Stator and Rotating Electric Machine

Abstract

To improve resistance to stress. [Solution] The stator has a fixed portion having an outer surface fitted into the frame, a planar portion that intersects with a plane passing through the rotation axis and the central axis of the bolt insertion hole and is parallel to the rotation axis, a first cylindrical surface connected to the planar portion in a region sandwiched between a first virtual cylinder with the rotation axis as its central axis and the distance from the rotation axis to the central axis of the bolt insertion hole as its radius, and a second virtual cylinder with the rotation axis as its central axis and the distance from the rotation axis to the outer surface as its radius, and located on the rotation axis side of the virtual plane passing through the entire planar portion, a second cylindrical surface connected to the first cylindrical surface in the above region and located on the rotation axis side of the virtual plane, with the midpoint of the arc when projected onto a plane perpendicular to the rotation axis located in the above region, and a third cylindrical surface connected to the second cylindrical surface inside the second virtual cylinder and connected to the outer surface on the side opposite to the rotation axis side of the virtual plane.

Description

Technical Field

[0001] The present invention relates to a stator and a rotating electric machine.

Background Art

[0002] Rotating electric machines such as motors and generators are used in various fields. As a document related to rotating electric machines, for example, Patent Document 1 can be cited. The motor generator disclosed in Patent Document 1 has a bolt fastening portion and includes a stator core fixed to a case by fastening bolts.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-described stator core interacts with the rotor by magnetic force. Therefore, the above-described stator core receives stress from the rotor when the speed at which the rotor rotates changes. Further, when the outer periphery of the above-described stator core is fitted into the case, the stator core receives stress from the case. And these stresses are also applied to the boundary between the bolt fastening portion of the stator core and the portion other than the bolt fastening portion and the vicinity of the boundary, and may damage the stator core.

[0005] Therefore, an object of the present invention is to provide a stator and a rotating electric machine that can improve durability against stress.

Means for Solving the Problems

[0006] To solve the above-mentioned problems, the stator of the present invention is connected to the plane portion in a region sandwiched between an outer circumferential surface fitted into the frame of a rotating electric machine, a bolt insertion hole protruding from the outer circumferential surface in a direction perpendicular to the rotor's rotation axis and into which a bolt is inserted, a plane portion intersecting a plane passing through the rotation axis and the central axis of the bolt insertion hole and parallel to the rotation axis, a first virtual cylinder with the rotation axis as its central axis and a radius equal to the distance from the rotation axis to the central axis of the bolt insertion hole, and a second virtual cylinder with the rotation axis as its central axis and a radius equal to the distance from the rotation axis to the outer circumferential surface, and is located on the rotation axis side of the virtual plane passing through the entire plane portion. The stator core comprises a fixed portion having a first cylindrical surface whose central axis is a straight line parallel to the axis of rotation, a second cylindrical surface which is connected to the first cylindrical surface in the region, is located on the axis of rotation side of the virtual plane, the midpoint of the arc when projected onto a plane perpendicular to the axis of rotation is located in the region, and whose central axis is a straight line parallel to the axis of rotation, and a third cylindrical surface which is connected to the second cylindrical surface inside the second virtual cylinder, is along the first virtual cylinder, is connected to the outer circumferential surface on the side opposite to the axis of rotation side of the virtual plane, and whose central axis is a straight line parallel to the axis of rotation.

[0007] In the stator of the present invention, if the radius of curvature of the second cylindrical surface is X (1 or more and 2 or less), and the radius of curvature of the first cylindrical surface and the radius of curvature of the third cylindrical surface are Y, then X <Y≦2Xである。

[0008] In the stator of the present invention, one of the fixed portions is provided with a set of the flat portion, the first cylindrical surface, the second cylindrical surface, and the third cylindrical surface on both sides around the rotation axis.

