Rotating electric machine

Abstract

A rotating electrical machine includes a stator, a shaft, a rotor core, a plurality of rotor conductors, an end ring, and a rectifying member. The rotor conductors are arranged at intervals in the circumferential direction of the rotation center shaft. Each of the rotor conductors includes a protruding portion protruding from an end portion of the rotor core in an axial direction. The end ring connects a front end portion of the protruding portion of the rotor conductor. The rectifying member covers the protruding portion of the rotor conductor across the outer peripheral surface of the end portion of the rotor core in the radial direction of the rotation center axis and the outer peripheral surface of the end ring in the radial direction.

Description

Technical Field

[0001] Broadly speaking, the embodiments described herein relate to rotating electrical machines. Background Art

[0002] Rotating electrical machines having squirrel-cage rotors are known (for example, patent document JP 2018-148793 A).

[0003] For example, a squirrel-cage rotor includes a rotor core, a plurality of rotor conductors, and end rings connecting these conductors.

[0004] Each rotor conductor has a protruding portion protruding from the rotor core. The end ring is connected to the protruding portion of the rotor conductor.

[0005] In this type of rotating electrical machine, the air flow generated in the rotating electrical machine flows along the protruding portions of the rotor conductors and the end rings, and the air flow flows along the stepped portion between the protruding portions of the rotor conductors and the end rings, so that mechanical losses may occur.

[0006] One of the technical problems to be solved by the present invention is to reduce the occurrence of mechanical losses. Summary of the Invention

[0007] A rotating electrical machine includes a stator, a shaft, a rotor core, a plurality of rotor conductors, end rings, and a rectifying member. The shaft extends through the inside of the stator. The shaft is rotatable relative to the stator about a rotation center axis. The rotor core has an end portion in the axial direction of the rotation center axis. The shaft is located inside the stator and is coupled to the shaft. The plurality of rotor conductors penetrate the rotor core in the axial direction. The plurality of rotor conductors are spaced apart in the circumferential direction of the rotation center axis. Each of the rotor conductors includes a protruding portion protruding from the end portion of the rotor core in the axial direction. The end rings connect the front end portions of the protruding portions of the plurality of rotor conductors. The rectifying member covers the protruding portions of the plurality of rotor conductors across the outer peripheral surface of the end portion of the rotor core in the radial direction of the rotation center axis and the outer peripheral surface of the end rings in the radial direction. Brief Description of the Drawings

[0008] Figure 1 is a cross-sectional view schematically showing a rotating electrical machine according to an embodiment of the present disclosure;

[0009] Figure 2 is a cross-sectional view schematically showing a part of the rotating electrical machine according to the embodiment;

[0010] Figure 3 is schematically showing along Figure 1 a cross-sectional view of a part of the rotating electrical machine according to the embodiment taken along line III-III in

[0011] Figure 4 is Figure 1 an enlarged view of cross-section IV in

[0012] Figure 5 is a cross-sectional view schematically showing a part of a rotating electrical machine of a comparative example, and this part corresponds to the part in Figure 4 DETAILED DESCRIPTION

[0013] Hereinafter, embodiments will be described with reference to the drawings. It should be noted that, in this specification, components according to the embodiments and descriptions of the components can be described in various expressions. The components and their descriptions are exemplary and are not limited by the expressions herein. Components can also be specified by names different from those herein. In addition, components can be described by expressions different from those in this specification.

[0014] In addition, the drawings are only schematic. The dimensional relationships of elements, the ratios of elements, etc. can be different from the actual ones. The drawings can include different dimensional relationships or different ratios from each other.

[0015] Figure 1 is a cross-sectional view schematically showing a rotating electrical machine 10 according to an embodiment. The rotating electrical machine 10 is, for example, a squirrel-cage three-phase induction motor and is used as a motor or a generator. It should be noted that the rotating electrical machine 10 is not limited to the above example.

[0016] The rotating electrical machine 10 includes a stator 11, a rotor 12, a housing 13, a shaft 14, a plurality of bearings 15, an inner fan 16, and an outer fan 17. The components of the rotating electrical machine 10 are not limited to the above example. The rotating electrical machine 10 may also include other components such as an outer fan cover.

