Coil and rotary electric machine

Abstract

To provide a coil and a rotary electric machine that can be easily manufactured and have higher cooling performance.SOLUTION: A coil is attached to a stator core that covers a rotor rotatable around an axial line from the outer peripheral side, and includes a plurality of unit coils and a sealing body for sealing the plurality of unit coils on both sides in an axial direction. The unit coil has a pair of divided bodies that are divided radially with respect to a dividing surface, and at least one of the divided surfaces of the pair of divided bodies is provided with a recessed groove that forms a refrigerant flow path through which refrigerant flows. The stator core has an annular yoke and a plurality of teeth protruding from the inner peripheral surface of the yoke to the inner peripheral side, and the refrigerant flow path is formed only in the portion that overlaps with the teeth of the unit coil as viewed in a circumferential direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a coil and a rotating electric machine. [Background technology]

[0002] An electric motor, which is a type of rotating electric machine, has a rotor that can rotate around an axis and a cylindrical stator that covers the rotor core from the outer periphery. The rotor has a rotor core and a permanent magnet. The stator has a stator core and a plurality of coils attached to the stator core. By passing electricity through the coil, an electromagnetic force is generated between the permanent magnet and the rotor rotates around the axis. Here, when forming the coil, it is common to wind a copper wire or the like around the teeth of the stator core and mold it into a ring shape. However, when forming the coil, it is necessary to insulate the windings of the coil from each other in order to reduce copper loss. For this reason, in the technology according to the following Patent Document 1, it is said that a laser is irradiated to copper powder, which is the material of the conductor, and ceramic powder, which is the material of the insulating layer, to form the insulating coating and the coil by three-dimensional additive manufacturing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-039662 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when insulation is performed using ceramic as described above, although an insulating effect can be obtained, there is a problem in that the heat generated in the coil is difficult to dissipate, resulting in the coil temperature becoming excessively high.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a coil and a rotating electric machine that can be easily manufactured and have higher cooling performance. [Means for solving the problem]

[0006] In order to solve the above problems, the coil disclosed herein is a coil that is attached to a stator core that covers a rotor rotatable around an axis from the outer periphery, and is annular with a central axis in the radial direction relative to the axis, and includes a plurality of unit coils stacked in the radial direction, and a sealing body that seals the plurality of unit coils in the axial direction, wherein the unit coil has a pair of divided bodies that are divided in the radial direction based on a dividing surface, and a recessed groove is formed in the dividing surface of at least one of the pair of divided bodies to form a refrigerant flow path through which a refrigerant flows, and the stator core has an annular yoke centered on the axis, and a plurality of teeth that protrude inward from an inner surface of the yoke and are spaced apart in the circumferential direction, and the refrigerant flow path is formed only in the portion that overlaps with the teeth of the unit coils when viewed from the circumferential direction.

[0007] A rotating electric machine according to the present disclosure includes the rotor core, the stator core, and the above-mentioned coil attached to the stator core. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a coil and a rotating electric machine that can be easily manufactured and have higher cooling performance. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a configuration of an electric motor according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view showing a configuration of a coil according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 13 is a cross-sectional view showing a first modified example of a coil according to an embodiment of the present disclosure. [Diagram 5] FIG. 13 is a cross-sectional view showing a second modified example of a coil according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a coil 30 and an electric motor 1 (rotating electric machine) according to an embodiment of the present disclosure will be described with reference to FIGS.

[0011] (Configuration of electric motor 1) As shown in Fig. 1, the electric motor 1 includes a rotor 10 and a stator 20. The rotor 10 is columnar and extends along an axis X, and is supported rotatably about the axis X. Although not shown in detail, the rotor 10 has a permanent magnet. The stator 20 is cylindrical and covers the rotor 10 from the outer periphery. In other words, the stator 20 is cylindrical and centered on the axis X. The stator 20 includes a stator core 21 and a coil 30.