[0009] The rotating electric machine of the present invention comprises one of the stators described above. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve durability against stress. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of a stator core according to the embodiment. [Figure 2] This is a diagram showing an example of a fixed part according to the embodiment. [Figure 3] This figure shows examples of the planar portion, the first cylindrical surface, the second cylindrical surface, and the third cylindrical surface according to the embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described using the case where the rotating electric machine is a motor as an example. Figure 1 is a diagram showing an example of a stator core according to the embodiment. The stator core 1 is an element that constitutes the stator of the motor, and is a cylindrical member into which a rotor, supported by a shaft in a manner that allows it to rotate around the rotation axis A, is inserted. The stator core is manufactured, for example, by stacking plate-shaped members made of electromagnetic steel in the direction of the rotation axis A. The rotation axis A extends in a direction perpendicular to the plane of the paper in Figures 1, 2, and 3. Furthermore, the stator core 1 has the structure shown in Figures 1, 2, and 3 in the entire direction of the rotation axis A.

[0013] As shown in Figure 1, the stator core 1 comprises a cylindrical portion 2, teeth 3, an outer circumferential surface 4, and a fixing portion 5. The cylindrical portion 2 is a cylindrical member. The teeth 3 are plate-shaped members that protrude from the inside of the cylindrical portion 2 toward the rotation axis A. The space between two adjacent teeth 3 in the direction of the rotation axis A is called a slot. A coil is placed in each slot. The outer circumferential surface 4 is the outer circumferential surface of the cylindrical portion 2 and is a cylindrical surface with the rotation axis A as its central axis. The outer circumferential surface 4 is fixed by being fitted into the frame, which is the housing of the motor. For example, the outer circumferential surface 4 is fixed to the frame by shrink fitting. The fixing portion 5 is a member that protrudes from the outer circumferential surface 4 in a direction perpendicular to the rotation axis A of the rotor. Also, unlike the outer circumferential surface 4 which is fitted into the frame, the fixing portion 5 does not come into contact with the frame. However, the fixing portion 5 may come into contact with the frame.

[0014] Figure 2 shows an example of a fixing part according to the embodiment. Figure 3 shows an example of a planar part, a first cylindrical surface, a second cylindrical surface, and a third cylindrical surface according to the embodiment. As shown in Figures 2 and 3, the fixing part 5 comprises a bolt insertion hole 50, a planar part 500, a first cylindrical surface 501, a second cylindrical surface 502, and a third cylindrical surface 503. In the following description, the planar part 500, the first cylindrical surface 501, the second cylindrical surface 502, and the third cylindrical surface 503 located in the lower right of the fixing part 5 shown in the upper right of Figure 1 will be used as an example. However, the fixing part 5 also has a similar planar part, a first cylindrical surface, a second cylindrical surface, and a third cylindrical surface in the upper left. In other words, the fixing part 5 has sets of planar parts, first cylindrical surfaces, second cylindrical surfaces, and third cylindrical surfaces on both sides around the rotation axis A. Furthermore, the same applies to the planar parts, first cylindrical surfaces, second cylindrical surfaces, and third cylindrical surfaces of other fixing parts 5.

[0015] The bolt insertion holes 50 are holes into which bolts are inserted to fix the stator core 1 to the frame. These bolts are often used to assist in fixing the stator core 1 by fitting its outer surface 4 into the frame. The flat surface 500 is a flat surface formed on the fixing part 5. The flat surface 500 intersects with the plane P1 that passes through the rotation axis A and the central axis of the bolt insertion hole 50, and is parallel to the rotation axis A. For example, two flat surfaces 500 are formed on one fixing part 5.

[0016] The first cylindrical surface 501 is a cylindrical surface that is connected to the planar portion 500 in the region sandwiched between the first virtual cylinder C1 and the second virtual cylinder C2. The first virtual cylinder C1 is a cylinder with the rotation axis A as its central axis and a radius equal to the distance from the rotation axis A to the central axis of the bolt insertion hole 50. The second virtual cylinder C2 is a cylinder with the rotation axis A as its central axis and a radius equal to the distance from the rotation axis A to the outer circumferential surface 4. Therefore, the second virtual cylinder C2 coincides with the outer circumferential surface 4. Furthermore, as described above, the outer circumferential surface 4 of the second virtual cylinder C2 is fitted into the frame, so it coincides with the interface between the stator core 1 and the frame.

