Rotating electric machine

Abstract

This rotating electric machine includes a stator, a rotor, a shaft, and a housing. The housing has a frame, a bracket, and a terminal member. The frame has a first inner peripheral surface, a second inner peripheral surface, a first joint surface, and a support part. The first inner peripheral surface forms a first through-hole in which the stator and the rotor are accommodated. The second inner peripheral surface forms a second through-hole in which the terminal member is accommodated. The first joint surface is connected to an end of the first inner peripheral surface in a first direction and is oriented in the first direction. The support part protrudes from the second inner peripheral surface and supports the terminal member. The bracket has a second joint surface facing the first joint surface and a protrusion, and closes an end of the frame in the first direction. The protrusion protrudes from the second joint surface in a second direction opposite to the first direction, and is fitted into the first through-hole. Further, the protrusion has an outer peripheral surface facing the first inner peripheral surface, and overlaps the support part in a direction intersecting with the first direction.

Description

rotating electrical machines

[0001] The present invention relates to a rotating electric machine.

[0002] Conventionally, a rotating electric machine is known that includes a rotor, a stator, and a housing that houses the rotor and the stator. A pressure-resistant explosion-proof motor, which is one type of rotating electric machine, is designed to prevent sparks from reaching the outside of the housing in the event of an explosion inside the rotating electric machine, for example.

[0003] Japanese Utility Model Application Publication No. 61-104750

[0004] In conventional rotating electric machines known as pressure-resistant and explosion-proof motors, measures are taken to design the gap connecting the inside and outside of the housing long in order to prevent sparks generated inside the rotating electric machine from reaching the outside of the housing. It would be beneficial for this type of rotating electric machine to have even greater pressure-resistant and explosion-proof properties.

[0005] One example of a problem to be solved by the present invention is to provide a rotating electric machine that can further improve pressure resistance and explosion proof performance.

[0006] A rotating electric machine according to an embodiment of the present invention includes a stator, a rotor, a shaft, and a housing. The rotor is rotatable inside the stator. The shaft is rotatable together with the rotor. The housing includes a frame, a bracket, and a terminal member electrically connectable to the stator. The frame includes a first inner circumferential surface, a second inner circumferential surface, a first joint surface, and a support portion. The first inner circumferential surface penetrates the frame in a first direction, which is a direction toward the outside of the housing in the axial direction of the shaft, and forms a first through hole in which the stator and the rotor are housed. The second inner circumferential surface penetrates the frame in a direction intersecting the first direction and forms a second through hole in which the terminal member is housed. The first joint surface is connected to an end of the first inner circumferential surface in the first direction and faces the first direction. The support portion protrudes from the second inner circumferential surface and supports the terminal member. The bracket has a second joint surface facing the first joint surface and a protrusion, and closes the end of the frame in the first direction. The protrusion protrudes from the second joint surface in a second direction opposite to the first direction and is fitted into the first through hole. Furthermore, the protrusion has an outer circumferential surface facing the first inner circumferential surface and overlaps with the support portion in a direction intersecting the first direction.

[0007] According to the rotating electric machine of the present invention, it is possible to obtain a rotating electric machine that can further improve pressure resistance and explosion proof properties.

[0008] Fig. 1 is a cross-sectional view showing a rotating electrical machine according to the present embodiment, and Fig. 2 is a cross-sectional view showing a frame, a bracket, and a terminal plate according to the present embodiment.

[0009] The rotating electric machine 1 according to this embodiment will be described below with reference to the drawings. The configuration of the embodiment described below, as well as the actions and results (effects) brought about by this configuration, are merely examples and are not limited to the following description. Note that in this specification, ordinal numbers are used only to distinguish between parts and components, and do not indicate order or priority.

[0010] 1 is a cross-sectional view schematically illustrating a rotating electric machine 1 according to the present embodiment. The rotating electric machine 1 according to the present embodiment is, for example, a pressure-resistant explosion-proof motor. However, the present invention is not limited to this, and the rotating electric machine 1 may be, for example, another rotating electric machine such as a generator. As shown in FIG. 1 , the rotating electric machine 1 includes a stator 11, a shaft 12, a rotor 13, a housing 14, two bearings 15, a terminal box 16, and a plurality of cables 17.

[0011] The stator 11 has a stator core 111 and a stator winding 112. The stator core 111 is fixed to the housing 14. The stator core 111 is located radially outward of the rotor 13 and is formed in a cylindrical shape surrounding the rotor 13. The stator winding 112 passes through a plurality of slots (not shown) formed in the stator core 111 so as to extend in the axial direction, and is fixed to the stator core 111.

[0012] The shaft 12 is supported by the housing 14 via two bearings 15 so as to be rotatable around a rotation axis Ax surrounded by the stator 11. In other words, the two bearings 15 support the shaft 12 so as to be rotatable relative to the housing 14. The rotation axis Ax is, for example, the central axis (center line) of the shaft 12. Note that the rotation axis Ax may be different from the central axis of the shaft 12.

[0013] In the following description, for convenience, the axial direction, radial direction, and circumferential direction of the rotation axis Ax are defined. The axial direction is the direction along the rotation axis Ax. The radial direction is the direction perpendicular to the rotation axis Ax. The circumferential direction is the direction around the rotation axis Ax. In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction are the axial direction, radial direction, and circumferential direction of the rotation axis Ax.

