Rotor

Abstract

The present invention provides a rotor that can reduce the inner diameter of the rotating rotor. [Solution] The rotor 100 includes a cylindrical first rotor core 21 and a plurality of first magnets 22 arranged circumferentially on the first rotor core 21, and a fixed rotor 20 fixed to a rotating shaft 10; a cylindrical second rotor core 31 and a plurality of second magnets 32 arranged circumferentially on the second rotor core 31, and a rotating rotor 30a provided adjacent to the fixed rotor 20 in the axial direction of the rotating shaft 10 and mounted on the rotating shaft 10 so as to be rotatable relative to the fixed rotor 20; and a spacer portion 40a positioned inside the inner circumferential surface 34 of the second rotor core 31 and rotating integrally with the rotating shaft 10. The rotating rotor 30a has a first protrusion 35 on the inner circumferential surface 34 of the second rotor core 31, and the spacer portion 40a has a second protrusion 45 that contacts the first protrusion 35 when the rotating rotor 30a rotates relative to the fixed rotor 20 and the first magnets 22 and the second magnets 32 face each other with the same polarity.

Description

Technical Field

[0001] The present invention relates to a rotor.

Background Art

[0002] A rotor for a rotating electric machine including a fixed rotor fixed to a rotating shaft and a rotating rotor provided adjacent to the fixed rotor in the axial direction of the rotating shaft and rotatable relative to the fixed rotor is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the rotor described in Patent Document 1, a rotating shaft, a rotation lock shaft, a hub, and a transmission plate are arranged inside a cylindrical rotating rotor. With such a configuration, the inner diameter of the rotating rotor becomes large, so the magnetic path is narrowed and the performance of the rotating electric machine deteriorates.

[0005] The present invention has been made in view of the above problems, and an object thereof is to reduce the inner diameter of the rotating rotor.

Means for Solving the Problems

[0006] The present invention relates to a rotor comprising: a fixed rotor fixed to a rotating shaft, comprising a cylindrical first rotor core and a plurality of first magnets arranged circumferentially on the first rotor core; a rotating rotor provided adjacent to the fixed rotor in the axial direction of the rotating shaft and mounted on the rotating shaft so as to be rotatable with respect to the fixed rotor, comprising a cylindrical second rotor core and a plurality of second magnets arranged circumferentially on the second rotor core; and a spacer portion positioned inward from the inner circumferential surface of the second rotor core and rotating integrally with the rotating shaft, wherein the rotating rotor has a first protrusion on the inner circumferential surface of the second rotor core, and the spacer portion has a second protrusion that abuts against the first protrusion when the rotating rotor rotates relative to the fixed rotor and the plurality of first magnets and the plurality of second magnets face each other with the same polarity. [Effects of the Invention]

[0007] According to the present invention, the inner diameter of the rotating rotor can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1(a) is a cross-sectional view of the rotor according to the embodiment, Figure 1(b) is a plan view of the fixed rotor viewed from the -X direction, and Figure 1(c) is a plan view of the rotating rotor viewed from the +X direction. [Figure 2] Figures 2(a) and 2(b) are plan views showing the rotation of the rotating rotor relative to the spacer portion in the embodiment. [Figure 3] Figure 3 is a plan view of a rotating rotor in a modified example of the embodiment. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described below with reference to the drawings. [Examples]

[0010] Figure 1(a) is a cross-sectional view of the rotor 100 according to an embodiment. Figure 1(b) is a plan view of the fixed rotor 20 viewed from the -X direction, and Figure 1(c) is a plan view of the rotating rotor 30a viewed from the +X direction. The axial direction of the rotation axis 10 is defined as the X-axis direction. The directions perpendicular to the X-axis direction and mutually perpendicular are defined as the Y-axis direction and the Z-axis direction. The rotor 100 is used by being incorporated into a rotating electric machine mounted on, for example, a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. Although Figure 1(c) shows the rotating rotor 30a, the configuration of the rotating rotor 30b is similar. As shown in Figures 1(a) to 1(c), the rotor 100 comprises a rotation axis 10, a fixed rotor 20, rotating rotors 30a and 30b, and spacer portions 40a and 40b.

