Rotary electric machine

Abstract

To provide a rotary electric machine which can prolong life of a bearing and which can be miniaturized.SOLUTION: A rotary electric machine includes: a rotor 2; a rotation shaft 5 which is connected to the rotor 2 and rotates with the rotor 2; a bearing 4 for supporting the rotation shaft 5; a labyrinth seal 16 installed on a side of the bearing 4; an earth brush 10 for removing shaft voltage generated in the rotation shaft 5; and a housing 1 for storing the rotor 2, the rotation shaft 5, the bearing 4, the labyrinth seal 16 and the earth brush 10. The labyrinth seal 16 includes a fixing member 11 fixed to the housing 1 and a rotation member 12 which is fixed to the rotation shaft 5 and rotates with the rotation shaft 5. The earth brush 10 is installed in the rotation member 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine provided with an earth brush.

Background Art

[0002] Rotating electrical machines such as generators and motors may be provided with an earth brush. The earth brush is a device for discharging the shaft voltage generated on the rotating shaft of the rotating electrical machine, and reduces the current flowing from the rotating shaft to the bearing.

[0003] Examples of conventional rotating electrical machines provided with an earth brush are described in Patent Document 1 and Patent Document 2. Patent Document 1 describes an earth brush installed inside a rotating electrical machine. Patent Document 2 describes a rotating machine in which the space between the earth brush and the bearing is separated by a seal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the earth brush comes into contact with the rotating shaft of the rotating electrical machine, it generates powder (wear powder) due to wear. There is a concern that this wear powder may enter the bearing and reduce the life of the bearing. In the earth brush described in Patent Document 1, no measures are taken to prevent the wear powder of the earth brush from entering the bearing.

[0006] In the rotating machine described in Patent Document 2, since the space between the ground brush and the bearing is separated by a seal, it is possible to prevent wear debris of the ground brush from entering the bearing. However, in the rotating machine described in Patent Document 2, since a space for the ground brush to contact the rotating shaft and a space for installing the seal are required, there is a concern that the length in the rotating shaft direction increases and the size becomes large. The rotating electrical machine is preferably as small as possible so that it can be installed regardless of the size of the installation space.

[0007] As described above, the conventional rotating electrical machine has a problem that it is difficult to achieve both a long life of the bearing and a reduction in the size of the rotating electrical machine.

[0008] An object of the present invention is to provide a rotating electrical machine capable of achieving both a long life of the bearing and a reduction in the size of the rotating electrical machine.

Means for Solving the Problems

[0009] The rotating electrical machine according to the present invention includes a rotor, a rotating shaft connected to the rotor and rotating together with the rotor, a bearing that supports the rotating shaft, a labyrinth seal installed on a side of the bearing, a ground brush that removes an axial voltage generated in the rotating shaft, and a housing that houses the rotor, the rotating shaft, the bearing, the labyrinth seal, and the ground brush. The labyrinth seal includes a fixed member fixed to the housing and a rotating member fixed to the rotating shaft and rotating together with the rotating shaft. The ground brush is installed on the rotating member.

Effects of the Invention

[0010] According to the present invention, it is possible to provide a rotating electrical machine capable of achieving both a long life of the bearing and a reduction in the size of the rotating electrical machine.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0012] Hereinafter, the rotating electrical machine according to an embodiment of the present invention will be described with reference to the drawings. The embodiments described below are merely examples of the embodiments of the present invention, and are not intended to limit the present invention to the following specific modes. In the drawings used in this specification, the same or corresponding components are denoted by the same reference numerals, and repeated explanations of these components may be omitted.

[0013] In the following description, the direction along the rotation axis of the rotating electrical machine is called the axial direction, the rotation direction of the rotation axis is called the circumferential direction, and the radial direction of the rotation axis is called the radial direction. In the axial direction, the direction toward the inside of the rotating electrical machine is called the inner axial direction, and the direction toward the outside of the rotating electrical machine is called the outer axial direction. In the radial direction, the direction toward the inside of the rotating electrical machine is called the inner radial direction, and the direction toward the outside of the rotating electrical machine is called the outer radial direction.

Examples

[0014] The rotating electrical machine according to Example 1 of the present invention will be described with reference to FIGS. 1 and 2.

