WO2008004286A1

WO2008004286A1 - Rotating electric machine and shaft for rotating electric machine

Info

Publication number: WO2008004286A1
Application number: PCT/JP2006/313378
Authority: WO
Inventors: Nobuhiro Kanei; Teturou Oogushi; Seiji Haga
Original assignee: Mitsubishi Electric Corporation
Priority date: 2006-07-05
Filing date: 2006-07-05
Publication date: 2008-01-10

Abstract

A rotating electric machine having a rotating shaft with a rotor and a hollow path axially extending in the shaft, where the rotor is cooled by allowing refrigerant pass through the path. A refrigerant inlet tube made up of circular tube groups is fixed in an intimately contacting manner to the inner peripheral surface of that portion of the hollow path in the shaft which corresponds to the rotor.

Description

Specification

Rotating electric machine and rotating electric machine shaft

Technical field

The present invention relates to a cooling structure for a rotating electrical machine such as a motor, and more particularly to a cooling structure of a type in which a hollow hole is provided in a rotor shaft to dissipate heat generated in the rotating electrical machine by injecting a coolant such as cooling water. The present invention relates to a rotating electric machine and a shaft of the rotating electric machine.

Background art

Conventionally, various cooling structures for cooling a Joule heat generated in a rotor by providing a refrigerant passage inside the rotor shaft and allowing the refrigerant to pass through the rotor shaft in order to cool a rotor such as an electric motor have been proposed. Being sung.

For example, by providing a hollow passage extending in the axial direction in the rotor shaft, and inserting a coil or fin made of a material with high thermal conductivity wound in a spiral shape into the passage, the above-mentioned A motor that efficiently cools the motor by the airflow flowing inside the passage (see, for example, Patent Documents 1 and 2), and a cooling liquid injection pipe that is fixed at one end to the motor casing in the hollow hole of the rotor shaft. There has been proposed one that can inject cooling water through a liquid injection pipe (see, for example, Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 10-14161

Patent Document 2: Japanese Patent Laid-Open No. 2000-34189

Patent Document 3: Japanese Patent Laid-Open No. 9-46973

Disclosure of the invention

Problems to be solved by the invention

[0004] However, in the motor described above, it is difficult to align the axial center of the rotor shaft and the refrigerant injection pipe inserted into the hollow hole of the rotor shaft, and also due to the shaft runout of the rotor shaft and the refrigerant injection pipe due to high-speed rotation. There was a problem that there was vibration, which could result in damage.

The present invention has been made to solve such a problem, and the object thereof is to align the axial center of the rotor shaft and the refrigerant injection pipe inserted into the hollow hole of the rotor shaft. It is an object of the present invention to provide an easily manufactured rotating electrical machine that can reduce complexity and can be used stably at high speed.

Means for solving the problem

[0005] In order to achieve the above-mentioned object, the present invention includes a shaft to which a rotor is attached and rotates, and a hollow passage extending in the axial direction is provided in the shaft, and a refrigerant is allowed to pass through the hollow passage. In the rotating electrical machine that cools the rotor by the above, a plurality of refrigerant injection pipes having a group of circular pipes are closely fixed to at least the inner peripheral surface of the rotor-corresponding portion of the hollow passage provided in the shaft. It is.

The present invention also provides a hollow passage extending in the axial direction of a rotating electrical machine shaft to which a rotor is attached, and a plurality of circular tube group forces that are closely fixed to at least the inner peripheral surface of the rotor in the passage. And a refrigerant injection pipe configured to cool the inlet by flowing the refrigerant through the passage.

The invention's effect

[0006] By configuring the present invention as described above, the complexity of aligning the shaft center during assembly can be reduced, workability is improved, and vibration due to shaft runout during high-speed rotation is eliminated. Thus, a cooling structure for a rotating electrical machine that can be used stably can be obtained. Brief Description of Drawings

FIG. 1 is a schematic cross section of a rotating electrical machine to which a cooling structure for a rotating electrical machine according to Embodiment 1 of the present invention is applied.