[0017] The stator 11 includes a stator core 21 and a stator winding 22. The stator core 21 is formed in a substantially cylindrical shape around a rotation center axis Ax.

[0018] The rotation center axis Ax is the rotation center of the rotor 12 and the shaft 14 in the rotating electrical machine 10. In one example, the rotation center axis Ax is an imaginary straight line passing through the center of the shaft 14. Hereinafter, unless otherwise specified, the axial direction, the circumferential direction, and the radial direction respectively refer to the axial direction, the circumferential direction, and the radial direction of the rotation center axis Ax. The axial direction is the direction along the rotation center axis Ax. The radial direction is the direction orthogonal to the rotation center axis Ax. The circumferential direction is the direction of rotation around the rotation center axis Ax.

[0019] The stator winding 22 is attached to the stator core 21 while passing through slots provided in the stator core 21.

[0020] ​The rotor 12 is a squirrel-cage rotor. The rotor 12 includes a rotor core 31, a plurality of rotor conductors 32, a pair of end rings 34, and a pair of rectifying members 61. Each end ring 34 is an example of a short-circuit ring.

[0021] The rotor core 31 is formed in a substantially cylindrical shape around the rotation center axis Ax. The rotor core 31 is disposed inside the stator core 21 of the stator 11. The rotor core 31 includes, for example, a core body 50 and a pair of clamping plates 52. The core body 50 includes a plurality of steel plates 51 arranged in the axial direction. The steel plates 51 are formed in a disk shape around the rotation center axis Ax. In one example, the steel plates 51 are made of ferromagnetic silicon steel. The clamping plates 52 are located on both sides of the core body 50 so as to clamp the core body 50 in the axial direction. Each clamping plate 52 is formed in a disk shape around the rotation center axis Ax and is made of a metallic material.

[0022] The rotor core 31 has an outer peripheral surface 31a and two end portions 31b. The outer peripheral surface 31a is formed in a substantially cylindrical shape. The outer peripheral surface 31a faces outward in the radial direction. The outer peripheral surface 31a faces the stator core 21 of the stator 11 with a gap K therebetween. The gap K serves as a flow path for a gas such as air. The end portion 31b is an end portion of the rotor core 31 in the axial direction. Each end portion 31b includes at least a part of the clamping plate 52. The axial end surface of the end portion 31b is substantially flat and faces in the axial direction.

[0023] The rotor core 31 includes a plurality of through holes 35. The through holes 35 penetrate the rotor core 31 in the axial direction. Therefore, the through holes 35 open on the axial end surfaces of the axial both ends 31b of the rotor core 31. The through holes 35 are arranged at substantially equal intervals in the circumferential direction. A part of the through holes 35 is separated from the outer peripheral surface 31a.

[0024] Figure 2 is a cross-sectional view schematically showing a part of the rotating electric machine 10 of the present embodiment. As Figure 2 shown, at the end portion 35a outside the radial direction of the through hole 35 of the clamping plate 52, it opens on the outer peripheral surface 52a of the clamping plate 52. The outer peripheral surface 52a of the clamping plate 52 is included in the outer peripheral surface 31a of the rotor core 31.

[0025] As Figure 1 and Figure 2 shown, a plurality of rotor conductors 32 are inserted into the through holes 35 of the rotor core 31 and pass through the rotor core 31 in the axial direction. The rotor conductors 32 are arranged at regular intervals in the circumferential direction. Each rotor conductor 32 has a protruding portion 32a ( Figure 1 ). The protruding portion 32a is also referred to as a straight portion. The protruding portion 32a protrudes in the axial direction from the end portion 31b of the rotor core 31. As Figure 2As shown in [reference], the end face 32b on the outer side in the radial direction of the rotor conductor 32 is formed to align with the outer peripheral surface 52a of the pressure plate 52 in the circumferential direction. The rotor conductor 32 is made of a conductive metal material. In one example, the rotor conductor 32 contains aluminum. The rotor conductor 32 is also referred to as a rotor bar.

[0026] Figure 3 is a schematic cross-sectional view showing a part of the rotating electric machine 10 according to an embodiment taken along the line III-III in [reference]. Figure 1 in [reference]. Figure 4 is Figure 1 an enlarged view of cross-section IV in [reference].

