Motor cooling structure

Abstract

To ensure better cooling performance of the rotor. [Solution] The motor cooling structure comprises a rotor having a rotor core and a plurality of permanent magnets embedded in the rotor core. Furthermore, the motor cooling structure comprises a plurality of oil passages formed at intervals in the circumferential direction of the rotor core and penetrating the rotor core in the axial direction, and cylindrical guide portions provided on one end or both ends in the axial direction of the rotor core, which guide the cooling oil supplied from the radially inward direction to the plurality of oil passages.

Description

Technical Field

[0001] The present disclosure relates to a cooling structure for a motor.

Background Art

[0002] Conventionally, there has been proposed a cooling structure for a motor including a stator around which a coil is wound, a rotor having a plurality of laminated steel plates fixed to a shaft and a plurality of magnets incorporated in the laminated steel plates, a plurality of cooling channels formed through the laminated steel plates in the axial direction in the vicinity of the magnets, a supply hole for supplying a cooling liquid in an oil hole at the center of the shaft to the outer peripheral surface of the shaft, and a plurality of receivers respectively attached at intervals in the circumferential direction of the rotor on one side surface in the axial direction of the rotor (see, for example, Patent Document 1). Here, each of the plurality of receivers communicates with a corresponding cooling channel, has an outer diameter side covered, and an inner diameter side opened so as to receive a cooling medium scattered from the supply hole. In this cooling structure of the motor, the cooling liquid in the oil hole of the shaft is scattered from the supply hole by the centrifugal force due to the rotation of the rotor, received by the receiver, and supplied to the cooling channel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described cooling structure of the motor, if the relationship between the position of the receiver and the position of the supply hole of the shaft is not appropriate, the cooling liquid may not be sufficiently received by the receiver, and the cooling performance of the rotor may not be sufficiently obtained.

[0005] The main object of the cooling structure of the motor of the present disclosure is to ensure more cooling performance of the rotor.

Means for Solving the Problems

[0006] The motor cooling structure of this disclosure employs the following means to achieve the main objective described above.

[0007] The motor cooling structure of this disclosure is A cooling structure for a motor comprising a rotor having a rotor core and a plurality of permanent magnets embedded in the rotor core, Multiple oil passages are formed at intervals in the circumferential direction of the rotor core, and each passage penetrates the rotor core in the axial direction. A cylindrical guide portion is provided on one end or both ends of the rotor core in the axial direction, which guides the cooling oil supplied from the radially inward side into the plurality of oil passages, The gist of it is that it is equipped with the following features.

[0008] The motor cooling structure of this disclosure includes a plurality of oil passages and a guide portion. The plurality of oil passages are formed to be spaced apart in the circumferential direction of the rotor core and to penetrate the rotor core in the axial direction. The guide portion is provided on one end or both ends in the axial direction of the rotor core, is cylindrical in shape, and guides the cooling oil supplied from the radially inner side to the plurality of oil passages. Because the guide portion is cylindrical, it can receive the cooling oil from the radially inner side more effectively and supply it to the plurality of oil passages formed in the rotor core. As a result, the rotor can be cooled more effectively. That is, the cooling performance of the rotor can be better ensured.

[0009] In the motor cooling structure of the present disclosure, the guide portion may include a first wall portion that is cylindrical and extends along the axial direction, and a second wall portion that extends radially inward from the end of the first wall portion that is farther from the rotor core, or it may include a wall portion that is cylindrical and whose inner diameter decreases as it moves away from the rotor core along the axial direction.

[0010] In the motor cooling structure of this disclosure, a plurality of guide portions with different inner diameters may be provided.

[0011] In the motor cooling structure of this disclosure, the plurality of oil passages may include holes in which the permanent magnets are arranged. This allows for better cooling of the permanent magnets. [Brief explanation of the drawing]

[0012] [Figure 1] This is a front view of the motor unit according to the embodiment of the disclosure. [Figure 2] This is a cross-sectional view AA in Figure 1. [Figure 3] This is a front view of the motor unit shown in Figure 1, with the guide section removed. [Figure 4] This is a cross-sectional view of a modified motor unit. [Figure 5] This is a cross-sectional view of a modified motor unit. [Figure 6] This is a cross-sectional view of a modified motor unit. [Modes for carrying out the invention]

[0013] Embodiments for implementing this disclosure will be described with reference to the drawings. Figure 1 is a front view of the motor unit 10 according to an embodiment of this disclosure. Figure 2 is a cross-sectional view of AA in Figure 1. Figure 3 is a front view of the motor unit 10 in Figure 1 with the guide portion 30 removed.

