Rotating Electric Machine

Abstract

To provide a rotary electric machine that can suppress vibration in a circumferential direction.SOLUTION: A rotary electric machine 100 comprises a stator 1, a rotor 2, and a housing 3 for accommodating the stator 1 and the rotor 2. The housing 3 comprises: a cylindrical accommodation unit 31 for accommodating the stator 1 and the rotor 2; a cooling flow path 4 arranged on the accommodation unit 31 and for cooling the stator 1; a plurality of first ribs 32 arranged at intervals in the cooling flow path 4 in a circumferential direction of the accommodation unit 31 and extending in an axial direction of the accommodation unit 31; and a second rib 36 arranged on an outer peripheral surface of the accommodation unit 31 and extending on an extension line of the first rib 32 in a radial direction of the accommodation unit 31. A length L2 of the second rib 36 in an axial direction is longer than a length L1 of the first rib 32.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine having a cooling passage through which a coolant flows. [Background technology]

[0002] Patent Document 1 discloses an electric motor having an inner cylinder that holds a stator, and an outer cylinder that is provided on the outer periphery of the inner cylinder and forms a cooling water flow path between the inner cylinder and the outer cylinder, through which cooling water flows. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-166031 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the electric motor described in Patent Document 1, the housing periodically twists in the circumferential direction as the rotor and shaft rotate, which can cause vibration in the circumferential direction. In the electric motor described in Patent Document 1, no measures were taken against such vibration in the circumferential direction.

[0005] The present invention has been made in consideration of such technical problems, and has an object to provide a rotating electric machine capable of suppressing circumferential vibration. [Means for solving the problem]

[0006] In one aspect of the present invention, a rotating electric machine includes a stator, a rotor, and a housing that accommodates the stator and the rotor. The housing includes a cylindrical accommodating section that accommodates the stator and the rotor, a cooling flow path that is provided in the accommodating section and that cools the stator, a plurality of first ribs that are provided in the cooling flow path at intervals in the circumferential direction of the accommodating section and extend in the axial direction of the accommodating section, and a second rib that is provided on an outer circumferential surface of the accommodating section and extends in the axial direction on an extension line of the first rib in the radial direction of the accommodating section, and the axial length of the second rib is longer than the length of the first rib. The cooling flow passage is configured to meander in the circumferential direction by arranging adjacent first ribs so as to be offset from each other in the axial direction, the second rib is arranged so as to overlap with a folded portion of the cooling flow passage in the radial direction, the accommodating portion, the first rib and the second rib are integrally formed, and the radial height of the second rib is at least 1 / 3 of the radial height of the first rib and is not more than the radial height of the first rib. Effect of the Invention

[0007] According to the present invention, the housing includes a plurality of first ribs extending in the axial direction of the housing portion, and a second rib provided on the outer circumferential surface of the housing portion and extending on an extension line of the first ribs in the radial direction of the housing portion, thereby increasing the circumferential rigidity of the housing. This makes it possible to suppress circumferential vibration of the rotating electric machine. Furthermore, since the second rib is provided on an extension line of the first rib in the radial direction of the housing portion, the first rib 32 and the second rib 36 can function in the same manner as a rib formed integrally with each other. This makes it possible to further increase the circumferential rigidity of the housing, and further suppress circumferential vibration of the rotating electric machine. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of a rotating electric machine. [Diagram 2] FIG. 2 is a perspective view of the housing. [Diagram 3] FIG. 3 is a side view of the housing. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a plan view of the cooling flow passage. [Figure 6] FIG. 6 is a graph showing the relationship between the ratio of the height of the first rib to the height of the second rib and the amount of twist in the circumferential direction of the housing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] 1 is a schematic cross-sectional view of a rotating electric machine 100. The rotating electric machine 100 is a motor, a generator, or a motor-generator that operates as a motor and a generator. The rotating electric machine 100 according to this embodiment operates as a motor that receives power from a battery (not shown) and is rotationally driven. When the rotating electric machine 100 receives rotational energy from an engine or drive wheels, it functions as a generator.

