Rotary electric machine

Abstract

This rotary electric machine comprises a housing having a cylindrical inner housing that houses a stator and a rotor, and a cylindrical outer housing that houses the inner housing. The inner housing has a cylinder part press-fitted to the tip part of the outer housing, and a flange part abutting the rear end part of the outer housing. The inner housing includes: a first groove part provided in an annular shape on an outer peripheral surface of the cylindrical part in the vicinity of the flange part; and a first seal member provided in the first groove part. The outer housing includes: a second groove part provided in an annular shape on an inner peripheral surface in the vicinity of the tip part; and a second seal member provided in the second groove part. A space formed between the outer peripheral surface of the cylindrical part of the inner housing, the inner peripheral surface of the outer housing, the first seal member, and the second seal member is configured as a refrigerant flow path through which a refrigerant flows.

Description

rotating electrical machines

[0001] The present invention relates to a rotating electric machine having a stator and a rotor.

[0002] 2. Description of the Related Art A rotating electric machine is known in which a cylindrical inner housing that houses a stator and a rotor is provided inside a cylindrical outer housing, and a refrigerant passage is formed between the two housings.

[0003] WO2023 / 002584A1 discloses a rotating electric machine in which an annular groove is provided on the outer peripheral surface of the inner housing near the tip end and the flange, and a sealing member is provided in the groove to seal between the outer peripheral surface of the inner housing and the inner peripheral surface of the outer housing.

[0004] However, in a rotating electrical machine in which seal members are provided near both ends of the inner housing, if misalignment occurs between the housings when assembling the inner housing to the outer housing, the seal member on the tip end side will be pushed axially into the housing while in contact with the inner circumferential surface of the outer housing. If the assembly work is continued in this state with the seal member being dragged by the inner circumferential surface of the housing, the seal member may be rolled up or damaged.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a rotating electric machine that can prevent the sealing member from being excessively dragged between the outer peripheral surface of the inner housing and the inner peripheral surface of the outer housing when assembling the inner housing to the outer housing.

[0006] According to one aspect of the present invention, the present invention is applied to a rotating electric machine configured by housing a stator and a rotor having a rotating shaft. The housing includes a cylindrical inner housing that houses the stator and rotor, and a cylindrical outer housing that houses the inner housing. The inner housing has a cylindrical portion that faces the inner circumferential surface of the outer housing and is press-fitted into the front end of the outer housing, and a flange that abuts the rear end of the outer housing. The inner housing further includes a first groove that is annularly formed on the outer circumferential surface of the cylindrical portion near the flange, and a first seal member that is provided in the first groove and seals between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the outer housing. The outer housing includes a second groove that is annularly formed on the inner circumferential surface near the front end, and a second seal member that is provided in the second groove and seals between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the outer housing. The space formed among the outer peripheral surface of the cylindrical portion, the inner peripheral surface of the outer housing, the first seal member, and the second seal member constitutes a refrigerant flow path through which the refrigerant flows.

[0007] Fig. 1 is a partial cross-sectional view of a rotating electric machine according to an embodiment of the present invention, seen from a direction perpendicular to the axis, showing a state in which an inner housing is assembled to an outer housing. Fig. 2 is a perspective view of the rotating electric machine according to an embodiment of the present invention, showing a state before the inner housing is assembled to the outer housing. Fig. 3 is a partial cross-sectional view of a rotating electric machine according to an embodiment of the present invention, seen from a direction perpendicular to the axis, showing a state immediately before the inner housing is assembled to the outer housing.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotating electric machine according to an embodiment of the present invention will now be described with reference to the drawings.

[0009] 1 is a partial cross-sectional view of a rotating electrical machine (motor 1) according to this embodiment, as viewed from a direction perpendicular to the axis. FIG. 2 is an exploded perspective view of a housing 10.

[0010] 1 and 2, the motor 1 includes a housing 10, a stator 13 housed in the housing 10, a rotor 15, and a rotating shaft 16 fixed to the rotor 15 and rotating coaxially with the rotor 15. The motor 1 receives electric power from a battery (not shown) to drive it to rotate.