[0012] The stator core 21 has a yoke 22 and a plurality of teeth 23. The yoke 22 has an annular shape centered on the axis X. The plurality of teeth 23 are provided on the inner peripheral surface of the yoke 22. The teeth 23 protrude radially inward with respect to the axis X from the inner peripheral surface of the yoke 22. The plurality of yokes 22 are provided at intervals in the circumferential direction with respect to the axis X.

[0013] The teeth 23 have a teeth body 41 and a flange portion 42. The teeth body 41 extends in the radial direction. The circumferential dimension of the teeth body 41 is constant throughout its radial extension. A coil 30, which will be described later, is arranged around the teeth body 41. A flange portion 42 is provided at the tip end (i.e., the radially inner end) of the teeth body 41. The flange portion 42 protrudes from the tip of the teeth body 41 towards both sides in the circumferential direction. The flange portion 42 is provided to prevent the coil 30, which will be described later, from falling off the teeth body 41.

[0014] (Configuration of coil 30) The coil 30 is provided so as to be wound around the tooth main body 41. That is, the coil 30 has an annular shape with a central axis extending in the radial direction relative to the axis line X. As shown in Figs. 2 and 3, the coil 30 has a plurality of unit coils 31 (four in one example) stacked in the radial direction, and a sealing body 32.

[0015] The unit coil 31 is annular with its central axis in the radial direction. The unit coil 31 has a rectangular cross-sectional shape when viewed from the axis X direction. The unit coil 31 has a pair of divided bodies 34 divided in the radial direction with a dividing surface 33 as a reference. A groove 36 that forms a refrigerant flow path 35 through which a refrigerant flows is formed in the dividing surface 33 of at least one of the pair of divided bodies 34. In the example of FIG. 2, the groove 36 is formed in each dividing surface 33 of the pair of divided bodies 34. The groove 36 has a rectangular cross-sectional shape that is concave in the radial direction. Therefore, the unit coil 31 has a C-shaped cross-sectional shape when viewed from the axis X direction.

[0016] A refrigerant flow path 35 is formed inside the unit coil 31 by facing the grooves 36 of a pair of divided bodies 34. A refrigerant such as oil or fat flows through this refrigerant flow path 35. The flow path cross-sectional area of ​​the refrigerant flow path 35 as viewed from the axial direction X is constant throughout the entire area in the axial direction X in each unit coil 31. As shown by the dashed lines in FIG. 2, a single coil 30 is formed by electrically connecting a plurality of unit coils 31 to each other. In the example of FIG. 2, the circumferential dimensions of the unit coils 31 are the same.

[0017] As shown in FIG. 3, the refrigerant flow paths 35 in each unit coil 31 communicate with each other via through flow paths 37. The through flow paths 37 extend in the radial direction. One through flow path 37 is provided at each end in the direction of the axis X. One through flow path 37 is connected to a refrigerant supply source. The refrigerant supplied from the through flow path 37 branches and flows into each refrigerant flow path 35. At this time, heat is exchanged between each unit coil 31 and the refrigerant, and the unit coil 31 is cooled. The other through flow path 37 is provided to discharge the refrigerant that has passed through the refrigerant flow path 35 to the outside.

[0018] 3, among the multiple refrigerant flow paths 35, the more radially inward the refrigerant flow paths 35 are, the larger their flow path cross-sectional area is when viewed from the axis X. This is because the more radially inward the refrigerant flow paths 35 are from the inlet (the radially outer end) of the through flow paths 37, the more likely pressure loss is to occur. Furthermore, all of the refrigerant flow paths 35 are formed only in the portions that overlap with the teeth 23 of the unit coil 31 when viewed from the circumferential direction. In other words, the refrigerant flow paths 35 are not formed at the end of the coil 30 in the axis X direction (i.e., the coil 30 end). The above-mentioned through flow paths 37 are formed at the coil 30 end.