[0014] The shaft 12 extends in the axial direction along the rotation axis Ax so as to penetrate the housing 14. The portion of the shaft 12 between both axial ends 12a is housed in the housing 14. On the other hand, both axial ends 12a of the shaft 12 protrude from the housing 14 to the outside.

[0015] Both ends 12a of the shaft 12 are coupled to, for example, various external devices, so that the rotation of the shaft 12 drives the external devices.

[0016] The rotor 13 is formed in a generally cylindrical shape extending in the axial direction, and is disposed generally concentrically with the stator 11. The rotor 13 is disposed inside the stator 11 with a gap therebetween. The rotor 13 has, for example, a plurality of permanent magnets. The rotor 13 is attached to a portion of the shaft 12 between both axial end portions 12a. Therefore, the rotor 13 rotates integrally with the shaft 12.

[0017] The stator 11 and the rotor 13 are not limited to the above configurations as long as they can generate rotational force by electromagnetic force. For example, the rotor 13 may have a rotor core made of a magnetic material and a conductor attached to the rotor core.

[0018] The housing 14 is formed into a box shape from, for example, metal. However, the housing 14 may be formed from other materials. The housing 14 houses the stator 11, a portion of the shaft 12, and the rotor 13. The housing 14 has a frame 21, two brackets 22, two oil throwers 23, two terminal plates 24, a first bolt 25, a second bolt 26, and a third bolt 27. The terminal plate 24 is an example of a terminal member.

[0019] A space 30 is provided inside the housing 14. The space 30 is a substantially cylindrical space extending in the axial direction. The space 30 is formed by being surrounded by the frame 21 and the two brackets 22. Note that the space 30 is not limited to being cylindrical, and may have other shapes.

[0020] The frame 21 is formed in a substantially cylindrical shape extending in the axial direction, and surrounds the stator 11, the rotor 13, and the space 30. In other words, the frame 21 is disposed substantially concentrically with the stator 11 and the rotor 13, and is fixed to the stator 11. Note that the frame 21 is not limited to a cylindrical shape and may have other shapes.

[0021] The frame 21 has protrusions 211. The protrusions 211 protrude in the radial direction from an outer surface 21a, which is the surface facing the outside of the frame 21. The protrusions 211 are positioned to be spaced apart from one another in the axial direction.

[0022] Two through holes 31 are provided in the protruding portion 211. The through holes 31 are holes that penetrate the protruding portion 211 in the radial direction. In other words, the through holes 31 penetrate the frame 21 in the radial direction to connect the space 30 to the outside of the housing 14. The two through holes 31 are arranged spaced apart from each other in the axial direction.

[0023] The through hole 31 has a first hole portion 31a and a second hole portion 31b. The through hole 31 is an example of a second through hole. The first hole portion 31a and the second hole portion 31b are part of the through hole 31. The inner diameter of the first hole portion 31a is slightly larger than the inner diameter of the second hole portion 31b. This forms a step in the through hole 31.

[0024] 1, the brackets 22 are formed in the shape of plates that intersect with the axial direction. The two brackets 22 are connected to both end portions 21b of the frame 21 in the axial direction by, for example, first bolts 25. In this way, the brackets 22 close both end portions 21b of the frame 21.

[0025] Fig. 2 is a cross-sectional view showing the frame 21, the bracket 22, and the terminal board 24 of this embodiment. In other words, Fig. 2 is an enlarged cross-sectional view of a portion of Fig. 1. As shown in Fig. 2, the bracket 22 has a protrusion 221.

[0026] The protrusion 221 protrudes from the inner surface of the bracket 22, which is the surface facing the space 30, along the axial direction and toward the center of the rotating electric machine 1. In other words, the protrusion 221 of one bracket 22 protrudes from the inner surface of the bracket 22 toward the other bracket 22.

[0027] The length of the protrusion 221 is a length that does not cover the second hole portion 31b of the frame 21. However, the length of the protrusion 221 is not limited to this. For example, the length of the protrusion 221 may be any length as long as it does not completely block the second hole portion 31b of the frame 21.

[0028] Furthermore, as shown in FIG. 1 , an opening 32 is provided in the bracket 22. The opening 32 opens in the axial direction in the bracket 22. The opening 32 connects the outside of the housing 14 to the space 30. Note that the opening 32 does not have to connect the outside of the housing 14 to the space 30 alone. For example, the opening 32 may be provided in the middle of a passage that connects the outside of the housing 14 to the space 30 alone. The shaft 12 is arranged to pass through the opening 32. In other words, the shaft 12 passes through the bracket 22 in the axial direction.

[0029] The oil throwers 23 are formed in the shape of a plate that intersects with the axial direction. The two oil throwers 23 are located inside the housing 14 relative to the brackets 22. Each oil thrower 23 is connected to the corresponding bracket 22 by a second bolt 26.

[0030] An opening 33 is provided in each oil thrower 23. The opening 33 opens the oil thrower 23 in the axial direction. The opening 33 is provided approximately concentrically with the opening 32 of the bracket 22. The shaft 12 is arranged to pass through the opening 33. In other words, the shaft 12 passes through the oil thrower 23 in the axial direction.