[0011] The motor 1 of this embodiment is mounted on, for example, an electric vehicle and functions as an electric motor that drives the wheels. The motor 1 also functions as a generator that receives driving force from the rotation of the wheels and generates electricity (regenerative power).

[0012] The housing 10 has an inner housing 11 and an outer housing 12. A stator 13 is fixed inside the inner housing 11, and a rotor 15 is rotatably provided inside the stator 13. The inner housing 11 is housed inside the outer housing 12. In other words, the housing 10 has a double-tube structure consisting of the inner housing 11 and the outer housing 12. The space formed between the outer peripheral surface of the inner housing 11 and the inner peripheral surface of the outer housing 12 constitutes a refrigerant flow path 100 for cooling the stator 13 and the rotor 15. The inner housing 11 and the outer housing 12 are formed by casting, for example, using an aluminum alloy as a material.

[0013] Next, we will explain the fixing structure of the inner housing 11 and the outer housing 12. The inner housing 11 has a cylindrical portion 11a and a flange portion 11b. The outer housing 12 has a cylindrical portion 12a, a front end portion 12b, a rear end portion 12c, and a press-fit wall 12d.

[0014] The tubular portion 11a of the inner housing 11 is a substantially cylindrical portion that accommodates the stator 13 and the rotor 15 therein. The tubular portion 12a of the outer housing 12 is a substantially cylindrical portion that accommodates the inner housing 11 therein.

[0015] When the inner housing 11 is assembled to the outer housing 12 , the outer peripheral surface of the cylindrical portion 11 a of the inner housing 11 faces the inner peripheral surface of the cylindrical portion 12 a of the outer housing 12 .

[0016] Furthermore, the tip of the tubular portion 11a is press-fitted into the tip portion of the outer housing 12 when the inner housing 11 is assembled to the outer housing 12. More specifically, the tip portion 12b of the outer housing 12 is provided at one end of the tubular portion 12a of the outer housing 12 as a surface perpendicular to the axial direction of the housing 10. The press-fit wall 12d protrudes radially inward from the inner circumferential surface of the tip portion of the tubular portion 12a. This press-fit wall 12d is provided in an annular shape along the inner circumference of the tubular portion 12a and is formed integrally with the tip portion 12b. In other words, by providing the press-fit wall 12d, the inside of the tubular portion 12a has a stepped structure near the tip portion 12b (a position close to the tip portion 12b). Furthermore, the inner diameter of the inner circumferential surface of the press-fit wall 12d is configured to be approximately the same as the outer diameter of the outer circumferential surface of the tubular portion 11a of the inner housing 11. With this configuration, when the inner housing 11 is assembled to the outer housing 12 , the tip of the cylindrical portion 11 a of the inner housing 11 is press-fitted and fixed into the press-fit wall 12 d of the outer housing 12 .

[0017] The flange 11 b of the inner housing 11 is a portion that extends perpendicularly to the axial direction of the housing 10 , that is, in the radial direction of the housing 10 , on the outer peripheral edge of the rear end of the cylindrical portion 11 a.

[0018] When the inner housing 11 is assembled to the outer housing 12, the flange portion 11b abuts against a rear end portion 12c of the outer housing 12. By fastening the flange portion 11b and the rear end portion 12c together with bolts 17, the inner housing 11 and the outer housing 12 are fixed together.

[0019] Next, we will explain in more detail the configuration of the inner housing 11. The inner housing 11 further has a first wall portion 11c, a second wall portion 11d, a third wall portion 11e, a first groove portion 11f, and a first seal member 11g.

[0020] The first wall portion 11c is provided on the outer peripheral surface of the tubular portion 11a near the flange portion 11b and protrudes in an annular shape, and the second wall portion 11d is provided on the outer peripheral surface of the tubular portion 11a near the tip end and protrudes in an annular shape.

[0021] The outer diameter of the outer peripheral surface of the first wall portion 11c and the outer diameter of the outer peripheral surface of the second wall portion 11d are substantially the same. In addition, the outer diameters of the outer peripheral surfaces of both wall portions are slightly smaller than the inner diameter of the inner peripheral surface of the outer housing 12. With this configuration, both wall portions function as insertion guides to prevent misalignment when assembling the inner housing 11 to the outer housing 12. Furthermore, when the inner housing 11 is assembled to the outer housing 12, a slight gap is created between the outer peripheral surfaces of both wall portions and the inner peripheral surface of the outer housing 12.