[0011] The fixed rotor 20 includes a first rotor core 21 and a plurality of first magnets 22, each provided in a plurality of first through-holes 23 that penetrate the first rotor core 21 in the X-axis direction. The first rotor core 21 has a cylindrical shape that extends parallel to the X-axis direction. The first magnets 22 are permanent magnets. The rotating shaft 10 is fitted and fixed inside the inner circumferential surface 24 of the first rotor core 21. Therefore, the fixed rotor 20 can rotate integrally with the rotating shaft 10. The plurality of first magnets 22 are arranged at a constant pitch in the circumferential direction of the first rotor core 21 so that their polarities alternate. For example, eight first magnets 22 are provided at a constant pitch in the circumferential direction of the first rotor core 21.

[0012] The rotating rotors 30a and 30b are provided adjacent to the fixed rotor 20 so as to sandwich it in the X-axis direction. The rotating rotors 30a and 30b include a second rotor core 31 and a plurality of second magnets 32 provided in each of a plurality of second through holes 33 that penetrate the second rotor core 31 in the X-axis direction. The second rotor core 31 has a larger inner diameter than the first rotor core 21 and is cylindrical in shape, extending parallel to the X-axis direction. The second magnets 32 are permanent magnets. The rotating shaft 10 is not fixed to the inner circumferential surface 34 of the second rotor core 31, but is mounted on the rotating shaft 10 via, for example, a bearing. Therefore, the rotating rotors 30a and 30b are mounted on the rotating shaft 10 so as to be rotatable relative to the rotating shaft 10 and the fixed rotor 20. The outer diameter of the second rotor core 31 is approximately the same as the outer diameter of the first rotor core 21.

[0013] Multiple second magnets 32 are arranged at a constant pitch in the circumferential direction of the second rotor core 31 so that their polarities alternate. For example, eight second magnets 32 are arranged at a constant pitch in the circumferential direction of the second rotor core 31. The distance from the central axis 11 of the rotation axis 10 to the second magnet 32 ​​is approximately the same as the distance from the central axis 11 to the first magnet 22. Therefore, the second magnets 32 can face the first magnet 22 in the X-axis direction. The number of second magnets 32 is the same as the number of first magnets 22 so that all second magnets 32 face all first magnets 22 in the X-axis direction.

[0014] The second rotor core 31 has a first protrusion 35 projecting toward the rotation axis 10 from its inner circumferential surface 34. Two of the first protrusions 35 are provided, for example, facing each other on either side of the rotation axis 10. The first protrusions 35 have a substantially rectangular shape when viewed from the X-axis direction. Note that the number of first protrusions 35 is not limited to two; there may be one, or three or more.

[0015] The spacer portions 40a and 40b are positioned inside the inner circumferential surface 34 of the second rotor core 31. The spacer portions 40a and 40b are cylindrical in shape and have a second protrusion 45 on their outer circumferential surface 46. The rotating shaft 10 is fitted and fixed to the inside of the inner circumferential surface 44 of the spacer portions 40a and 40b. Therefore, the spacer portions 40a and 40b are rotatable integrally with the rotating shaft 10. For example, two second protrusions 45 are provided, facing each other across the rotating shaft 10 and rotated 90° around the rotating shaft 10 relative to the first protrusion 35. Note that the number of second protrusions 45 is not limited to two; there may be one or three or more.

[0016] The rotating shaft 10 is formed from a steel material such as carbon steel or special steel. The first rotor core 21 and the second rotor core 31 are formed from, for example, electrical steel sheet. The spacer portions 40a and 40b are formed from a steel material such as carbon steel or special steel. The rotating shaft 10 and the spacer portions 40a and 40b may be made of the same material and / or different component concentrations of the steel material. The rotating shaft 10 and the spacer portions 40a and 40b may be made of a non-magnetic metal material such as aluminum or stainless steel. The first rotor core 21 and the second rotor core 31 may be made of a magnetic material such as amorphous metal, nanocrystalline soft magnetic material, or compacted magnetic core.

