Rotary electric machine

Abstract

To provide a rotary electric machine capable of reducing generation of a mechanical loss.SOLUTION: A rotary electric machine comprises a stator, a shaft, a rotor core 31, a plurality of rotor conductors 32, an end ring 34, and a rectification member 61. The rotor conductors 32 are disposed side by side while penetrating the rotor core 31 in an axial direction and being spaced from each other in a circumferential direction of a rotation center axis, and each of the rotor conductors includes a protrusion 32a protruding from an end 31b of the rotor core 31 in the axial direction. The end ring 34 connects tips 32d of the protrusions 32a of the plurality of rotor conductors 32. The rectification member 61 covers the protrusions 32a of the plurality of rotor conductors 32 over an outer peripheral surface 31a in the end 31b in a radial direction of the rotation center axis and an outer peripheral surface 34a in the end ring 34 in the radial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a rotating electrical machine.

Background Art

[0002] A rotating electrical machine having a cage rotor is known. The cage rotor has, for example, a rotor core, a plurality of rotor conductors, and an end ring connecting the plurality of rotor conductors. The rotor conductors have protruding portions protruding from the rotor core, and the end ring is connected to the protruding portions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of rotating electrical machine, for example, when the airflow generated in the rotating electrical machine flows along the protruding portions of the rotor conductors and the end ring, it flows along the step or the like between the protruding portions of the rotor conductors and the end ring, so mechanical losses are likely to occur.

[0005] An example of the problem to be solved by the present invention is to obtain a rotating electrical machine capable of reducing the occurrence of mechanical losses.

Means for Solving the Problems

[0006] A rotating electrical machine according to an embodiment of the present invention includes a stator, a shaft that extends through the inside of the stator and is rotatable about a rotation center axis with respect to the stator, a rotor core that has an axial end portion of the rotation center axis, is located inside the stator, and is coupled to the shaft, a plurality of conductive rotor conductors that penetrate the rotor core in the axial direction and are arranged at intervals in the circumferential direction of the rotation center axis, each having a protruding portion that protrudes from the end portion in the axial direction, an end ring that connects the tip ends 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 radially outer peripheral surface of the rotation center axis at the end portion and the radially outer peripheral surface of the end ring.

Advantages of the Invention

[0007] According to the present invention, a rotating electrical machine capable of reducing the occurrence of mechanical losses can be obtained.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Embodiments will be described below with reference to the drawings. In this specification, the components according to the embodiments and the descriptions of the components may be described in a plurality of expressions. The components and their descriptions are examples and are not limited by the expressions in this specification. The components may be specified by different names from those in this specification. Also, the components may be described by expressions different from those in this specification.

[0010] Also, the drawings are schematic, and the dimensional relationships of the respective elements, the ratios of the respective elements, etc. may be different from the actual ones. Also, there may be portions where the dimensional relationships and ratios of the drawings are different from each other.

[0011] FIG. 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. Note that the rotating electrical machine 10 is not limited to this example.

[0012] 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. Note that the rotating electrical machine 10 is not limited to this example. For example, the rotating electrical machine 10 may further include other components such as an outer fan cover.

[0013] The stator 11 includes a stator core 21 and a stator winding 22. The stator core 21 is formed in a substantially cylindrical shape surrounding the rotation center axis Ax.

[0014] The rotation center axis Ax is the center of rotation of the rotor 12 and the shaft 14 in the rotating electrical machine 10 and is, for example, 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 are 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.

[0015] The stator winding 22 penetrates through the slots provided in the stator core 21 and is attached to the stator core 21.

[0016] The rotor 12 is a squirrel-cage rotor. The rotor 12 includes a rotor core 31, a plurality of rotor conductors 32, two end rings 34, and two rectifying members 61. The end ring 34 is an example of a short-circuit ring.

