The stator 2 is fixed to the inner peripheral surface of the housing 3 by shrink fitting or the like.

[0011] (Configuration of Coil for Electric Motor) Next, the configuration of the coil 20 for the electric motor will be described with reference to FIGS. 2 to 4. As shown in FIG. 2, the coil 20 for the electric motor includes two coils (an inner peripheral side coil 22 and an outer peripheral side coil 24) wound around the coil axis O2, cooling parts 23 and 25 provided on these coils respectively, and a stator core 26.

[0012] The coil axis O2 extends in the radial direction of the main axis O1 described above. The inner peripheral coil 22 is located on the radially inner side in the direction of the coil axis O2, and the outer peripheral coil 24 is located on the radially outer side in the direction of the coil axis O2. As shown in FIG. 4, these inner peripheral coil 22 and outer peripheral coil 24 are wound so as to form a rectangular or circular annular shape when viewed from the direction of the coil axis O2. Although not shown in detail, the inner peripheral coil 22 and the outer peripheral coil 24 are electrically connected to each other. The inner peripheral coil 22 and the outer peripheral coil 24 have the same dimensions as each other. Also, the inner peripheral coil 22 and the outer peripheral coil 24 are formed of a conductor.

[0013] As shown in FIG. 2, a pair of cooling portions 23 are integrally provided on the inner peripheral coil 22. One cooling portion 23 is provided on one side of the inner peripheral coil 22 in the direction of the main axis O1, and the other cooling portion 23 is provided on the other side of the inner peripheral coil 22 in the direction of the main axis O1.

[0014] The cooling portion 23 has a first portion 23a that protrudes radially outward from the inner peripheral coil 22 toward the coil axis O2, and a second portion 23b that extends from the tip of the first portion 23a toward one side in the direction of the coil axis O2. Thereby, the cooling portion 23 has an L-shaped cross-sectional shape. Also, as shown in FIG. 3, the second portion 23b is rectangular when viewed from the direction of the main axis O1. Further, as shown in FIG. 4, at least one of the first portion 23a and the second portion 23b has one or a plurality (in FIG. 4, three ventilation holes h are formed in the first portion 23a as an example) of ventilation holes h formed therein. These ventilation holes h are arranged at intervals in the direction of the main axis O1.

[0015] As shown again in FIG. 2, a pair of cooling portions 25 are integrally provided on the outer peripheral side coil 24. One cooling portion 25 is provided on one side in the direction of the main axis O1 of the outer peripheral side coil 24, and the other cooling portion 25 is provided on the other side in the direction of the main axis O1 of the outer peripheral side coil 24. That is, the cooling portion 23 of the inner peripheral side coil 22 described above and this cooling portion 25 are provided, for example, at the same position in the circumferential direction with respect to the coil axis O2. Note that at least a part of the cooling portion 23 and the cooling portion 25 may overlap each other in the circumferential direction with respect to the axis O2.

[0016] The cooling portion 25 has a first portion 25a that protrudes radially outward from the outer peripheral side coil 24 in the direction of the coil axis O2, and a second portion 25b that extends from the tip of the first portion 25a in one direction of the coil axis O2. Thereby, the cooling portion 25 has an L-shaped cross-sectional shape. Further, as shown in FIG. 3, the second portion 25b is rectangular when viewed from the direction of the main axis O1. Furthermore, although not shown in detail, similar to the first portion 23a, a plurality (for example, three) of ventilation holes h are formed in the first portion 25a. Note that similar ventilation holes h may be formed in the second portion 25b. Also, the number of the ventilation holes h may be one or a plurality. These ventilation holes h are arranged at intervals in the circumferential direction with respect to the main axis O1. Also, the ventilation holes h in the first portion 23a and the ventilation holes h in the first portion 25a overlap each other when viewed from the direction of the coil axis O2.

[0017] In the cooling portions 23 and 25 configured as described above, as shown in FIG. 2, the first portion 23a of the cooling portion 23 located on the other side in the direction of the coil axis O2 (that is, radially inward with respect to the main axis O1) has a larger protruding length than the first portion 25a of the cooling portion 25 located on one side in the direction of the coil axis O2. In other words, the first portion 23a has a larger radial length with respect to the coil axis O2 than the first portion 25a. Also, the second portion 23b corresponding to the first portion 23a located on the other side of the coil axis O2 is located radially outward.

