Rotating electric machines, and bearings for rotating electric machines

Abstract

To provide a rotary electric machine and a bearing of the rotary electric machine, which can improve reliability of a temperature change.SOLUTION: A rotary electric machine includes: a shaft which can rotate around a central axis; and a bearing for rotatably supporting the shaft. The bearing has a temperature indicating part formed by applying temperature indicating paint which irreversibly changes a color with a temperature change.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Conventionally, a technique for measuring temperature by providing a temperature sensor near an internal component of a rotating electrical machine, for example, a coil, is known.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the installation of the temperature sensor is restricted depending on the shape and location of the measurement target. In this case, it may be difficult to install the temperature sensor on the bearing that supports the shaft. Therefore, there is a problem in confirming the temperature change of the bearing in the conventional configuration.

[0005] Therefore, embodiments of the present invention provide a rotating electrical machine and a bearing of the rotating electrical machine that can improve the reliability against temperature changes.

Means for Solving the Problems

[0006] The rotating electrical machine according to the embodiment includes a shaft rotatable around a central axis and a bearing that rotatably supports the shaft. The bearing has a temperature indicating portion formed by applying a temperature indicating paint that irreversibly changes color with a temperature change.

[0007] The bearing of the rotating electrical machine according to the embodiment is a bearing that rotatably supports the shaft of the rotating electrical machine, and has a temperature indicating portion formed by applying a temperature indicating paint that irreversibly changes color with a temperature increase. [Brief explanation of the drawing]

[0008] [Figure 1] A side view showing a partially cutaway section of an example of a rotating electric machine according to the first embodiment. [Figure 2] A schematic cross-sectional view showing an example of a temperature-indicating section for a bearing according to the first embodiment. [Figure 3] A cross-sectional view showing an example of a bearing according to the first embodiment, along the line X3-X3 in Figure 2. [Figure 4] A schematic cross-sectional view showing an example of a temperature-indicating section for a bearing according to the second embodiment. [Modes for carrying out the invention]

[0009] Several embodiments will be described below with reference to the drawings. In multiple embodiments, substantially identical elements are denoted by the same reference numerals, and their descriptions are omitted. Furthermore, for the sake of clarity, the dimensions of each component may be enlarged in the drawings as needed, and the dimensional ratios between components may not be the same as those in reality.

[0010] (First Embodiment) First, a first embodiment of the present invention will be described with reference to Figures 1 to 3. The rotating electric machine 1 in the embodiment shown in Figure 1 is a totally enclosed fan-cooled type, protected by, for example, a totally enclosed outer casing structure. The rotating electric machine 1 is used to rotate a load machine (not shown), such as a pump or a blower. As shown in Figure 1, the rotating electric machine 1 comprises a housing 10, a stator 21, a rotor 22, a shaft 23, and a fan 24. In the following description, the direction parallel to the rotation center axis O of the rotor 22 is referred to as the axial direction. When the rotor 22 is rotated around the rotation center axis O, the direction in which the outer surface of the rotor 22 rotates is referred to as the circumferential direction. The direction perpendicular to the rotation center axis O is referred to as the radial direction. Also, the right side of the plane of Figure 1 is referred to as the side on which the rotating electric machine 1 is connected to the load machine, i.e., the load side, and the left side of the plane of Figure 1 is referred to as the non-load side.

[0011] The housing 10 constitutes the outer casing of the rotating electric machine 1. The housing 10 includes a frame 11, brackets 12 and 13, bearings 30, and a fan cover 14. The frame 11 is formed, for example, in a cylindrical shape, with openings at both ends in the axial direction. The frame 11 has a plurality of fins (not shown) for heat dissipation. The fins protrude radially from the frame 11 and extend along the axial direction. The brackets 12 and 13 are provided at the openings at both ends of the frame 11. The brackets 12 and 13 cover the outer circumference of the housing 10 in the axial direction.