[0017] The rotor core 31 is formed in a substantially cylindrical shape surrounding the rotation center axis Ax and is disposed inside the stator core 21. The rotor core 31 has, for example, a core body 50 and two holding plates 52. The core body 50 has a plurality of steel plates 51 arranged in the axial direction. The steel plates 51 are formed in a disc shape surrounding the rotation center axis Ax and are made of, for example, ferromagnetic silicon steel. The two holding plates 52 are located on both axial sides of the core body 50 and sandwich the core body 50 in the axial direction. The holding plate 52 is formed in a disc shape surrounding the rotation center axis Ax and is made of a metal material.

[0018] 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 and faces radially outward. The outer peripheral surface 31a faces the stator core 21 of the stator 11 with a gap K therebetween. The gap K functions as a flow path. The end portion 31b is an end portion of the rotor core 31 in the axial direction. The end portion 31b includes, for example, at least a part of the holding plate 52. The axial end surface of the end portion 31b is formed substantially flat and faces in the axial direction.

[0019] A plurality of through holes 35 are provided in the rotor core 31. The through holes 35 penetrate the rotor core 31 in the axial direction. Therefore, the through holes 35 open at the axial end surfaces of both end portions 31b of the rotor core 31 in the axial direction. The plurality of through holes 35 are arranged at substantially equal intervals in the circumferential direction with spaces therebetween. A part of the through holes 35 is spaced apart from the outer peripheral surface 31a.

[0020] FIG. 2 is a cross-sectional view schematically showing a part of the rotating electrical machine 10 of the embodiment. As shown in FIG. 2, the radially outer end 35a of the through hole 35 in the pressing plate 52 opens to the outer peripheral surface 52a of the pressing plate 52. The outer peripheral surface 52a of the pressing plate 52 is included in the outer peripheral surface 31a of the rotor core 31.

[0021] As shown in FIGS. 1 and 2, a plurality of rotor conductors 32 are inserted into the through holes 35 of the rotor core 31, penetrate the rotor core 31 in the axial direction, and are arranged at intervals in the circumferential direction. The rotor conductor 32 has a protruding portion 32a (FIG. 1). The protruding portion 32a is also referred to as a straight portion. The protruding portion 32a protrudes axially from the end 31b of the rotor core 31. As shown in FIG. 2, the radially outer end face 32b of the rotor conductor 32 is formed so as to be aligned with the outer peripheral surface 52a of the pressing plate 52 in the circumferential direction. The rotor conductor 32 is made of a conductive metal material. For example, the rotor conductor 32 contains aluminum. The rotor conductor 32 is also referred to as a rotor bar.

[0022] FIG. 3 is a cross-sectional view schematically showing a part of the rotating electrical machine 10 of the embodiment along line III-III in FIG. 1. FIG. 4 is an enlarged view of part IV in FIG. 1.

[0023] As shown in FIGS. 1 and 3, the end ring 34 is formed in a substantially annular shape surrounding the rotation center axis Ax. As shown in FIGS. 1 and 4, the end ring 34 is connected to the tip 32d of the protruding portion 32a of the rotor conductor 32 outside the rotor core 31. The end ring 34 electrically connects a plurality of rotor conductors 32 to each other. The end ring 34 is fixed to the plurality of rotor conductors 32 by a coupling tool such as a screw. The end ring 34 rotates integrally with the rotor core 31 and the rotor conductor 32. As shown in FIG. 4, 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 forms the bottom of the recess 34b. The end ring 34 is made of, for example, a metal material and has conductivity. The material of the end ring 34 is, for example, copper.

[0024] As shown in FIG. 1, the rectifying member 61 extends across the end portion 31b of the rotor core 31 and the end ring 34. Specifically, as shown in FIGS. 1, 2, and 4, the rectifying member 61 extends across the radially outer peripheral surface 31a at the end portion 31b of the rotor core 31 and the radially outer peripheral surface 34a of the end ring 34, covering the protruding portions 32a of the plurality of rotor conductors 32. The rectifying member 61 is fixed to the end ring 34, for example, by a fixing portion such as a screw. The rectifying member 61 rotates integrally with the rotor core 31, the rotor conductors 32, and the end ring 34. The Young's modulus of the material of the rectifying member 61 is larger than the Young's modulus of the material of the end ring 34. The rectifying member 61 is made of, for example, iron. The rectifying member 61 is also referred to as a protective ring, a cover member, or a reinforcing member.