[0017] Specifically, the first cylindrical surface 501 is smoothly connected to the planar portion 500 on line segment L1 within the region sandwiched between the first virtual cylinder C1 and the second virtual cylinder C2. Line segment L1 is parallel to the axis of rotation A, its length is equal to the length of the stator core 1 in the direction of the axis of rotation A, and its entirety overlaps with the surface of the stator core 1. Furthermore, the first cylindrical surface 501 is a cylindrical surface with a straight line parallel to the axis of rotation A as its central axis. Moreover, the entirety of the first cylindrical surface 501 is located on the side of the axis of rotation A than the virtual plane P2 that passes through the entire planar portion 500.

[0018] The second cylindrical surface 502 is a cylindrical surface connected to the first cylindrical surface 501 in the region sandwiched between the first virtual cylinder C1 and the second virtual cylinder C2. Specifically, the second cylindrical surface 502 is smoothly connected to the first cylindrical surface 501 on line segment L2 within that region. Line segment L2 is parallel to the axis of rotation A, its length is equal to the length of the stator core 1 in the direction of the axis of rotation A, and its entirety overlaps with the surface of the stator core 1. Furthermore, the second cylindrical surface 502 is a cylindrical surface whose central axis is a straight line parallel to the axis of rotation A. In addition, the second cylindrical surface 502 is located on the side of the axis of rotation A than the virtual plane P2.

[0019] Furthermore, the second cylindrical surface 502 is located in a region where the midpoint of the arc, when projected onto a plane perpendicular to the axis of rotation A, is sandwiched between the first virtual cylinder C1 and the second virtual cylinder C2. In other words, the second cylindrical surface 502 includes a line segment L3 that passes through the midpoint, is perpendicular to the axis of rotation A, and is located within that region. The line segment L3 is parallel to the axis of rotation A, its length is equal to the length of the stator core 1 in the direction of the axis of rotation A, and its entirety overlaps with the surface of the stator core 1.

[0020] The third cylindrical surface 503 is connected to the second cylindrical surface 502 inside the second virtual cylinder C2. Specifically, the third cylindrical surface 503 is smoothly connected to the second cylindrical surface 502 on the line segment L4 inside the second virtual cylinder C2. The line segment L4 is parallel to the rotation axis A, has a length equal to the length of the stator core 1 in the direction of the rotation axis A, and entirely overlaps with the surface of the stator core 1. Therefore, a part of the second cylindrical surface 502 and a part of the third cylindrical surface 503 are located inside the second virtual cylinder C2.

[0021] Also, the third cylindrical surface 503 is connected to the outer peripheral surface 4 on the side opposite to the rotation axis A side with respect to the virtual plane P2. Specifically, the third cylindrical surface 503 is smoothly connected to the outer peripheral surface 4 on the line segment L5 on the side opposite to the rotation axis A side with respect to the virtual plane P2. The line segment L5 is parallel to the rotation axis A, has a length equal to the length of the stator core 1 in the direction of the rotation axis A, and entirely overlaps with the surface of the stator core 1. Also, the third cylindrical surface 503 is a cylindrical surface having a straight line parallel to the rotation axis A as its central axis. Furthermore, the third cylindrical surface 503 is along the first virtual cylinder C2.