[0031] A bearing chamber 34 is provided between the bracket 22 and the oil thrower 23 connected to the bracket 22. The bearing chamber 34 communicates with an opening 32 of the bracket 22 and an opening 33 of the oil thrower 23.

[0032] The two bearings 15 are provided in the bearing chamber 34. The two bearings 15 are attached to the bracket 22, for example, in the bearing chamber 34. The bearings 15 support the shaft 12 rotatably about the rotation axis Ax.

[0033] An oil passage 35 is provided in each of the two brackets 22. The oil passage 35 connects the bearing chamber 34 with the outside of the housing 14. The bearing chamber 34 can be supplied with lubricant through the oil passage 35.

[0034] The terminal board 24 is, for example, a member that can be electrically connected to the stator 11. The terminal board 24 is housed in the through hole 31. The terminal board 24 has a cover 241 and a plurality of terminals 242.

[0035] The cover 241 is formed in a plate shape and is connected to the frame 21 by the third bolt 27. The terminals 242 are, for example, conductors that pass through the cover 241. In this embodiment, the multiple terminals 242 are electrically connected to the terminal box 16.

[0036] The terminal box 16 is formed into a box shape from, for example, metal. However, the terminal box 16 may be formed from other materials. The terminal box 16 is located outside the housing 14. Therefore, the terminal box 16 is electrically connected to the stator 11 via a plurality of terminals 242.

[0037] The cables 17 electrically connect, for example, the stator windings 112, sensors arranged in the space 30, and the plurality of terminals 242. In other words, the terminal box 16 is electrically connected to the stator windings 112, sensors arranged in the space 30, and the like via the plurality of terminals 242 and the cables 17.

[0038] The frame 21, bracket 22, oil thrower 23, and terminal plate 24 are joined together by a spigot joint. A spigot joint is also called a spigot joint. In a spigot joint, a protrusion or plug on one member is fitted into a recess or hole on the other member. However, the frame 21, bracket 22, oil thrower 23, and terminal plate 24 may also be joined together by other methods.

[0039] The housing 14 further has an inner surface 40. The inner surface 40 is the surface of the housing 14 that faces the space 30. In other words, the inner surface 40 faces the inside of the housing 14. The inner surface 40 forms (may also be expressed as defining or partitioning) the space 30. In other words, the inner surface 40 is the surface of the housing 14 that is exposed to the space 30.

[0040] The inner surface 40 includes parts of the frame 21, the bracket 22, the oil thrower 23, and the terminal board 24. Therefore, the inner surface 40 has a partial inner surface 41 included in the frame 21, a partial inner surface 42 included in the bracket 22, a partial inner surface 43 included in the oil thrower 23, and a partial inner surface 44 included in the terminal board 24. Each of the partial inner surfaces 41 to 44 is part of the inner surface 40, and forms (defines or partitions) a part of the space 30.

[0041] As shown in FIG. 2 , a through hole 50 is provided in the frame 21. The through hole 50 penetrates the frame 21 in the axial direction. The through hole 50 has a space 30 and two fitting openings 51. The two fitting openings 51 are provided at both axial end portions 21b of the through hole 50. The space 30 is located between the two fitting openings 51. The two fitting openings 51 are holes that communicate between the space 30 and the outside of the housing 14. The through hole 50 is an example of a first through hole.

[0042] In this embodiment, the through hole 50 is part of the space inside the frame 21. However, the through hole 50 can also be expressed as penetrating the end 21b of the frame 21 in the axial direction. In other words, the space inside the frame 21 includes the space 30 and the through hole 50. Therefore, the through hole 50 can also be expressed as accommodating the stator 11, part of the shaft 12, and the rotor 13. The axial direction is an example of the first direction. In other words, the first direction is the direction toward the outside of the housing 14.

[0043] The frame 21 further has an inner circumferential surface 52, a joint surface 53, and a stepped surface 54. The inner circumferential surface 52 is an example of a first inner circumferential surface, the joint surface 53 is an example of a first joint surface, and the stepped surface 54 is an example of a first surface.

[0044] The inner circumferential surface 52 is a substantially cylindrical curved surface extending in the axial direction. The inner circumferential surface 52 forms (defines or defines) at least a portion of the through hole 50. The inner circumferential surface 52 faces inward in the radial direction. In other words, the inner circumferential surface 52 faces toward the inside of the through hole 50. Note that the radial direction is an example of a direction intersecting with the first direction.

[0045] The joint surface 53 is provided, for example, at the end 21b of the frame 21 in the axial direction. The joint surface 53 may be provided at another position. The joint surface 53 is connected to the end of the inner circumferential surface 52 at the outer side Dxo in the axial direction. The outer side Dxo in the axial direction is a direction toward the outside of the housing 14 in the axial direction and is included in the axial direction. The outer side Dxo in the axial direction is an example of the first direction.

[0046] The joining surface 53 is, for example, a substantially annular plane extending radially outward from the end of the inner circumferential surface 52. The joining surface 53 faces the outer axial direction Dxo. The outer axial direction Dxo is perpendicular to the direction in which the inner circumferential surface 52 faces. Note that the joining surface 53 may face in another direction that intersects with the direction in which the inner circumferential surface 52 faces.

