Rotating electric machines

Abstract

According to one embodiment, a rotating electric machine includes a first housing, a stator, a rotor, a bearing, an oil tank, and a cooling unit. The rotor includes a rotor core housed in the first housing and a shaft to which the rotor core is fixed. The bearing supports the shaft in a manner such that the shaft can rotate relative to the first housing. The oil tank stores lubricating oil for lubricating the bearing. The cooling unit includes a second housing, a cooling unit, a pump, and an electric motor, and is connected to the first housing. The cooling unit is housed in the second housing and cools the lubricating oil. The pump is housed in the second housing and circulates the lubricating oil between the oil tank and the cooling unit. The electric motor is used to drive the pump.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Japanese patent application No. 2020-165572 filed on September 30, 2020, and its entire contents are incorporated herein by reference. Technical Field

[0003] Generally speaking, embodiments described herein relate to rotating electrical machines. Background Art

[0004] A conventionally known rotating electric machine includes a cooling portion configured to cool lubricating oil for a bearing to cool the bearing, wherein the bearing supports a shaft of a rotor.

[0005] For example, the conventional technology is described in Japanese Patent Application Publication No. 2019-201516.

[0006] A rotating electric machine of this type would be beneficial if a novel configuration could be obtained that, for example, made it easy to install the rotating electric machine at a location for installing the rotating electric machine. Summary of the invention

[0007] It is therefore an object of the present invention to achieve a rotating electric machine having a novel construction which makes it easy to install the rotating electric machine at its installation location.

[0008] According to one embodiment, a rotating electric machine generally includes: a first housing; a stator accommodated in the first housing; a rotor having a rotor core and a shaft, wherein the rotor core is accommodated in the first housing and the rotor core is fixed to the shaft; a bearing that supports the shaft in a manner that the shaft can rotate relative to the first housing; an oil tank that stores lubricating oil for lubricating the bearing; and a cooling unit mounted to the first housing, the cooling unit including: a second housing; a cooling part that is accommodated in the second housing and cools the lubricating oil; a pump that is accommodated in the second housing and circulates the lubricating oil between the oil tank and the cooling part; and a driving source that drives the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic side view of a fully enclosed external fan cooling type rotating electrical machine according to one embodiment;

[0010] Figure 2 is a schematic front view of a fully enclosed external fan cooling type rotating electrical machine according to the embodiment;

[0011] Figure 3is a schematic cross-sectional view of a rotating electrical machine body in a fully enclosed external fan cooling type rotating electrical machine according to the embodiment; and

[0012] Figure 4 : is a schematic configuration diagram of a bearing cooling device in a totally enclosed external fan cooling type rotating electrical machine according to this embodiment. DETAILED DESCRIPTION

[0013] The following discloses an exemplary embodiment of the present invention. The configurations (technical features) of the embodiments described below are merely examples, and the actions and results (effects) described below brought about by these configurations are also examples.

[0014] Structure of a fully enclosed external fan cooling type rotating electrical machine 1

[0015] Figure 1 is a schematic side view of a totally enclosed external fan cooling type rotating electrical machine 1 according to one embodiment. Figure 2 1 is a schematic front view of a totally enclosed external fan cooling type rotating electrical machine 1 according to one embodiment.

[0016] like Figure 1 and Figure 2 As shown, a fully enclosed external fan cooling type rotating electric machine 1 includes a rotating electric machine body 2 that performs a rotating motion, a cooling device 3, a bearing cooling device 4, and a control device 5. A closed space filled with a cooling gas such as air is provided between the rotating electric machine body 2 and the cooling device 3 inside the fully enclosed external fan cooling type rotating electric machine 1. The rotating electric machine body 2 is cooled by heat exchange between the cooling gas in the closed space heated by the heat of the rotating electric machine body 2 and the external air that occurs in the cooling device 3. The bearing cooling device 4 cools the bearing 16 of the rotating electric machine body 2 by cooling the lubricating oil of the bearing 16. The control device 5 controls the rotating motion of the fully enclosed external fan cooling type rotating electric machine 1, and also controls the cooling unit 50. The fully enclosed external fan cooling type rotating electric machine 1 is an example of a rotating electric machine.