[0012] The bearings 30 are provided on brackets 12 and 13, respectively, and rotatably support the shaft 23. The fan cover 14 is provided on the non-load side end of the frame 11. The fan cover 14 covers the fan 24 and protects it. The fan cover 14 has an air intake (not shown), through which outside air is drawn into the rotating electric machine 1. The stator 21 is fixed inside the housing 10. The stator 21 has a stator core 211 and stator windings 212. The stator core 211 is configured, for example, in a cylindrical shape and is formed by laminating multiple circular electromagnetic steel sheets. The stator windings 212 are wound around the stator core 211.

[0013] The rotor 22 is located inside the stator 21 and is rotatably mounted relative to the stator 21 with a gap between them. In other words, the rotating electric machine 1 is configured as, for example, an inner rotor type rotating electric machine. The rotor 22, although not shown in detail, is composed of a rotor core made by stacking multiple disc-shaped electromagnetic steel sheets, and permanent magnets embedded in this rotor core.

[0014] The shaft 23 is provided through the center of the rotor 22 and is configured to rotate integrally with the rotor 22 around the rotational axis O. In other words, the rotational axis of the shaft 23 coincides with the rotational axis O of the rotor 22. The axial ends of the shaft 23 are rotatably supported relative to the housing 10 via bearings 30. The fan 24 is provided at the non-load end of the shaft 23 and rotates in conjunction with the rotation of the shaft 23. The rotation of the fan 24 blows air toward the outer circumference of the housing 10, and the rotating electric machine 1 is cooled by heat exchange with the fins.

[0015] Furthermore, the bearing 30 can be made up of, for example, a rolling bearing or a sliding bearing. In this embodiment, the bearing 30 is made up of a rolling bearing. In this case, as shown in Figures 2 and 3, the bearing 30 has an inner ring 31, an outer ring 32, rolling elements 33, and a temperature-indicating part 34. The inner ring 31 and the outer ring 32 are formed in a cylindrical shape, for example. The inner ring 31 and the outer ring 32 are arranged with a predetermined distance between them, and the inner ring 31 is located inside the outer ring 32. In other words, the outer diameter of the inner ring 31 is set to be smaller than the outer diameter of the outer ring 32.

[0016] The rolling elements 33 are composed of, for example, balls or rollers, and a plurality of them are arranged along the circumferential direction of the bearing 30 between the outer circumference 312 of the inner ring 31 and the inner circumference 321 of the outer ring 32. The plurality of rolling elements 33 are held together by a cage (not shown) so as not to come into contact with each other. The temperature indicator 34 can be provided, for example, on part or all of the outer or inner surface of the bearing 30. In this embodiment, the temperature indicator 34 is provided on a part of the inner surface of the bearing 30, in this case on either the outer circumference 312 of the inner ring 31 or the inner circumference 321 of the outer ring 32, or both. In other words, the temperature indicator 34 is provided in a region of the bearing 30 that does not come into contact with other components around the bearing 30. The temperature indicator 34 may be provided on either the inner circumference 311 of the inner ring 31 or the outer circumference 322 of the outer ring 32, or both.

[0017] The temperature indicating part 34 is formed by applying a temperature indicating paint that irreversibly changes color with temperature changes. The temperature indicating paint uses heavy metals such as cobalt, nickel, lead, iron, and copper, and changes color as a result of changes in composition due to thermal decomposition or the like. The temperature at which the color change of the temperature indicating paint starts, that is, the color change temperature, can be set, for example, within the range of 60°C to 120°C. Also, the temperature indicating paint is applied uniformly, for example, with a predetermined thickness. The thickness of the temperature indicating paint is not limited to being uniform and may be non-uniform.

[0018] Here, a temperature difference occurs between the inner ring 31 and the outer ring 32 of the bearing 30 due to, for example, the influence of heat generation and heat dissipation during the driving of the rotating electric machine 1. Therefore, in this embodiment, different types of temperature indicating paints are applied to the inner ring side temperature indicating part 341 on the inner ring 31 side and the outer ring side temperature indicating part 342 on the outer ring 32 side. Different types mean, for example, that the color change temperatures are different. That is, depending on the difference in the tendency of temperature change between the inner ring 31 and the outer ring 32 of the bearing 30, where the temperature indicating paint is applied, temperature indicating paints with different color change temperatures can be applied to each of the temperature indicating parts 341 and 342.

