Rotor

Abstract

A rotor is provided with: a rotor shaft; and a rotor core attached to the rotor shaft and configured to be rotatable together with the rotor shaft. The rotor core has a plurality of holes penetrating from a surface thereof to the rotor shaft.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a rotor. In particular, it relates to a rotor for a motor. Background Technology

[0002] Japanese Patent Application Publication No. 2001-190047 discloses a rotor in which a cooling oil passage is formed in the yoke along the axial direction. In the rotor of Japanese Patent Application Publication No. 2001-190047, the rotor is cooled by supplying lubricating oil to the cooling oil passage via a supply passage by an oil pump. Summary of the Invention

[0003] In the rotor described in Japanese Patent Application Publication No. 2001-190047, an oil pump is used to supply lubricating oil to the cooling oil circuit, thus increasing the number of motor components. This specification provides a technique for effectively cooling the rotor with a simple structure.

[0004] The technology disclosed in this specification is specifically embodied in a rotor used in a motor. The rotor includes: a rotor shaft; and...

[0005] A rotor core, which is mounted on the rotor shaft and configured to rotate together with the rotor shaft.

[0006] The rotor core has a plurality of holes extending from its surface to the rotor shaft.

[0007] When the rotor rotates, the circumferential speed on the inner diameter side of the rotor is faster than that on the outer diameter side. In the rotor described above, the rotor core has multiple holes extending from its surface to the rotor shaft. Therefore, inside each hole, due to the difference in circumferential speed between the inner and outer diameter sides of the rotor, the air pressure on the inner diameter side is lower than that on the outer diameter side. Through this pressure difference, when the rotor rotates, air flows into the interior of each hole, being drawn from the outer diameter side to the inner diameter side. This allows for air cooling of the rotor core's interior. Therefore, in the above structure, the rotor can be effectively cooled with a simple design.

[0008] In one embodiment of this technology, the plurality of holes are inclined radially relative to the rotor when viewed along the axial direction of the rotor. In this configuration, for example, by rotating the rotor so that the inclination direction of each hole is aligned with the rotation direction of the rotor, air can be efficiently allowed to flow into the interior of each hole.

[0009] In one embodiment of this technology, each of the plurality of holes may be located at a different position in the circumferential direction of the rotor. In this configuration, the holes can be arranged in a balanced manner along the circumferential direction of the rotor, thereby enabling uniform cooling efficiency of the entire rotor.

[0010] In one embodiment of this technology, the positions of adjacent holes in the circumferential direction of the rotor in the axial direction of the rotor may be different. In this structure, the holes can be arranged in a balanced manner along the axial direction of the rotor, thus enabling the overall cooling efficiency of the rotor to be uniform.

[0011] The technology disclosed in this specification is specifically embodied in another rotor used in the motor.

[0012] The rotor has: Rotor shaft; and A rotor core, which is mounted on the rotor shaft and configured to rotate together with the rotor shaft.

[0013] The surface of the rotor core is provided with a groove that extends spirally from one end of the rotor's axial direction to the other end. The groove is configured such that the cross-sectional area decreases from one end to the other end.

[0014] In the rotor described above, when the rotor rotates, air flows not only over the surface of the rotor core but also along the interior of each slot. Because the multiple slots increase the surface area of ​​the rotor core, effective air cooling of the rotor is achieved. Furthermore, each slot on the surface of the rotor core is configured to extend in a spiral shape, and its cross-sectional area decreases from one end of the rotor's axial direction to the other. The air velocity flowing within the slots increases as the slot's cross-sectional area decreases. Therefore, for example, by rotating the rotor so that the direction of rotation of the slots from one end to the other is opposite to the rotor's rotation direction, the air gradually accelerates within the slots. Thus, effective air cooling of the rotor is achieved. Therefore, in the above structure, the rotor can be effectively cooled with a simple design. Attached Figure Description

[0015] Hereinafter, with reference to the accompanying drawings, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described, in which the same reference numerals denote the same elements, and wherein: Figure 1 This is a cross-sectional view of a motor 2 having the rotor 10 described in Embodiment 1.