[0019] The unit coils 31 are sealed in the axial direction X by a seal 32. The seal 32 is provided to seal the opening of the refrigerant flow path 35 and to integrally connect the unit coils 31. A resin is preferably used as the seal 32. Both ends of the unit coils 31 in the axial direction X may be sealed by the seal 32.

[0020] In obtaining the coil 30 as described above, three-dimensional additive manufacturing is preferably used. That is, a laser is irradiated onto metal powder to melt and solidify the powder, thereby obtaining a desired shape. In forming the coil 30 as described above, a method of repeating additive manufacturing for each unit coil 31 is considered. After the element of the coil 30 made of metal is completed, an insulating coating is formed on the surface of the element. Thereafter, the element is compressed in the direction of the axis X, and then the seal 32 is formed, thereby completing the coil 30.

[0021] (Action and effect) Next, the operation of the electric motor 1 will be described. To drive the electric motor 1, first, a current is supplied to each coil 30. Then, an electromagnetic force is generated between the coils 30 and the permanent magnets of the rotor 10. This electromagnetic force provides a rotational force to the rotor 10. This causes the rotor 10 to rotate around the axis X. The rotational force of the rotor 10 is extracted from the shaft end and is used for various purposes.

[0022] Here, in forming the coil 30, it is common to wind a copper wire or the like around the teeth 23 of the stator core 21 to form a ring shape. However, in forming the coil 30, it is necessary to insulate the windings of the coil 30 from each other in order to reduce copper loss. For this reason, in the past, the insulating coating and the coil 30 were sometimes formed by three-dimensional additive manufacturing by irradiating a laser onto copper powder, which is the material for the conductor, and ceramic powder, which is the material for the insulating layer.

[0023] However, when insulating with ceramic as described above, although an insulating effect can be obtained, there is a problem that the heat generated in the coil 30 is difficult to dissipate, and as a result, the temperature of the coil 30 becomes excessively high. Therefore, the above-mentioned configurations are adopted in this embodiment.

[0024] According to the above configuration, the refrigerant flow passage 35 is formed by the recessed groove 36 formed in the divided body 34. The coil 30 can be efficiently cooled by flowing the refrigerant through this refrigerant flow passage 35. In addition, since the refrigerant flow passage 35 is formed in each unit coil 31, the cooling effect in the entire coil 30 can be uniformed. This makes it possible to suppress local heat generation in the coil 30. Furthermore, since the refrigerant flow passage 35 is formed only in the region where heat generation is likely to increase, that is, the region overlapping with the teeth 23 when viewed from the circumferential direction, rather than in the end of the coil 30, heat generation in the coil 30 can be more effectively suppressed. In addition, eddy current loss can be effectively reduced while minimizing deterioration of DC copper loss. On the other hand, if the refrigerant flow passage 35 is also formed in the end of the coil 30, the heat absorption capacity of the refrigerant is wasted, and there is a possibility that the desired heat absorption performance cannot be obtained in the most important region where heat generation is likely to increase. There is also a possibility that eddy current loss increases. According to the above configuration, such a possibility is reduced, and the entire coil 30 can be efficiently and stably cooled. As a result, it is possible to further improve the efficiency of the electric motor 1. In addition, when performing three-dimensional additive manufacturing to manufacture the coil 30, by dividing the unit coil 31 into a pair of divided bodies 34, the hollow structure is eliminated, which makes it possible to reduce supports, eliminates the need to consider powder removal, and makes the manufacturing process easier.

[0025] Furthermore, with the above configuration, the refrigerant can be supplied to the refrigerant flow passage 35 through one through passage 37, and the refrigerant used to cool the coil 30 in the refrigerant flow passage 35 can be discharged to the outside through the other through passage 37. This allows the refrigerant to continue to flow smoothly between the refrigerant supply source and the coil 30. As a result, the efficiency of the electric motor 1 can be further improved. A pump is preferably used to pump the refrigerant.

