Rotating electric machine case and rotating electric machine

Abstract

To provide a rotating electric machine case and a rotating electric machine capable of suppressing non-uniformity of a cooling effect.SOLUTION: A rotating electric machine case 20 includes a hollow main body 21, and a flow path 30 provided between an inner peripheral portion 213 and an outer peripheral portion 214 of the main body, and causes a coolant to flow from one end to the other end in the axial direction of the main body. The inner diameter of the main body is constant in the axial direction of the main body, and the dimension S1 from the inner peripheral portion to the outer peripheral portion of the main body is larger on the downstream side 212 than on the upstream side 211 of the flow path.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotating electric machine case and a rotating electric machine. [Background technology]

[0002] Conventionally, in rotating electric machines such as electric motors and generators, a structure is known in which a coolant such as water flows through a flow path provided inside a case on the outside of a stator in order to prevent excessive heat generation due to the operation of the rotating electric machine. Then, by cooling the case with the coolant, the stator is cooled from the outside, and overheating of the rotating electric machine is suppressed.

[0003] In such a water-cooled configuration for a rotating electrical machine, the temperature of the coolant flowing through the flow passage increases from the inlet side to the outlet side of the flow passage, which may result in an uneven cooling effect, and this may lead to a situation in which the temperature of the stator becomes uneven. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-065394 A Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an embodiment of the present invention provides a case for a rotating electric machine, and a rotating electric machine, which can suppress unevenness in the cooling effect. [Means for solving the problem]

[0006] The rotating electric machine case of one embodiment comprises a hollow body, and a flow path provided between an inner periphery and an outer periphery of the body, through which a refrigerant passes from one axial end of the body to the other axial end, the inner diameter of the body being constant in the axial direction of the body, and the dimension from the inner periphery to the outer periphery of the body being larger downstream than upstream of the flow path.

[0007] A rotating electric machine according to an embodiment includes the rotating electric machine case described above, a stator fixed to the inside of the rotating electric machine case, and a rotor rotatably provided with a gap between them with respect to the stator. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an external appearance of an example of a rotating electric machine according to a first embodiment; [Diagram 2] FIG. 1 is a cross-sectional view showing an internal configuration of an example of a rotating electric machine according to a first embodiment; [Diagram 3] FIG. 1 is a diagram showing a positional relationship between a main body and a flow path inside a case of an example of a rotating electric machine according to a first embodiment; [Figure 4] FIG. 1 is a plan view showing an example of a flow path in an example of a rotating electric machine according to a first embodiment; [Diagram 5] FIG. 11 is an enlarged cross-sectional view showing an example of the positional relationship of flow paths inside a case according to a conventional configuration. [Figure 6] FIG. 11 is a perspective view showing another example of the configuration of the case in the example of the rotating electric machine according to the first embodiment; [Figure 7] FIG. 11 is an enlarged cross-sectional view showing another example of the positional relationship between the main body and the flow passages inside the case of the rotating electric machine according to the first embodiment; [Figure 8] FIG. 11 is an enlarged cross-sectional view showing the relationship between the center distances between adjacent flow paths in an example of a rotating electric machine according to a second embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a number of embodiments will be described with reference to the drawings. Note that substantially the same elements in the number of embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

[0010] (First embodiment) 1 and 2 includes a stator 11, a rotor 12, a shaft 13, and a case 20. In the following description, a direction parallel to a central axis O of the rotating electric machine is referred to as an axial direction. When the rotor 12 is rotated around the central axis O, the direction of movement of the outer circumferential surface of the rotor 12 is referred to as a circumferential direction. A direction perpendicular to the central axis O is referred to as a radial direction.

[0011] The stator 11 is fixed to the inside of the case 20. The stator 11 has a stator core 111 and a stator winding 112. The stator core 111 is configured, for example, in a cylindrical shape, and is formed by laminating a plurality of disk-shaped electromagnetic steel sheets. The stator winding 112 is wound around the stator core 111. The stator winding 112 is electrically connected to a power supply unit (not shown), and is supplied with a driving current from the power supply unit.

