Rotating electric machine rotor

Abstract

The rotary electric machine rotor according to the present disclosure includes: a rotor shaft extending in the direction of the rotation axis; and a rotor core fixedly fitted to the outer periphery of the rotor shaft and formed of laminated steel plates. In addition, the inner diameter of the rotor core is smaller than the outer diameter of the rotor shaft. In addition, the inner edge portion of each laminated steel plate is made thinner than its outer edge portion, and the inner edge portion abuts on the outer peripheral surface of the rotor shaft and bends in the direction of the rotation axis along the outer peripheral surface of the rotor shaft.

Description

Technical Field

[0001] The present disclosure relates to rotating electric machine rotors. Background Art

[0002] In a rotating electric machine, due to the centrifugal force caused by the high-speed rotation of the rotor, a phenomenon may occur where the rotor shaft and the rotor core, which are fixedly fitted to each other, are separated from each other. In order to solve the above problem, the inner diameter of the rotor core may be made smaller than the outer diameter of the rotor shaft. However, simply making the inner diameter of the rotor core smaller than the outer diameter of the rotor shaft causes the rotor core to be easily damaged. Japanese Unexamined Patent Application Publication No. 2014-64409 discloses a technology for making the cross section of the outer peripheral surface of the rotor shaft polygonal. Summary of the invention

[0003] By making the cross section of the outer peripheral surface of the rotor shaft polygonal as in the technique disclosed in Japanese Unexamined Patent Application Publication No. 2014-64409, stress concentrates at the corners of the outer peripheral surface of the rotor shaft, which may cause degradation of the rotor core and the like.

[0004] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a rotating electric machine rotor suitable for reducing stress load on a rotor core while maintaining constraint between a rotor shaft and the rotor core even when the rotor rotates at a high speed.

[0005] A rotating electrical machine rotor according to the present disclosure comprises:

[0006] a rotor shaft extending in the direction of the axis of rotation; and

[0007] The rotor core is fixedly fitted to the outer periphery of the rotor shaft and is formed by stacking steel plates.

[0008] The inner diameter of the rotor core is smaller than the outer diameter of the rotor shaft, and

[0009] The inner edge portion of each laminated steel plate is made thinner than the outer edge portion thereof, and the inner edge portion abuts on the outer peripheral surface of the rotor shaft and bends in the direction of the rotation axis along the outer peripheral surface of the rotor shaft.

[0010] According to the present disclosure, a rotating electric machine rotor can be provided that is suitable for reducing stress load on a rotor core while maintaining constraint between a rotor shaft and the rotor core even when the rotor rotates at a high speed.

[0011] The above and other objects, features and advantages of the present disclosure will be more fully understood from the detailed description given below and the accompanying drawings which are given by way of illustration only and thus should not be regarded as limiting the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a vertical cross-sectional view of a rotating electric machine using the rotating electric machine rotor according to the first embodiment of the present disclosure;

[0013] Figure 2 is a vertical cross-sectional view of a fastening unit of a rotor shaft and a rotor core when the rotating electric machine rotor according to the first embodiment of the present disclosure is stationary;

[0014] Figure 3 is a vertical cross-sectional view of a fastening unit of a rotor shaft and a rotor core when the rotating electric machine rotor according to the first embodiment of the present disclosure rotates at a high speed;

[0015] Figure 4 is a horizontal cross-sectional view of a fastening unit of a rotor shaft and a rotor core of a rotary electric machine rotor according to a first embodiment of the present disclosure;

[0016] Figure 5 is a diagram showing an example of a through hole provided in a rotor core of a rotary electric machine rotor according to a first embodiment of the present disclosure; and

[0017] Figure 6 is a horizontal cross-sectional view of a fastening unit of a rotor shaft and a rotor core of a rotary electric machine rotor according to a second embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] Hereinafter, the embodiments will be described with reference to the accompanying drawings. It is noted that, since the accompanying drawings are simplified, the technical scope of the embodiments should not be narrowly understood based on the description of these drawings. In addition, the same figure numerals represent the same structural elements, and repeated explanations thereof are omitted. In addition, in the following description, when the number of structural elements, etc. (including number, numerical value, quantity, range, etc.) is mentioned, the number is not limited to the specific number described, and can be a number larger than those specific numbers, unless otherwise explicitly stated or unless it is obvious that the number should be limited to the specific number described.