[0027] As Figure 1 and Figure 3 shown in [reference], the end ring 34 is formed in a substantially circular ring shape around the rotation center axis Ax. As Figure 1 and Figure 4 shown in [reference], the end ring 34 is connected to the front end portion 32d of the protruding portion 32a of the rotor conductor 32 outside the rotor core 31. The end ring 34 electrically connects the rotor conductors 32 to each other. The end ring 34 is fixed to the rotor conductor 32 by a joining tool such as a screw. The end ring 34 rotates integrally with the rotor core 31 and the rotor conductor 32. As Figure 4 shown in [reference], a recess 34b is provided on the outer peripheral surface 34a of the end ring 34. The outer peripheral surface 34a includes a bottom surface 34aa that serves as the bottom of the recess 34b. The end ring 34 has conductivity. In one example, the end ring 34 is made of a metal material. The material of the end ring 34 can be copper.

[0028] As Figure 1 shown in [reference], each rectifying member 61 extends between the end portion 31b of the rotor core 31 and the end ring 34. Specifically, as Figure 1 , Figure 2 and Figure 4 shown in [reference], the rectifying member 61 extends on the outer peripheral surface 31a in the radial direction of the end portion 31b of the rotor core 31 and the outer peripheral surface 34a in the radial direction of the end ring 34, covering the protruding portion 32a of the rotor conductor 32. The rectifying member 61 is fixed to the end ring 34 by a fixing tool such as a screw. The rectifying member 61 rotates integrally with the rotor core 31, the rotor conductor 32, and the end ring 34. The Young's modulus of the material of the rectifying member 61 is greater than the Young's modulus of the material of the end ring 34. In one example, the rectifying member 61 is made of iron. The rectifying member 61 is also referred to as a protection ring, a covering member, or a strengthening member.

[0029] As Figure 3 and Figure 4As shown, the rectifying member 61 is formed in a substantially cylindrical shape around the rotation center axis Ax. The rectifying member 61 has an outer peripheral surface 61a and an inner peripheral surface 61b. The outer peripheral surface 61a is formed in a cylindrical shape around the rotation center axis Ax. In the radial direction, the outer peripheral surface 61a is located at the same position as the outer peripheral surface 31a of the core body 50 of the rotor core 31, or is located inside the outer peripheral surface 31. In other words, the outer peripheral surface 61a of the rectifying member 61 does not protrude outward in the radial direction relative to the outer peripheral surface 31a of the core body 50.

[0030] The rectifying member 61 includes a base portion 61c and a reinforcing portion 61d. The base portion 61c extends in the axial direction from the outer peripheral surface 31a of the end portion 31b of the rotor core 31. The base portion 61c is disposed in a concave portion 32c (an example of a first concave portion) on the end face 32b of the rotor conductor 32. The reinforcing portion 61d is connected to the base portion 61c and is disposed in a concave portion 34b of the end ring 34. The reinforcing portion 61d is joined (fixed) to the end ring 34 by a joining tool such as a screw. The reinforcing portion 61d reinforces the end ring 34 and also reinforces the base portion 61c.

[0031] A concave portion 61e (an example of a second concave portion) is provided on the inner peripheral surface 61b of the rectifying member 61. The concave portion 61e of the rectifying member 61 and the concave portion 32c of the rotor conductor 32 face each other to form a space 91 therebetween.

[0032] The housing 13 includes a frame 41 and a pair of bearing brackets 42. The frame 41 is formed in a substantially cylindrical shape around the rotation center axis Ax. The stator 11 and the rotor 12 are disposed inside the frame 41. The stator core 21 is fixed to the frame 41.

[0033] The bearing brackets 42 are connected to both ends of the frame 41 in the axial direction. The bearing brackets 42 enclose the space inside the frame 41. The bearing brackets 42 hold the corresponding bearings 15.

[0034] The shaft 14 is formed in a substantially cylindrical shape extending along the rotation center axis Ax. The shaft 14 passes through the bearing brackets 42 and extends across the inside and outside of the housing 13. The shaft 14 is supported by the bearings 15 so as to be rotatable about the rotation center axis Ax.