[0047] A bolt hole 55 is provided in the joint surface 53. In other words, the frame 21 is provided with a bolt hole 55 that opens at the joint surface 53. The bolt hole 55 extends in the axial direction from the joint surface 53. A female thread is formed on the inner surface of the bolt hole 55. The female thread of the bolt hole 55 can fit onto the male thread of the first bolt 25.

[0048] The stepped surface 54 is provided, for example, at a position spaced apart from the joint surface 53 to an inner axial direction Dxi. The inner axial direction Dxi is a direction toward the inside of the housing 14 in the axial direction and is included in the axial direction. The inner axial direction Dxi is the opposite direction to the outer axial direction Dxo and is an example of the second direction.

[0049] One end 54a of the stepped surface 54 in the radial direction is connected to an end of the inner peripheral surface 52 on the inner side Dxi in the axial direction. The stepped surface 54 is connected to the edge 41a of the partial inner surface 41 of the frame 21. The other end 54b of the stepped surface 54 in the radial direction is located on the opposite side to the end 54a.

[0050] The stepped surface 54 is, for example, a substantially annular plane extending radially inward from the end of the inner circumferential surface 52. The stepped surface 54 faces outward in the axial direction Dxo. Therefore, the stepped surface 54 intersects with the axial direction. Note that the stepped surface 54 may face in another direction intersecting with the direction in which the inner circumferential surface 52 faces. The direction in which the stepped surface 54 faces may be different from the direction in which the joining surface 53 faces.

[0051] The radial length of the stepped surface 54 is shorter than the axial length of the inner circumferential surface 52. In other words, the distance between the ends 54 a and 54 b of the stepped surface 54 is shorter than the distance between the joining surface 53 and the stepped surface 54.

[0052] The protrusion 221 of the bracket 22 is formed in a generally cylindrical shape and is fitted into a fitting opening 51, which is part of the through-hole 50. The fitting opening 51 is a part of the internal space of the frame 21 into which the protrusion 221 is fitted. The protrusion 221 has an outer peripheral surface 61 and an end surface 62. The end surface 62 is an example of a second surface.

[0053] The outer peripheral surface 61 is a substantially cylindrical curved surface extending in the axial direction. The diameter of the outer peripheral surface 61 is equal to or slightly shorter than the diameter of the inner peripheral surface 52. In addition, the length of the outer peripheral surface 61 in the axial direction is substantially equal to the length of the inner peripheral surface 52.

[0054] The outer peripheral surface 61 faces radially outward. In other words, the outer peripheral surface 61 faces the inner peripheral surface 52. The outer peripheral surface 61 may be in contact with the inner peripheral surface 52 or may be slightly spaced apart from the inner peripheral surface 52. The outer peripheral surface 61 and the inner peripheral surface 52 are arranged substantially concentrically and substantially parallel to each other.

[0055] The end surface 62 is provided at the end of the protrusion 221 on the inner side Dxi in the axial direction. In other words, the end surface 62 is the end surface of the protrusion 221 on the inner side Dxi in the axial direction. The end surface 62 may be provided at another position.

[0056] One end 62a of the end face 62 in the radial direction is connected to an end of the outer peripheral surface 61 on the inner side Dxi in the axial direction. The end 62b is connected to the edge 42a of the partial inner surface 42 of the bracket 22. The other end 62b of the end face 62 in the radial direction is located opposite to the end 62a.

[0057] The end face 62 is, for example, a substantially annular plane extending radially inward from the end of the outer circumferential surface 61. The end face 62 faces inward in the axial direction Dxi. Therefore, the end face 62 intersects with the axial direction. Note that the end face 62 may face in another direction intersecting with the direction in which the inner circumferential surface 52 faces.

[0058] The end surface 62 faces the stepped surface 54. The end surface 62 may be in contact with the stepped surface 54 or may be slightly spaced apart from the stepped surface 54. The end surface 62 and the stepped surface 54 are arranged substantially concentrically and substantially parallel to each other.

[0059] The bracket 22 further has a flange 222. The flange 222 protrudes radially outward from the protrusion 221 and covers the joint surface 53 of the frame 21. The flange 222 has a joint surface 63. The joint surface 63 is an example of a second joint surface.

[0060] The joining surface 63 is provided, for example, at an end of the flange 222 on the inner side Dxi in the axial direction. The joining surface 63 may be provided at another position. The joining surface 63 is connected to an end of the outer peripheral surface 61 on the outer side Dxo in the axial direction.

[0061] The joint surface 63 is, for example, a substantially annular plane extending radially outward from the end of the outer circumferential surface 61 of the protrusion 221. The joint surface 63 faces inward in the axial direction Dxi. That is, the protrusion 221 protrudes from the joint surface 63 toward the inward in the axial direction Dxi. Note that the joint surface 63 may face in another direction intersecting the direction in which the inner circumferential surface 52 faces.

[0062] The joint surface 63 faces the joint surface 53 of the frame 21. The joint surface 63 may be in contact with the joint surface 53 or may be slightly spaced apart from the joint surface 53. The joint surface 63 and the joint surface 53 are arranged substantially concentrically and substantially parallel to each other.