[0015] FIG. 1 is a side view of the rotating electrical machine 100 according to the present embodiment. Using FIG. 1, the overall configuration of the rotating electrical machine 100 according to the present embodiment will be described.

[0016] The rotating electrical machine 100 according to the present embodiment includes a housing 1, a rotor 2, a stator 3, bearings 4, a rotating shaft 5, air holes 6, an air inlet 7, an exhaust port 8, a rear ventilation passage 9, an earth brush 10, a labyrinth seal 16, and a brush holder 13. The labyrinth seal 16 includes a fixed member 11 fixed to the housing 1 and a rotating member 12 that rotates together with the rotating shaft 5 as constituent members.

[0017] The rotating electrical machine 100 is used as a generator or a motor. For example, the rotating electrical machine 100 can be connected to an engine and used as a generator. Hereinafter, as an example, the rotating electrical machine 100 will be described as a generator connected to an engine.

[0018] The housing 1 is a casing of the rotating electrical machine 100 and includes an air inlet 7 and an exhaust port 8. The housing 1 houses the rotor 2, the stator 3, the bearings 4, the rotating shaft 5, the earth brush 10, the labyrinth seal 16, and the brush holder 13. Further, the housing 1 includes a ground connection (not shown).

[0019] The rotor 2 is composed of laminated electromagnetic steel sheets. The rotor 2 may include permanent magnets, and the rotating electrical machine 100 may be configured as a permanent magnet type synchronous motor. Further, the rotor 2 may include windings, and the rotating electrical machine 100 may be configured as a wound type synchronous motor. Further, the rotor 2 may include secondary conductors and a short-circuit ring, and the rotating electrical machine 100 may be configured as an induction motor. The effects achieved by the rotating electrical machine 100 according to the present embodiment can be obtained regardless of the type of the motor. Further, the rotor 2 includes air holes 6 that are ventilation holes for cooling.

[0020] The stator 3 includes laminated electromagnetic steel sheets and coils, is disposed with a gap (air gap) provided between it and the rotor 2, and is fixed to the housing 1. The stator 3 and the housing 1 are fixed to each other by a plurality of fixing portions provided at predetermined intervals in the circumferential direction. A rear ventilation passage 9 for flowing the refrigerant axially is provided between these fixing portions.

[0021] The bearing 4 is fixed to the housing 1 and supports the rotating shaft 5 so that the rotating shaft 5 rotates smoothly. The bearing 4 may be provided at one end of the rotating shaft 5 or at both ends. A labyrinth seal 16 is installed on the side of the bearing 4 (the side on the inner side in the axial direction). In this embodiment, since the rotating electrical machine 100 is a generator connected to an engine, the bearing 4 is installed at one axial end in the rotating electrical machine 100. The bearing 4 may be installed at both axial ends.

[0022] The rotating shaft 5 is connected to the rotor 2 and rotates together with the rotor 2. In this embodiment, since the rotating electrical machine 100 is a generator connected to an engine, one end of the rotating shaft 5 is supported by the bearing 4 and the other end is supported by a bearing provided in the engine. The rotating shaft 5 may have both ends supported by the bearing 4.

[0023] The air hole 6 is provided in the rotor 2 and is a flow path for the refrigerant that cools the rotor 2.

[0024] The air inlet 7 is provided at one axial end of the housing 1 and is an inlet for the refrigerant. When the refrigerant contains dust and there is a risk of fouling the inside of the rotating electrical machine 100, the air inlet 7 may be provided with a dust removal filter or the like.

[0025] The exhaust port 8 is provided at the other axial end of the housing 1 and is an outlet for the refrigerant. The exhaust port 8 may be provided with a filter or the like for collecting dust such as wear debris of the carbon brush 10 generated inside the rotating electrical machine 100.

[0026] The rear ventilation passage 9 is provided in the stator 3 and is a flow path for the refrigerant that cools the stator 3.

[0027] The ground brush 10 is a conductive member, which is provided inside the housing 1 of the rotating electrical machine 100 and is installed on the rotating member 12 of the labyrinth seal 16. The ground brush 10 contacts the rotating member 12 to remove the shaft voltage generated on the rotating shaft 5 and suppress the electrolytic corrosion of the bearing 4. As shown in FIG. 1 for example, the ground brush 10 is provided on the outer side in the radial direction of the rotating member 12 and contacts the portion on the outer side in the radial direction of the rotating member 12. The ground brush 10 may be provided on the inner side in the axial direction of the rotating member 12 and contact the portion on the inner side in the axial direction of the rotating member 12. Note that the rotating electrical machine 100 includes one ground brush 10 in the configuration shown in FIG. 1, but may include a plurality of ground brushes 10 in order to improve the effect of removing the shaft voltage.