[0014] The motor unit 10 of this embodiment is installed in electric vehicles, hybrid vehicles, fuel cell vehicles, etc. This motor unit 10 comprises a motor 12 configured as a synchronous generator motor and a guide section 30 used to guide cooling oil that cools the motor 12. The motor 12 comprises a rotor 20 fixed to a rotor shaft 14 and a stator (not shown) that houses the rotor 20 in the center.

[0015] The rotor 20 includes a rotor core 22 and a plurality of permanent magnets 27, 28. The rotor core 22 is formed by laminating a plurality of electromagnetic steel plates each formed in a cylindrical shape, and is configured in a cylindrical shape as a whole. The inner circumference of the rotor core 22 is fixed to a rotor shaft 14 inserted therein. The rotor core 22 includes a plurality of through holes 23, a plurality of through holes 24, and a plurality of through holes 26. End plates may be disposed on both sides of the rotor core 22 in the axial direction. In this case, the end plates are formed in a shape in which the positions of the plurality of through holes 23, the plurality of through holes 24, the plurality of through holes 26, etc. are aligned with the rotor core 22.

[0016] The plurality of through holes 23 are each formed from the central portion to the outer peripheral portion in the radial direction of the rotor core 22 at a predetermined interval (45° interval in the embodiment) in pairs, so as to penetrate the rotor core 22 in the axial direction. Each pair of through holes 23 has a first portion 23a and a second portion 23b, respectively. The two first portions 23a forming a pair each extend substantially linearly along the circumferential direction of the rotor core 22. The two second portions 23b forming a pair each extend substantially linearly from the end portions on the separated sides of the two first portions 23a forming a pair to the outer peripheral portion of the rotor core 22 while being separated from each other.

[0017] The plurality of through holes 24 are each formed on the outer peripheral portion of the rotor core 22 at a predetermined interval (45° interval in the embodiment) in pairs, so as to penetrate the rotor core 22 in the axial direction. Each pair of through holes 24 extends substantially linearly along the circumferential direction of the rotor core 22 on the outer peripheral side of the rotor core 22 and between the two second portions 23b, relative to the two first portions 23a forming a pair.

[0018] The plurality of through holes 26 are each formed on the inner peripheral portion of the rotor core 22 at an interval (45° interval in the embodiment) in the circumferential direction of the rotor core, so as to penetrate the rotor core 22 in the axial direction.

[0019] The plurality of permanent magnets 27 and 28 are each formed in a substantially rectangular parallelepiped shape. Two of the plurality of permanent magnets 27 are inserted and fixed into each of the plurality of through holes 23. One of the plurality of permanent magnets 28 is inserted and fixed into each of the plurality of through holes 24.

[0020] The guide portion 30 is made of, for example, resin and includes a first wall portion 31 and a second wall portion 32. The first wall portion 31 has a cylindrical shape with an inner diameter that is the same as or slightly larger than the outermost diameter of the plurality of through holes 26 of the rotor core 22 (the distance from the axis of the rotor core 22 to the farthest position of the wall surface on the outer diameter side of the through hole 26), and extends along the axial direction of the rotor core 22. The end portion of the first wall portion 31 on the rotor core 22 side is fixed to the rotor 20 (for example, an end plate) by welding, caulking, or the like. The second wall portion 32 extends radially inward from the end portion of the first wall portion 31 on the side far from the rotor core 22. The guide portion 30 temporarily stores the cooling oil supplied from the oil passage 80 provided in a case or the like that houses the motor unit 10, and guides it to the plurality of through holes 26.

[0021] In the embodiment, the cooling oil from the oil passage 80 is discharged along the axial direction of the rotor core 22 and hits the rotor shaft 14 and the rotor 20, and moves radially outward due to their rotation. It is received by the guide portion 30 and guided to the plurality of through holes 26, and flows through the plurality of through holes 26 (see the thick arrows in FIG. 2). Thereby, the rotor 20 is cooled. Although the relative positions of the oil passage 80 and the plurality of through holes 26 change sequentially as the rotor 20 rotates, since the guide portion 30 includes the cylindrical first wall portion 31, the cooling oil from the oil passage 80 can be sufficiently received by the guide portion 30 and guided to the plurality of through holes 26. Further, since the guide portion 30 includes the second wall portion 32 that extends radially inward from the end portion of the first wall portion 31 on the side far from the rotor core 22, it is possible to suppress the cooling oil received by the first wall portion 31 from moving to the outside of the guide portion 30 (the side away from the rotor core 22). As a result, the cooling oil from the oil passage 80 can be sufficiently supplied by the plurality of through holes 26, and the rotor 20 can be cooled more sufficiently. That is, the cooling performance of the rotor 20 can be more ensured.