[0063] The length of the end face 62 in the radial direction is shorter than the length of the outer circumferential surface 61 in the axial direction. In other words, the distance between the end 62 a and the end 62 b of the end face 62 is shorter than the distance between the joining surface 63 and the end face 62.

[0064] A through hole 64 is provided in the joint surface 63. In other words, the bracket 22 is provided with a through hole 64 that opens at the joint surface 63. The through hole 64 axially passes through the flange 222. The through hole 64 has a diameter that allows the first bolt 25 to pass through the inside of the through hole 64. The through hole 64 communicates with the bolt hole 55.

[0065] The first bolt 25 is inserted from outside the housing 14 through the through hole 64 of the bracket 22 and into the bolt hole 55 of the frame 21. In other words, the first bolt 25 fits into the through hole 64 and the bolt hole 55. In this way, the first bolt 25 connects the frame 21 and the bracket 22 to each other.

[0066] As described above, the stepped surface 54 of the frame 21 is connected to the edge 41 a of the partial inner surface 41. Furthermore, the end surface 62 of the bracket 22 is connected to the edge 42 a of the partial inner surface 42. That is, the stepped surface 54 and the end surface 62 are connected to the inner surface 40.

[0067] The partial inner surface 41 faces radially inward at an edge 41 a. The partial inner surface 42 faces radially inward at an edge 42 a. The edge 41 a of the partial inner surface 41 and the edge 42 a of the partial inner surface 42 are located at approximately the same position in the radial direction. Therefore, the partial inner surfaces 41 and 42 form a substantially continuous surface.

[0068] The frame 21 further has an inner circumferential surface 71, a joint surface 72, a first stepped surface 73, and a second stepped surface 74. The inner circumferential surface 71 is a generally cylindrical surface extending in the radial direction. The inner circumferential surface 71 forms (defines or defines) a portion of the through hole 31. The inner circumferential surface 71 faces inward of the through hole 31. The inner circumferential surface 71 is an example of a second inner circumferential surface.

[0069] The joint surface 72 is connected to an end of the inner circumferential surface 71 at the radially outer side Dro. The radially outer side Dro is a direction toward the outside of the housing 14 in one of the multiple radial directions in which the through hole 31 extends. The radially outer side Dro is included in the radial direction. Note that the radially outer side Dro is an example of a direction intersecting with the first direction.

[0070] The joining surface 72 is, for example, a substantially annular plane extending from the end of the inner circumferential surface 71 in a direction perpendicular to the radial direction. The joining surface 72 faces the radially outer side Dro. The radially outer side Dro is perpendicular to the direction in which the inner circumferential surface 71 faces. Note that the joining surface 72 may face in another direction that intersects with the direction in which the inner circumferential surface 71 faces.

[0071] A bolt hole 75 is provided in the joint surface 72. In other words, the frame 21 is provided with a bolt hole 75 that opens at the joint surface 72. The bolt hole 75 extends radially from the joint surface 72. A female thread is formed on the inner surface of the bolt hole 75. The female thread of the bolt hole 75 can fit onto the male thread of the third bolt 27.

[0072] The first stepped surface 73 is provided, for example, at a position spaced apart from the joining surface 72 to a radially inner side Dri. The radially inner side Dri is a direction toward the inside of the housing 14 in the one radial direction in which the through hole 31 extends, among multiple radial directions. The radially inner side Dri is included in the radial direction. The radially inner side Dri is the opposite direction to the radially outer side Dro. Note that the radially inner side Dri is an example of a direction intersecting with the first direction.

[0073] One end 73a of the first stepped surface 73 in a direction perpendicular to the radial direction is connected to an end of the inner peripheral surface 71 on the radially inner side Dri. The other end 73b of the first stepped surface 73 in a direction perpendicular to the radial direction is connected to the second stepped surface 74. End 73b is located on the opposite side of end 73a.

[0074] The first stepped surface 73 is, for example, a substantially annular plane extending from the end of the inner circumferential surface 71 in a direction perpendicular to the radial direction. The first stepped surface 73 faces the outer side Dro in the radial direction. Therefore, the first stepped surface 73 intersects with the radial direction. Note that the first stepped surface 73 may face in another direction intersecting with the direction in which the inner circumferential surface 71 faces. The direction in which the first stepped surface 73 faces may be different from the direction in which the joining surface 72 faces.

[0075] The length of the first stepped surface 73 in a direction perpendicular to the radial direction is shorter than the length of the inner circumferential surface 71. In other words, the distance between the ends 73 a and 73 b of the first stepped surface 73 is shorter than the distance between the joining surface 72 and the first stepped surface 73.

[0076] The second stepped surface 74 is a generally cylindrical surface that extends radially inward Dri from the first stepped surface 73. The second stepped surface 74 forms (defines or defines) a portion of the through hole 31. The second stepped surface 74 faces the inside of the through hole 31.

[0077] An end 74a of the radially outer Dro of the second step surface 74 is connected to an end 73b of the first step surface 73. The second step surface 74 is connected to an edge 41b of the partial inner surface 41 of the frame 21. An end 74b of the radially inner Dri of the second step surface 74 is located opposite the end 74a.