[0016] Figure 2 This is a perspective view of the rotor 10 involved in Embodiment 1.

[0017] Figure 3 This is a cross-sectional view of the rotor 10 involved in Embodiment 1.

[0018] Figure 4 The rotor 100 involved in Embodiment 2 is related to... Figure 3 The corresponding sectional view.

[0019] Figure 5This is a perspective view of the rotor 200 involved in Embodiment 3. Detailed Implementation

[0020] Example 1

[0021] Referring to the accompanying drawings, the rotor 10 and the motor 2 equipped with the rotor 10 of Embodiment 1 will be described. While not particularly limited, the motor 2 can be used as a prime mover to drive the wheels in an electric vehicle. Electric vehicles include, for example, battery electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and fuel cell electric vehicles.

[0022] like Figure 1 As shown, the motor 2 includes a stator 4 and a rotor 10. The stator 4 includes a stator core 6 and a coil 8. The stator core 6 is constructed using a soft magnetic material. Although it is an example, the stator core 6 in this embodiment has a structure of stacked multiple electromagnetic steel plates (not shown). The stator core 6 has a cylindrical shape extending axially (in the direction of the rotation axis A). The stator core 6 is disposed on the outer periphery of the rotor core 20 at predetermined intervals from the rotor core 20. The coil 8 is made of a wire with an insulating film and is wound around the stator core 6. The coil 8 has coil ends 8a and 8b that protrude outward from each end face of the stator core 6 in the axial direction.

[0023] The rotor 10 is located inside the stator 4. The rotor 10 is spaced apart from the stator 4. The rotor 10 includes a rotor shaft 12 and a rotor core 20. The rotor shaft 12 is rotatably supported about the rotation axis A by bearings mounted on the housing (not shown) of the motor 2.

[0024] The rotor core 20 is fixed to the rotor shaft 12 and is configured to rotate together with the rotor shaft 12 about the rotation axis A. The rotor core 20 is constructed using a soft magnetic material. Although this is just one example, the rotor core 20 of this embodiment has a structure in which multiple electromagnetic steel plates are stacked axially. Multiple permanent magnets (not shown) are arranged on the rotor core 20 along the circumference of the rotor 10.

[0025] like Figure 2 and Figure 3 As shown, the rotor core 20 has multiple holes 30. (As indicated...) Figure 3 As shown, each hole 30 extends from the surface 20a of the rotor core 20 to the rotor shaft 12. The number of holes 30 is not particularly limited, but in this embodiment, eight holes 30 are provided on the rotor core 20. Each hole 30 extends linearly along the radial direction of the rotor 10. Each hole 30 is located at different positions along the circumference of the rotor 10. The holes 30 are arranged at equal intervals along this circumference. Furthermore, as... Figure 2As shown, the two adjacent holes 30 in the circumferential direction of the rotor 10 are positioned differently in the axial direction. In this embodiment, each hole 30 is arranged in a spiral pattern along this axial direction. The cross-sectional shape of each hole 30 is not particularly limited; for example, it can be rectangular, circular, etc. Furthermore, each hole 30 can be formed, for example, by stamping after laminating electromagnetic steel sheets. And, from... Figure 2 , Figure 3 And then Figures 4 to 5 Note that the diagram of stator 4 has been omitted.

[0026] Next, the method of cooling the rotor 10 will be explained. When the rotor 10 rotates, the circumferential speed on the inner diameter side (i.e., the rotor shaft 12 side) of the rotor 10 is faster than the circumferential speed on the outer diameter side (i.e., the surface 20a side). Therefore, inside each hole 30, due to the difference in circumferential speed between the inner and outer diameter sides of the rotor 10, the air pressure on the inner diameter side of the rotor 10 is lower than the air pressure on the outer diameter side. By generating this pressure difference, when the rotor 10 rotates, air flows into the interior of each hole 30, and is drawn from the outer diameter side of the rotor 10 to the inner diameter side. Thus, air cooling of the interior of the rotor core 20 is possible. Therefore, in the rotor 10 of Embodiment 1, the rotor 10 can be effectively cooled with a simple structure.