[0017] Figures 2(a) and 2(b) are plan views showing the rotation of the rotating rotor 30a relative to the spacer portion 40a in the embodiment. The rotation of the rotating rotor 30b relative to the spacer portion 40b is similar, so its illustration and explanation are omitted. Figure 2(a) shows the case when the rotating rotor 30a rotates relative to the fixed rotor 20 and spacer portion 40a such that the second magnet 32 ​​of the rotating rotor 30a faces the first magnet 22 of the fixed rotor 20 with the same polarity (N poles facing each other or S poles facing each other). Facing each other with the same polarity is sometimes called same-polarity facing. Figure 2(b) shows the case when the rotating rotor 30a rotates relative to the fixed rotor 20 and spacer portion 40a such that the second magnet 32 ​​of the rotating rotor 30a faces the first magnet 22 of the fixed rotor 20 with the opposite polarity (N pole and S pole facing each other). Facing each other with opposite polarity is sometimes called opposite-polarity facing. Whether to use same-polarity or opposite-polarity opposing orientations is selected by controlling the phase of the current supplied to the stator coil of the rotating electric machine to rotate the rotating rotors 30a and 30b.

[0018] As shown in Figures 2(a) and 1(b), when the second magnet 32 ​​of the rotating rotor 30a and the first magnet 22 of the stationary rotor 20 are opposite each other with the same polarity, the effective magnetic flux from the first magnet 22 and the second magnet 32 ​​increases. Therefore, the magnetomotive force increases, and when the rotating electric machine equipped with the rotor 100 is operated as an electric motor, high torque characteristics can be obtained, and when it is operated as a generator, high power generation characteristics can be obtained.

[0019] In the case of opposing polarities, the rotating rotor 30a rotates relative to the spacer portion 40a and the fixed rotor 20, and the side surface of the first protrusion 35 provided on the inner circumferential surface 34 of the second rotor core 31 comes into contact with the side surface of the second protrusion 45 provided on the spacer portion 40a. As a result, the torque of the rotating rotor 30a is transmitted to the rotating shaft 10 via the spacer portion 40a. Therefore, for example, when a rotating magnetic field is formed by passing current through the stator coil, the torque of the rotating rotor 30a is transmitted to the rotating shaft 10 in addition to the torque of the fixed rotor 20. Furthermore, the rotational energy of the rotating shaft 10 can be converted into current flowing through the stator coil and regenerated.

[0020] When the rotating rotor 30a rotates relative to the spacer portion 40a and the first convex portion 35 abuts against the second convex portion 45, the second magnet 32 of the rotating rotor 30a and the first magnet 22 of the fixed rotor 20 face each other with the same poles. That is, the abutment of the first convex portion 35 and the second convex portion 45 also has the function of positioning the rotating rotor 30a so that the second magnet 32 of the rotating rotor 30a faces the first magnet 22 of the fixed rotor 20 with the same poles without the rotating rotor 30a rotating too much.

[0021] As shown in FIGS. 2(b) and 1(b), when the second magnet 32 of the rotating rotor 30a and the first magnet 22 of the fixed rotor 20 face each other with opposite poles, the amount of effective magnetic flux by the first magnet 22 and the second magnet 32 decreases. Therefore, the weakening field effect is obtained. When the rotating electrical machine including the rotor 100 operates as a motor, an effect of improving the efficiency in the low torque region drive is obtained, and when it operates as a generator, an effect of improving the efficiency in the low power generation region is obtained.

[0022] In the case of opposite pole facing, the first convex portion 35 provided on the inner peripheral surface 34 of the second rotor core 31 and the second convex portion 45 provided on the spacer portion 40a do not contact each other. The first convex portion 35 and the second convex portion 45 are, for example, at positions rotated 90° with respect to the rotating shaft 10. The spacer portion 40a and the fixed rotor 20 rotate integrally with the rotating shaft 10, and the rotating rotor 30a rotates in synchronization with the fixed rotor 20 because the second magnet 32 of the rotating rotor 30a faces the first magnet 22 of the fixed rotor 20 with opposite poles. Therefore, in the case of opposite pole facing, the rotating rotor 30a and the spacer portion 40a maintain the state shown in FIG. 2(b) and rotate together with the rotating shaft 10.