[0022] The third wall portion 11e is a wall portion that protrudes in an annular shape from the outer peripheral surface of the tubular portion 11a, and is provided closer to the flange portion 11b than the first wall portion 11c and spaced apart from the first wall portion 11c. The outer diameter of the outer peripheral surface of the third wall portion 11e is smaller than the inner diameter of the inner peripheral surface of the outer housing 12. A gap between the first wall portion 11c and the third wall portion 11e in the axial direction of the housing 10 forms the first groove portion 11f. That is, the first groove portion 11f is formed by a portion of each of the first wall portion 11c and the third wall portion 11e.

[0023] The first seal member 11g is a so-called O-ring and is fitted in the first groove 11f. Before the inner housing 11 is assembled to the outer housing 12, and with the first seal member 11g fitted in the first groove 11f, the outer diameter of the first seal member 11g is slightly larger than the inner diameter of the inner circumferential surface of the tubular portion 12a of the outer housing 12. Therefore, when the inner housing 11 is assembled to the outer housing 12, the first seal member 11g is crushed between the outer circumferential surface of the tubular portion 11a and the inner circumferential surface of the tubular portion 12a. This creates a seal between the outer circumferential surface of the tubular portion 11a and the inner circumferential surface of the tubular portion 12a at the rear end of the housing 10.

[0024] Next, a more detailed description will be given of the configuration of the outer housing 12. The outer housing 12 further includes a fourth wall portion 12e, a second groove portion 12f, and a second seal member 12g.

[0025] The fourth wall portion 12e is spaced from the press-fit wall 12d in the axial direction of the housing 10 and is provided to protrude in an annular shape from the inner circumferential surface of the tubular portion 12a. The inner diameter of the inner circumferential surface of the fourth wall portion 12e is larger than the outer diameter of the outer circumferential surface of the inner housing 11. The gap between the press-fit wall 12d and the fourth wall portion 12e in the axial direction of the housing 10 forms the second groove portion 12f. That is, the second groove portion 12f is formed by a portion of each of the press-fit wall 12d and the fourth wall portion 12e.

[0026] The second seal member 12g is a so-called O-ring and is fitted in the second groove 12f. Furthermore, before the inner housing 11 is assembled to the outer housing 12, and with the second seal member 12g fitted in the second groove 12f, the inner diameter of the second seal member 12g is slightly smaller than the outer diameter of the outer peripheral surface of the tubular portion 11a of the inner housing 11. Therefore, when the inner housing 11 is assembled to the outer housing 12, the first seal member 11g is crushed between the outer peripheral surface of the tubular portion 11a and the inner peripheral surface of the tubular portion 12a. This forms a seal between the outer peripheral surface of the tubular portion 11a and the inner peripheral surface of the tubular portion 12a at the tip end of the housing 10.

[0027] Furthermore, when the inner housing 11 is assembled to the outer housing 12, the first seal member 11g and the second seal member 12g have approximately the same outer diameter and also have approximately the same inner diameter.

[0028] With the above-described configuration, the space surrounded by the first seal member 11g and the second seal member 12g between the outer peripheral surface of the cylindrical portion 11a of the inner housing 11 and the inner peripheral surface of the cylindrical portion 12a of the outer housing 12 constitutes the refrigerant flow path 100. The stator 13 and the rotor 15 are cooled by circulating a refrigerant through the refrigerant flow path 100. For example, cooling water is used as the refrigerant.

[0029] 1, a pair of coil ends 14a and 14b protrude from both ends of the stator 13 in the housing axial direction. The first coil end 14a at the rear end of the housing is positioned opposite the first wall portion 11c in the radial direction of the motor 1. The second coil end 14b at the front end of the housing is positioned opposite the space between the inner housing 11 and the outer housing 12, surrounded by the second wall portion 11d and the second seal member 12g in the radial direction of the motor 1. In this way, by positioning the first coil end 14a and the second coil end 14b opposite the portion through which the refrigerant flows, it is possible to improve the heat dissipation performance of both coil ends.

