Rotating Electric Machine

Abstract

To suppress temperature rise of a bearing by reducing heat transmission to the bearing and heat conduction from each portion of a rotary electric machine due to inside air to improve lubrication life of the bearing.SOLUTION: A rotary electric machine comprises: a rotor having a shaft 8; a stator 2 arranged opposite to the rotor at a predetermined gap (air gap) and supported by a stator frame 17; a bearing which supports the shaft by rotation; and an end bracket 5a which holds the bearing. A heat insulating layer 19 for preventing inflow of heat to the bearing is provided on the inside of a machine or the outside of the machine at the end bracket, and an inner fan 9 which is attached to the shaft and circulates air in the machine is provided. The heat insulating layer is characterized in that the heat insulating layer is provided in the end bracket on a side where the inner fan is installed, and a recess 21 is provided on the inside air side or the outside air side of the end bracket, heat insulating material is arranged in the recess, and the heat insulating material is sealed by a cover 22 fixed to the end bracket by a bolt.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine having an improved cooling structure for a bearing portion that supports a rotor shaft. [Background technology]

[0002] Generally, in a rotating electric machine which is roughly composed of a stator, a rotor, and a bearing section which supports the rotor shaft, as the power density increases, the coil temperature, the cooling air temperature inside the rotating electric machine, and the temperature of the bearing section increase.

[0003] Bearings such as rolling bearings are lubricated with grease or oil, and reducing the temperature rise in the bearings reduces the deterioration of the grease or oil, leading to an extension of the lubrication life of the bearings.

[0004] In order to reduce the temperature rise of the bearings, various cooling methods are provided for rotating electric machines. The cooling methods for rotating electric machines include an open type in which cooling air is taken in from the outside to cool each part inside the rotating electric machine, and a totally enclosed type in which no cooling air is introduced into the rotating electric machine. The totally enclosed type generally has a lower cooling capacity than the open type, so there is a demand for improving the cooling performance of the bearings in particular.

[0005] Patent Documents 1 and 2 are cited as prior art documents relating to improving the cooling performance of a bearing portion in a rotating electrical machine.

[0006] Patent Document 1 discloses a rotating electric machine that is provided with a fan for cooling the exhaust-side bearing and a ventilation passage, while Patent Document 2 discloses a rotating electric machine that cools the oil tank and bracket of a sliding bearing with air discharged from a cooler fan. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5143094 [Patent Document 2] Japanese Unexamined Patent Publication No. 63-107439 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the structure disclosed in Patent Document 1 has the disadvantage that the structure is complicated, requiring a bearing cooling fan and ventilation passages, while the structure disclosed in Patent Document 2 has the problem that the bracket does not have an insulating layer, making it impossible to reduce the rise in bearing temperature due to heat conduction from the stator core.

[0009] The present invention has been made in consideration of the above points, and its object is to improve the heat transfer to the bearing by the inside air and Stator core, stator frame, end bracket The present invention provides a rotating electric machine capable of suppressing a rise in the temperature of a bearing by reducing heat conduction from the bearing, thereby improving the lubrication life of the bearing. [Means for solving the problem]

[0010] In order to achieve the above object, the rotating electric machine of the present invention is a rotating electric machine comprising a rotor having a shaft, a stator disposed opposite the rotor with a predetermined gap (air gap) and supported by a stator frame, a bearing for supporting the rotation of the shaft, and an end bracket for holding the bearing, and a heat insulating layer for preventing heat from flowing into the bearing is provided on the inside or outside of the end bracket. The shaft is fitted with an internal fan for circulating air inside the aircraft, the heat insulating layer is disposed on the end bracket on the side where the internal fan is disposed, and the heat insulating layer is provided with a recess on the internal air side or the external air side of the end bracket, a heat insulating material is disposed in the recess, and the heat insulating material is enclosed by a cover that is bolted to the end bracket. It is characterized by: Effect of the Invention

[0011] According to the present invention, heat transfer to the bearing by the inside air and Stator core, stator frame, end bracket This reduces heat conduction from the bearing, suppresses temperature rise in the bearing, and improves the lubrication life of the bearing. [Brief description of the drawings]