[0078] The radial length of the second stepped surface 74 is shorter than the radial length of the inner circumferential surface 71. In other words, the distance between the end 74 a and the end 74 b of the second stepped surface 74 is shorter than the distance between the joining surface 72 and the first stepped surface 73.

[0079] The frame 21 further has a step 76. The step 76 protrudes from the inner circumferential surface 71 and supports the terminal board 24. The step 76 is spaced radially inwardly Dri from the joining surface 72. The first stepped surface 73 and the second stepped surface 74 are provided on the step 76. The step 76 is an example of a support portion.

[0080] In the step 76, the surface facing radially inward is the inner circumferential surface 52. Therefore, the stepped surface 54 can be expressed as, for example, a substantially annular plane extending from the surface facing the radially inward Dri of the step 76 toward the radially inward Dri.

[0081] In this embodiment, the end surface 62 overlaps with the step 76 in the axial direction. In other words, the protrusion 221 overlaps with the step 76 in the axial direction. This increases the length of the outer circumferential surface 61 in the axial direction.

[0082] The cover 241 of the terminal board 24 has a stopper portion 243 and a flange 244. The stopper portion 243 is formed in a generally columnar shape and is fitted into the through hole 31. Therefore, the stopper portion 243 closes the through hole 31. The stopper portion 243 has an outer peripheral surface 81, a first stepped surface 82, and a second stepped surface 83.

[0083] The outer peripheral surface 81 is a generally cylindrical surface extending in the radial direction. The size of the outer peripheral surface 81 is equal to or slightly smaller than the size of the inner peripheral surface 71. In addition, the length of the outer peripheral surface 81 in the radial direction is generally equal to the length of the inner peripheral surface 71.

[0084] The outer peripheral surface 81 faces the inner peripheral surface 71. The outer peripheral surface 81 may be in contact with the inner peripheral surface 71 or may be slightly spaced apart from the inner peripheral surface 71. The outer peripheral surface 81 and the inner peripheral surface 71 are disposed substantially parallel to each other.

[0085] One end 82a of the first stepped surface 82 in a direction perpendicular to the radial direction is connected to an end of the outer circumferential surface 81 on the radially inner side Dri. The other end 82b of the first stepped surface 82 in a direction perpendicular to the radial direction is connected to the second stepped surface 83.

[0086] The first stepped surface 82 is, for example, a substantially annular plane extending from the end of the outer circumferential surface 81. The first stepped surface 82 faces inward in the radial direction Dri. Therefore, the first stepped surface 82 intersects with the radial direction. Note that the first stepped surface 82 may face in another direction that intersects with the direction in which the inner circumferential surface 71 faces.

[0087] The first step surface 82 faces the first step surface 73 of the frame 21. The first step surface 82 may be in contact with the first step surface 73 or may be slightly spaced apart from the first step surface 73. The first step surfaces 73, 82 of the frame 21 and the cover 241 are arranged substantially parallel to each other.

[0088] The second stepped surface 83 is a generally cylindrical surface extending radially inwardly from the first stepped surface 82. An end 83a of the second stepped surface 83 on the radially outer side Dri is connected to an end 82b of the first stepped surface 82. The second stepped surface 83 is connected to an edge 44a of the partial inner surface 44 of the terminal board 24. An end 83b of the second stepped surface 83 on the radially inner side Dri is located opposite the end 83a.

[0089] The second step surface 83 faces the second step surface 74 of the frame 21. The second step surface 83 may be in contact with the second step surface 74 or may be slightly spaced apart from the second step surface 83. The second step surfaces 74, 83 of the frame 21 and the cover 241 are arranged substantially parallel to each other.

[0090] The flange 244 protrudes radially outward from the plug portion 243 and covers the joint surface 72 of the frame 21. The flange 244 has a joint surface 84. The joint surface 84 is provided, for example, at an end of the flange 244 on the radially inner side Dri. The joint surface 84 may be provided at another position. The joint surface 84 is connected to an end of the outer circumferential surface 81 on the radially outer side Dro.

[0091] The joining surface 84 is, for example, a substantially annular plane extending from the end of the outer circumferential surface 81. The joining surface 84 faces inward in the radial direction Dri. Note that the joining surface 84 may face in another direction intersecting the direction in which the inner circumferential surface 71 faces.

[0092] The joint surface 84 faces the joint surface 72 of the frame 21. The joint surface 84 may be in contact with the joint surface 72, or may be slightly spaced apart from the joint surface 72. The joint surface 84 and the joint surface 72 are disposed approximately parallel to each other.

[0093] The length of the first step surface 82 in a direction perpendicular to the radial direction is shorter than the length of the outer circumferential surface 81 in the radial direction. In other words, the distance between the ends 82a and 82b of the first step surface 82 is shorter than the distance between the joining surface 84 and the first step surface 82. Furthermore, the distance between the ends 83a and 83b of the second step surface 83 is shorter than the distance between the joining surface 84 and the first step surface 82.

[0094] A through hole 85 is provided in the joint surface 84. In other words, the cover 241 is provided with a through hole 85 that opens at the joint surface 84. The through hole 85 penetrates the flange 244 in the radial direction. The through hole 85 has a diameter that allows the third bolt 27 to pass through the inside of the through hole 85. The through hole 85 communicates with the bolt hole 75.