[0030] Next, we will explain how to assemble the motor 1. The motor 1 is assembled by fixing the stator 13 to the inside of the inner housing 11 by so-called shrink fitting, and then press-fitting the inner housing 11 into the outer housing 12.

[0031] The stator 13 is formed so that its outer diameter is slightly larger than the inner diameter of the inner housing 11. The stator 13 is shrink-fitted, i.e., the inner housing 11 is heated to expand its inner diameter before being inserted into the inner housing 11, and as the inner housing 11 cools, the inner diameter of the inner housing 11 shrinks, bringing the inner wall of the inner housing 11 and the outer wall of the stator 13 into tight contact. This fixes the stator 13 to the inner housing 11.

[0032] As shown in FIG. 2 , the inner housing 11, which includes the stator 13 and the rotor 15 disposed inside the stator 13, is inserted into the cylindrical portion 12a of the outer housing 12 from the rear end 12c of the outer housing 12. Then, the tip of the cylindrical portion 11a is press-fitted into the press-fit wall 12d of the outer housing, and at the same time, the flange portion 11b abuts against the rear end 12c of the outer housing 12. Then, the flange portion 11b and the rear end 12c are fixed together with bolts 17. This fixes the inner housing 11 and the outer housing 12 together. The rotating shaft 16 of the rotor 15 protrudes outside the motor 1 from shaft holes formed in the inner housing 11 and the outer housing 12.

[0033] Here, in conventional rotating electric machines in which a groove is provided on each of the outer peripheral surfaces of the inner housing near both ends, and a sealing member is provided in each of the grooves to seal between the outer peripheral surface of the inner housing and the inner peripheral surface of the outer housing, the following problem arose.

[0034] If misalignment occurs between the inner and outer housings when assembling the inner housing to the outer housing, the seal member at the tip end will be pushed axially into the housing while in contact with the inner circumferential surface of the outer housing. If the assembly work continues with the seal member dragged by the inner circumferential surface of the housing, the seal member may be curled up or damaged, resulting in a problem of reduced sealing performance.

[0035] Therefore, the present invention has the following configuration to prevent the seal member from being excessively dragged between the outer peripheral surface of the inner housing and the inner peripheral surface of the outer housing.

[0036] As shown in FIG. 1, a second groove 12f is provided in the cylindrical portion 12a near the tip end 12b of the outer housing 12, and a second seal member 12g is fitted in the second groove 12f.

[0037] With this configuration, as shown in Figure 3, when the inner housing 11 is assembled to the outer housing 12, the second seal member 12g provided on the outer housing 12 does not come into contact with the tubular portion 11a of the inner housing 11 until just before the tip of the tubular portion 11a of the inner housing 11 is pressed into the press-fit wall 12d at the tip of the outer housing 12.

[0038] In addition to the above, since the first seal member 11g is provided in the first groove portion 11f near the flange portion 11b of the inner housing 11, it does not come into contact with the tubular portion 12a of the outer housing 12 until just before the flange portion 11b abuts against the rear end portion 12c of the outer housing 12.

[0039] As described above, in the rotating electric machine (motor 1) of this embodiment, the housing 10 includes a cylindrical inner housing 11 that houses the stator 13 and the rotor 15, and a cylindrical outer housing 12 that houses the inner housing 11. The inner housing 11 has a cylindrical portion 11a that faces the inner circumferential surface of the outer housing 12 and is press-fitted into the front end portion of the outer housing 12, and a flange portion 11b that abuts against the rear end portion 12c of the outer housing 12. The inner housing 11 further includes a first groove portion 11f that is annularly provided on the outer circumferential surface of the cylindrical portion 11a near the flange portion 11b, and a first seal member 11g that is provided in the first groove portion 11f and provides a seal between the outer circumferential surface of the cylindrical portion 11a and the inner circumferential surface of the outer housing 12. The outer housing 12 includes a second groove 12f provided annularly on the inner circumferential surface near the tip end 12b, and a second seal member 12g provided in the second groove 12f to seal between the outer circumferential surface of the tubular portion 11a and the inner circumferential surface of the outer housing 12. The space formed among the outer circumferential surface of the tubular portion 11a, the inner circumferential surface of the outer housing 12, the first seal member 11g, and the second seal member 12g constitutes a refrigerant flow path 100 through which the refrigerant flows.