[0026] Here, the radially inner refrigerant flow passage 35 is far from the inlet of the through passage 37, so the pressure loss of the refrigerant tends to be large. According to the above configuration, the more radially inner the refrigerant flow passage 35 is where the pressure loss of the refrigerant tends to be, the larger the flow passage cross-sectional area as viewed from the direction of the axis X becomes. This reduces the static pressure of the refrigerant in the radially inner flow passage, making it possible to reduce the pressure loss. Therefore, the refrigerant can continue to flow more smoothly to each unit coil 31 regardless of the radial position. As a result, it becomes possible to further improve the efficiency of the electric motor 1.

[0027] Furthermore, according to the above configuration, the refrigerant flows through the inside of the coil 30 of the electric motor 1, so that the coil 30 can be constantly and efficiently cooled. This makes it possible to provide a highly efficient electric motor 1 with a small amount of heat generation.

[0028] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0029] For example, in the above embodiment, an example has been described in which the divided bodies 34 of each unit coil 31 are each formed with a groove 36. However, it is also possible to adopt the configuration shown in FIG. 4 as a first modified example. In the example shown in the figure, the groove 36 is formed in only one of the pair of divided bodies 34. With such a configuration, it is possible to obtain the same effect as that described above. In addition, since there is no need to accurately fit the grooves 36 together, it is also possible to simplify the manufacturing process and reduce manufacturing costs.

[0030] It is also possible to adopt the configuration shown in Fig. 5 as a second modified example. In the example shown in Fig. 5, a groove 36 is formed on each side of one divided body 34. In other words, the divided body 34 has an H-shaped cross section. By combining these divided bodies 34 together, the grooves 36 form a refrigerant flow path 35. With this configuration, it is possible to obtain the same effects as those described above.

[0031] In addition, the number of coils 30 and the number of teeth 23 described in the above embodiment are merely examples, and can be increased or decreased as appropriate according to the design and specifications. In any case, the same effects as those described above can be obtained.

[0032] Furthermore, the number of unit coils 31 is also an example, and can be changed as appropriate according to the design and specifications. In any case, the same effects as those described above can be obtained.

[0033] As described in the above embodiment, it is preferable to use three-dimensional additive manufacturing to obtain the coil 30. However, other methods such as casting may be used as long as the manufacturing is physically possible.

[0034] In the above embodiment, an example has been described in which the cross-sectional area of ​​the refrigerant flow passage 35 increases toward the radially inner side. However, the configuration of the refrigerant flow passage 35 is not limited to this, and the cross-sectional area of ​​the refrigerant flow passage 35 may be constant throughout the entire radial direction. When manufacturing efficiency is important, it is advantageous to adopt such a configuration.

[0035] Furthermore, in the above embodiment, an example has been described in which the coil 30 is used in the electric motor 1. However, the application of the coil 30 is not limited to the electric motor 1, and the coil 30 can also be used in a generator, which is another type of rotating electric machine. In this case, by applying a rotational force to the rotor 10, an induced current is generated in the coil 30, and AC power can be obtained.

[0036] <Additional Notes> The coil 30 and the rotating electric machine described in each embodiment can be understood, for example, as follows.

[0037] (1) A coil 30 according to a first aspect is a coil 30 attached to a stator core 21 that covers an outer periphery of a rotor 10 that is rotatable about an axis X, and includes a plurality of annular unit coils 31 having a central axis in a radial direction relative to the axis X, and a sealing body 32 that seals the plurality of unit coils 31 in the direction of the axis X. The unit coil 31 has a pair of divided bodies 34 divided in the radial direction based on a dividing surface 33, and a groove 36 that forms a refrigerant flow path 35 through which a refrigerant flows is formed in the dividing surface 33 of at least one of the pair of divided bodies 34. The stator core 21 has an annular yoke 22 centered on the axis X, and a plurality of teeth 23 that protrude inward from an inner circumferential surface of the yoke 22 and are spaced apart in the circumferential direction, and the refrigerant flow path 35 is formed only in a portion that overlaps with the teeth 23 when viewed in the circumferential direction.