[0025] As shown in FIG. 4, the rectifying member 61 is formed in a substantially cylindrical shape surrounding 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 surrounding the rotation center axis Ax. The radial position of the outer peripheral surface 61a is, for example, the same position as the outer peripheral surface 31a of the core body 50 of the rotor core 31, and is located radially inward of the outer peripheral surface 31a. That is, the outer peripheral surface 61a of the rectifying member 61 does not protrude radially outward with respect to the outer peripheral surface 31a of the core body 50.

[0026] Further, the rectifying member 61 has 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 base portion 61c is received in the recess 32c of the rotor conductor 32. The reinforcing portion 61d is connected to the base portion 61c and is received in the recess 34b of the end ring 34. The reinforcing portion 61d is coupled (fixed) to the end ring 34 by a coupling tool such as a screw. The reinforcing portion 61d reinforces the end ring 34 and also reinforces the base portion 61c.

[0027] Further, a concave portion 61e 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 overlap each other. The concave portion 61e of the rectifying member 61 and the concave portion 32c of the rotor conductor 32 form a space 91.

[0028] The housing 13 has a frame 41 and two bearing brackets 42. The frame 41 is formed in a substantially cylindrical shape surrounding 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.

[0029] The two bearing brackets 42 are connected to both ends of the frame 41 in the axial direction. The bearing brackets 42 block the space inside the frame 41. Each of the bearing brackets 42 holds a corresponding bearing 15.

[0030] 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 rotatably supported by the bearings 15 around the rotation center axis Ax.

[0031] The shaft 14 extends axially through the inside of the stator 11 and the rotor 12. The shaft 14 is coupled to the rotor core 31 of the rotor 12. The rotor 12 and the shaft 14 can rotate integrally around the rotation center axis Ax with respect to the stator 11.

[0032] The inner fan 16 is coupled to the shaft 14 inside the housing 13. The inner fan 16 can rotate integrally with the shaft 14 around the rotation center axis Ax. By rotating, the inner fan 16 generates an air flow for cooling the stator 11 and the rotor 12.

[0033] The outer fan 17 is coupled to the shaft 14 outside the housing 13. The outer fan 17 can rotate about the rotation center axis Ax integrally with the shaft 14. By rotating, the outer fan 17 generates, for example, an air flow flowing along the outer surface of the housing 13. The air flow generated by the outer fan 17 may pass through a cooling pipe that cools the inside of the housing 13.

[0034] The flow of the gas (for example, air) inside the housing 13 in the rotating electric machine 10 having the above configuration will be described. The gas inside the housing 13 shown in FIG. 1 is sent toward the gap K between the stator core 21 and the rotor core 31 by the inner fan 16 that rotates integrally with the shaft 14. The gas flows in the axial direction through the gap K 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 inner fan 16 side among the two rectifying members 61 and flows into the gap K. That is, the rectifying member 61 rectifies the gas so that it flows toward the gap K along the axial direction. Further, 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 inner fan 16 among the two rectifying members 61. That is, the rectifying member 61 rectifies the gas so that it flows toward the gap K along the axial direction.

[0035] Here, the rotating electric machine 110 of the comparative example will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view schematically showing a part of the rotating electric machine 110 of the comparative example corresponding to FIG. 4. The rotating electric machine 110 of the comparative example is different from the rotating electric machine 10 of the present embodiment in that the rectifying member 61 is not provided. As shown in FIG. 5, in the rotating electric machine 110 of the comparative example, since the end face 32b and the recess 32c of the rotor conductor 32 and the outer peripheral surface 34a of the end ring 34 are exposed, the gas flows along the step between the rotor conductor 32 and the end ring 34. In the rotating electric machine 110 of the comparative example having such a configuration, a relatively large mechanical loss occurs. Further, in such a rotating electric machine 110 of the comparative example, the gas easily moves relative to the recess 32c of the rotor conductor 32 in the circumferential direction.