[0022] Also, when the radius of curvature of the first cylindrical surface 501 and the radius of curvature of the third cylindrical surface 503 are Y, and the radius of curvature of the second cylindrical surface 502 is X, it is preferable that X < Y ≦ 2X. In this case, the radius of curvature X of the second cylindrical surface 502 is preferably 1 or more and 2 or less. Also, in this case, the radius of curvature X of the second cylindrical surface 502 is more preferably 1.2 or more and 1.8 or less. Furthermore, in this case, the radius of curvature X of the second cylindrical surface 502 is most preferably 1.4 or more and 1.6 or less.

[0023] The stator core according to the embodiment has been described above. The stator core 1 includes a flat portion 500, a first cylindrical surface 501, a second cylindrical surface 502, and a third cylindrical surface 503 having the structural features described above. However, the features regarding the radius of curvature are not essential here. Thereby, the stator core 1 can relieve the stress in the direction around the rotation axis A received from the rotor when the rotational speed of the rotor changes, and the stress in the direction perpendicular to the rotation axis A received from the frame. The rotational speed of the rotor changes, for example, when the rotor starts rotating from a stationary state, or when the rotational speed of the rotor is increased while the rotor is rotating. Also, the rotational speed of the rotor changes, for example, when the rotor stops rotating from a rotating state, or when the rotational speed of the rotor is decreased while the rotor is rotating.

[0024] The stator core 1 mainly relieves the stress in the direction around the rotation axis A received from the rotor when the rotational speed of the rotor changes by the portion of the second cylindrical surface 502 sandwiched between the line segment L2 and the line segment L3 and the first cylindrical surface 501. Also, the stator core 1 mainly relieves the stress in the direction perpendicular to the rotation axis A received from the frame by the portion of the second cylindrical surface 502 sandwiched between the line segment L3 and the line segment L4 and the third cylindrical surface 503. Further, the stator core 1 effectively relieves the stress in the direction perpendicular to the rotation axis A received from the frame by the portion of the second cylindrical surface 502 and the third cylindrical surface 503 located inside the second virtual cylinder C2.

[0025] However, each part of the first cylindrical surface 501, each part of the second cylindrical surface 502, and each part of the third cylindrical surface 503 can relieve the stress in the direction around the rotation axis A received from the rotor and the stress in the direction perpendicular to the rotation axis A received from the frame when the rotation speed of the rotor changes. Here, there are variations for each motor in terms of the angle of the rotor when the rotation speed of the rotor begins to change, the size and position of the slight gap between the outer peripheral surface 4 and the frame, etc., and the size and position of the slight gap between the bolt insertion hole 50 and the bolt, etc., and these may also change depending on the situation in which the motor is used. Therefore, the effect that each part of the first cylindrical surface 501, each part of the second cylindrical surface 502, and each part of the third cylindrical surface 503 can relieve these two stresses is particularly effective.

[0026] Also, when the radius of curvature of the first cylindrical surface 501 and the radius of curvature of the third cylindrical surface 503 are Y, and the radius of curvature of the second cylindrical surface 502 is X, it may be X < Y ≦ 2X (X: 1 or more and 2 or less). That is, the stator core 1 has the radius of curvature of the second cylindrical surface 502 as 1 or more, and the radius of curvature of the first cylindrical surface 501 and the radius of curvature of the third cylindrical surface 503 are made larger than 1. Thereby, the stator core 1 can avoid at least one of the stress in the direction around the rotation axis A received from the rotor and the stress in the direction perpendicular to the rotation axis A received from the frame concentrating at a specific location when the rotation speed of the rotor changes. Also, the stator core 1 has the radius of curvature of the second cylindrical surface 502 as 2 or less, and the radius of curvature of the first cylindrical surface 501 and the radius of curvature of the third cylindrical surface 503 as 4 or less. Thereby, the stator core 1 can more effectively relieve the stress in the direction perpendicular to the rotation axis A received from the frame.