[0017] Rotating motor body 2

[0018] Figure 3 2 is a schematic cross-sectional view of a rotating electrical machine body 2 in a fully enclosed external fan cooling type rotating electrical machine 1 according to this embodiment. Figures 1 to 3 As shown in FIG. 1 , the rotating electrical machine body 2 includes a housing 11, a rotor 12, a stator 13, a bearing 16, and an oil groove 17. Figure 3 In the figure, the oil groove 17 is omitted.

[0019] In the following description, for convenience, three directions perpendicular to each other are defined. The X direction is along the longitudinal direction of the housing 11 and the axial direction of the rotation center axis Ax of the rotor 12. The Y direction is along the lateral direction of the housing 11 and the direction perpendicular to the axial direction of the rotation center axis Ax. The Z direction is along the up and down direction of the housing 11. The X direction, the Y direction, and the Z direction are orthogonal to each other. The Y direction is an example of a direction perpendicular to the rotation center axis Ax. Here, the rotation center axis Ax is the center axis (center line) of the shaft 14 of the rotor 12. That is, the axial, radial, and circumferential directions of the rotation center axis Ax are the same as the axial, radial, and circumferential directions of the shaft 14. In the following description, the terms "axial", "radial", and "circumferential" refer to the axial, radial, and circumferential directions of the rotation center axis Ax, that is, unless otherwise specified, they refer to the axial, radial, and circumferential directions of the shaft 14.

[0020] The housing 11 is formed in a box shape. The housing 11 accommodates a rotor 12 and a part of a stator 13. The housing 11 is an example of a first housing.

[0021] The housing 11 has a plurality of walls, such as a bottom wall 11 a , a top wall 11 b , two end walls 11 c and 11 d , and two side walls 11 e and 11 f .

[0022] The bottom wall 11a and the top wall 11b extend in a direction perpendicular to the Z direction (XY plane) and are spaced apart and parallel to each other in the Z direction. The bottom wall 11a forms the lower end of the housing 11, and the top wall 11b forms the upper end of the housing 11.

[0023] The end wall 11c and the end wall 11d each extend in a direction (YZ plane) perpendicular to the axial direction (i.e., perpendicular to the X direction), and are spaced apart from each other and arranged in parallel in the X direction. The end wall 11c extends over a span between the ends of the bottom wall 11a and the top wall 11b in a direction opposite to the X direction. The end wall 11d extends over a span between the ends of the bottom wall 11a and the top wall 11b in the X direction. Each of the end walls 11c and 11d is an example of a first wall.

[0024] The side wall 11e and the side wall 11f each extend in a direction (XZ plane) perpendicular to the axial direction (i.e., perpendicular to the Y direction), and are spaced apart and arranged in parallel in the Y direction. The side wall 11e extends over a span between the ends of the bottom wall 11a and the top wall 11b facing the Y direction. The side wall 11f extends over a span between the ends of the bottom wall 11a and the top wall 11b facing the direction opposite to the Y direction. Each of the side walls 11e and 11f is an example of a second wall.

[0025] The top wall 11b is connected to the cooling device 3. The side wall 11e is connected to the cooling unit 50 of the bearing cooling device 4. The side wall 11f is connected to the control device 5. That is, the cooling unit 50 and the control device 5 are arranged on opposite sides relative to the housing 11. In other words, the housing 11 is arranged between the cooling unit 50 and the control device 5. The cooling device 3, the cooling unit 50 and the control device 5 are all arranged outside the housing 11.

[0026] The rotor 12 includes a shaft 14 and a rotor core 15. The rotor core 15 is fixed to a portion of the shaft 14 between opposite ends in the axial direction thereof.

[0027] The shaft 14 is supported by the housing 11 through two bearings 16 so as to be rotatable around the rotation center axis Ax. In other words, the two bearings 16 support the shaft 14 so that the shaft 14 can rotate relative to the housing 11. The two bearings 16 are positioned on opposite sides of the rotor core 15 in the axial direction. That is, the rotor core 15 is located between the two bearings 16 in the axial direction.