[0012] [Figure 1] 1 is a vertical sectional view showing a first embodiment of a rotating electric machine according to the present invention; [Diagram 2]1 is an enlarged partial cross-sectional view showing the vicinity of a bearing in a rotating electric machine according to a first embodiment of the present invention; [Diagram 3] FIG. 5 is a vertical sectional view showing a second embodiment of a rotating electric machine according to the present invention. [Figure 4] FIG. 11 is a vertical sectional view showing a third embodiment of a rotating electric machine according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The rotating electrical machine of the present invention will be described below based on the illustrated embodiments. In each embodiment, the same reference numerals are used for the same components. EXAMPLES

[0014] 1 and 2 show a rotating electric machine according to a first embodiment of the present invention.

[0015] As shown in FIG. 1, the rotating electric machine 1 of this embodiment is roughly composed of a stator 2, a stator frame 3 supporting the stator 2, end brackets 5a, 5b fixed to the stator frame 3 and holding bearings 4a, 4b arranged at two axial positions on either side of the stator 2 and a rotor 6 described later, a rotating rotor 6 that is rotatably supported by the bearings 4a, 4b and arranged opposite the stator 2 with a predetermined gap (air gap 28) therebetween and has a shaft 8, a rotor core 7 that constitutes the rotor 6, an inner fan 9 that is attached to the shaft 8 and arranged on one bearing 4a side and circulates air within the rotating electric machine 1, an air cooler 11 provided on the upper part of the stator frame 3, and an outer fan 12 that is attached to the shaft 8 and arranged on the other bearing 4b side and introduces cooling air to the air cooler 11.

[0016] The air cooler 11 includes a group of pipes 14 through which the outside air 13 flows, and removes heat from the inside air 15 that has cooled the stator 2 and the rotor 6. The external fan 12 is a blower, and is connected to the other end of the shaft 8 (the side opposite to the side where the internal fan 9 is disposed), and sends the first outside air 13a into the air cooler 11 from the inlet of the external fan duct 16.

[0017] Next, a ventilation cooling configuration for the rotating electrical machine 1 in this embodiment will be described.

[0018] As shown in Figure 1, the internal fan 9 introduces the internal air 15 cooled by the air cooler 11 into the rotating electric machine 1 and divides it into a first internal air 15a flowing toward the inside of the rotor 6, a second internal air 15b flowing toward the air gap 28, and a third internal air 15c flowing to the stator coil end portion 29, and these internal air 15 cool the stator 2 and the rotor 6.

[0019] In addition, the first internal air 15a flowing toward the inside of the rotor 6 cools the rotor 6 and then flows into the air gap 28, while the second internal air 15b flowing toward the air gap 28 merges with the first internal air 15a that has flowed into the air gap 28 to cool the stator 2 and then flows into the stator frame 17.

[0020] In addition, the third internal air 15c flowing through the stator coil end portion 29 cools the stator coil end portion 29, then flows into the stator frame 17 and merges with the first internal air 15a and the second internal air 15b, and finally cools the stator coil end portion 29 downstream of the cooling air 13b on the side where the internal fan 9 is installed, and after raising its temperature, the internal air is guided by the internal fan 9 to the air cooler 11 as shown by arrow 18.

[0021] As described above, the air cooler 11 includes a tube group 14 made up of a plurality of tubes therein, and removes heat from the internal air 15 that has cooled the stator 2 and the rotor 6. Inside the tube group 14, the first external air 13a, which is a secondary refrigerant, is guided by the external fan 12 and flows. When the internal air 15 passes between the tubes of the tube group 14 inside the air cooler 11, it exchanges heat with the first external air 13a inside the tubes via the tube walls and is cooled.

[0022] The above is the configuration of a typical rotating electric machine 1, in particular the cooling system of the rotating electric machine 1 in which internal air 15 flows in one direction parallel to the shaft 8 of the rotor 6 to cool the rotor 6 and the stator 2.

[0023] In the cooling system of this rotating electrical machine 1, the internal air, indicated by arrow 18 and having a raised temperature after cooling rotor 6 and stator 2, may raise the temperature of bearing 4a.