[0019] In the following, for the sake of clarity, explanation will be given below with reference to the xyz three-dimensional orthogonal coordinate system. The z direction is the thickness direction of the rotor and is the stacking direction of the laminated steel plates. The xy plane is a plane parallel to the rotor and parallel to the main surface of the laminated steel plates. In addition, although the explanation is given on the assumption that the positive z direction is the upward direction, this direction may vary depending on the orientation of the rotating electrical machine.

[0020] <First Embodiment>

[0021] Will refer to Figure 1 , Figure 2 and Figure 3 A rotary electric machine rotor 10 according to a first embodiment is described. Figure 1 is a vertical cross-sectional view of a rotary electric machine 1 using a rotary electric machine rotor 10 according to the first embodiment. Figure 2 1 is a vertical cross-sectional view of a fastening unit of the rotor shaft 11 and the rotor core 12 when the rotary electric machine rotor 10 according to the first embodiment is stationary. Figure 3 1 is a vertical cross-sectional view of a fastening unit of the rotor shaft 11 and the rotor core 12 when the rotary electric machine rotor 10 of the first embodiment rotates at a high speed. Figure 4 1 is a horizontal cross-sectional view of a fastening unit of a rotor shaft 11 and a rotor core 12 of a rotary electric machine rotor 10 according to the first embodiment.

[0022] Figure 1 The rotary electric machine 1 shown in FIG. 1 is composed of a rotary electric machine rotor 10 and a stator 20 according to the first embodiment. The rotary electric machine rotor 10 includes a rotor shaft 11 and a rotor core 12. The rotor core 12 includes a magnet 13. Furthermore, the stator 20 includes a stator core 21 and a coil 22. The rotor core 12 is composed of laminated steel plates 14.

[0023] like Figure 1 As shown in , the rotor shaft 11 is a tubular member extending in the positive z direction, and extends in the direction of the rotation axis of the rotating electric machine rotor 10. The rotor shaft 11 is inserted into the shaft hole 15 provided in the rotor core 12. The rotor shaft 11 may be made of a metal such as low carbon steel or an iron-based alloy. A refrigerant passage 16 is provided inside the rotor shaft 11. At this time, by causing the refrigerant to flow through the refrigerant passage 16, the rotating electric machine rotor 10 can be cooled.

[0024] like Figure 1 As shown in , the rotor core 12 is fixedly fitted to the outer periphery of the rotor shaft 11 and is composed of laminated steel plates 14. The rotor core 12 is formed by stacking laminated steel plates 14 that are punched into an annular shape in an upward direction (positive z direction). The plurality of laminated steel plates 14 constituting the rotor core 12 are integrally connected to each other by bonding, welding, etc. In order to minimize the energy loss caused by the eddy current generated inside the rotor core 12, the laminated steel plates 14 constituting the rotor core 12 can be electrically insulated from each other by an insulating film formed on the surface of both sides of each laminated steel plate 14.

[0025] like Figure 1 As shown in FIG. 1 , the magnet 13 is inserted into the magnet hole 17 extending in the circumferential direction of the outer edge portion of the laminated steel plate 14, and the magnet hole 17 is sealed with the magnet fixing member 18. The current flowing through the coil 22 generates a rotating magnetic field, and the rotating electric machine rotor 10 rotates due to the electromagnetic action between the rotating magnetic field and the rotor core 12.

[0026] Here, there is a problem that a gap is easily generated in the fastening unit of the rotor shaft 11 and the rotor core 12 due to the centrifugal force generated when the rotor core 12 rotates at a high speed. Due to the generation of the gap, there is a possibility that the rotation phase between the rotor shaft 11 and the rotor core 12 is shifted or decomposed when the rotor core 12 rotates at a high speed. In order to solve the above problem, there is a method of making the outer diameter of the rotor shaft 11 smaller than the inner diameter of the rotor core 12. However, by adopting the above configuration, a new problem is generated that the rotor core 12 is easily damaged.

[0027] In order to solve the above-mentioned problem, the inner edge portion of each laminated steel plate 14 constituting the rotor core 12 according to the first embodiment is made thinner than the outer edge portion thereof. Figure 2 and Figure 3 Here, the inner diameter of the rotor core 12 is smaller than the outer diameter of the rotor shaft 11. Therefore, when the rotor shaft 11 is inserted into the shaft hole 15 of the laminated steel plates 14, the inner edge portion of each laminated steel plate 14 abuts on the outer peripheral surface of the rotor shaft 11 and bends in the direction of the rotation axis along the outer peripheral surface of the rotor shaft 12. As a result, Figure 2 As shown in , when the rotor core is stationary, the inner edge portion of each laminated steel plate 14 contacts the outer peripheral surface of the rotor shaft 11 while being elastically deformed like a spring.