[0022] The motor unit 10 (cooling structure for the motor 12) of the embodiment described above includes a guide portion 30 having a cylindrical first wall portion 31 and a second wall portion 32 extending radially inward from the end of the first wall portion 31 furthest from the rotor core 22. This allows the cooling oil from the oil passage 80 to be more adequately received by the guide portion 30 and supplied sufficiently through the multiple through holes 26, thereby allowing the rotor 20 to be cooled more effectively.

[0023] In the embodiment described above, the motor unit 10 is configured such that cooling oil is supplied to the guide section 30 from an oil passage 80 provided in the case, but it is not limited to this. For example, as shown in the modified motor unit 10B of Figure 4, cooling oil that has flowed through an oil passage provided in the rotor shaft 14 and a plurality of oil passages 80B formed at intervals in the circumferential direction of the rotor shaft 14 and communicating the inside and outside of the rotor shaft 14 may be supplied to the guide section 30.

[0024] In the embodiment described above, the motor unit 10 is provided with a guide portion 30 for guiding cooling oil through a plurality of through holes 26, but it is not limited to this. For example, instead, a guide portion may be provided for guiding cooling oil through a plurality of through holes 23 (the gap between the through holes 23 and the permanent magnets 27). This would allow for better cooling of the plurality of permanent magnets 27. Alternatively, a guide portion may be provided for guiding cooling oil through a plurality of through holes 24 (the gap between the through holes 24 and the permanent magnets 28). This would allow for better cooling of the plurality of permanent magnets 28.

[0025] In the embodiments described above, the motor unit 10 shown in Figures 1 to 3 was explained, but the invention is not limited thereto. For example, as shown in the modified motor unit 10C in Figure 5, a guide section 40 may be provided in addition to the same hardware configuration as the motor unit 10. Also, as shown in the modified motor unit 10D in Figure 6, a guide section 50 may be provided in addition to the same hardware configuration as the motor unit 10. These will be explained in order below.

[0026] A modified motor unit 10C of Figure 5 will be described. The guide section 40 is positioned on the same side as the guide section 30 relative to the rotor core 22. The guide section 40, like the guide section 30, is made of resin, for example, and comprises a first wall section 41 and a second wall section 42. The first wall section 41 is cylindrical in shape, having an inner diameter that is the same as or slightly larger than the outermost diameter of the multiple through holes 24 of the rotor core 22 (the distance from the axis of the rotor core 22 to the furthest point on the outer diameter side of the wall surface of the through hole 24), and extends along the axial direction of the rotor core 22. The end of the first wall section 41 on the rotor core 22 side is fixed to the rotor 20 (for example, an end plate) by welding, riveting, etc. The second wall section 42 extends radially inward from the end of the first wall section 41 on the side furthest from the rotor core 22. The guide section 40 temporarily stores cooling oil from the oil passage 80C provided in the case that houses the motor unit 10 and guides it to the multiple through holes 24. In this modified example, in addition to the cooling oil from the oil passage 80 being received by the guide section 30 and guided through the multiple through holes 26, the cooling oil from the oil passage 80C is received by the guide section 40 and guided through the multiple through holes 24 (see the thick arrows in Figure 6). As a result, the multiple permanent magnets 28 can be cooled more effectively than in the embodiment described above.

[0027] In the modified motor unit 10C, a guide portion 30 for guiding cooling oil into a plurality of through holes 26 and a guide portion 40 for guiding cooling oil into a plurality of through holes 24 are provided. However, the motor unit is not limited to this, and it is sufficient to have at least two of the following on the same side of the rotor core 22: a guide portion for guiding cooling oil into a plurality of through holes 26, a guide portion for guiding cooling oil into a plurality of through holes 23, and a guide portion for guiding cooling oil into a plurality of through holes 24.