[0024] For this reason, in this embodiment, in order to prevent overheating due to a rise in temperature of the bearing 4a, an insulating layer 19 that prevents heat from flowing into the bearing 4a is provided on the end bracket 5a on the side where the internal fan 9 is installed and on the downstream side of the cooling air to which the bearing 4a is attached.

[0025] FIG. 2 shows an enlarged view of the vicinity of the bearing 4a provided with the heat insulating layer 19 in the rotating electrical machine 1 of this embodiment.

[0026] As shown in FIG. 2, the flow of heat into the bearing 4a is, in order, heat transfer from the inside air to the end bracket 5a, as indicated by arrow 18, and heat conduction from the end bracket 5a to the bearing 4a.

[0027] Specifically, heat is transferred from the end bracket 5a to the outer ring 4c, grease 4g, and balls 4d, and some heat is transferred from the stator 2 through the stator frame 3 to the end bracket 5a, and some heat is transferred from the shaft 8 to the inner ring 4f, balls 4d, and grease 4g. Furthermore, there is heat generated by friction between the balls 4d and the inner ring 4f and outer ring 4c, and by the balls 4d stirring the grease 4g.

[0028] When there is no device for cooling the lubricant of the bearing 4a, the bearing 4a is cooled mainly by heat transfer from the bearing box 20 exposed to the outside air to the outside air. In particular, in a rolling bearing lubricated with grease, there are basically no other cooling elements.

[0029] For this reason, in this embodiment, a simple structure is realized that reduces the heat input to the bearing 4a and improves cooling in order to reduce the temperature of the bearing 4a, suppress the deterioration of the grease 4g, and extend the lubrication life of the bearing 4a. That is, a heat insulating layer 19 is provided on the indoor air side of the end bracket 5a at a portion exposed to the indoor air diverted from the indoor air indicated by the arrow 18, and exposed to the indoor air diverted from the inner fan 9.

[0030] Specifically, a recess 21 is provided on the inside air side of the end bracket 5a, a heat insulating material 24 is placed in this recess 21, and the heat insulating material 24 is enclosed by a cover 22 that is bolted to the end bracket 5a.

[0031] The heat insulating material 24 may be ordinary glass wool, rock wool, vacuum heat insulating material, or an air layer.

[0032] When the insulation material 14 is used as an air layer, it is important that the cover 22 covering the air layer in the recess 21 has bolts 23 properly installed on the inner and outer periphery of the cover 22 to prevent the insulation layer 19 and the diverted inside air 18a from passing back and forth. In this case, an outside air communication pipe 25 or a valve may be provided to communicate the insulation layer 19 with the outside air, and low-temperature outside air may be introduced into the insulation layer 19.

[0033] The recess 21, insulating layer 19, and insulating material 24 provided in the end bracket 5a described above provide thermal resistance to the heat transmitted from the stator 2 through the stator frame 3, thereby suppressing the heat input to the bearing 4a and reducing the temperature rise of the bearing 4a.

[0034] Furthermore, by providing fins (not shown) on the outer surface of the end bracket 5a to improve the heat transfer characteristics of the outer surface of the end bracket 5a with the outside air, the temperature of the bearing 4a can be further reduced.

[0035] In this embodiment, the intake air of the external fan 12, which is an intake fan of the air cooler 11 directly connected to the rotor 6, is used as cooling air 13b for cooling (see FIG. 1). That is, the cooling air 13b of the external fan 12 is taken in through the piping 26 from the external fan duct 16, and the cooling air 13b is discharged to the bearing 4a, the bearing box 20, the end bracket 5a, the cooling fins, etc., thereby removing heat from the bearing 4a and reducing the temperature of the bearing 4a.

[0036] Furthermore, although not shown, the temperature of the bearing 4a can be reduced by devising or combining the above-mentioned configurations. For example, the recess 21 of the end bracket 5a in which the heat insulating layer 19 is provided may be provided on the outside air side, and the heat insulating material 24 may be provided in this recess 21 to form the heat insulating layer 19. This also means that the heat insulating layer 19 is provided on the outside side of the end bracket 5a.