[0095] The third bolt 27 is inserted from outside the housing 14 through the through hole 85 of the cover 241 and into the bolt hole 75 of the frame 21. In other words, the third bolt 27 fits into the through hole 85 and the bolt hole 75. In this way, the third bolt 27 connects the frame 21 and the cover 241 to each other.

[0096] As described above, the second stepped surface 74 of the frame 21 is connected to the edge 41 a of the partial inner surface 41. Furthermore, the second stepped surface 83 of the terminal board 24 is connected to the edge 44 a of the partial inner surface 44. Therefore, the second stepped surfaces 74, 83 are connected to the inner surface 40.

[0097] The partial inner surface 41 faces the radially inward Dri at an edge 41a. The partial inner surface 44 faces the radially inward Dri at an edge 44a. The edge 41a of the partial inner surface 41 and the edge 44a of the partial inner surface 44 are located at approximately the same position in the radial direction. Therefore, the partial inner surface 41 and the partial inner surface 44 form a substantially continuous surface.

[0098] The rotating electric machine 1, which is an explosion-proof motor, can prevent sparks from reaching the outside of the housing 14 even if an explosion occurs in the space 30. The following description will be given of the case where an explosion occurs in the space 30. The rotating electric machine 1 has various configurations that can prevent an explosion from occurring in the space 30.

[0099] 2 , gaps G1, G2, and G3 may be provided between the frame 21 and the bracket 22. The gap G1 is provided between the joint surface 53 and the joint surface 63. The gap G2 is provided between the inner circumferential surface 52 and the outer circumferential surface 61. The gap G3 is provided between the stepped surface 54 and the end surface 62.

[0100] Gap G1 extends in the radial direction and communicates with the outside of the housing 14. Furthermore, gap G1 communicates with the outside of the housing 14 through the through-hole 64. Gap G3 extends in the radial direction and communicates with the space 30. Gap G2 extends in the axial direction and communicates between gap G1 and gap G3. For this reason, there is a risk that the space 30 will communicate with the outside of the housing 14 through gaps G1, G2, G3 and the through-hole 64.

[0101] If an explosion occurs in space 30, there is a risk that sparks will enter gap G3. However, the sparks will collide with inner circumferential surface 52 at the portion where gap G3 and gap G2 are connected, causing a pressure loss. The sparks, with their pressure reduced, will travel axially through gap G2, which is longer than gap G3. Therefore, the rotating electric machine 1 can extinguish the sparks in gap G2.

[0102] Furthermore, in this embodiment, the outer peripheral surface 61 of the protrusion 221 overlaps with the step 76 in the radial direction. That is, the length of the outer peripheral surface 61 in the axial direction is increased. This increases the gap G2 between the inner peripheral surface 52 and the outer peripheral surface 61. Therefore, the rotating electric machine 1 makes it easier for sparks to be extinguished in the gap G2.

[0103] Next, gaps G4, G5, G6, and G7 may be provided between frame 21 and terminal board 24. Gap G4 is provided between joining surface 72 and joining surface 84. Gap G5 is provided between inner circumferential surface 71 and outer circumferential surface 81. Gap G6 is provided between first stepped surface 73 and first stepped surface 82. Gap G7 is provided between second stepped surface 74 and second stepped surface 83.

[0104] Gap G4 extends in a direction perpendicular to the radial direction and communicates with the outside of the housing 14. Furthermore, gap G4 communicates with the outside of the housing 14 through the through-hole 85. Gap G7 extends in the radial direction and communicates with the space 30. Gap G5 extends in the radial direction and communicates between gap G4 and gap G6. Gap G6 extends in a direction perpendicular to the radial direction and communicates between gap G5 and gap G7. For this reason, there is a risk that the space 30 will communicate with the outside of the housing 14 through gaps G4, G5, G6, G7 and the through-hole 85.

[0105] If an explosion occurs in the space 30, there is a risk that sparks will enter the gap G7. However, the sparks will collide with the first stepped surface 82 at the portion where the gap G7 and the gap G6 are connected, causing a pressure loss. The sparks, whose pressure has been reduced, will travel through the gap G6 in a direction perpendicular to the radial direction. Therefore, the rotating electric machine 1 can extinguish the sparks in the gap G6.

[0106] There is a risk that the sparks will pass through the gap G6. However, the sparks will collide with the inner circumferential surface 71 at the portion where the gap G5 and the gap G4 are connected, causing a pressure loss. The sparks, whose pressure has been reduced, will travel radially through the gap G5, which is longer than the gap G6. Therefore, the rotating electric machine 1 can extinguish the sparks in the gap G5. Therefore, the rotating electric machine 1 of this embodiment can improve pressure resistance and explosion proof performance.