[0012] The rotor 12 is provided inside the stator 11 and is rotatable relative to the stator 11 via a gap. That is, in this embodiment, the rotating electric machine 1 is configured as, for example, an inner rotor type rotating electric machine. The rotor 12 has a rotor core 121 and a through hole 122. The rotor core 121 is formed by, for example, laminating a plurality of disk-shaped electromagnetic steel sheets. A permanent magnet (not shown) is embedded in the rotor core 121. The through hole 122 is provided in the center of the rotor 12, and the shaft 13 is inserted therethrough.

[0013] Shaft 13 is formed, for example, in a cylindrical shape, and passes through through hole 122. Shaft 13 is fixed to rotor core 121 by fitting with rotor core 121 by shrink fitting, press fitting, or the like. Shaft 13 rotates integrally with rotor 12 as rotor 12 rotates.

[0014] For example, one end of the shaft 13 protrudes outward from the case 20, in this case, to the left side of the paper in Fig. 2. A load is connected to the part of the shaft 13 that protrudes outward from the case 20. In this embodiment, of both ends of the shaft 13, the end to which the load is connected may be referred to as the load side, and the end to which the load is not connected may be referred to as the anti-load side. In the example of Fig. 2, the left side of the paper in the shaft 13 is the load side, and the right side is the anti-load side.

[0015] The case 20 has a main body 21 and a flow path 30. The main body 21 is made of, for example, an aluminum alloy, and is configured to be hollow with both axial ends 211, 212 open. The main body 21 is set to a size capable of accommodating the stator 11 and the rotor 12 therein. In this case, the stator 11 is fixed to an inner peripheral portion 213 of the main body 21 by shrink fitting, press fitting, or the like. In addition, the axial center of the main body 21 coincides with the central axis O of the rotor 12.

[0016] 2, the inner diameter of the main body 21 is set to be constant in the axial direction of the main body 21. In other words, the inner diameter of the main body 21 does not change from one end 211 to the other end 212 in the axial direction of the main body 21. On the other hand, the outer diameter of the main body 21 varies in the axial direction of the main body 21. In other words, the outer diameter of the main body 21 changes from one end 211 to the other end 212 in the axial direction of the main body 21.

[0017] Specifically, the outer periphery 214 of the main body 21 is formed so as to become more distant from the central axis O of the main body 21 in the axial direction from one end 211 to the other end 212 of the main body 21. That is, the main body 21 is formed in a shape in which a cylindrical shape with a constant inner diameter passes through the center of a truncated cone that spreads from one end side to the other end side in the axial direction of the shaft 13, that is, in the shape of a so-called conical cylinder. That is, in the case of this embodiment, the main body 21 is formed in a conical cylinder shape that spreads from the load side to the anti-load side, for example.

[0018] As a result, the outer circumferential portion 214 of the main body 21 is formed to incline radially outward from one end 211 to the other end 212 in the axial direction of the main body 21. Therefore, as shown in Fig. 2, the dimension S1 from the inner circumferential portion 213 to the outer circumferential portion 214 of the main body 21 gradually increases from one end 211 to the other end 212 in the axial direction of the main body 21. The dimension S1 means a variable indicating the thickness dimension of the main body 21 at an arbitrary point in the axial direction of the main body 21.

[0019] 2, the flow path 30 is formed between an inner peripheral portion 213 and an outer peripheral portion 214 of the main body 21. The flow path 30 is for passing a refrigerant such as water or oil. The flow path 30 extends from one end 211 in the axial direction of the main body 21 to the other end 212, and is configured as a single flow path that does not branch along the way. In other words, the one end 211 in the axial direction of the main body 21 is the upstream side of the flow path 30, and the other end 212 is the downstream side of the flow path 30.

[0020] 3 and 4, the flow passage 30 is formed, for example, in a spiral shape centered on the central axis O. In this case, as shown in Fig. 2, when a cross section cut along a plane along the central axis O of the main body 21 is viewed, the center-to-center distance L between adjacent flow passages 30 is equal in the direction along the axial direction of the main body 21. That is, the center-to-center distance L between adjacent flow passages 30 is equal on the upstream side and downstream side of the flow passage 30.