[0018] Furthermore, as shown in FIGS. 2 and 3, at least a part of the second portion 23b of the cooling part 23 and at least a part of the second portion 25b of the cooling part 25 overlap in the radial direction with respect to the coil axis O2. Also, the second portion 25b of the cooling part 25 protrudes more toward one side in the direction of the coil axis O2 than the second portion 23b of the cooling part 23. Therefore, when viewed from the radial direction of the coil axis O2, at least a part of the second portion 25b of the cooling part 25 is exposed.

[0019] Also, a thin film-like insulating layer formed of an enamel resin or the like is provided on the surfaces of the inner peripheral side coil 22, the outer peripheral side coil 24, the cooling part 23, and the cooling part 25.

[0020] (Configuration of the stator core) Next, the configuration of the stator core 26 will be described with reference to FIG. 3. The stator core 26 is inserted inside the inner peripheral side coil 22 and the outer peripheral side coil 24 that form a rectangular or circular ring shape. The stator core 26 has a yoke portion 26a, teeth 26b, and a tip portion 26c. One surface (circumferential surface 26s) of the yoke portion 26a on one side in the direction of the coil axis O2 has an arcuate cross-sectional shape. As a result, when a plurality of stator cores 26 are connected, the circumferential surfaces 26s are continuous to form a cylindrical surface.

[0021] The teeth 26b protrude from the yoke portion 26a toward the other side in the direction of the coil axis O2. The teeth 26b have a smaller cross-sectional area than the yoke portion 26a when viewed in the direction of the coil axis O2. The inner peripheral side coil 22 and the outer peripheral side coil 24 are wound around the teeth 26b. A tip portion 26c is provided on the other side of the teeth 26b in the direction of the coil axis O2. The tip portion 26c protrudes in the radial direction with respect to the coil axis O2. As a result, the inner peripheral side coil 22 and the outer peripheral side coil 24 are held by the teeth 26b so as not to fall off.

[0022] (Method for manufacturing the electric motor) Next, with reference to FIG. 5, a method for manufacturing the electric motor 100 (and a method for manufacturing the coil 20 for an electric motor) will be described. As shown in the figure, the method for manufacturing the electric motor 100 includes a step S1 of manufacturing the inner peripheral side coil 22, the outer peripheral side coil 24, the cooling part 23, and the cooling part 25 by additive manufacturing, a step S2 of attaching the stator core 26 to the inner peripheral side coil 22 and the outer peripheral side coil 24, a step S3 of connecting a plurality of stator cores 26, and a step S4 of attaching the rotor 1.

[0023] In step S1, by using the Additive Modelling (AM) manufacturing method, fine powder metal is laminated and cured to obtain a predetermined shape of the inner peripheral side coil 22, the outer peripheral side coil 24, the cooling part 23, and the cooling part 25. Then, the above-described insulating layer is formed on the surfaces of the inner peripheral side coil 22, the outer peripheral side coil 24, the cooling part 23, and the cooling part 25. In step S2, after removing the teeth 26b and the tip parts 26c of the stator core 26 from the yoke part 26a, the inner peripheral side coil 22 and the outer peripheral side coil 24 are attached to the teeth 26b. Thereby, the coil 20 for an electric motor is completed. In step S3, the stator cores 26 of a plurality of coils 20 for an electric motor are connected in the circumferential direction around the main axis O1 to form an annular stator 2. Finally, in step S4, the rotor 1 is inserted into the stator 2. Thus, all the steps in the method for manufacturing the electric motor 100 are completed.

[0024] (Function and Effect) Next, an example of the operation of the electric motor 100 will be described. When operating the electric motor 100, first, an electric current is supplied from the outside to the inner peripheral side coil 22 and the outer peripheral side coil 24. Thereby, a magnetic field is formed around these inner peripheral side coil 22 and outer peripheral side coil 24. Due to the interaction between this magnetic field and the magnetic field of the permanent magnet built in the rotor 1, an electromagnetic force is generated. Based on this electromagnetic force, the rotor 1 rotates around the main axis O1.