[0028] Here, the outer peripheral surface of the rotor shaft 11 according to the first embodiment and the inner peripheral surface of the rotor core 12 according to the first embodiment have an octagonal shape, respectively. The shape with an octagonal cross section may be a shape with rounded corners (R-processed) or a shape with chamfers. Note that the shape of the outer peripheral surface of the rotor shaft 11 and the shape of the inner peripheral surface of the rotor core 12 are not limited to the octagonal shape, and may be any other polygonal shape. By adopting a polygonal shape for the rotor shaft and the rotor core, as with the rotor shaft 11 and the rotor core 12 according to the first embodiment, there is no need to tighten with a nut.

[0029] like Figure 3 As shown in , when the rotor core 12 rotates at a high speed, the bent portion of each laminated steel plate 14, that is, the inner edge portion of each laminated steel plate 14 that is elastically deformed like a spring, expands and contracts according to the number of rotations of the rotor core 12 (that is, the magnitude of the centrifugal force). Therefore, when the rotor core 12 rotates at a high speed, the rotor core 12 is in close contact with the rotor shaft 11, and the rotor core 12 and the rotor shaft 11 continue to constrain each other. As a result, the rotational phase shift or decomposition between the rotor shaft 11 and the rotor core 12 when the rotor core 12 rotates at a high speed can be suppressed. In addition, the inner edge portion of each laminated steel plate 14 that is formed thinly is in close contact with the rotor core 12 while being elastically deformed, thereby maintaining the constraint between the rotor shaft and the rotor core, and the stress load on the rotor core can be reduced.

[0030] like Figure 4As shown in , the outer peripheral surface of the rotor shaft 11 and the inner peripheral surface of the rotor core 12 according to the first embodiment both have an octagonal shape. Note that the shape of the above-mentioned surface is not limited to the octagonal shape, and may be any other polygonal shape. By making the cross section of the outer peripheral surface of the rotor shaft and the cross section of the inner peripheral surface of the rotor core polygonal as in the rotor shaft 11 and the rotor core 12 according to the first embodiment, it is not necessary to tighten with a nut.

[0031] In addition, if Figure 4 As shown in , the rotor core 12 has concavo-convex formed on its inner circumferential surface. Each corner of the rotor core 12 is formed as a concave portion of the concavo-convex. The concentration of stress at the corners of the rotor core 12 having an octagonal shape may be a cause of degradation of the rotor core, etc. However, by forming the corners as concave portions, the concentration of stress at the corners can be suppressed when the rotor core 12 rotates at a high speed. Therefore, by forming the concavo-convex on the inner circumferential surface of the rotor core 12, local deformation of the laminated steel plates 14 can be avoided, thereby preventing the laminated steel plates 14 from cracking due to their deformation. Therefore, the rotor shaft 11 and the rotor core 12 are constructed to be less susceptible to damage.

[0032] In addition, if Figure 4 As shown in FIG. 1 , a through hole 19 extending in the direction of the rotation axis of the rotary electric machine 10 is provided in each protrusion of the rotor core 12. Here, the protrusion formed at the inner edge portion of the rotor core 12 (that is, formed at the inner edge portion of each laminated steel plate 14) is bent and elastically deformed like a spring, as shown in FIG. Figure 2 and Figure 3 As shown in . By providing the through hole 19 in the rotor core 12, it is possible to suppress the increase in iron loss due to stress when the rotor core 12 rotates at a high speed. In addition, if the laminated steel plates 14 are thick, the laminated steel plates 14 have rigidity, so when the rotor shaft 11 is inserted into the rotor core 12, the laminated steel plates 14 are prone to cracking. Therefore, by providing the through hole 19, the inner edge portion of each laminated steel plate 14 can be easily bent, so that it is possible to suppress the laminated steel plates 14 from cracking when the rotor shaft 11 is inserted into the rotor core 12.

[0033] Figure 5 1 is a diagram showing an example in which the through hole 19 is provided inside the rotor core 12. Figure 5 As shown in FIG. 1 , the shape of the through hole 19 may be circular, polygonal, etc., and any shape may be adopted.

[0034] Therefore, it is possible to avoid generation of a gap in a fastening unit of the rotor shaft 11 and the rotor core 12 due to a centrifugal force generated when the rotor core 12 rotates at a high speed.