[0028] One end 14a and the other end 14b of the shaft 14 in the axial direction protrude from the housing 11 to the outside of the housing 11. The one end 14a is coupled to an object (not shown) to which the end 14a is to be coupled. An external fan (not shown) is fixed to the other end 14b. The external fan rotates integrally with the shaft 14. In addition, the shaft 14 has an internal fan 18 fixed between each of the two bearings 16 and the rotor core 15. The internal fan 18 rotates integrally with the shaft 14.

[0029] Two bearings 16 are respectively arranged on the two end walls 11c and 11d. For example, the bearings 16 are sliding bearings or rolling bearings. The bearings 16 are lubricated with lubricating oil.

[0030] Figure 1 and Figure 2 The oil groove 17 shown stores lubricating oil for the bearing 16. An oil groove 17 is provided for each bearing 16. That is, two oil grooves 17 are provided. Two oil grooves 17 are provided on the two end walls 11c and 11d. Each oil groove 17 is provided below the corresponding bearing 16, that is, on one side in the direction opposite to the Z direction. The oil groove 17 is also called an oil storage groove.

[0031] like Figure 3As shown in FIG. 1 , the stator 13 includes a stator core 19 and a stator winding 20. The stator core 19 is fixed to the housing 11. That is, the stator 13 is fixed to the housing 11. The stator core 19 is located outside the rotor core 15 in the radial direction and is formed into a cylindrical shape surrounding the rotor core 15. The stator winding 20 is fixed to the stator core 19 in a manner of passing through a plurality of slots (not shown) formed on an inner circumferential portion 19a of the stator core 19 in a manner extending in the axial direction.

[0032] Cooling device 3

[0033] like Figure 1 and Figure 2 As shown in FIG. 1 , the cooling device 3 is stacked on and fixed to the top wall 11b of the housing 11. The cooling device 3 cools the rotor 12 and the stator 13 by exchanging heat between the air inside the housing 11 and the outside air (i.e., the air outside the housing 11). The air inside the housing 11 circulates between the housing 11 and the cooling device 3 by the internal fan 18, and the outside air is introduced into the cooling device 3 by the external fan.

[0034] Bearing cooling device 4

[0035] like Figure 1 and Figure 2 As shown in FIG. 1 , the bearing cooling device 4 includes a cooling unit 50 and two piping portions 55. The cooling unit 50 is connected to two bearings 16 and two oil grooves 17 via the two piping portions 55. The lubricating oil flowing out of the oil groove 17 flows into the cooling unit 50 via the two piping portions 55, and the lubricating oil flowing out of the cooling unit 50 flows into the oil groove 17 after being supplied to the bearing 16.

[0036] Figure 4 is a schematic structural diagram of a bearing cooling device 4 in a fully enclosed external fan cooling type rotating electrical machine 1 according to this embodiment. Figure 4 As shown in , the cooling unit 50 includes a housing 51 , a cooling portion 53 , a pump 52 , a motor 60 , and an alternating current to direct current (AC-DC) converter 54 .

[0037] The housing 51 is formed in a box shape. The housing 11 accommodates the cooling portion 53, the pump 52, the motor 60, and the AC-DC converter 54 therein. The housing 51 is fixed to the side wall 11e of the housing 11 of the rotating electric machine body 2 by a coupling member (for example, a bolt). The housing 51 is provided with a ventilating port for ventilating the internal air of the housing 51. The housing 51 is an example of a second housing.

[0038] The cooling unit 53 cools the lubricating oil. The cooling unit 53 includes a heat exchanger through which the lubricating oil flows and a fan. The lubricating oil flows through the heat exchanger. The fan generates wind so that air flows along the surface of the heat exchanger. The lubricating oil inside the heat exchanger is cooled by heat exchange with air (external air) existing outside the heat exchanger. Power is supplied to the fan of the cooling unit 53 from the AC-DC converter 54.

[0039] The pump 52 is driven by the motor 60 to circulate the lubricating oil between the cooling unit 53 and the oil tank 17. Electric power is supplied to the motor 60 from the AC-DC converter 54. The motor 60 is an example of a driving source.

[0040] In the present embodiment, one pump 52 , one motor 60 , and one cooling unit 53 are provided. The pump 52 circulates the lubricating oil between the cooling unit 53 and the two oil tanks 17 .