[0037] This prevents the temperature from rising due to heat transfer from the end bracket 5a caused by the inflow and outflow of inside air into and out of the insulating layer 19, suppresses temperature rise in the bearing 4a, and makes it possible to improve the lubrication life of the bearing 4a.

[0038] In addition, by providing an outside air communication pipe 25 and a valve that connect the insulating layer 19 to the outside air, an external refrigerant or a refrigerant of the air cooler 11, such as air or water, can be circulated through the outside air communication pipe 25 to provide the effect of suppressing the temperature rise of the bearing 4a and improving the lubrication life of the bearing 4a.

[0039] The simplest method is to take in the cooling air 13b from the external fan 12 through the piping 26 from the external fan duct 16, and then circulate the cooling air 27 that has taken in through the piping 26 through the external air communication piping 25 that connects the insulation layer 19 to the outside air to cool the end bracket 5a, which more effectively suppresses the temperature rise of the bearing 4a and more effectively improves the lubrication life of the bearing 4a.

[0040] As described above, according to this embodiment, the heat transfer to the bearing 4a by the inside air and the heat conduction from the rotor core 7 are reduced, thereby suppressing the temperature rise of the bearing 4a and improving the lubrication life of the bearing 4a. EXAMPLES

[0041] FIG. 3 shows a second embodiment of the rotating electric machine 1 according to the present invention.

[0042] The rotating electric machine 1 of the second embodiment shown in Fig. 3 is almost the same as the rotating electric machine 1 of the first embodiment shown in Fig. 1, but is different in that the inner fan 9 is provided on the side of the outer fan 12. That is, the inner fan 9 is provided on the side of the outer fan 12, and the insulating layer 19 is provided on the end bracket 5b on the side where the inner fan 9 is provided.

[0043] In the rotating electric machine 1 of this embodiment, the bearing 4b on the exhaust side of the internal fan 9 may be overheated and the temperature may rise due to the diverted internal air 18a that has cooled the rotor 6 and the stator 2 and has been heated.

[0044] For this reason, in the rotating electric machine 1 of the second embodiment, a heat insulating layer 19 is provided on the end bracket 5b to which the bearing 4b on the downstream side of the cooling air is attached on the side where the internal fan 9 is located, in order to prevent overheating of the bearing 4b on the exhaust side of the internal fan 9. The other configurations are the same as those of the rotating electric machine 1 of the first embodiment.

[0045] Also, similarly to the first embodiment, an outside air communication pipe 25 and a valve are provided to connect the insulating layer 19 with the outside air, and an external refrigerant or a refrigerant of the air cooler 11, such as air or water, is circulated through the outside air communication pipe 25 to reduce the temperature rise of the bearing 4b.

[0046] The simplest is to outside fan duct 16 Therefore, by taking in the cooling air 13b from the external fan 12 through piping 26 and circulating this cooling air 27 through the outside air communication piping 25 that connects the insulating layer 19 to the outside air to cool the end bracket 5b, the temperature rise of the bearing 4b can be more effectively reduced.

[0047] Of course, with this embodiment, the same effects as those of embodiment 1 can be obtained, and since the bearing 4b on the exhaust side of the internal air is close to the external fan duct 16, there is also the effect that the piping 26 can be shortened when the cooling air 13b of the external fan 12 is used for cooling. EXAMPLES

[0048] FIG. 4 shows a third embodiment of the rotating electric machine 1 according to the present invention.

[0049] The rotating electric machine 1 of the third embodiment shown in FIG. 4 is almost the same as the rotating electric machine 1 of the second embodiment shown in FIG. 3, but the outside air 13 is introduced from an external fan 12, which is an intake fan of a cooler directly connected to the rotor 6, around the bearing 4b, the bearing box 20, the end bracket 5b, and the cooling fins 30 to cool the bearing 4b. b The heat is absorbed from the bearings. b The other configurations are the same as those of the rotating electrical machine 1 of the second embodiment.

[0050] In this embodiment, it goes without saying that the same effects as in the second embodiment can be obtained, and furthermore, the cooling of the bearing 4b can be enhanced.