[0025] Here, as the motor 100 operates, the inner peripheral side coil 22 and the outer peripheral side coil 24 generate heat. As the heat generation progresses, the insulating layer may be damaged, which may affect the stable operation of the motor 100. Therefore, in the present embodiment, the cooling portions 23 and 25 are provided as described above.

[0026] According to the above configuration, the cooling portions 23 and 25 can dissipate the heat of the inner peripheral side coil 22 and the outer peripheral side coil 24, thereby avoiding a temperature rise. Further, each of the cooling portions 23 and 25 is formed in an L shape by the first portions 23a and 25a and the second portions 23b and 25b. Also, a plurality of the second portions 23b and 25b are arranged so as to overlap in the radial direction. Thereby, the occupied area of the cooling portions 23 and 25 when viewed from the direction of the coil axis O2 is reduced, and the motor coil 20 can be miniaturized.

[0027] Furthermore, according to the above configuration, since at least a part of the plurality of the second portions 23b and 25b do not overlap with each other, for example, when blowing air to the cooling portions 23 and 25 by a fan or the like from the outside, the blowing air can be brought into contact with all of the second portions 23b and 25b. Thereby, cooling can be performed more efficiently.

[0028] Also, according to the above configuration, since the insulating layer is provided, the cooling portions 23 and 25 are electrically insulated from each other. Thereby, the distance between the cooling portions 23 and 25 can be made as small as possible. As a result, the motor coil 20 can be further miniaturized.

[0029] In addition, according to the above configuration, since the ventilation holes h are formed in the first portions 23a and 25a, for example, when blowing air by a fan or the like from the outside, the blowing air can be distributed to each of the cooling portions 23 and 25 through the ventilation holes h. Thereby, cooling can be performed more efficiently. As an example of mounting the above fan, an example in which a plurality of blades are provided on the end surface in the direction of the main axis O1 of the rotor 1 to form a fan can be considered.

[0030] Also, according to the above manufacturing method, since the inner peripheral coil 22, the outer peripheral coil 24, and the cooling parts 23 and 25 are integrally formed by laminated manufacturing, the motor coil 20 can be manufactured more easily and in a shorter time.

[0031] The embodiments of the present disclosure have been described above. Note that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the above embodiment, an example of forming a two-layer coil including the inner peripheral coil 22 and the outer peripheral coil 24 has been described. However, the number of coils is not limited to two, and may be three or more.

[0032] Also, as a modified example of the cooling parts 23 and 25 described in the above embodiment, a configuration as shown in FIG. 6 can be adopted. In the example of the figure, an opening A and a fin part 27 are formed in the second parts 23b and 25b. The opening A penetrates the second parts 23b and 25b. The fin part 27 covers at least a part of the opening A by protruding from the edge of the opening A. According to this configuration, the exhaust heat efficiency of the second parts 23b and 25b is improved by the opening A and the fin part 27 formed in the second parts 23b and 25b. Thereby, the heat of the coil can be released earlier.

[0033] Furthermore, as shown in FIG. 7 as another modified example, it is also possible to provide a rib 28 that connects the second parts 23b and 25b in the radial direction of the coil axis O2. According to this configuration, since the second parts 23b and 25b are connected by the rib 28, for example, the possibility that the second parts 23b and 25b come into contact with each other when vibration occurs can be reduced. Thereby, noise can be suppressed.

[0034] In addition, as a further modification example, as shown in FIG. 8, it is also possible to adopt a configuration in which an end portion on one side in the direction of the coil axis O2 of the two second portions 23b and 25b is covered and a connecting portion 29 connected to the housing 3 is further provided. The connecting portion 29 is integrally formed of a resin or metal having high thermal conductivity. According to this configuration, the heat of the second portions 23b and 25b can be released to the housing 3 through the connecting portion 29. As a result, the cooling of the electric motor 100 can be performed more efficiently.

[0035] <Appendix> The electric motor coil 20, the method for manufacturing the electric motor coil 20, and the electric motor 100 described in each embodiment are understood as follows, for example.