FIG. 2 is an axial sectional view showing a sectional structure of a shaft according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of part C in FIG. 2 above.

4 is a schematic cross-sectional view taken along a plane perpendicular to the shaft axis (AA in FIG. 2) according to Embodiment 1 of the present invention.

FIG. 5 is an axial sectional view showing a sectional structure of a shaft according to a second embodiment of the present invention.

6 is a schematic cross-sectional view taken along a plane (BB in FIG. 5) perpendicular to the shaft axis according to Embodiment 2 of the present invention.

FIG. 7 is a configuration diagram of an annular plate 26 having a circular tube group according to a second embodiment of the present invention.

FIG. 8 is an enlarged view of part D in FIG. BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Embodiment 1.

Hereinafter, a cooling structure for a rotating electrical machine as an object of the present invention will be described. 1 to 4 are diagrams showing a cooling structure according to Embodiment 1 of the present invention, and FIG. 1 is a subject of application of the present invention, in which a hollow hole is provided in a rotor shaft, and a coolant such as cooling water is injected therein. 1 is a cross-sectional view of a rotary electric machine of the type to be described. First, the schematic structure and operation thereof will be described. The figure shows an example in which the present invention is applied to a motor. The present invention includes a generator, a generator, and the like that are not limited to a motor, and can be applied to general rotating electrical machines including a rotor that needs to be cooled.

In FIG. 1, a motor 1 is configured by housing a rotating portion of a rotor (rotor) 2 and a stator (stator) 3 that supports the rotor 1 while surrounding it in a non-contact manner. ing. The frame 4 has a cylindrical shape along the axial direction of the rotor 2 and the stator 3. A stator 3 is fixed to a predetermined portion of the inner peripheral surface of the frame 4, the stator 3 has a thick cylindrical shape, and the outer peripheral surface thereof has the same diameter as the inner peripheral surface of the frame 4. A coil winding 5 for forming a rotating magnetic field is wound around the stator 3, and a part of the coil winding 5 protrudes outward from both ends of the stator 3 as a coil end 6.

[0010] In addition, on the inner side of the inner peripheral surface of the stator 3, there is provided a rotor 2 that is fixed integrally with the shaft 11 in a non-contact state with the stator 3. The rotor 2 has a cylindrical shape and is provided so as to be surrounded by the stator 3 at a position corresponding to the stator 3 in the axial direction. A plurality of aluminum slot bars 7 are embedded in the rotor 2 along the axial direction. Since the rotor 2 and the stator 3 are provided substantially concentrically, the circumferential gap (gap) existing between the rotor 2 and the stator 3 is constant.

Disc-shaped end brackets 8 and 9 are fixed to both ends in the longitudinal direction of the frame 4. Each of the end brackets 8 and 9 is provided with a bearing 10 at the center thereof, and a shaft 11 passes therethrough. The rotor 2 and the shaft 11 are fixed by shrinkage fitting. The shaft 11 is provided with a hollow hole 11 a having a circular cross section and extending in the axial direction coaxially with the shaft 11, and this forms a refrigerant passage 12. The refrigerant passage 12 has air, water, Cooling medium 13 such as glycol or lubricating oil is allowed to pass through.

When a current is passed through the coil winding 5 wound around the stator 3 to form a rotating magnetic field, the slot bar 7 embedded in the port 2 receives a force, and the rotor 2 moves together with the shaft 11. While rotating, an eddy current is generated in the rotor 2 due to a change in the magnetic flux passing through the rotor 2. At this time, the heat generated by the copper loss due to the coil wire and the iron loss due to the stator core is conducted to the frame 4 through the stator 3 and released from the frame 4 to the atmosphere outside the motor.