[0041] Each piping section 55 includes a plurality of pipes 55a to 55e. An end 55f on the inlet side of the piping section 55 is connected to the corresponding oil groove 17, and the other end 55g on the outlet side of the piping section 55 is connected to the bearing 16. The pipes 55a and 55b extend between the oil groove 17 and the pump 52. The pipe 55a includes an end 55f. The pipe 55c extends between the pump 52 and the cooling section 53. The pipes 55d and 55e extend between the cooling section 53 and the bearing 16. The pipe 55e includes an end 55g.

[0042] A coupling 56 is provided between the pipeline 55a and the pipeline 55b and between the pipeline 55d and the pipeline 55e. The coupling 56 between the pipeline 55a and the pipeline 55b detachably couples the pipeline 55a and the pipeline 55b. The coupling 56 between the pipeline 55d and the pipeline 55e detachably couples the pipeline 55d and the pipeline 55e. Each coupling 56 comprises a flange 57 arranged on one of the pipelines 55a and 55d, another flange 57 arranged on the other of the pipelines 55b and 55e, and a coupling 58 such as a bolt that connects the two flanges 57 together. By removing the coupling 58, the two flanges 57 can be separated from each other. Here, the pipelines 55b to 55d in the piping portion 55 are included in the cooling unit 50. Therefore, the cooling unit 50 can be disassembled from the pipelines 55a and 55e, and therefore can be disassembled from the bearing 16 and the oil groove 17.

[0043] In the bearing cooling device 4 having the above configuration, when the motor 60 drives the pump 52 to rotate, the lubricating oil circulates between the oil groove 17 and the cooling portion 53. Specifically, the lubricating oil flowing out of each of the two oil grooves 17 flows into the cooling portion 53 after passing through the corresponding pipes 55a and 55b, the pump 52, and the pipe 55c. The lubricating oil flowing into the cooling portion 53 is cooled by the cooling portion 53 while flowing through the cooling portion 53, and then flows out of the cooling portion 53. The lubricating oil flowing out of the cooling portion 53 is supplied to each bearing 16 after passing through the corresponding pipes 55d and 55e. Therefore, the bearing 16 is cooled while being lubricated. The lubricating oil supplied to each bearing 16 enters the corresponding oil groove 17. That is, the lubricating oil returns to the oil groove 17.

[0044] Effects of implementation methods

[0045] As described above, in the present embodiment, the fully enclosed external fan cooling type rotating electric machine 1 (rotating electric machine) includes a housing 11 (first housing), a stator 13, a rotor 12, a bearing 16, an oil groove 17, and a cooling unit 50. The stator 13 is accommodated in the housing 11. The rotor 13 includes a rotor core 15 accommodated in the housing 11, and a shaft 14 to which the rotor core 15 is fixed. The bearing 16 supports the shaft 14 in a manner that the shaft 14 is rotatable relative to the housing 11. The oil groove 17 stores lubricating oil for lubricating the bearing 16. The cooling unit 50 includes a housing 51, a cooling unit 53, a pump 52, and a motor 60 (driving source), and is mounted on the housing 11. The cooling unit 53 is accommodated in the housing 51, and cools the lubricating oil. The pump 52 is accommodated in the housing 51, and circulates the lubricating oil between the cooling unit 53 and the oil groove 17. The motor 60 drives the pump 52.