[0035] The shaft 14 extends axially through the inside of the stator 11 and the rotor 12. The rotor core 31 of the rotor 12 is joined to the circumferential surface 14a of the shaft 14. The rotor 12 and the shaft 14 can rotate integrally about the rotation center axis Ax relative to the stator 11.

[0036] The inner fan 16 is joined to the shaft 14 inside the housing 13. The inner fan 16 can rotate integrally with the shaft 14 about the rotation center axis Ax. The inner fan 16 rotates to generate an air flow for cooling the stator 11 and the rotor 12.

[0037] The external fan 17 is coupled to the shaft 14 outside the housing 13. The external fan 17 can rotate integrally with the shaft 14 about the rotation center axis Ax. The external fan 17 rotates to generate an air flow, for example, flowing along the outer surface of the housing 13. The air flow generated by the external fan 17 can pass through the cooling tubes that cool the inside of the housing 13.

[0038] The flow of gas (e.g., air) inside the housing 13 of the rotating electric machine 10 having the above structure will be described below. Through the internal fan 16 that rotates integrally with the shaft 14, the Figure 1 gas inside the housing 13 is sent to the gap K between the stator core 21 and the rotor core 31. The gas flows through the gap K in the axial direction and cools the stator core 21 and the rotor core 31. At this time, the gas flows along the outer peripheral surface 61a of the rectifying member 61 on the side of the internal fan 16 among the two rectifying members 61 and flows into the gap K. That is, the rectifying member 61 rectifies the gas so that the gas flows toward the gap K in the axial direction. After flowing out from the gap K, the gas flows along the outer peripheral surface 61a of the rectifying member 61 on the side opposite to the internal fan 16 among the two rectifying members 61. That is, the rectifying member 61 rectifies the gas so that the gas flows toward the gap K in the axial direction.

[0039] Meanwhile, the rotating electric machine 110 of the comparative example will be described with reference to Figure 5 FIG. Figure 5 FIG. 12 is a cross-sectional view schematically showing a part of the rotating electric machine 110 of the comparative example, and this part corresponds to the Figure 4 part in FIG. Compared with the rotating electric machine 10 according to the embodiment of the present disclosure, the rotating electric machine 110 of the comparative example does not have a rectifying member (61). As shown in Figure 5 FIG. 12, in the rotating electric machine 110 of the comparative example, the end face 132b and the recess 132c of the rotor conductor 132 and the outer peripheral surface 134a of the end ring 134 are exposed. Therefore, the gas flows along the stepped portion between the end face 132b of the recess 132c of the rotor conductor 132 and the outer peripheral surface 134a of the end ring 134. In the rotating electric machine 110 of the comparative example having such a structure, relatively large mechanical losses may occur. In addition, in such a rotating electric machine 110 of the comparative example, the gas tends to move in the circumferential direction with respect to the recess 132c of the rotor conductor 132.

[0040] On the other hand, in the rotating electric machine 10 of the present disclosure, the rectifying member 61 is provided to straddle between the outer peripheral surface 31a in the radial direction of the end portion 31b of the rotor core 31 and the outer peripheral surface 34a in the radial direction of the end ring 34, covering the protruding portion 32a of the rotor conductor 32. According to this structure, as shown in Figure 4As shown in the figure, the rectifying member 61 covers the end face 32b of the recess 32c including the rotor conductor 32 and the outer peripheral surface 34a of the recess 34b including the end ring 34. Therefore, the gas flows along the outer peripheral surface 61a of the rectifying member 61, thereby suppressing the occurrence of mechanical losses in the rotating electric machine 10. In addition, in the present embodiment, the gas in the recess 32c (space 91) of the rotor conductor 32 tends to rotate integrally with the rotor conductor 32. Therefore, the occurrence of mechanical losses in the rotating electric machine 10 can be further suppressed.