[0040] This configuration prevents the first seal member 11g and the second seal member 12g from being excessively dragged between the outer peripheral surface of the inner housing 11 and the inner peripheral surface of the outer housing 12 when the inner housing 11 is assembled to the outer housing 12. This prevents the seal members from being turned over or damaged. As a result, the sealing performance of the seal members can be improved.

[0041] Furthermore, conventional rotating electrical machines have also had the following problems.

[0042] To prevent the seal member from being excessively dragged, a stepped structure is sometimes adopted in which the inner diameter of the outer housing gradually increases from the front end to the rear end. However, adopting such a structure also increases the outer diameter of the outer housing, resulting in an overall increase in the radial size of the housing.

[0043] However, in the present invention, it is not necessary to employ a stepped structure for the outer housing, which prevents the housing 10 from becoming large in the radial direction.

[0044] In this embodiment, when the inner housing 11 is assembled to the outer housing 12, the first wall portion 11c and the second wall portion 11d of the inner housing 11 function as guides.

[0045] This configuration can prevent misalignment between the housings, thereby preventing the first seal member 11g and the second seal member 12g from being crushed obliquely with respect to the axial direction of the housing 10 between the outer peripheral surface of the inner housing 11 and the inner peripheral surface of the outer housing 12. As a result, it is possible to more reliably prevent both seal members from being turned over or damaged.

[0046] In this embodiment, the outer diameter of the outer peripheral surface of the first wall portion 11 c and the outer diameter of the outer peripheral surface of the second wall portion 11 d of the inner housing 11 are slightly smaller than the inner diameter of the inner peripheral surface of the outer housing 12 .

[0047] With this configuration, when assembling the inner housing 11 to the outer housing 12, the inner housing 11 can be easily inserted into the outer housing 12.

[0048] In this embodiment, the first coil end 14a of the stator 13 is disposed in a position facing the first wall portion 11c of the inner housing 11 in the radial direction of the motor 1. The second coil end 14b is disposed between the inner housing 11 and the outer housing 12 in a position facing the space surrounded by the second wall portion 11d of the inner housing 11 and the second seal member 12g of the outer housing 12 in the radial direction of the motor 1.

[0049] With this configuration, the refrigerant flowing through the refrigerant flow path 100 can cool the stator 13 and rotor 15, as well as the first coil end 14a and the second coil end 14b, making it possible to efficiently remove heat.

[0050] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0051] In the above embodiment, the motor 1 has been described as being used in an electric vehicle, but it may also be used as a drive device for devices other than vehicles, such as various electrical appliances or industrial machines.

[0052] Furthermore, the outer diameter of the outer peripheral surface of the first wall portion 11c and the outer diameter of the outer peripheral surface of the second wall portion 11d of the inner housing 11 do not necessarily need to be smaller over the entire circumferential direction than the inner diameter of the inner peripheral surface of the outer housing 12. In other words, as long as the inner housing 11 can be easily inserted into the outer housing 12, the outer diameter of the outer peripheral surface of the first wall portion 11c and the outer diameter of the outer peripheral surface of the second wall portion 11d may be smaller than the inner diameter of the inner peripheral surface of the outer housing 12 only over a specific range, such as half, one-third, or one-quarter of the circumferential direction.

[0053] 2, a partition wall 11h may be provided on the outer peripheral surface of the cylindrical portion 11a of the inner housing 11 between the first wall portion 11c and the second wall portion 11d. In this case, the partition wall 11h is provided to protrude in a spiral shape along the outer periphery of the cylindrical portion 11a. The outer diameter of the outer peripheral surface of the partition wall 11h is formed to be approximately the same as the inner diameter of the inner peripheral surface of the outer housing 12. With this configuration, the refrigerant flow path 100 has a spiral structure. Therefore, the refrigerant flows spirally around the inner housing 11 from one side to the other in the axial direction of the housing 10. This improves the cooling efficiency of the stator 13, the coil ends 14a and 14b, and the rotor 15.