[0036] (1) The electric motor coil 20 according to the first aspect includes a coil (inner peripheral side coil 22, outer peripheral side coil 24) formed of a conductor wound around an axis (coil axis O2), and a plurality of cooling portions 23 and 25 provided corresponding to different winding layers in the conductor. Each of the cooling portions 23 and 25 includes a first portion 23a and 25a protruding radially outward from each of the winding layers, and a second portion 23b and 25b extending from the tips of the first portions 23a and 25a toward one side in the axial direction. The first portions 23a and 25a have a larger protruding length than the first portions 23a and 25a located on the other side in the axial direction, and the second portions 23b and 25b are located more radially outward than the second portions 23b and 25b corresponding to the first portions 23a and 25a located on the other side in the axial direction. At least a part of the plurality of second portions 23b and 25b are arranged so as to overlap with a space in the radial direction.

[0037] According to the above configuration, the heat of the coil can be released by the cooling portions 23 and 25, and the temperature rise can be avoided. Further, each of the cooling portions 23 and 25 is formed by the first portions 23a and 25a and the second portions 23b and 25b. In addition, the plurality of second portions 23b and 25b are arranged so as to overlap in the radial direction. Thereby, the exclusive area of the cooling portions 23 and 25 is reduced, and the electric motor coil 20 can be miniaturized.

[0038] (2) In the motor coil 20 according to the second aspect, the second portions 23b and 25b corresponding to the first portions 23a and 25a located on one side in the axial direction protrude more toward the one side in the axial direction.

[0039] According to the above configuration, since at least a part of the plurality of second portions 23b and 25b do not overlap with each other, for example, when blowing air to the cooling portions 23 and 25 from the outside by a fan or the like, the blowing air can be brought into contact with all the second portions 23b and 25b. Thereby, the coil can be cooled more efficiently.

[0040] (3) The motor coil 20 according to the third aspect further includes an insulating layer formed on the surfaces of the coil and the cooling portions 23 and 25.

[0041] According to the above configuration, since the insulating layer is provided, the cooling portions 23 and 25 are electrically insulated from each other. Thereby, it becomes possible to reduce the interval between the cooling portions 23 and 25. As a result, the motor coil 20 can be further miniaturized.

[0042] (4) In the motor coil 20 according to the fourth aspect, at least one of a ventilation hole h penetrating the first portions 23a and 25a in the radial direction and another ventilation hole h penetrating the second portions 23b and 25b in the circumferential direction is formed.

[0043] According to the above configuration, since the ventilation hole is formed in at least one of the first portions 23a and 25a and the second portions 23b and 25b, for example, when blowing air from the outside by a fan or the like, the blowing air can be distributed to each of the cooling portions 23 and 25 through the ventilation hole h. Thereby, the coil can be cooled more efficiently.

[0044] (5) In the motor coil 20 according to the fifth aspect, an opening A is formed in the second portions 23b and 25b, and a fin portion 27 that covers at least a part of the opening A is provided.

[0045] According to the above configuration, the heat dissipation efficiency of the second parts 23b and 25b is improved by the openings A formed in the second parts 23b and 25b and the fin part 27. Thereby, the heat of the coil can be released earlier.

[0046] (6) The electric motor coil 20 according to the sixth aspect further includes a rib 28 that connects the second parts 23b and 25b adjacent to each other.

[0047] According to the above configuration, since the second parts 23b and 25b are connected by the rib 28, for example, when vibration occurs, the possibility that the second parts 23b and 25b come into contact with each other can be reduced. Thereby, noise can be suppressed.

[0048] (7) In the electric motor coil 20 according to the seventh aspect, it further includes a connecting part 29 that covers the ends of the plurality of second parts 23b and 25b on one side in the axial direction and is connected to the housing 3.

[0049] According to the above configuration, the heat of the second parts 23b and 25b can be released to the housing 3 through the connecting part 29.

[0050] (8) The electric motor 100 according to the eighth aspect includes a rotor 1 having a permanent magnet, a plurality of stator cores 26 annularly connected so as to cover the rotor 1 from the outer peripheral side, and the electric motor coil 20 according to any one of the above aspects in which the stator core 26 is inserted into the inner peripheral side of the coil.

[0051] According to the above configuration, it is possible to provide an electric motor 100 that is more miniaturized and has improved cooling efficiency.