[0036] In contrast, in the rotating electrical machine 10 of the present embodiment, the rectifying member 61 covers the protruding portions 32a of the plurality of rotor conductors 32 across the radially outer peripheral surface 31a at the end portion 31b of the rotor core 31 and the radially outer peripheral surface 34a of the end ring 34. Therefore, since the gas flows along the outer peripheral surface 61a of the rectifying member 61, the occurrence of mechanical loss in the rotating electrical machine 10 is suppressed. Further, in the present embodiment, the gas in the recess 32c (space 91) of the rotor conductor 32 rotates integrally with the rotor conductor 32 and thus the occurrence of mechanical loss in the rotating electrical machine 10 is suppressed.

[0037] As described above, the rotating electrical machine 10 of the 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 about the rotation center axis Ax with respect to the stator 11. The rotor core 31 has an end portion 31b in the axial direction of the rotation center axis Ax, is positioned inside the stator 11, and is coupled to the shaft 14. The rotor conductors 32 penetrate the rotor core 31 in the axial direction and are arranged at intervals from each other in the circumferential direction of the rotation center axis Ax, and each has a protruding portion 32a protruding axially from the end portion 31b. The rotor conductors 32 are conductive. The end ring 34 connects the tip ends 32d of the protruding portions 32a of the plurality of rotor conductors 32. The rectifying member 61 covers the protruding portions 32a of the plurality of rotor conductors 32 across the radially outer peripheral surface 31a of the rotation center axis Ax at the end portion 31b and the radially outer peripheral surface 34a of the end ring 34.

[0038] According to such a configuration, since the commutation member 61 covers the protruding portions 32a of the plurality of rotor conductors 32 across the outer peripheral surface 31a in the radial direction of the rotation center axis Ax at the end portion 31b and the outer peripheral surface 34a in the radial direction of the end ring 34, the gas inside the rotating electrical machine 110 flows along the outer peripheral surface 61a of the commutation member 61. Therefore, the occurrence of mechanical loss (wind loss) in the rotating electrical machine 110 can be reduced. Accordingly, high efficiency of the rotating electrical machine 10 can be achieved. Further, since the occurrence of mechanical loss (fluid loss) in the rotating electrical machine 110 is reduced, the generation of heat due to mechanical loss can be reduced, and thus the rotating electrical machine 110 can be prevented from becoming high temperature. Further, since the commutation member 61 is provided in this way, the strength and rigidity of the rotor core 31 can be improved.

[0039] Further, a recess 34b is provided on the outer peripheral surface 34a of the end ring 34. The commutation member 61 has 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 inserted into the recess 34b of the end ring 34.

[0040] According to such a configuration, the end ring 34 and the base portion 61c can be reinforced by the reinforcing portion 61d.

[0041] In the above description, suppression is defined as, for example, preventing the occurrence of an event, action, or influence, or reducing the degree of an event, action, or influence.

[0042] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0043] 10... Rotating electric machine, 11... Stator, 14... Shaft, 31... Rotor core, 31a, 34a... Outer peripheral surface, 31b... End portion, 32... Rotor conductor, 32a... Protrusion, 32d... Tip portion, 34... End ring, 34b... Recess, 61... Rectifying member, 61c... Base portion, 61d... Reinforcing portion, Ax... Rotation center axis.

Claims

1. A stator; A shaft extending through the inside of the stator and rotatable about a rotation center axis with respect to the stator; A rotor core having an axial end portion of the rotation center axis, located inside the stator, and coupled to the shaft; A plurality of conductive rotor conductors penetrating the rotor core in the axial direction and arranged at intervals in the circumferential direction of the rotation center axis, each having a protruding portion protruding in the axial direction from the end portion; An end ring connecting the tip ends of the protruding portions of the plurality of rotor conductors; A rectifying member covering the protruding portions of the plurality of rotor conductors across the radially outer peripheral surface of the rotation center axis at the end portion and the radially outer peripheral surface of the end ring; A rotating electrical machine comprising the above components.

2. A recess is provided on the outer peripheral surface of the end ring; The rectifying member A base portion extending in the axial direction from the outer peripheral surface of the end portion; A reinforcing portion connected to the base portion, inserted into the recess, and coupled to the end ring; having The rotating electrical machine according to Claim 1.

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