[0038] According to the above configuration, the refrigerant flow paths 35 are formed by the grooves 36 formed in the division body 34. The coil 30 can be efficiently cooled by flowing a refrigerant through the refrigerant flow paths 35. Furthermore, since the refrigerant flow paths 35 are formed in each unit coil 31, the cooling effect can be made uniform throughout the coil 30. This makes it possible to suppress localized heat generation in the coil 30. Furthermore, the refrigerant flow paths 35 are formed only in areas where heat generation is likely to increase, that is, areas that overlap with the teeth 23 when viewed from the circumferential direction, rather than at the ends of the coil 30, so that heat generation in the coil 30 can be suppressed even more effectively.

[0039] (2) The coil 30 according to the second aspect is the coil 30 of (1), and has a through flow passage 37 that radially penetrates both ends of the plurality of unit coils 31 in the direction of the axis X and is connected to each of the refrigerant flow passages 35.

[0040] According to the above configuration, the refrigerant can be supplied to the refrigerant flow passage 35 through one through passage 37, and the refrigerant used to cool the coil 30 in the refrigerant flow passage 35 can be discharged to the outside through the other through passage 37. This makes it possible to keep the refrigerant circulating smoothly.

[0041] (3) The coil 30 according to a third aspect is the coil 30 of (2), wherein the refrigerant flow paths 35 formed in the unit coils 31 on the radially inner side have a larger flow path cross-sectional area as viewed from the direction of the axis X.

[0042] Here, the radially inner refrigerant flow passage 35 is far from the inlet of the through passage 37, so the pressure loss of the refrigerant tends to be large. According to the above configuration, the flow passage cross-sectional area as viewed from the axis X direction becomes larger as the refrigerant flow passage 35 becomes more radially inner where the pressure loss of the refrigerant tends to be large. This reduces the static pressure of the refrigerant in the radially inner flow passage, making it possible to reduce the pressure loss. Therefore, the refrigerant can continue to flow more smoothly.

[0043] (4) A rotating electric machine according to a fourth aspect includes the rotor 10, the stator core 21, and the coil 30 according to any one of claims 1 to 3 attached to the stator core 21.

[0044] According to the above-described configuration, since the coolant flows through the inside of the coil 30, it is possible to constantly and efficiently cool the coil 30. As a result, it is possible to provide a highly efficient rotating electric machine with a small amount of heat generation. [Explanation of symbols]

[0045] REFERENCE SIGNS LIST 1...electric motor 10...rotor 20...stator 21...stator core 22...yoke 23...teeth 30...coil 31...unit coil 32...sealing body 33...dividing surface 34...dividing body 35...coolant passage 36...groove 37...through passage 41...teeth body 42...flange X...axis

Claims

1. A coil attached to a stator core that covers an outer periphery of a rotor that can rotate around an axis, a plurality of unit coils each having an annular shape with a central axis extending in a radial direction with respect to the axis line and stacked in the radial direction; a seal that seals the plurality of unit coils in the axial direction; Equipped with The unit coil has a pair of divided bodies that are divided in a radial direction based on a dividing surface, and a groove that forms a refrigerant flow path through which a refrigerant flows is formed on the dividing surface of at least one of the pair of divided bodies, The stator core is An annular yoke centered on the axis; a plurality of teeth protruding from an inner peripheral surface of the yoke toward an inner peripheral side and spaced apart in a circumferential direction; having The coolant flow path is formed only in a portion of the unit coil that overlaps with the teeth when viewed in the circumferential direction.

2. The coil according to claim 1 , further comprising through-flow passages that extend radially through both ends of the unit coils in the axial direction and communicate with the respective refrigerant flow passages.

3. The coil according to claim 2 , wherein the refrigerant flow paths have a larger flow path cross-sectional area as viewed from the axial direction toward the radially inner side of the unit coil.

4. The rotor; The stator core; The coil according to any one of claims 1 to 3 attached to the stator core; A rotating electric machine comprising:

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