[0023] [Modified Example] Figure 3 is a plan view of the rotating rotor 30a in a modified example of the embodiment. Although Figure 3 shows the rotating rotor 30a, the same applies to the rotating rotor 30b. In the embodiment, as shown in Figure 1(c), the first protrusion 35 provided on the inner circumferential surface 34 of the second rotor core 31 is shown as an example where the side surface extends straight from the inner circumferential surface 34 toward the rotation axis 10. On the other hand, in the modified example, as shown in Figure 3, the portion 38 of the first protrusion 35 that connects to the inner circumferential surface 34 is rounded by R processing. The base portion 38 of the first protrusion 35 is the point where the stress is greatest when the first protrusion 35 abuts against the second protrusion 45 and the torque of the rotating rotor 30a is transmitted to the rotation axis 10. The rounded shape of the base portion 38 of the first protrusion 35 helps to alleviate the stress and suppress damage to the first protrusion 35.

[0024] According to the embodiment and its modified form, as shown in Figures 2(a) and 2(b), a spacer portion 40a that rotates integrally with the rotating shaft 10 is positioned inside the inner circumferential surface 34 of the second rotor core 31 that constitutes the rotating rotor 30a. The rotating rotor 30a has a first protrusion 35 on the inner circumferential surface 34 of the cylindrical second rotor core 31. The spacer portion 40a has a second protrusion 45 that abuts against the side surface of the first protrusion 35 when the rotating rotor 30a rotates relative to the fixed rotor 20 and the second magnet 32 ​​of the rotating rotor 30a and the first magnet 22 of the fixed rotor 20 face each other with the same polarity. As a result, when the second magnet 32 ​​faces the first magnet 22 with the same polarity, the torque of the rotating rotor 30a is transmitted to the rotating shaft 10, so that high torque characteristics can be obtained when used as an electric motor and high power generation characteristics can be obtained when used as a generator. Furthermore, since only the rotating shaft 10 and the spacer portion 40a are located inside the inner circumferential surface 34 of the second rotor core 31, the number of parts is reduced, allowing the inner diameter of the rotating rotor 30a to be reduced. Therefore, the narrowing of the magnetic path is suppressed, and the deterioration of the performance of the rotating electric machine can be suppressed.

[0025] In the embodiments and their modifications, the spacer portions 40a and 40b are separate components from the rotating shaft 10, and the rotating shaft 10 is fitted inside the inner circumferential surfaces 44 of the spacer portions 40a and 40b. However, the invention is not limited to this case, and the spacer portions 40a and 40b may be formed integrally with the rotating shaft 10 by machining the rotating shaft 10.

[0026] Since the first protrusion 35 abuts against the second protrusion 45, a wear-resistant coating (for example, a hard ceramic coating such as titanium nitride, titanium carbonitride, or chromium nitride) may be applied to the surface of the first protrusion 35 that abuts against the second protrusion 45.

[0027] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0028] 10...Rotation axis, 11...Central axis, 20...Fixed rotor, 21...First rotor core, 22...First magnet, 23...First through hole, 24...Inner circumferential surface, 30a, 30b...Rotating rotor, 31...Second rotor core, 32...Second magnet, 33...Second through hole, 34...Inner circumferential surface, 35...First protrusion, 38...Part, 40a, 40b...Spacer part, 44...Inner circumferential surface, 45...Second protrusion, 46...Outer circumferential surface, 100...Rotor

Claims

[Claim 1] A fixed rotor is fixed to a rotating shaft and includes a cylindrical first rotor core and a plurality of first magnets arranged circumferentially on the first rotor core. A rotating rotor comprising a cylindrical second rotor core and a plurality of second magnets arranged circumferentially on the second rotor core, provided adjacent to the fixed rotor in the axial direction of the rotating shaft, and mounted on the rotating shaft so as to be rotatable relative to the fixed rotor, The second rotor core comprises a spacer portion positioned inward from the inner circumferential surface and rotating integrally with the rotation shaft, The rotating rotor has a first protrusion on the inner circumferential surface of the second rotor core, The spacer portion is a rotor having a second protrusion that contacts the first protrusion when the rotating rotor rotates relative to the stationary rotor and the plurality of first magnets and the plurality of second magnets face each other with the same polarity.

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