[0107] As described above, the rotating electric machine 1 of this embodiment includes the stator 11, the rotor 13, the shaft 12, and the housing 14. The rotor 13 is rotatable inside the stator 11. The shaft 12 is rotatable together with the rotor 13. The housing 14 includes a frame 21, a bracket 22, and a terminal plate 24 electrically connectable to the stator 11. The frame 21 includes an inner circumferential surface 52, an inner circumferential surface 71, a joint surface 53, and a step 76. The inner circumferential surface 52 forms a through hole 50 on the axially outer side Dxo that penetrates the frame 21 and accommodates the stator 11 and the rotor 13. The inner circumferential surface 71 forms a through hole 31 that penetrates the frame 21 in the radial direction and accommodates the terminal plate 24. The joint surface 53 is connected to an end of the inner circumferential surface 52 on the axially outer side Dxo and faces the axially outer side Dxo. The step 76 protrudes from the inner circumferential surface 71 and supports the terminal board 24. The bracket 22 has a joint surface 63 facing the joint surface 53 and a protrusion 221, and closes the end 21b of the frame 21 on the axially outer side Dxo. The protrusion 221 protrudes from the joint surface 63 to the axially inner side Dxi and is fitted into the through-hole 50. Furthermore, the protrusion 221 has an outer circumferential surface 61 facing the inner circumferential surface 52 and overlaps with the step 76 in the radial direction.

[0108] In the rotating electric machine 1 described above, the bracket 22 is fitted into a through hole 50 that penetrates the frame 21 in the axial direction, and the terminal board 24 is fitted into a through hole 31 that penetrates the frame 21 in the radial direction.

[0109] For example, a gap may occur between the inner circumferential surface 52 and the outer circumferential surface 61 and between the joining surfaces 53 and 63. The gap G1 between the joining surfaces 53 and 63 may communicate with the space 30 through the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61. The direction in which the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61 extends is different from the direction in which the gap G1 between the joining surfaces 53 and 63 extends.

[0110] Furthermore, the protrusion 221 of the present embodiment overlaps with the step 76 of the frame 21 in the radial direction. That is, in the present embodiment, the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61 extends to the step 76. This increases the distance of the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61.

[0111] For example, if an explosion occurs in the space 30, sparks generated by the explosion will enter the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61 and collide with the inner circumferential surface 52 or the outer circumferential surface 61. Therefore, the rotating electric machine 1 of this embodiment causes a pressure loss due to the collision of the sparks, and can prevent the sparks from passing through the gap G1 between the joint surfaces 53 and 63 and reaching the outside of the housing 14. Therefore, the rotating electric machine 1 of this embodiment can improve pressure resistance and explosion proof properties.

[0112] In this embodiment, the frame 21 has a stepped surface 54 that extends radially inward Dri from the step 76 and faces axially outward Dxo. The bracket 22 has an end surface 62 that faces the stepped surface 54.

[0113] In the rotating electric machine 1 of this embodiment, a gap G3 is generated between the stepped surface 54 and the end face 62. The direction in which the gap G3 between the stepped surface 54 and the end face 62 extends is different from the direction in which the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61 extends, and is the same as the direction in which the gap G1 between the joining surfaces 53 and 63 extends.

[0114] For example, if an explosion occurs in the space 30, sparks generated by the explosion will enter the gap G3 between the stepped surface 54 and the end face 62, and then pass through the gap G2 between the inner circumferential surface 52 and the outer circumferential surface 61. That is, in the rotating electric machine 1, the provision of the gap G3 between the stepped surface 54 and the end face 62 increases the creepage distance of the gap between the frame 21 and the bracket 22. This allows the rotating electric machine 1 of this embodiment to have even better pressure resistance and explosion proof properties.

[0115] Although the embodiments of the present invention have been described above, the above embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, format, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be appropriately changed and implemented.

[0116] DESCRIPTION OF SYMBOLS 1 Rotating electric machine 11 Stator 12 Shaft 13 Rotor 14 Housing 21 Frame 21b End 22 Bracket 221 Protrusion 24 Terminal board (terminal member) 31 Through hole (second through hole) 50 Through hole (first through hole) 51 Fitting opening 52 Inner peripheral surface (first inner peripheral surface) 53 Joint surface (first joint surface) 54 Stepped surface (first surface) 61 Outer peripheral surface 62 End surface (second surface) 63 Joint surface (second joint surface) 71 Inner peripheral surface (second inner peripheral surface) 76 Step (support portion) Dxo Axial outer side (first direction) Dxi Axial inner side (second direction) Dro Radial outer side Dri Radial inner side

Claims

a housing having a stator, a rotor rotatable inside the stator, a shaft rotatable together with the rotor, a frame, a bracket, and a terminal member electrically connectable to the stator, wherein the frame has: a first inner circumferential surface that penetrates the frame in a first direction, which is a direction toward the outside of the housing in the axial direction of the shaft, and forms a first through hole in which the stator and the rotor are housed; a second inner circumferential surface that penetrates the frame in a direction intersecting the first direction and forms a second through hole in which the terminal member is housed; a first joint surface that is connected to an end of the first inner circumferential surface in the first direction and faces the first direction; and a support portion that protrudes from the second inner circumferential surface and supports the terminal member; and the bracket has: a second joint surface that faces the first joint surface; and a protrusion that protrudes from the second joint surface in a second direction opposite to the first direction and is fitted into the first through hole, and closes an end of the frame in the first direction, the protrusion has an outer circumferential surface facing the first inner circumferential surface and overlaps with the support portion in a direction intersecting with the first direction.

2. A rotating electric machine as set forth in claim 1, wherein said frame extends from said support portion in a direction intersecting a first direction and has a first surface facing said first direction, and said protrusion has a second surface facing said first surface.

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