[0054] In this embodiment, the inner diameter of the inner peripheral surface of the fourth wall portion 12e of the outer housing 12 may be slightly larger than the outer diameter of the outer peripheral surface of the inner housing 11. With this configuration, when the inner housing 11 is assembled to the outer housing 12, the fourth wall portion 12e functions as an insertion guide to prevent misalignment.

[0055] Furthermore, in this embodiment, when the inner housing 11 is assembled to the outer housing 12, it is desirable that the gap between the second wall portion 11d and the fourth wall portion 12e in the axial direction of the housing 10 be as narrow as possible. Specifically, it is desirable that the width of this gap be approximately the same as the width of the gap between the outer peripheral surface of the first wall portion 11c of the inner housing 11 and the inner peripheral surface of the outer housing 12. Because the fourth wall portion 12e is provided near the tip end portion 12b on the inside of the outer housing 12, it is difficult to process the dimensions in the axial direction of the housing 10, and there is a risk of dimensional tolerances occurring between the second wall portion 11d and the fourth wall portion 12e. However, if processing accuracy can be improved, it is possible to narrow this gap.

[0056] Furthermore, although the first groove portion 11f in this embodiment has been described as being formed by a portion of each of the first wall portion 11c and the third wall portion 11e, it may also be formed as an annular groove recessed directly into the outer peripheral surface of the tubular portion 11a of the inner housing 11.

[0057] Furthermore, although the second groove portion 12f in this embodiment has been described as being formed by a portion of each of the press-fit wall 12d and the fourth wall portion 12e, it may also be formed as an annular groove recessed directly into the inner surface of the tubular portion 12a of the outer housing 12.

Claims

1. A rotating electric machine constructed by accommodating a stator and a rotor having a rotating shaft within a housing, the housing comprising: a cylindrical inner housing that accommodates the stator and the rotor; and a cylindrical outer housing that accommodates the inner housing, the inner housing having a cylindrical portion that faces the inner peripheral surface of the outer housing and is press-fitted into the front end of the outer housing, and a flange that abuts against the rear end of the outer housing, the inner housing further comprising: a first groove portion that is annularly provided on the outer peripheral surface of the cylindrical portion near the flange; and a first seal member that is provided in the first groove and seals between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the outer housing, the outer housing comprising: a second groove portion that is annularly provided on the inner peripheral surface near the front end; and a second seal member that is provided in the second groove and seals between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the outer housing, a space formed among the outer peripheral surface of the cylindrical portion, the inner peripheral surface of the outer housing, the first seal member, and the second seal member is configured as a refrigerant flow path through which a refrigerant flows.

2. A rotating electric machine according to claim 1, wherein, when the inner housing is assembled to the outer housing, the outer diameter of the first seal member is equal to the outer diameter of the second seal member, and the inner diameter of the first seal member is equal to the inner diameter of the second seal member.

3. A rotating electric machine according to claim 1, wherein the inner housing has a first wall portion and a second wall portion that protrude annularly from the outer peripheral surface of the cylindrical portion and are spaced apart in the axial direction of the rotating shaft, and the first wall portion and the second wall portion are arranged so as to be located between the first seal member and the second seal member in the axial direction.

4. A rotating electric machine according to claim 3, wherein the outer diameter of the outer peripheral surface of the first wall portion and the outer diameter of the outer peripheral surface of the second wall portion are smaller than the inner diameter of the inner peripheral surface of the outer housing.

5. A rotating electric machine according to claim 3 or 4, wherein the first wall portion is formed so that one end in the axial direction abuts against the first seal member, and constitutes a part of the first groove portion.

6. A rotating electric machine according to claim 5, wherein the stator has a pair of coil ends protruding from both ends in the axial direction, a first of the coil ends being arranged so as to face the first wall portion in the radial direction of the rotating electric machine, and a second of the coil ends being arranged so as to face the space between the inner housing and the outer housing and surrounded by the second seal member and the second wall portion in the radial direction.

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