[0021] As described above, the outer periphery 214 of the main body 21 is inclined radially outward from one end 211 in the axial direction of the main body 21 to the other end 212 with respect to the central axis O. For this reason, the dimension S1 from the inner periphery 213 to the outer periphery 214 of the main body 21 is set to be larger on the downstream side of the flow passage 30 than on the upstream side. Then, as shown in FIG. 2, when a cut surface cut along a plane passing through the central axis O of the main body 21 is viewed, the dimension S2 from a portion of each flow passage 30 facing the outer periphery 214 of the main body 21 to the outer periphery 214 of the main body 21 is set to be larger on the downstream side of the flow passage 30 than on the upstream side.

[0022] As shown in Fig. 2 etc., the cross-sectional shape of the flow path 30 can be circular, but may be other shapes such as rectangular or polygonal. The cross-sectional area of ​​the flow path 30 is constant on the upstream side and downstream side of the flow path 30, but may be set so that the cross-sectional area on the downstream side is smaller than that on the upstream side. Furthermore, the flow path 30 is not limited to a spiral configuration, and may be configured to meander along the axial direction from one end 211 to the other end 212 of the main body 21 in the axial direction, but is not limited thereto.

[0023] The flow path 30 has an inlet 31 and an outlet 32. The inlet 31 and the outlet 32 ​​communicate with the inside and outside of the main body 21. As shown in Figs. 2 and 3, the inlet 31 and the outlet 32 ​​are formed between the inner peripheral part 213 and the outer peripheral part 214 of the main body 21 along the axial direction of the main body 21. The inlet 31 is formed on one end 211 side of the main body 21, and the outlet 32 ​​is formed on the other end 212 side of the main body 21. That is, the inlet 31 is formed upstream of the flow path 30, and the outlet 32 ​​is formed downstream of the flow path 30. The inlet 31 and the outlet 32 ​​face in opposite directions to each other in the axial direction of the main body 21.

[0024] 2, when viewed from a cross section cut along a plane passing through the central axis O of the main body 21, the inlet 31 and the outlet 32 ​​are disposed on the same axis parallel to the central axis O of the main body 21. The inlet 31 and the outlet 32 ​​may be provided on the outer circumferential portion 214 of the main body 21, toward the radially outer side of the main body 21.

[0025] The inlet 31 is a portion where the refrigerant flows into the flow path 30. On the other hand, the outlet 32 ​​is a portion where the refrigerant flows out from the flow path 30. In this case, the inlet 31 and the outlet 32 ​​are connected to pipes, hoses, etc. (not shown). The refrigerant is supplied to the inlet 31 from these pipes, hoses, etc., and the refrigerant flows into the flow path 30 from the inlet 31. The refrigerant that flows into the flow path 30 passes through the flow path 30 while removing heat transferred to the main body 21 from the stator 11 that generates heat due to the operation of the rotating electric machine 10, and is then discharged from the outlet 32 ​​to the outside of the main body 21.

[0026] Here, the main body 21 is manufactured by casting, for example. At this time, a pipe made of steel such as stainless steel and manufactured in the same shape as the flow path 30 is cast into the pre-manufactured main body 21 and integrated with the main body 21, so that the flow path 30 can be formed inside the main body 21. It is also conceivable that the flow path 30 can be formed inside the main body 21 using a core (not shown) or the like that is pre-manufactured in the same shape as the flow path 30, but this is not limiting.

[0027] According to the embodiment described above, the rotating electric machine case 20 includes a hollow main body 21 and a flow path 30. The flow path 30 is provided between an inner peripheral portion 213 and an outer peripheral portion 214 of the main body 21, and passes a refrigerant from one end portion 211 to the other end portion 212 in the axial direction of the main body 21. The inner diameter of the main body 21 is constant in the axial direction of the main body 21.