[0028] A modified motor unit 10D of Figure 6 will be described. The guide section 50 is positioned on the opposite side of the rotor core 22 from the guide section 30. The guide section 50, like the guide section 30, is made of resin, for example, and comprises a first wall section 51 and a second wall section 52. The first wall section 51 is cylindrical in shape and has an inner diameter that is the same as or slightly larger than the outermost diameter of each first section 23a of the plurality of through holes 23 of the rotor core 22 (the distance from the axis of the rotor core 22 to the furthest point on the outer diameter side of the wall surface of the first section 23a), and extends along the axial direction of the rotor core 22. The end of the first wall section 51 on the rotor core 22 side is fixed to the rotor 20 (for example, an end plate) by welding, riveting, etc. The second wall section 52 extends radially inward from the end of the first wall section 51 that is furthest from the rotor core 22. The guide section 50 temporarily stores cooling oil from the oil passage 80D, which is provided in the case housing the motor unit 10, and guides it to the multiple through holes 23 (first section 23a). In this modified example, in addition to the cooling oil from the oil passage 80 being received by the guide section 30 and guided to the multiple through holes 26 and flowing through the multiple through holes 26, the cooling oil from the oil passage 80D is also received by the guide section 50 and guided to the multiple through holes 23 and flowing through the multiple through holes 23 (see the thick arrows in Figure 5). As a result, the multiple permanent magnets 27 can be cooled more effectively than in the embodiment described above.

[0029] In the modified motor unit 10D, a guide portion 50 is provided on the side of the rotor core 22 opposite to the guide portion 30 for guiding cooling oil into a plurality of through holes 23 (the gap between the through holes 23 and the permanent magnets 27), but the motor unit is not limited to this. For example, a guide portion may be provided on the side of the rotor core 22 opposite to the guide portion 30 for guiding cooling oil into a plurality of through holes 24 (the gap between the through holes 24 and the permanent magnets 28). This would allow for better cooling of the plurality of permanent magnets 28.

[0030] In the embodiment described above, the guide portion 30 of the motor unit 10 has a cylindrical first wall portion 31 and a second wall portion 32 extending radially inward from the end of the first wall portion 31 furthest from the rotor core 22, but is not limited to this. For example, the guide portion may have a cylindrical wall portion whose inner diameter decreases as it moves away from the rotor core 22 along the axial direction of the rotor core 22. Even in this case, the movement of the cooling oil received by the guide portion toward the side away from the rotor core 22 can be suppressed to some extent. The guide portions 40 and 50 of the motor units 10C and 10D can be similarly replaced.

[0031] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on the main elements of the embodiment and the means for solving the problem will be explained. In the embodiment, the rotor core 22 corresponds to the "rotor core", the multiple permanent magnets 27, 28 correspond to the "multiple permanent magnets", the rotor 20 corresponds to the "rotor", and the motor 12 corresponds to the "motor". At least a portion of the multiple through holes 26, multiple through holes 23, and multiple through holes 24 corresponds to the "multiple oil passages", and at least a portion of the guide parts 30, 40, 50 corresponds to the "guide parts".

[0032] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0033] Although the embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0034] This disclosure can be used in industries such as motor manufacturing. [Explanation of symbols]

[0035] 10, 10B, 10D, 10C Motor unit, 12 Motor, 14 Rotor shaft, 20 Rotor, 22 Rotor core, 23, 24, 26 Through hole, 23a First part, 23b Second part, 27, 28 Permanent magnet, 30, 40, 50 Guide part, 31, 41, 51 First wall part, 32, 42, 52 Second wall part, 80, 80B, 80C, 80D Oil passage.

Claims

1. A cooling structure for a motor comprising a rotor having a rotor core and a plurality of permanent magnets embedded in the rotor core, Multiple oil passages are formed at intervals in the circumferential direction of the rotor core, and each passage penetrates the rotor core in the axial direction. A cylindrical guide portion is provided on one end or both ends of the rotor core in the axial direction, and guides the cooling oil supplied from the radially inward side into the plurality of oil passages, A motor cooling structure equipped with [a specific feature].

2. A motor cooling structure according to claim 1, The guide portion comprises a cylindrical first wall portion extending along the axial direction and a second wall portion extending radially inward from the end of the first wall portion furthest from the rotor core, or a cylindrical wall portion whose inner diameter decreases as it moves away from the rotor core along the axial direction. Motor cooling structure.

3. A motor cooling structure according to claim 1 or 2, The device comprises a plurality of guide portions with different inner diameters, Motor cooling structure.

4. A motor cooling structure according to claim 1 or 2, The plurality of oil passages include holes in which the permanent magnets are arranged. Motor cooling structure.

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