In addition, when eddy current is generated in the rotor 2, the rotor 2 is integrally formed with the rotor 2 by shrink fitting so that heat is generated by the copper loss due to the slot bar 7 and the iron loss due to the rotor core. In addition, a coolant passage 12 is provided in the shaft 11, and a cooling medium 13 fed through a supply source force (not shown) flows and passes therethrough, so that there is a gap between the shaft 11 and the cooling medium 13. Heat exchange takes place at. Therefore, since the shaft 11 can be relatively cooled, the rotor 2 can also be cooled by its internal force.

2 to 4 show details of the rotor shaft structure of the rotating electrical machine of the present invention. A refrigerant injection pipe 21 having a circular tube group is integrally formed by shrink fitting on the inner peripheral surface of the refrigerant passage 12 which is a hollow through hole provided in the shaft 11 supporting the rotor 2. In shrink fitting, only the rotor shaft 11 is heated to 120 to 150 ° C. and expanded, and the centers of the rotor shaft 11 and the refrigerant injection pipe 21 are aligned so that the refrigerant injection pipe 21 reaches the entire length of the rotor 2. This is done by inserting to almost the corresponding position. Subsequent cooling causes the refrigerant injection pipe 21 with the circular tube group to be fixed to the inner surface of the shaft 11, and has a uniform cross section in the axial direction of the shaft 11 (that is, parallel to the axis). Only positions and lengths corresponding to the overall length of 2 will be provided.

[0015] The configuration of the refrigerant injection pipe 21 including the circular pipe group is as shown in Figs.

That is, a plurality of circular tubes 22 having a circular cross section with a large inner diameter are arranged in two steps in the outer circumferential direction, and a plurality of circular tubes 23 having an inner diameter force and a circular cross section are arranged in two steps in the inner circumferential direction and in the radial direction. Deploy. The circular pipes 22 and 23 are made of a material having a high thermal conductivity, such as copper or iron, and are shrink-fitted into the refrigerant passage 12 which is a hollow through hole having a circular cross section of the shaft 11. Since it is in close contact with the peripheral surface, the heat of the shaft 11 is easily transmitted to the refrigerant injection pipe 21 having a circular tube group. The heat from the rotor 2 is conducted to the shaft 11, and the inner peripheral surface force of the refrigerant passage 12 in the shaft 11 is also passed through the cooling medium 13 and the refrigerant injection pipe 21 including the circular pipe groups 22 and 23. Heat is dissipated to the cooling medium 24 that passes through the circular pipe 22 having a large inner diameter and the cooling medium 25 that passes through the circular pipe 23 having a small inner diameter. At this time, since the cooling medium 13 is agitated by the shaft 21 having the circular pipe group, as shown in FIG. 3, at the outflow portion of the refrigerant injection pipe 21 having the circular pipe group, the jet 32 and the jet 33 As a result, the flow is disturbed, the heat transfer from the shaft 11 to the cooling medium 13, 24, 25 is increased, and the cooling effect is increased.

[0017] Further, since the refrigerant injection pipe 21 including the circular pipe group has a uniform cross-sectional shape and dimensions in the axial direction, the cooling effect of the rotor 2 is increased uniformly in the axial direction of the shaft 11. . Furthermore, since the heat transfer surface area is increased by the refrigerant injection pipe 21 having the circular tube group, and the member having a high thermal conductivity is also formed as described above, the heat of the shaft 11 passes through the refrigerant injection pipe 21. Thus, heat is smoothly radiated to the cooling medium 13 and the effect of increasing the cooling effect of the rotor is also obtained.