[0019] In this case, a temperature indicating paint with a higher color change temperature than that of the outer ring side temperature indicating part 342 on the outer ring 32 side is applied to the inner ring side temperature indicating part 341 on the inner ring 31 side. Note that the same temperature indicating paint may be applied to the inner ring side temperature indicating part 341 on the inner ring 31 side and the outer ring side temperature indicating part 342 on the outer ring 32 side. Also, a temperature indicating paint with a lower color change temperature than that of the outer ring side temperature indicating part 342 on the outer ring 32 side may be applied to the inner ring side temperature indicating part 341 on the inner ring 31 side.

[0020] According to the embodiment described above, the rotating electric machine 1 includes a shaft 23 and a bearing 30. The shaft 23 is rotatable around the central axis. The bearing 30 supports the shaft rotatably. And the bearing 30 has a temperature indicating part 34. The temperature indicating part 34 is formed by applying a temperature indicating paint that irreversibly changes color with temperature changes.

[0021] According to this, for example, it is possible to accurately confirm the temperature change of the bearing 30 where it is difficult to install a temperature detection device such as a thermistor or a thermocouple. As a result, it is possible to accurately grasp the occurrence of problems such as poor installation of the bearing 30 or abnormal load on the bearing 30. As a result, the reliability with respect to temperature changes can be improved.

[0022] Further, the bearing 30 has an inner ring 31, an outer ring 32, and rolling elements 33 disposed between the outer periphery 312 of the inner ring 31 and the inner periphery 321 of the outer ring 32. The temperature indicating portions 34 are provided on the inner ring 31 and the outer ring 32, respectively, and different types of temperature indicating paints are applied to the inner ring 31 and the outer ring 32.

[0023] According to this, due to the influence of temperature received from components around the bearing 30 inside the rotating electric machine 1, etc., the tendency of temperature change may be different between the inner ring 31 and the outer ring 32. Therefore, by applying paints with different starting temperatures of discoloration, for example, to the inner ring 31 and the outer ring 32, it is possible to flexibly respond to the difference in the tendency of temperature change between the inner ring 31 and the outer ring 32. As a result, the reliability with respect to temperature changes can be further improved.

[0024] Furthermore, the inner ring side temperature indicating portion 341 on the inner ring 31 is provided on the outer periphery 312 of the inner ring 31. The outer ring side temperature indicating portion 342 on the outer ring 32 is provided on the inner periphery 321 of the outer ring 32. According to this, it is possible to provide the temperature indicating portions 341 and 342 of the inner ring 31 and the outer ring 32, that is, the coating regions where the temperature indicating paints are applied, on the inner side of the bearing 30. As a result, it is possible to suppress the occurrence of problems such as the temperature indicating paint coming into contact with other members around the bearing 30 and peeling off during the assembly of the rotating electric machine 1, for example.

[0025] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 4. The configuration of this second embodiment differs from that of the first embodiment in the configuration of the temperature-indicating section 34. Specifically, in this embodiment, the temperature-indicating section 34 is divided into multiple sections, in this case four, along the circumferential direction of the bearing 30. In this case, the temperature-indicating section 34 is divided at 90-degree intervals in the circumferential direction of the bearing 30. Furthermore, in this embodiment, the temperature-indicating section 34 is provided on the outer circumference 312 of the inner ring 31 and the inner circumference 321 of the outer ring 32.

[0026] In this case, the same type of temperature-indicating paint is applied to the areas of the inner ring 31 and outer ring 32 of the bearing 30 that overlap radially when the bearing 30 is viewed from the axial direction. Different types of temperature-indicating paint may be applied to the areas of the inner ring 31 and outer ring 32 that overlap radially when the bearing 30 is viewed from the axial direction. In the following description, when it is necessary to specify each of the multiple temperature-indicating sections 34, the inner ring side temperature-indicating section 341 on the inner ring 31 side will be distinguished as the first inner ring side temperature-indicating section 341a, the second inner ring side temperature-indicating section 341b, the third inner ring side temperature-indicating section 341c, and the fourth inner ring side temperature-indicating section 341d, and the outer ring side temperature-indicating section 342 on the outer ring 32 side will be distinguished as the first outer ring side temperature-indicating section 342a, the second outer ring side temperature-indicating section 342b, the third outer ring side temperature-indicating section 342c, and the fourth outer ring side temperature-indicating section 342d.