[0028] When the ground brush 10 abuts against the rotating member 12 of the labyrinth seal 16, it wears and generates wear debris.

[0029] The labyrinth seal 16 includes a fixed member 11 and a rotating member 12, and is installed on the side (the side on the inner side in the axial direction) of the bearing 4. In this embodiment, since the bearing 4 is installed at one end portion in the axial direction, the labyrinth seal 16 is also located at one end portion in the axial direction in the rotating electrical machine 100.

[0030] Also, since the ground brush 10 is installed so as to contact the rotating member 12 of the labyrinth seal 16, it is located at one end portion in the axial direction in the rotating electrical machine 100.

[0031] The fixed member 11 and the rotating member 12 of the labyrinth seal 16 are disk-shaped members having concavo-convex portions formed by concave portions and convex portions. The labyrinth seal 16 has a labyrinth structure formed by combining the concavo-convex portions of the fixed member 11 and the concavo-convex portions of the rotating member 12, and prevents dust such as wear debris of the ground brush 10 from entering the inside of the bearing 4.

[0032] Note that the concave and convex portions of the fixed member 11 and the rotating member 12 may have concave and convex portions extending in the axial direction or concave and convex portions extending in the radial direction. In the example shown in FIG. 1, the concave and convex portions of the fixed member 11 and the rotating member 12 have concave and convex portions extending in the axial direction. Also, the number of concave and convex portions in the concave and convex portions of the fixed member 11 and the rotating member 12 is not limited to the number shown in FIG. 1 and may be any number.

[0033] The fixed member 11 is fixed to the housing 1. The rotating member 12 is fixed to the rotating shaft 5. Therefore, the rotating member 12 rotates together with the rotating shaft 5 with the same rotation center as the rotating shaft 5. The rotating member 12 is made of a conductive material. Therefore, the ground brush 10 is electrically connected to the rotating shaft 5 via the rotating member 12.

[0034] The brush holder 13 is a member that fixes the ground brush 10 to the housing 1 and is fixed to the housing 1. The brush holder 13 electrically connects the ground brush 10 and the housing 1. Note that since the ground brush 10 is fixed to the brush holder 13, it does not rotate even when the rotating shaft 5 rotates.

[0035] In the rotating electrical machine 100 according to the present embodiment, with the above configuration, the rotating shaft 5 is electrically connected to the rotating member 12 of the labyrinth seal 16, the rotating member 12 is electrically connected to the ground brush 10, the ground brush 10 is electrically connected to the brush holder 13, and the brush holder 13 is electrically connected to the housing 1. Therefore, the shaft voltage generated in the rotating shaft 5 is transmitted to the housing 1 via the rotating member 12, the ground brush 10, and the brush holder 13 without passing through the bearing 4. The shaft voltage transmitted to the housing 1 is discharged by the ground to the ground installed in the housing 1.

[0036] The flow of the refrigerant inside the rotating electrical machine 100 will be described with reference to FIG. 2.

[0037] FIG. 2 is a diagram showing the flow of the refrigerant flowing inside the rotating electrical machine 100 according to the present embodiment. In FIG. 2, the flow of the refrigerant is indicated by an arrow 17.

[0038] The refrigerant flows into the interior of the rotating electric machine 100 from the intake port 7 and cools the rotor 2 and the stator 3. The refrigerant that has flowed into the interior of the rotating electric machine 100 is discharged from the exhaust port 8 to the outside of the rotating electric machine 100 through the air holes 6, the gap between the rotor 2 and the stator 3, and the rear ventilation path 9. Inside the rotating electric machine 100, the refrigerant flows toward the rotor 2 and the stator 3 with the earth brush 10 as the windward side. The earth brush 10 preferably has an axial position that is leeward (i.e., axially inward) of the bearing 4.