[0052] (9) The manufacturing method of the motor coil 20 according to the ninth aspect includes a coil (inner peripheral side coil 22, outer peripheral side coil 24) composed of a conductor wound around an axis (coil axis O2), and a plurality of cooling parts 23, 25 provided corresponding to different winding layers in the conductor. Each of the cooling parts 23, 25 includes a first part 23a, 25a protruding radially outward from each of the winding layers, and a second part 23b, 25b extending from the tip of the first part 23a, 25a toward one side in the axial direction. The first parts 23a, 25a have a larger protruding length than the first parts 23a, 25a located on the other side in the axial direction, and the second parts 23b, 25b are located more radially outward than the second parts 23b, 25b corresponding to the first parts 23a, 25a located on the other side in the axial direction. At least a part of the plurality of second parts 23b, 25b is arranged to overlap with a radial interval. The manufacturing method of the motor coil 20 includes a step (step S1) of integrally forming the coil and the cooling parts 23, 25 by laminated molding.

[0053] According to the above configuration, since the coil and the cooling parts 23, 25 are integrally formed by laminated molding, the motor coil 20 can be manufactured more easily and in a shorter time.

Explanation of Signs

[0054] 100 Motor 1 Rotor 2 Stator 3 Housing 20 Motor coil 22 Inner peripheral side coil 23 Cooling part 23a First part 23b Second part 24 Outer peripheral side coil 25 Cooling part 25a First part 25b Second part 26 Stator core 26a Yoke part 26b Teeth 26c Tip part 27 Fin part 28 ribs 29 connecting part A opening h ventilation hole O1 main axis O2 coil axis

Claims

1. A coil composed of a conductor wound around an axis, a plurality of cooling portions provided corresponding to different winding layers in the conductor, and comprising, each of the cooling portions, a first portion protruding radially outward from each of the winding layers, and a second portion extending from the tip of the first portion toward one side in the axial direction, the first portions are provided at intervals so as to be adjacent to each other in the axial direction, and the protruding length of the first portion located on the other side in the axial direction is larger than that of the first portion located on one side in the axial direction, the second portion is located more radially outward than the second portion corresponding to the first portion located on one side in the axial direction with respect to the second portion corresponding to the first portion located on the other side in the axial direction, the second portions corresponding to the first portions adjacent to each other in the axial direction are arranged so that at least a part thereof overlaps with a radial interval. A coil for an electric motor.

2. The coil for an electric motor according to claim 1, wherein the second portion corresponding to the first portion located on one side in the axial direction protrudes more toward one side in the axial direction.

3. The coil for an electric motor according to claim 1 or 2, further comprising an insulating layer formed on the surfaces of the coil and the cooling portions.

4. The coil for an electric motor according to any one of claims 1 to 3, wherein at least one of a ventilation hole penetrating the first portion in the radial direction and another ventilation hole penetrating the second portion in the circumferential direction is formed.

5. The coil for an electric motor according to any one of claims 1 to 4, wherein an opening is formed in the second portion, and a fin portion covering at least a part of the opening is provided.

6. The coil for an electric motor according to any one of claims 1 to 5, further comprising ribs connecting the second portions adjacent to each other.

7. The coil for an electric motor according to any one of claims 1 to 6, further comprising a connecting portion that covers the ends of the plurality of second portions on one side in the axial direction and is connected to a housing.

8. A rotor having a permanent magnet, a plurality of stator cores annularly connected so as to cover the rotor from the outer peripheral side, and the coil for an electric motor according to any one of claims 1 to 7, wherein the stator core is inserted into the inner peripheral side of the coil, and an electric motor comprising.

9. A coil composed of a conductor wound around an axis, a plurality of cooling portions provided corresponding to different winding layers in the conductor, comprising, each of the cooling parts has a first part protruding radially outward from each of the winding layers, and a second part extending from the tip of the first part toward one side in the axial direction, wherein the first parts are provided at intervals so as to be adjacent to each other in the axial direction, and the first part located on the other side in the axial direction has a larger protruding length than the first part located on one side in the axial direction, the second part is located more radially outward than the second part corresponding to the first part located on one side in the axial direction with respect to the second part corresponding to the first part located on the other side in the axial direction, a method for manufacturing an electric motor coil, wherein the second parts corresponding to the first parts adjacent to each other in the axial direction are arranged so that at least a part thereof overlaps with a radial interval, the method for manufacturing an electric motor coil including a step of integrally forming the coil and the cooling part by additive manufacturing.

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