[0051] The above-mentioned embodiments have been described in detail to easily explain the present invention, and are not necessarily limited to those including all of the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0052] Reference Signs List 1... rotating electric machine, 2... stator, 3... stator frame, 4a, 4b... bearings, 4c... outer ring, 4d... balls, 4g... grease, 4f... inner ring, 5a, 5b... end brackets, 6... rotor, 7... rotor core, 8... shaft, 9... inner fan, 11... air cooler, 12... outer fan, 13... outside air, 13a... first outside air, 13b... cooling air, 14... tube group, 15... inside air, 15a... first inside air, 15 b...second internal air, 15c...third internal air, 16...external fan duct, 17...stator frame, 18...arrow indicating internal air flow, 18a...diverted internal air, 19...insulating layer, 20...bearing box, 21...recess, 22...cover, 23...bolt, 24...insulating material, 25...external air connecting piping, 26...piping, 27...cooling air, 28...air gap, 29...stator coil end portion, 30...cooling fins.

Claims

1. A rotating electric machine comprising: a rotor having a shaft; a stator disposed opposite the rotor with a predetermined gap (air gap) therebetween and supported by a stator frame; a bearing for supporting the rotation of the shaft; and an end bracket for holding the bearing, A heat insulating layer is provided on the inside or outside of the end bracket to prevent heat from entering the bearing, An internal fan attached to the shaft for circulating air inside the aircraft; The heat insulating layer is disposed on the end bracket on the side where the inner fan is installed, A rotating electric machine characterized in that the insulating layer is formed by providing a recess on the inside air side or the outside air side of the end bracket, placing insulating material in this recess, and sealing the insulating material with a cover that is bolted to the end bracket.

2. 2. The rotating electric machine according to claim 1, A rotating electric machine, characterized in that the heat insulating layer is installed on the end bracket on the exhaust side of the inside air.

3. 2. The rotating electric machine according to claim 1, The bearings rotatably support the shaft at two points in the axial direction, sandwiching the stator and the rotor therebetween, Moreover, the rotor is provided with an air cooler provided on an upper portion of the stator frame, an outer fan disposed on one side of the bearing and attached to the shaft to introduce cooling air into the air cooler, and an inner fan disposed on the other side of the bearing and attached to the shaft to circulate air inside the rotor, A rotating electric machine, characterized in that the heat insulating layer is arranged on the end bracket on the side where the inner fan is arranged.

4. 4. The rotating electric machine according to claim 3, A rotating electric machine characterized in that the insulating layer is installed on the indoor air side of the end bracket at a location exposed to the diverted indoor air diverted from the indoor air, which inputs heat to the end bracket from the diverted indoor air.

5. 5. The rotating electric machine according to claim 4, A rotating electric machine characterized in that fins are provided on an outer surface of the end bracket.

6. 2. The rotating electric machine according to claim 1, The bearings rotatably support the shaft at two points in the axial direction, sandwiching the stator and the rotor therebetween, Moreover, the rotor is provided with an air cooler provided on an upper portion of the stator frame, an outer fan disposed on one side of the bearing and attached to the shaft to introduce cooling air into the air cooler, and an inner fan attached to the shaft to circulate air inside the rotor, A rotating electric machine characterized in that the inner fan is installed on the outer fan side, and the insulating layer is disposed on the end bracket on the side on which the inner fan is installed.

7. 6. A rotating electric machine according to claim 5, A rotating electric machine comprising: an outside air communication pipe and / or a valve for communicating the heat insulating layer with outside air; and outside air being introduced into the heat insulating layer via the outside air communication pipe and / or the valve.

8. A rotating electric machine according to claim 7, A rotating electric machine characterized in that cooling air introduced from the outer fan duct of the outer fan is taken in through piping, and the cooling air taken in through the piping is circulated through the outside air communication piping that connects the insulation layer to the outside air to cool the end bracket.

9. 7. A rotating electric machine according to claim 6, A rotating electric machine characterized in that air taken in from the outer fan is guided at least to around the bearing and the end bracket on the outer fan side.

10. 2. The rotating electric machine according to claim 1, 11. A rotating electric machine, wherein the heat insulating material is any one of an air layer, glass wool, rock wool, and vacuum heat insulating material.

Images