[0018] The refrigerant injection pipe 21 provided with the circular pipe group includes an outer circular pipe 22 having a large inner diameter and an inner pipe 20 having an inner diameter of 20% to 25% of the inner diameter of the refrigerant passage 12, and an inner small circular pipe 23 having an inner diameter. Good results can be obtained if the inner diameter is 10% to 15% of the inner diameter of the refrigerant passage 12 and eight are arranged in the circumferential direction. More specifically, when the inner diameter of the shaft 11 is 4 Omm, the refrigerant injection pipe 21 provided with a group of circular pipes, for example, the outer diameter of the circular pipe 22 is 10 mm, the inner diameter is 8 mm, and the inner diameter is 8 Good results can be obtained when the inner diameter is 23 mm and the inner diameter is 8 mm. Also, at 15 OOr / min, the heat transfer coefficient on the inner wall surface is compared with the case where the refrigerant injection pipe 21 with the circular tube group is not provided (when only the hollow through hole is provided in the shaft 11). As a result, it was confirmed that the improvement was about 1.6 times.

[0019] Embodiment 2.

FIGS. 5 to 8 show a cooling structure for a rotating electrical machine according to the second embodiment of the present invention, and FIG. 1 described in the first embodiment is similarly applied to the second embodiment. In the drawings of the second embodiment, the same reference numerals as those in the first embodiment denote the same or corresponding parts. 5 is an axial sectional view showing the sectional structure of the rotor shaft according to the second embodiment, FIG. 6 is a sectional view taken along the line B-B, FIG. 7 is a perspective view of the refrigerant injection pipe, and FIG. 5 shows an enlarged view of part D.

In the second embodiment, the refrigerant injection pipe 21 having the circular pipe plate 26 is provided on the inner peripheral surface of the refrigerant passage 12 that is a hollow through hole provided in the shaft 11 that supports the rotor 2. It is integrally formed by shrink fitting. As shown in the figure, the refrigerant injection pipe 21 provided with the annular plate 26 is formed by passing through the annular plate 26 having a plurality of small-diameter circular tubes 28 in the circumferential direction and having a uniform cross section in the hollow axial direction. The large-diameter circular tube 29 having the holes 29a is arranged on the outer periphery with a predetermined interval in the axial direction thereof. The annular plate 26 is integrally attached to the large-diameter circular pipe 29 by welding or the like. A plurality of annular plates 26 are provided at positions substantially corresponding to the entire length of the rotor 2. The shaft 11 and the refrigerant injection pipe 21 have the same axis.

[0021] The refrigerant injection pipe 21 is made of a material having a high thermal conductivity such as copper or iron, and is shrink-fitted into the refrigerant passage 12 which is a hollow through hole of the rotor shaft 11, so that the inner circumference of the refrigerant passage 12 is obtained. The shaft 11 is in close contact with the surface so that the heat of the shaft 11 can be easily transferred to the annular plate 26. At this time, as in the first embodiment, the shrink fitting is performed by heating only the rotor shaft 11 to 120 to 150 ° C. so that the center of the rotor shaft 11 and the large-diameter circular tube 29 having the through hole 29a are aligned. Then, the circular tube 29 is inserted in the axial direction in the refrigerant passage 12 to a position substantially corresponding to the entire length of the rotor 2. Since the outer diameters of the plurality of annular plates 26 are all the same, as in the first embodiment, it is not necessary to align the center of the shaft at the time of assembly, and workability is improved. Furthermore, since vibration due to shaft runout during high-speed rotation is eliminated, a rotating electrical machine that can be used stably at high-speed rotation can be obtained.

Heat from the rotor 2 is conducted to the shaft 11, and flows from the inner peripheral surface of the refrigerant passage 12 in the shaft 11 through the cooling medium 13 and the plurality of small diameter circular pipes 28 in the annular plate 26. Furthermore, heat is radiated to the cooling medium 31 flowing through the through hole 29a through the annular plate 26. At this time, since the cooling medium 13 is agitated by the annular plate 26 having the small-diameter circular tube 28, as shown in FIG. 8, a jet 34 is generated at the outflow portion of the annular plate 26, and the flow is disturbed. Therefore, the heat transfer from the shaft 11 to the cooling medium 13, 30, 31 is increased, and the cooling effect is increased.