[0028] 5, for example, when the dimension S1 from the inner periphery 213 to the outer periphery 214 of the main body 21, that is, the thickness of the main body 21, is constant on the upstream side and the downstream side of the flow path 30, the temperature of the coolant flowing through the flow path 30 gradually increases from the upstream side to the downstream side of the flow path 30. For this reason, the cooling efficiency is lower on the downstream side of the flow path 30 than on the upstream side, which may result in an uneven cooling effect on the upstream side and the downstream side of the flow path 30.

[0029] Therefore, in this embodiment, the dimension S1 from the inner periphery 213 to the outer periphery 214 of the main body 21 is larger on the downstream side of the flow path 30 than on the upstream side. Furthermore, there is no cavity other than the flow path 30 inside the main body 21. Therefore, it is possible to ensure a heat capacity of the main body 21 in proportion to the dimension S1. According to this, by making the dimension S1 from the inner periphery 213 to the outer periphery 214 of the main body 21, i.e., the thickness of the main body 21, larger on the downstream side of the flow path 30 than on the upstream side, it is possible to make the heat capacity of the main body 21 on the refrigerant outflow side larger than that on the refrigerant inflow side.

[0030] This facilitates heat transfer from the refrigerant to the main body 21 at the outflow side of the refrigerant. This prevents the temperature of the refrigerant from increasing as it moves from the inflow side to the outflow side. This prevents a decrease in the cooling efficiency at the outflow side of the refrigerant, and as a result, prevents the cooling effect from becoming uneven.

[0031] Furthermore, the dimension S1 from the inner periphery 213 to the outer periphery 214 of the main body 21 gradually increases from one end 211 to the other end 212 in the axial direction of the main body 21. This makes it possible to more accurately eliminate unevenness in the cooling effect by easing the temperature gradient of the refrigerant from one end 211 to the other end 212 in the axial direction of the main body 21.

[0032] Furthermore, the rotating electric machine case 20 further includes an inlet 31 and an outlet 32. The inlet 31 is provided on one end 211 side in the axial direction of the main body 21, and is a portion through which the refrigerant flows into the flow path 30. The outlet 32 ​​is provided on the other end 212 side in the axial direction of the main body 21, and is a portion through which the refrigerant flows out of the flow path 30. The inlet 31 and the outlet 32 ​​are arranged on the same axis parallel to the central axis O of the main body 21.

[0033] According to this, by arranging the inlet 31 and the outlet 32 ​​on the same axis parallel to the central axis O of the main body 21, the routing of pipes etc. connected to the inlet 31 and the outlet 32 ​​can be simplified, thereby improving the assembly ability of the case 20.

[0034] 6 and 7, the case 20 may be configured such that a part of the outer circumferential portion 214 of the main body 21 protrudes in a stepped shape along the axial direction of the main body 21. In this case, in the example of FIGS. 6 and 7, the main body 21 has a thin-walled portion 41 and a thick-walled portion 42. The thin-walled portion 41 is disposed on one end portion 211 side of the main body 21 in the axial direction. As shown in FIG. 7, the thickness t1 of the thin-walled portion 41 is set to a dimension approximately twice as large as the diameter of the flow path 30.

[0035] The thick-walled portion 42 is disposed on the other end 212 side in the axial direction of the main body 21. That is, the thick-walled portion 42 is disposed on the downstream side of the flow path 30 relative to the thin-walled portion 41. As shown in FIG. 7, the thick-walled portion 42 has the same inner diameter as the thin-walled portion 41, and is formed to extend radially outward at a substantially right angle to the axial direction of the main body 21. The thickness t2 of the thick-walled portion 42 is set to a dimension different from the thickness t1 of the thin-walled portion 41. In this case, the thickness t2 of the thick-walled portion 42 is set to a dimension larger than the thickness t1 of the thin-walled portion 41. The axial length of the thick-walled portion 42 may be the same as or different from the axial length of the thin-walled portion 41, and can be arbitrarily set according to the cooling performance required for the case 20.

[0036] This also makes the thickness of the main body 21 greater on the downstream side of the flow path 30 than on the upstream side, so that the heat capacity of the main body 21 on the refrigerant outflow side can be made greater than that on the refrigerant inflow side. This makes it possible to prevent the temperature of the refrigerant from increasing from the inflow side to the outflow side. This makes it possible to prevent the cooling effect from becoming uneven.