[0027] Then, different types of thermochromic paint are applied to each of the divided temperature-indicating sections 341a-341d and 342a-342d. In this case, each of the temperature-indicating sections 341a-341d and 342a-342d can be coated with thermochromic paints that, for example, have different discoloration temperatures. In other words, multiple thermochromic paints set within a range where the discoloration temperatures do not overlap can be used for each of the temperature-indicating sections 341a-341d and 342a-342d. Note that some of the temperature-indicating sections 341a-341d and 342a-342d may be coated with the same type of thermochromic paint.

[0028] The discoloration temperature of the first temperature indicators 341a and 342a can be set within the range of 40°C to 60°C. The discoloration temperature of the second temperature indicators 341b and 342b can be set within the range of 60°C to 80°C. The discoloration temperature of the third temperature indicators 341c and 342c can be set within the range of 80°C to 100°C. The discoloration temperature of the fourth temperature indicators 341d and 342d can be set within the range of 100°C to 120°C. Specifically, the temperature at which discoloration begins in each temperature indicator 341a to 341d and 342a to 342d can be set to values ​​of 60°C, 80°C, 100°C, and 120°C.

[0029] According to this second embodiment, by dividing the temperature-indicating section 34 into multiple sections and applying, for example, temperature-indicating paints with different color change temperatures to each of the temperature-indicating sections 341a to 341d and 342a to 342d, the temperature rise of the bearing 30 can be confirmed in stages. This allows for more accurate confirmation of the temperature change of the bearing 30.

[0030] Furthermore, the number of divisions in the temperature-indicating section 34 is not limited to four; it can be set to any number of two, three, or five or more. By dividing the temperature-indicating section 34 into, for example, five or more sections and applying temperature-indicating paint with different color change temperatures to each of these divisions, it is possible to identify uneven temperature increases in the bearing 30, that is, localized temperature increases in the bearing 30. By identifying these localized temperature increases, it becomes possible to accurately determine whether or not there is an abnormality in the bearing 30.

[0031] In the embodiments described above, specific numerical values ​​were given for the discoloration temperature of the thermochromic paint and the number of divisions in the thermochromic section. However, these specific values ​​are merely examples and can be changed as appropriate. Furthermore, the embodiments described above can be combined with each other. Although several embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0032] In the drawing, 1 represents the rotating electric machine, 23 the shaft, 30 the bearing, 31 the inner ring, 32 the outer ring, 33 the rolling element, and 34 the temperature indicator.

Claims

1. A shaft that can rotate around a central axis, The shaft is supported by a bearing that allows it to rotate freely, The bearing has a temperature-indicating portion formed by applying a temperature-indicating paint that irreversibly changes color with temperature changes. The temperature-indicating section is divided into multiple sections along the circumferential direction of the bearing. Each of the temperature-indicating sections is coated with a different type of temperature-indicating paint. Rotating electric machine.

2. The bearing comprises an inner ring, an outer ring, and rolling elements disposed between the outer circumference of the inner ring and the inner circumference of the outer ring. The temperature-indicating section is provided on the inner ring and the outer ring, respectively. The inner ring and the outer ring are coated with different types of the aforementioned temperature-insulating paint. The rotating electric machine according to claim 1.

3. The temperature-indicating portion in the inner ring is provided on the outer circumference of the inner ring. The temperature-indicating portion in the outer ring is provided on the inner circumference of the outer ring. The rotating electric machine according to claim 2.

4. A bearing that rotatably supports the shaft of a rotating electric machine, It has a temperature-indicating section formed by applying a temperature-indicating paint that irreversibly changes color as the temperature rises, The temperature-indicating section is divided into multiple sections along the circumferential direction of the bearing. Each of the temperature-indicating sections is coated with a different type of temperature-indicating paint. Bearings for rotating electrical machinery.

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