[0035] By the configuration of the rotary electric machine rotor 10 according to the first embodiment, even when the rotor core 12 rotates at a high speed, it is possible to reduce the stress load on the rotor core 12 while maintaining the constraint between the rotor shaft 11 and the rotor core 12 .

[0036] <Second Embodiment>

[0037] Will refer to Figure 6 A rotary electric machine rotor 10 according to a second embodiment is described. Figure 6 1 is a horizontal cross-sectional view of a fastening unit of a rotor shaft 11 and a rotor core 12 of a rotary electric machine rotor 10 according to the second embodiment.

[0038] like Figure 6 As shown in , the outer peripheral surface of the rotor shaft 11 and the inner peripheral surface of the rotor core 12 according to the second embodiment have an octagonal shape like the outer peripheral surface of the rotor shaft 11 and the inner peripheral surface of the rotor core 12 according to the first embodiment. Note that the shape of the above-mentioned surface is not limited to the octagonal shape, and may be any other polygonal shape. Note that in Figure 6 In the Figure 4 The concavities and convexities on the inner peripheral surface of the rotor core 12 are formed as shown in FIG.

[0039] The difference between the second embodiment and the first embodiment is that, in the second embodiment, a plurality of through holes extending in the direction of the rotation axis of the rotating electric machine rotor 10 are arranged along the circumferential direction at the peripheral portion of the rotor shaft 11, and a rod-shaped member 11a is inserted into each through hole. The rod-shaped member 11a is preferably made of a metal (such as tungsten) having a higher specific gravity than the specific gravity of iron making the rotor shaft 11. In addition, the rod-shaped member 11a includes a linear member such as a wire. In addition, the peripheral portion of the rotor shaft has a thickness difference, and by making the deformation amount of the rotor shaft due to the centrifugal force greater than the deformation amount of the rotor core due to the centrifugal force, the generation of a gap in the fastening unit of the rotor shaft 11 and the rotor core 12 can be avoided.

[0040] like Figure 6 As shown in , by inserting the rod-shaped member 11a into the rotor shaft 11, the outer diameter of the rotor shaft 11 becomes larger due to the centrifugal force caused when the rotor shaft 11 rotates at a high speed. Therefore, the generation of a gap in the fastening unit of the rotor shaft 11 and the rotor core 12 can be avoided.

[0041] With the configuration of the rotating electric machine rotor according to the second embodiment, even when the rotor rotates at a high speed, it is possible to reduce the stress load on the rotor core while maintaining the constraint between the rotor shaft and the rotor core.

[0042] Therefore, according to the above disclosure, it will be obvious that the embodiments of the present disclosure can be changed in many ways. Such changes should not be regarded as departing from the spirit and scope of the present disclosure, and all such modifications that will be obvious to those skilled in the art are intended to be included in the scope of the appended claims.

Claims

1. Rotating electric machine rotor, including: a rotor shaft extending in the direction of the axis of rotation; as well as The rotor core is fixedly fitted to the outer periphery of the rotor shaft and is formed by stacking steel plates, wherein The inner diameter of the rotor core is smaller than the outer diameter of the rotor shaft, The inner edge portion of each laminated steel plate is made thinner than the outer edge portion thereof, and the inner edge portion abuts on the outer peripheral surface of the rotor shaft and bends in the direction of the rotation axis along the outer peripheral surface of the rotor shaft, A plurality of through holes extending in the direction of the rotation axis are arranged along the circumferential direction of the rotor shaft at the peripheral edge portion thereof, a rod-shaped member made of a metal having a higher specific gravity than that of the metal making the rotor shaft is inserted into each of the plurality of through holes so that the outer diameter of the rotor shaft becomes larger due to a centrifugal force caused when the rotor shaft rotates at a high speed; and The peripheral portion of the rotor shaft has a thickness difference, and a deformation amount of the rotor shaft due to centrifugal force is greater than a deformation amount of the rotor core due to centrifugal force.

2. The rotating electrical machine rotor according to claim 1, wherein: The rotor core has concavities and convexities formed on an inner circumferential surface thereof.

3. The rotating electrical machine rotor according to claim 2, wherein: A through hole extending in the direction of the rotation axis is provided in each protruding portion of the concavoconvex.

4. The rotating electrical machine rotor according to any one of claims 1 to 3, wherein: A cross section of an outer peripheral surface of the rotor shaft and a cross section of an inner peripheral surface of the rotor core are polygonal.

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