[0037] Second embodiment Next, a second embodiment will be described with reference to Fig. 8. The configuration of the second embodiment differs from that of the first embodiment in that the center-to-center distance between adjacent flow paths 30 is different when viewed from a cross section cut along a plane passing through the central axis O of the main body 21. Specifically, in the first embodiment, when viewed from a cross section cut along a plane passing through the central axis O of the main body 21, the center-to-center distance L between adjacent flow paths 30 can be set to be equal on the upstream side and downstream side.

[0038] On the other hand, in this embodiment, when a cross section cut along a plane passing through the central axis O of the main body 21 is viewed, the center-to-center distance between adjacent flow paths 30 decreases toward the downstream side. That is, as shown in Fig. 8, the center-to-center distance L1 between adjacent flow paths 30 on the upstream side is greater than the center-to-center distance L2 on the downstream side. Therefore, the cross-sectional area of ​​the flow paths 30 relative to the cross-sectional area of ​​the main body 21 occupies a larger proportion on the side of one end 212 of the main body 21 in the axial direction than on the side of the other end 211.

[0039] According to this, the area where the refrigerant comes into contact with heat transferred from the stator 11, etc., on the inner periphery 213 side of the main body 21 can be made larger on the downstream side than on the upstream side. This makes it possible to increase the area where heat exchange takes place on the downstream side, where the refrigerant temperature tends to be higher than on the upstream side, and as a result, it is possible to further prevent the cooling effect from becoming uneven.

[0040] In this embodiment, as shown in Fig. 8, the thickness of the main body 21 is constant between the upstream side and the downstream side, i.e., it does not change, but it is not limited to this, and the thickness of the main body 21 may be greater on the downstream side than on the upstream side, as in the first embodiment. This makes it possible to more effectively prevent the cooling effect from becoming uneven.

[0041] Although several embodiments of the present invention have been described above, these embodiments are presented as examples 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 modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0042] In the drawings, 1 indicates a rotating electric machine, 11 indicates a stator, 12 indicates a rotor, 20 indicates a case, 21 indicates a main body, 211 and 212 indicate ends, 213 indicates an inner periphery, 214 indicates an outer periphery, 30 indicates a flow path, 31 indicates an inlet, and 32 indicates an outlet.

Claims

1. A hollow body; A flow path is provided between an inner circumferential portion and an outer circumferential portion of the main body, and the flow path passes a coolant from one end portion of the main body to the other end portion in the axial direction of the main body. an inner diameter of the body is constant in an axial direction of the body, and a dimension from the inner peripheral portion to the outer peripheral portion of the body is larger on a downstream side of the flow path than on an upstream side of the flow path, a dimension from a portion of the flow path facing the outer periphery of the main body to the outer periphery of the main body is larger on a downstream side of the flow path than on an upstream side of the flow path; Case for rotating electrical machine.

2. A hollow body; a flow path formed in a spiral shape between an inner circumferential portion and an outer circumferential portion of the main body, through which a coolant flows from one end portion of the main body to the other end portion in an axial direction of the main body; When viewed from a cross section cut along a plane passing through a central axis of the body, the center-to-center distance between adjacent flow paths becomes smaller toward the downstream of the flow paths. Case for rotating electrical machine.

3. A dimension from the inner peripheral portion to the outer peripheral portion of the main body gradually increases from one end to the other end in the axial direction of the main body. The rotating electrical machine case according to claim 2 .

4. an inlet provided at one end side in an axial direction of the main body, through which a refrigerant flows into the flow path; An outlet provided on the other end side of the main body in the axial direction and through which the refrigerant flows out of the flow path, The inlet and the outlet are arranged on a same axis parallel to a central axis of the main body. The rotating electrical machine case according to claim 1 .

5. A rotating electric machine case according to any one of claims 1 to 4, a stator fixed to an inside of the rotating electric machine case; A rotor rotatably provided with respect to the stator via a gap. Rotating electric motor.

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