[0027] Furthermore, in the rotor 10 of Embodiment 1, the holes 30 are positioned differently in the circumferential direction, and adjacent holes 30 in the circumferential direction are positioned differently in the axial direction. Therefore, the holes 30 are arranged in a balanced manner along the circumferential and axial directions of the rotor 10, which enables the overall cooling efficiency of the rotor 10 to be uniform.

[0028] Furthermore, as described above, the rotor 10 in Embodiment 1 is air-cooled by rotating on its own. Therefore, there is no need to provide additional components for cooling the rotor 10. Components for cooling the rotor 10 include, for example, a fan for air cooling the rotor, an oil pump for supplying refrigerant to cool the rotor, and a supply path for supplying the refrigerant. Therefore, the number of components in the motor 2 can be reduced. Moreover, since the rotor 10 in Embodiment 1 is cooled by air (gas), the resistance to the rotation of the rotor 10 is smaller compared to cooling based on liquid refrigerant, which can reduce the losses of the motor 2.

[0029] Example 2

[0030] Next, the rotor 100 of Embodiment 2 will be described. Figure 4 It is the same as in Example 1. Figure 3 The corresponding sectional view. In the rotor 100 of Embodiment 2, the structure of the plurality of holes 130 provided in the rotor core 120 is different from that in Embodiment 1. Regarding other structures, they are the same as in Embodiment 1.

[0031] like Figure 4As shown, each hole 130 is radially inclined relative to the rotor 100 when viewed axially. More specifically, each hole 130 extends in a concave curve in its inclined direction. Similar to Embodiment 1, each hole 130 is arranged at equal intervals circumferentially. Furthermore, similar to Embodiment 1, each hole 130 is arranged in a spiral configuration along the axial direction on the surface 120a of the rotor core 120. Each hole 130 can be formed, for example, by machining each electromagnetic steel plate constituting the rotor core 120 corresponding to each hole 130, and then stacking the electromagnetic steel plates while aligning them.

[0032] In the rotor 100 of Embodiment 2, similarly to Embodiment 1, air flows into the interior of each hole 130 by utilizing the air pressure difference between the outer diameter side and the inner diameter side of the rotor 100 caused by the rotation of the rotor 100. As a result, the interior of the rotor core 120 can be air-cooled.

[0033] Furthermore, in the rotor 100 of Embodiment 2, by rotating the rotor 100 so that the tilting direction of each hole 130 is aligned with the rotation direction of the rotor 100, air can be effectively allowed to flow into the interior of each hole 130. For example, when the motor 2 equipped with the rotor 100 is applied to an electric vehicle, the rotation direction of the rotor 100 corresponding to the forward rotation direction of the wheels (the forward direction of the vehicle) is set as... Figure 4 The direction R1 is effective. Typically, the frequency of a vehicle moving forward is higher than the frequency of it moving backward, therefore the frequency at which the motor 2 heats up is also higher. Therefore, by setting the direction R1 to the rotation direction of the rotor 100 corresponding to the vehicle's forward direction, the rotor 100 can be cooled more effectively.

[0034] Furthermore, in embodiments 1 and 2 described above, multiple holes 30 and 130 can be provided axially at the same angular position in the circumferential direction of the rotor cores 20 and 120. Also, adjacent holes 30 and 130 in the circumferential direction can be provided at the same position in the axial direction.

[0035] Furthermore, in Embodiment 2, each hole 130 may not be bent. For example, each hole 130 may have a straight shape that is inclined relative to the radial direction. Also, in Embodiment 2, the inclination directions of each hole 130 may be opposite.