[0039] In the rotating electric machine 100 according to this embodiment, the labyrinth seal 16 including the fixed member 11 and the rotating member 12 can prevent foreign matters such as wear debris of the earth brush 10 from entering the bearing 4. Further, in the rotating electric machine 100 according to this embodiment, the earth brush 10 is located leeward of the bearing 4 and the refrigerant flows from the earth brush 10 toward the rotor 2 and the stator 3, so the wear debris of the earth brush 10 is less likely to enter the bearing 4. Therefore, in the rotating electric machine 100 according to this embodiment, the bearing 4 can have a longer life.

[0040] Also, in the rotating electric machine 100 according to this embodiment, the earth brush 10 is installed on the rotating member 12 of the labyrinth seal 16, and the earth brush 10 is provided on the radially outer side or the axially inner side of the rotating member 12, so there is no need for the space for contacting the earth brush 10 required for the conventional rotating electric machine with the rotating shaft 5, and the axial length can be shortened and the size can be reduced.

[0041] The rotating electric machine 100 according to this embodiment has the configuration as described above, and can achieve both a longer life of the bearing 4 and a smaller size of the rotating electric machine 100.

Embodiment

[0042] The rotating electric machine 100 according to Embodiment 2 of the present invention will be described with reference to FIG. 3. In this embodiment, an example of the configuration of the earth brush 10 included in the rotating electric machine 100 will be described.

[0043] FIG. 3 is a diagram showing an example of the configuration of the ground brush 10 included in the rotating electrical machine 100 according to the present embodiment.

[0044] The ground brush 10 includes a brush head 101 that contacts the rotating member 12 of the labyrinth seal 16, a conductive member 102 having a spring function, and a fastening portion 103 fixed to the brush holder 13. The conductive member 102 is a member that presses the brush head 101 against the rotating member 12 by the spring function.

[0045] The effects exhibited by the rotating electrical machine 100 according to the present embodiment will be described.

[0046] In the rotating electrical machine 100 according to the present embodiment, since the ground brush 10 includes the conductive member 102 having a spring function, even if the brush head 101 slides and wears against the rotating member 12, the force for pressing the brush head 101 against the rotating member 12 can be obtained by the conductive member 102. Therefore, in the rotating electrical machine 100 according to the present embodiment, the contact state between the ground brush 10 and the rotating member 12 of the labyrinth seal 16 can be maintained well over a long period of time, and it is possible to discharge the rotating shaft 5 and suppress electrolytic corrosion of the bearing 4 over a long period of time. For this reason, in the rotating electrical machine 100 according to the present embodiment, the life of the bearing 4 can be further extended.

Embodiment

[0047] The rotating electrical machine 100 according to Embodiment 3 of the present invention will be described with reference to FIG. 4. In the present embodiment, an example of the arrangement of the ground brush 10 included in the rotating electrical machine 100 will be described.

[0048] FIG. 4 is a diagram showing an example of the arrangement of the ground brush 10 included in the rotating electrical machine 100 according to the present embodiment, and corresponds to a diagram of the A-A cross section of the rotating electrical machine 100 shown in FIG. 1 viewed along the axial direction. FIG. 4 shows the rotating shaft 5, the rotating member 12 of the labyrinth seal 16, and the ground brush 10.

[0049] In FIG. 4, the horizontally extending broken line 18 indicates a horizontal line passing through the center of the rotating shaft 5. Also in FIG. 4, the concave portions of the uneven portions of the rotating member 12 are indicated by hatching.

[0050] In the rotating electric machine 100 according to this embodiment, the ground brush 10 is located below the center position of the rotating shaft 5 and is disposed at the lower part of the rotating electric machine 100. The position of the ground brush 10 shown in FIG. 4 is merely an example, and the ground brush 10 can be disposed at any position as long as it is below the center position of the rotating shaft 5.

[0051] The effects exhibited by the rotating electric machine 100 according to this embodiment will be described.

[0052] The ground brush 10 abuts against the rotating member 12 of the labyrinth seal 16 and wears to generate wear debris. As described in the first embodiment, since the labyrinth seal 16 has a labyrinth structure formed by the fixed member 11 and the rotating member 12, the bearing 4 is prevented from having dust such as wear debris of the ground brush 10 entering therein. However, if dust should enter the inside of the bearing 4, there is a concern that the life of the bearing 4 may be shortened.