[0046] According to such a configuration, the cooling unit 50 including the cooling portion 53, the pump 52, and the motor 60 is mounted to the housing 11. Therefore, for example, the cooling portion 53, the pump 52, and the motor 60 as a structure for cooling the lubricating oil, the fully enclosed external fan cooling type rotating electric machine 1 is easier to install in the installation position where the fully enclosed external fan cooling type rotating electric machine 1 is to be installed, compared with a structure not mounted to the housing 11. In the case of a structure where the cooling portion 53, the pump 52, and the motor 60 are not mounted to the housing 11, since, for example, the cooling portion 53, the pump 52, and the motor 60 must be connected to the bearing 16 and the oil groove 17 at the installation site, the installation of the fully enclosed external fan cooling type rotating electric machine 1 is laborious. Examples of places where the fully enclosed external fan cooling type rotating electric machine 1 is installed are various factories. In addition, according to the above configuration, the circulation of the lubricating oil achieved by the cooling unit 50 makes it possible to both supply the lubricating oil to the bearing 16 and cool the bearing 16. Therefore, for example, it is not necessary to provide a forced lubrication mechanism or a water cooling mechanism on the bearing 16. Therefore, the cost of the fully enclosed external fan cooling type rotating electric machine 1 can be reduced. Here, for example, when the horizontally arranged fully enclosed external fan cooling type rotating electrical machine 1 is a high-speed type or has a specification of a high temperature environment, a bearing equipped with a forced lubrication mechanism is used. For example, in a vertically arranged (vertical) type fully enclosed external fan cooling type rotating electrical machine (not shown), a bearing equipped with a water cooling mechanism is used.

[0047] In addition, in this embodiment, two bearings 16 and two oil grooves 17 are provided. The rotor core 15 is located between the two bearings 16 in the axial direction of the shaft 14. The pump 52, the motor 60, and the cooling unit 53 are provided one each. The pump 52 circulates the lubricating oil between the cooling unit 53 and the two oil grooves 17.

[0048] According to this configuration, the two bearings 16 can be cooled and lubricated by each of the pump 52, the motor 60, and the cooling unit 53. Therefore, compared with a configuration in which two pumps 52, two motors 60, and two cooling units 53 are provided for each of the two bearings 16, the configuration of the fully enclosed external fan cooling type rotating electrical machine 1 can be simpler.

[0049] In addition, in the present embodiment, the housing 11 has two end walls 11c and 11d (first wall) arranged at intervals from each other in the axial direction, and two side walls 11e and 11f (second wall) arranged at intervals from each other in a direction perpendicular to the axial direction. The bearing 16 is provided on each of the end walls 11c and 11d. The cooling unit 50 is arranged outside the housing 11 and fixed to one of the two side walls 11e and 11f (for example, the side wall 11e).

[0050] According to this configuration, the cooling unit 50 is fixed to the side wall 11e where the two bearings 16 and the two oil grooves 17 are not installed. Therefore, an area for installing the cooling unit 50 can be easily ensured, and the cooling unit 50 can be easily installed and removed.

[0051] According to one embodiment of the present invention, a rotating electrical machine of a novel structure that is easy to install at an installation site can be obtained.

[0052] Although several embodiments have been described, these embodiments are given by way of example only and are not intended to limit the scope of the invention. In fact, the novel methods and systems described herein may be embodied in a variety of other forms; in addition, 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 attached claims and their equivalents are intended to cover such forms or modifications that fall within the scope and spirit of the invention.

Claims

1. A rotating electrical machine, comprising: a first shell; a stator received in the first housing; a rotor having a rotor core and a shaft, wherein the rotor core is received in the first housing and the rotor core is fixed to the shaft; a bearing for supporting the shaft so that the shaft can rotate relative to the first housing; An oil tank storing lubricating oil for lubricating the bearing; a cooling unit mounted to the first housing, arranged outside the first housing and exposed to the outside of the rotating electrical machine; A control device for controlling the cooling unit; as well as A cooling device is used to cool the rotor and the stator. The cooling unit comprises: a second shell; a cooling unit, housed in the second housing, for cooling the lubricating oil; a pump, housed in the second housing, for circulating the lubricating oil between the oil tank and the cooling portion; and a driving source for driving the pump, The first housing includes: two first walls spaced apart from each other in the axial direction of the shaft; two second walls spaced apart from each other in a direction orthogonal to the axial direction; and a top wall connecting the two first walls and the two second walls. The cooling unit is mounted to one of the two second walls, The control device is mounted to the other of the two second walls, The cooling device is mounted to the top wall.

2. The rotating electrical machine according to claim 1, wherein: The bearing and the oil groove are respectively provided with two; The rotor core is located between the two bearings in the axial direction of the shaft; The pump, the driving source and the cooling unit are each provided with one; The pump circulates the lubricating oil between the cooling portion and the two oil tanks.

3. The rotating electrical machine according to claim 2, wherein: The bearing is disposed on each of the first walls.

Images