[0027] Also, the four fixing parts 5 of the stator core 1 each have a flat part 500, a first cylindrical surface 501, a second cylindrical surface 502, and a set of a flat part, a first cylindrical surface, a second cylindrical surface, and a third cylindrical surface similar to those on both sides around the rotation axis A in the same manner. Thereby, the stator core 1 can effectively relieve these stresses regardless of the direction of the stress in the direction around the rotation axis A received from the rotor and the direction of the stress in the direction perpendicular to the rotation axis A received from the frame when the rotation speed of the rotor changes.

[0028] In the embodiments described above, the example of a rotating electric machine being a motor was used, but the invention is not limited to this. The stator core 1 in the embodiment may be, for example, an element that constitutes a generator instead of a motor.

[0029] Furthermore, in the embodiments described above, the example given was that the fixing of the stator core 1 by shrink-fitting the outer circumferential surface 4 to the frame is assisted by bolts inserted into bolt insertion holes 50, but the embodiment is not limited to this. For example, the fixing of the stator core by bolts inserted into bolt insertion holes according to the embodiment may be assisted by the force of the gap fitting between the outer circumferential surface of the stator core and the frame. Also, for example, the outer circumferential surface of the stator core according to the embodiment may not be fitted to the frame, and the stator core may be fixed to the frame only by bolts inserted into bolt insertion holes.

[0030] Furthermore, although the above-described embodiment has been explained using the example of a case where the stator core 1 has the structure shown in Figures 1, 2, and 3 throughout the direction of the rotation axis A, it is not limited to this. The stator core according to the embodiment may have the structure shown in Figures 1, 2, and 3 in a part of the direction of the rotation axis A.

[0031] Preferred embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above. That is, the present invention includes embodiments that have been modified, substituted, or redesigned in accordance with the spirit of the present invention, and these embodiments are not excluded. [Explanation of Symbols]

[0032] 1... Stator core, 2... Cylindrical section, 3... Teeth, 4... Outer surface, 5... Fixing section, 50... Bolt insertion hole, 500... Flat section, 501... First cylindrical surface, 502... Second cylindrical surface, 503... Third cylindrical surface, C1... First virtual cylinder, C2... Second virtual cylinder, P2, P22... Virtual plane, L1, L2, L3, L4, L5... Line segments, A... Rotation axis

Claims

1. A region is connected to the plane portion in which a component is sandwiched between an outer circumferential surface fitted into the frame of a rotating electric machine, a bolt insertion hole protruding from the outer circumferential surface in a direction perpendicular to the rotor's rotation axis and into which a bolt is inserted, a plane portion intersecting a plane passing through the rotation axis and the central axis of the bolt insertion hole and parallel to the rotation axis, a first virtual cylinder with the rotation axis as its central axis and the distance from the rotation axis to the central axis of the bolt insertion hole as its radius, and a second virtual cylinder with the rotation axis as its central axis and the distance from the rotation axis to the outer circumferential surface as its radius, and is located on the rotation axis side of the virtual plane passing through the entire plane portion, and is parallel to the rotation axis. A stator having a stator core having a fixed portion on which a first cylindrical surface with a straight line as its central axis is formed, a second cylindrical surface connected to the first cylindrical surface in the region, located on the rotation axis side of the virtual plane, the midpoint of the arc when projected onto a plane perpendicular to the rotation axis is located in the region, and a straight line parallel to the rotation axis is formed, and a third cylindrical surface connected to the second cylindrical surface inside the second virtual cylinder, along the first virtual cylinder, connected to the outer circumferential surface on the side opposite to the rotation axis side of the virtual plane, and a straight line parallel to the rotation axis is formed.

2. If the radius of curvature of the second cylindrical surface is X (1 or more and 2 or less), and the radii of curvature of the first cylindrical surface and the radii of curvature of the third cylindrical surface are Y, then X < Y ≤ 2X. The stator according to claim 1.

3. One of the fixed parts comprises a set of the flat part, the first cylindrical surface, the second cylindrical surface, and the third cylindrical surface on both sides around the rotation axis. The stator according to claim 1.

4. A rotating electric machine comprising a rotor according to any one of claims 1 to 3.

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