[0053] In the rotating electric machine 100 according to this embodiment, since the ground brush 10 is located below the center position of the rotating shaft 5, the wear powder of the ground brush 10 falls from a position below the center of the rotating shaft 5 to the lower part of the rotating electric machine 100. That is, in this embodiment, the flying distance of the wear powder blown by the refrigerant can be made shorter than the case where the ground brush 10 is located above the center position of the rotating shaft 5. For this reason, in the rotating electric machine 100 according to this embodiment, the amount of wear powder entering the inside of the bearing 4 can be reduced, and the life of the bearing 4 can be further extended.

[0054] Incidentally, the vertical position of the ground brush 10 may be determined according to the refrigerant flow rate so that the wear powder of the ground brush 10 does not enter the inside of the bearing 4. For example, when the refrigerant flow rate is large (when the refrigerant wind speed is high), the wear powder is blown by the refrigerant to a position far from the bearing 4 (the flying distance of the wear powder is long), so the vertical position of the ground brush 10 may be a position close to the center position of the rotating shaft 5 (a high position). Also, for example, when the refrigerant flow rate is small (when the refrigerant wind speed is low), the wear powder falls at a position close to the bearing 4 (the flying distance of the wear powder is short), so the vertical position of the ground brush 10 is preferably a position far from the center position of the rotating shaft 5 (a low position).

Embodiment

[0055] The rotating electric machine 100 according to Embodiment 4 of the present invention will be described with reference to FIGS. 5 to 7. In this embodiment, an example of a window portion provided in the rotating electric machine 100 will be described. In the following description, the rotating electric machine 100 according to this embodiment will be mainly described with respect to the differences from the rotating electric machine 100 according to Embodiment 1.

[0056] FIG. 5 is a side view of the rotating electric machine 100 according to this embodiment.

[0057] In the rotating electric machine 100 according to this embodiment, the housing 1 includes a window portion 14. The window portion 14 is, for example, an inspection window, and includes an opening 14a provided in the housing 1 and a lid 14b provided in the opening 14a. The lid 14b is openable and closable. Normally, the lid 14b is closed to prevent dust from entering the inside of the rotating electric machine 100 from the outside, and is opened to open the window portion 14 in a predetermined case such as when inspecting the inside of the rotating electric machine 100.

[0058] FIG. 6 is a diagram for explaining the ground brush 10 included in the rotating electric machine 100 according to this embodiment.

[0059] In the rotating electrical machine 100 according to this embodiment, the brush holder 13 includes a fixture 15 that fixes the ground brush 10 to the brush holder 13. The ground brush 10 is fastened to the brush holder 13 by the fixture 15. As the fixture 15, any member (for example, a fastening member such as a bolt) can be used as long as it is a member that fixes the ground brush 10 to the brush holder 13.

[0060] FIG. 7 is a view showing an enlarged view of the periphery of the window portion 14 in the rotating electrical machine 100 according to this embodiment. The lid 14b of the window portion 14 includes a handle 14c. An operator can open the lid 14b by the handle 14c.

[0061] As described in the first embodiment, the brush holder 13 is fixed to the housing 1. The fixture 15 that fixes the ground brush 10 to the brush holder 13 is arranged so as to face the opening 14a of the window portion 14. That is, the fixture 15 is arranged at a position where it can be visually observed from the outside of the housing 1 through the opening 14a of the window portion 14. When the fixture 15 is arranged so as to face the opening 14a of the window portion 14, an operator can easily perform work on the fixture 15 from the window portion 14.

[0062] The effect exhibited by the rotating electrical machine 100 according to this embodiment will be described.

[0063] In the rotating electrical machine 100 according to this embodiment, since the housing 1 includes the window portion 14, an operator can easily inspect the inside of the rotating electrical machine 100 without disassembling the rotating electrical machine 100.

[0064] Further, the ground brush 10 is particularly severely worn among the components of the rotating electrical machine 100, and the inspection frequency is higher than that of other components. In the rotating electrical machine 100 according to this embodiment, since the fixture 15 that fixes the ground brush 10 is arranged so as to face the opening 14a of the window portion 14, an operator can easily perform work such as removing the ground brush 10 from the brush holder 13 or attaching it to the brush holder 13.