[0041] As described above, the rotating electric machine 10 of the present embodiment includes a stator 11, a shaft 14, a rotor core 31, a plurality of rotor conductors 32, an end ring 34, and a rectifying member 61. The shaft 14 extends through the inside of the stator 11 and is rotatable relative to the stator 11 about the rotation center axis Ax. The rotor core 31 has an end portion 31b in the axial direction of the rotation center axis Ax. The rotor core 31 is located inside the stator 11 and is coupled to the shaft 14. The rotor conductors 32 penetrate the rotor core 31 in the axial direction. The rotor conductors 32 are spaced apart from each other in the circumferential direction of the rotation center axis Ax. Each rotor conductor 32 has a protruding portion 32a that protrudes axially from the end portion 31b. The rotor conductors 32 are conductive. The end ring 34 connects the front end portions 32d of the protruding portions 32a of the rotor conductors 32. The rectifying member 61 spans the outer peripheral surface 31a of the end portion 31b in the radial direction of the rotation center axis Ax and the outer peripheral surface 34a of the end ring 34 in the radial direction, covering the protruding portions 32a of the rotor conductors 32.

[0042] According to the above structure, the rectifying member 61 spans the outer peripheral surface 31a of the end portion 31b in the radial direction of the rotation center axis Ax and the outer peripheral surface 34a of the end ring 34 in the radial direction, covering the protruding portions 32a of the rotor conductors 32. Therefore, the gas inside the rotating electric machine 10 flows along the outer peripheral surface 61a of the rectifying member 61. Therefore, the occurrence of mechanical losses (windage losses) in the rotating electric machine 10 can be reduced. High efficiency of the rotating electric machine 10 can be achieved. In addition, the occurrence of mechanical losses (fluid losses) in the rotating electric machine 10 is reduced, so that the heat generated due to the mechanical losses can be reduced. As a result, the rotating electric machine 10 can be prevented from having a high temperature. In addition, since the rectifying member 61 is provided as described above, the strength and rigidity of the rotor core 31 can be improved.

[0043] In addition, the outer peripheral surface 34a of the end ring 34 includes a recess 34b. The rectifying member 61 includes a base portion 61c and a reinforcing portion 61d. The base portion 61c extends axially from the outer peripheral surface 31a of the end portion 31b of the rotor core 31. The reinforcing portion 61d is connected to the base portion 61c and is provided in the recess 34b of the end ring 34.

[0044] According to such a structure, the reinforcing portion 61d can reinforce the end ring 34 and the base portion 61c.

[0045] In the foregoing description, the term "inhibit" is defined as preventing the occurrence of an event, action, or effect, or reducing the degree of an event, action, or effect.

[0046] While certain embodiments have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the invention. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the invention.

Claims

1. A rotating electric machine, comprising: A stator; A shaft that extends through the inside of the stator and is capable of rotating relative to the stator about a rotation center axis; A rotor core having an end portion in the axial direction of the rotation center axis, located inside the stator, and coupled to the shaft; A plurality of rotor conductors that penetrate the rotor core in the axial direction and are spaced apart in the circumferential direction of the rotation center axis, and each of the rotor conductors includes a protruding portion that protrudes from the end portion of the rotor core in the axial direction; An end ring that connects the front end portions of the protruding portions of the plurality of rotor conductors; and A rectifying member that covers the protruding portions of the plurality of rotor conductors across the outer peripheral surface of the end portion of the rotor core in the radial direction of the rotation center axis and the outer peripheral surface of the end ring in the radial direction.

2. The rotating electric machine according to claim 1, wherein A concave portion is provided on the outer peripheral surface of the end ring, The rectifying member includes: A base portion that extends in the axial direction from the outer peripheral surface of the end portion of the rotor core, and A reinforcing portion that is connected to the base portion, is provided in the concave portion, and is coupled to the end ring.

3. The rotating electric machine according to claim 1, wherein The outer peripheral surface of the rectifying member is in the same position as the outer peripheral surface of the rotor core in the radial direction of the rotation center axis.

4. The rotating electric machine according to claim 1, wherein The outer peripheral surface of the rectifying member is located inside the outer peripheral surface of the rotor core in the radial direction of the rotation center axis.

5. The rotating electric machine according to any one of claims 1 to 4, wherein Each of the plurality of rotor conductors includes an end face provided with a first concave portion, The rectifying member includes an inner peripheral surface provided with a second concave portion, and The first concave portion and the second concave portion face each other to form a space therebetween.

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