[0036] Example 3

[0037] Next, the rotor 200 of Example 3 will be described. Figure 5 It is the same as in Example 1. Figure 2 The corresponding perspective view. In the rotor 200 of Embodiment 3, instead of the hole 30 of Embodiment 1, a plurality of slots 230 are provided on the surface 220a of the rotor core 220. Other structures are the same as in Embodiment 1.

[0038] like Figure 5 As shown, each slot 230 extends from one end 200a to the other end 200b along the axial direction of the rotor 200. Each slot 230 extends spirally along the axial direction. Each slot 230 is configured such that its cross-sectional area decreases from one end 200a to the other end 200b. Specifically, as... Figure 5 As shown, each slot 230 is configured such that its width gradually narrows from one end 200a to the other end 200b. Furthermore, each slot 230 is configured such that its depth gradually decreases from one end 200a to the other end 200b. Each slot 230 can be formed, for example, by machining each electromagnetic steel plate constituting the rotor core 220 in accordance with each slot 230, and then stacking the electromagnetic steel plates while aligning them.

[0039] In the rotor 200 of Embodiment 3, when the rotor 200 rotates, air flows not only along the surface 220a of the rotor core 220, but also along the interior of each slot 230. In Embodiment 3, since the multiple slots 230 increase the surface area of ​​the rotor core 220, the rotor core 220 can be effectively air-cooled. Therefore, in the above structure, the rotor 200 can be effectively cooled with a simple structure.

[0040] Furthermore, each slot 230 is configured to extend spirally along the axial direction, and its cross-sectional area decreases from one end 200a to the other end 200b. The airflow velocity within the slot 230 increases as the cross-sectional area of ​​the slot 230 decreases. Therefore, by rotating the rotor 200 so that the rotation direction of each slot 230 from one end 200a to the other end 200b is opposite to the rotation direction of the rotor 200, the airflow within the slot 230 gradually accelerates, effectively cooling the rotor core 220. For example, in the case where the motor 2 equipped with the rotor 200 is applied to an electric vehicle, the rotation direction of the rotor 200 corresponding to the forward rotation direction of the wheels (the vehicle's forward direction) is set as... Figure 5 The direction R2 is effective. By setting the direction R2 to the rotation direction of the rotor 200 corresponding to the vehicle's forward direction, the rotor 200 can be cooled more effectively.

[0041] Furthermore, in the above embodiment 3, each groove 230 only needs to be configured such that its cross-sectional area decreases from one end 200a to the other end 200b. For example, it can also be configured such that the width of each groove 230 is constant, and only the depth decreases from one end 200a to the other end 200b. Furthermore, it can also be configured such that the depth of each groove 230 is constant, and only the width decreases from one end 200a to the other end 200b.

Claims

1. A rotor for use in a motor, said rotor being characterized by comprising: Rotor shaft; and A rotor core, which is mounted on the rotor shaft and configured to rotate together with the rotor shaft. The rotor core has a plurality of holes extending from its surface to the rotor shaft.

2. The rotor according to claim 1, characterized in that, The plurality of holes are inclined relative to the radial direction of the rotor when viewed along the axial direction of the rotor.

3. The rotor according to claim 1 or 2, characterized in that, Each of the plurality of holes is located in a different position in the circumferential direction of the rotor.

4. The rotor according to claim 3, characterized in that, The holes adjacent to each other in the circumferential direction of the rotor are located at different positions in the axial direction of the rotor.

5. A rotor for use in a motor, said rotor being characterized by comprising: Rotor shaft; and A rotor core, which is mounted on the rotor shaft and configured to rotate together with the rotor shaft. The surface of the rotor core is provided with a groove that extends spirally from one end of the rotor's axial direction to the other end. The groove is configured such that the cross-sectional area decreases from one end to the other end.

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