[0065] Therefore, in the rotating electrical machine 100 according to this embodiment, the inspection cost can be reduced by labor saving and inspection time shortening of the ground brush 10, the frequency of the inspection work and replacement work of the ground brush 10 can be increased, and the life of the bearing 4 can be further extended.

Embodiment

[0066] Example 5 of the present invention will be described with reference to FIG. 8. In this example, an example of a vehicle equipped with the rotating electrical machine 100 according to any one of Examples 1 to 4 will be described. In this example, as an example, an example in which the vehicle equipped with the rotating electrical machine 100 is a dump truck will be described.

[0067] FIG. 8 is a diagram schematically showing an example of the configuration of a dump truck 1000 equipped with the rotating electrical machine 100.

[0068] The dump truck 1000 includes a rotating electrical machine 100, an engine 200, and a hydraulic pump 300. The rotating shaft 5 of the rotating electrical machine 100 and the rotating shaft of the engine 200 are connected to each other. Also, the rotating shaft 5 of the rotating electrical machine 100 and the rotating shaft of the hydraulic pump 300 are connected to each other. With this configuration, the driving force generated by the engine 200 is transmitted to the rotating electrical machine 100 and the hydraulic pump 300. The rotating electrical machine 100 converts the driving force of the engine 200 into electric power. The hydraulic pump 300 converts the driving force of the engine 200 into power for lifting the loading platform of the dump truck 1000.

[0069] In this embodiment, the dump truck 1000 includes the rotating electrical machine 100 according to any one of Examples 1 to 4, that is, a long-life and small-sized rotating electrical machine 100. Therefore, in this embodiment, the life of the dump truck 1000 itself can be extended, and the functionality of the dump truck 1000 can be improved by expanding the loading platform space or the like.

[0070] Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the above embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to the embodiments having all the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. Further, it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to delete a part of the configuration of each embodiment, or add or replace other configurations.

Explanation of Reference Numerals

[0071] 1…Housing, 2…Rotor, 3…Stator, 4…Bearing, 5…Rotating shaft, 6…Air hole, 7…Air inlet, 8…Exhaust port, 9…Rear ventilation path, 10…Earth brush, 11…Fixing member, 12…Rotating member, 13…Brush holder, 14…Window portion, 14a…Opening, 14b…Cover, 14c…Handle, 15…Fastener, 16…Labyrinth seal, 17…Arrow indicating the flow of refrigerant, 18…Dashed line indicating the horizontal line passing through the center of the rotating shaft, 100…Rotating electric machine, 101…Brush head, 102…Conductive member, 103…Fastening portion, 200…Engine, 300…Hydraulic pump, 1000…Dump truck.

Claims

1. A rotor, a rotating shaft connected to the rotor and rotating together with the rotor, a bearing that supports the rotating shaft, a labyrinth seal installed on the side of the bearing, an earth brush that removes the shaft voltage generated in the rotating shaft, a housing that houses the rotor, the rotating shaft, the bearing, the labyrinth seal, and the earth brush, comprising: The labyrinth seal includes a fixed member fixed to the housing and a rotating member fixed to the rotating shaft and rotating together with the rotating shaft, The earth brush is installed on the rotating member, A rotating electrical machine characterized by the above.

2. The rotating member has a disk shape and the same rotation center as the rotating shaft, The rotating electrical machine according to Claim 1.

3. The bearing and the earth brush are located at one end in the axial direction, which is the direction along the rotating shaft, The housing has an air inlet at the one end and an exhaust port at the other end in the axial direction, The rotating electrical machine according to Claim 1.

4. The earth brush includes a brush head that contacts the rotating member and a conductive member having a spring function, The rotating electrical machine according to Claim 1.

5. The earth brush is located below the center of the rotating shaft, The rotating electrical machine according to Claim 1.

6. The housing includes a window portion having an opening and a lid that can be opened and closed provided in the opening, The rotating electrical machine according to Claim 1.

7. A brush holder that is fixed to the housing and fixes the earth brush to the housing, The brush holder includes a fixture that fixes the earth brush to the brush holder, The fixture is arranged to face the opening of the window portion, The rotating electrical machine according to Claim 6.

8. The radial direction of the rotating shaft is the diameter direction, and the direction along the rotating shaft is the axial direction, The earth brush is provided on the outer side in the diameter direction or the inner side in the axial direction of the rotating member, The rotating electrical machine according to Claim 1.

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