[0023] In addition, the annular plate 26 having the small-diameter circular tube 28 and the circular tube 29 having the hollow axially uniform cross-section and the through-hole 29a have a uniform cross-sectional shape and dimensions in the axial direction. Because there is The cooling effect of the rotor is increased uniformly in the axial direction of the shaft 11. Further, since the annular plate 26 and the large-diameter circular tube 29 are also configured with a member having a high thermal conductivity, the heat of the shaft 11 is radiated to the cooling medium 13, 30, 31 through these members, The circular plate 26 and the large-diameter circular tube 29 have the effect of increasing the heat transfer surface area and increasing the cooling effect of the rotor.

Note that the refrigerant injection pipe 21 including the annular plate 26 provided with the small-diameter circular pipe 28 and the circular pipe 29 having a through hole 29a having a uniform cross section in the hollow axial direction is the same as the small-diameter circular pipe 28. When the inner diameter is 10% to 15% of the inner diameter of the refrigerant passage 12, the inner diameter of the through hole 29a is 50% to 55% of the inner diameter of the refrigerant passage 12, and eight small diameter circular pipes 28 are arranged around the circular pipe 29. Good results are obtained. More specifically, for example, when the shaft inner diameter force was 0 mm, it was confirmed that good results could be obtained by providing the inner diameter of the circular hole 28 5 mm, eight circumferential directions, and the inner diameter 20 mm of the through hole 29a. In addition, the heat transfer on the inner wall surface is compared with the case where the circular pipe 29 having the annular plate 26 and the through hole 29a is not provided (that is, the case where only the hollow through hole is provided in the shaft 11). As a result, it was confirmed that the rate was improved by about 1.2 times at 1500r / min.

Claims

The scope of the claims

[1] A rotary electric machine that includes a rotating shaft with a rotor attached thereto, and that has a hollow passage extending in the axial direction in the shaft, and that cools the rotor by passing a refrigerant through the hollow passage. A rotating electric machine, wherein a plurality of refrigerant injection pipes having a group of circular pipes are tightly fixed to at least an inner peripheral surface of a rotor-corresponding portion of a hollow passage provided in the rotary passage.

[2] The refrigerant injection pipe is structured such that a plurality of large-diameter circular pipes and a plurality of small-diameter circular pipes arranged in the circumferential direction are arranged in multiple stages in the radial direction. The rotating electrical machine according to claim 1.

[3] The refrigerant injection pipe has a large-diameter circular pipe that is 20% to 25% of the inner diameter of the hollow refrigerant passage.

3. The rotating electrical machine according to claim 2, wherein the small-diameter circular tube is 10% to 15% of the inner diameter of the hollow refrigerant passage.

[4] The refrigerant injection pipe includes an annular plate having a plurality of small-diameter circular pipes in the circumferential direction, and the outer circumference of the large-diameter circular pipe having a through-hole having a uniform cross section in the hollow axial direction. 2. The rotating electrical machine according to claim 1, wherein the rotating electric machine is configured with a force arranged in the axial direction at a predetermined interval.

[5] The refrigerant injection pipe has a small-diameter circular pipe that is 10% to 15% of the inner diameter of the hollow refrigerant passage.

5. The rotating electrical machine according to claim 4, wherein an inner diameter of the through hole is 50% to 55% of an inner diameter of the hollow refrigerant passage.

6. The rotating electrical machine according to any one of claims 1 to 5, wherein the refrigerant injection pipe is fixed to the shaft by shrink fitting.

7. The rotating electrical machine according to any one of claims 1 to 5, wherein the refrigerant injection pipe is formed of a member having a large thermal conductivity! /.

[8] A shaft on which a rotor is attached and rotates, and a hollow passage extending in an axial direction;

And a refrigerant injection pipe comprising a plurality of circular pipe groups that are closely fixed to the inner peripheral surface of the rotor corresponding portion of the passage, and the rotor is cooled by flowing the refrigerant through the passage. shaft.