[0011] As shown in Fig. 1, the rotating electric machine 100 has a stator 1, a rotor 2, and a housing 3 that accommodates the stator 1 and the rotor 2. The rotating electric machine 100 is, for example, a synchronous rotating electric machine. When the rotating electric machine 100 operates as an electric motor, its operation is controlled by applying a three-phase alternating current generated by an inverter unit constituted by a power module or the like based on a command from a controller (not shown). When the rotating electric machine 100 operates as a generator, it generates electric power by rotating using a driving force from an engine (not shown) or driving wheels (not shown).

[0012] As shown in Fig. 1, the stator 1 has a stator core 1a and a stator coil 1b wound around the stator core 1a. The rotor 2 is provided on the inner periphery of the stator 1 with a slight gap between it and the stator 1. The rotor 2 is attached to a shaft 7 and supported within the stator 1 so as to be rotatable.

[0013] One end of the shaft 7 penetrates the bottom 33 of the housing 3 and protrudes to the outside, and is connected to a drive wheel (not shown) via a worm reduction mechanism (not shown), or to an engine (not shown) via a speed increase mechanism (not shown).

[0014] As shown in Figs. 1 and 2, the housing 3 is formed in a cylindrical shape with a bottom. The housing 3 is made of, for example, an aluminum alloy and is formed by casting. The housing 3 includes a cylindrical accommodation section 31 that forms a space S for accommodating the stator 1 and the rotor 2, a cooling flow path 4 that is provided in the accommodation section 31 and cools the rotating electric machine 100, a plurality of first ribs 32 that are provided in the cooling flow path 4 at intervals in the circumferential direction of the accommodation section 31 and extend in the axial direction of the accommodation section 31, a flange 34 that is provided at one end of the accommodation section 31 and to which a gear box (not shown) that constitutes a reduction mechanism is attached, and a flange 35 that is provided at the other end of the accommodation section 31 and to which an inverter unit (not shown) is attached. In the following description, the axial direction of the accommodation section 31 and the rotating electric machine 100 is simply referred to as the axial direction, the circumferential direction of the accommodation section 31 and the rotating electric machine 100 is simply referred to as the circumferential direction, and the radial direction of the accommodation section 31 and the rotating electric machine 100 (direction perpendicular to the rotation axis) is simply referred to as the radial direction.

[0015] As shown in FIG. 4, the cooling passage 4 is formed inside the housing 31 so as to cover the outer periphery of the stator 1 along the circumferential direction. In the rotating electric machine 100, a coolant supplied from a pump (not shown) flows into the cooling passage 4 from an inlet (not shown) provided in the housing 31, and cools the stator 1, the rotor 2, and the like while passing through the cooling passage 4. The coolant that has passed through the cooling passage 4 flows out from an outlet (shown in the figure) to the outside. The coolant that has flowed out to the outside is cooled in a cooler (not shown) and then returns to the pump and is discharged from the pump again. The coolant may be a liquid such as water, oil, or coolant liquid, or a fluid such as gas.

[0016] Next, the cooling flow passage 4 will be specifically described with reference to Figures 4 and 5. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Figure 5 is a plan view of the cooling flow passage 4.

[0017] 4 and 5, a plurality of first ribs 32 are provided at equal intervals in the circumferential direction in the cooling flow passage 4. In this embodiment, a case in which four first ribs 32 are provided will be described as an example, but the number of first ribs 32 may be more or less than this. The first ribs 32 are formed integrally with the accommodation portion 31.

[0018] 5, the first rib 32 is formed to have a length in the axial direction that is shorter than the axial width W of the cooling flow passage 4. As a result, a gap C is formed between the first rib 32 and the side wall 4a in the axial direction of the cooling flow passage 4. The cooling flow passage 4 is formed by the space between adjacent first ribs 32 and the gap C.

[0019] Adjacent first ribs 32 are provided so as to be shifted from each other in the axial direction within the cooling flow passage 4. As a result, the cooling flow passage 4 is partitioned into a meandering shape by the first ribs 32, as shown by the arrows in Fig. 5. By configuring the cooling flow passage 4 to be meandering in this manner, the flow passage length of the cooling flow passage 4 can be increased, and therefore the cooling efficiency of the refrigerant flowing through the cooling flow passage 4 can be improved.

[0020] 1 and 4, the housing 3 further includes a second rib 36 provided on the outer circumferential surface 31a of the accommodating portion 31. The second rib 36 is located on an extension line of the first rib 32 in the radial direction, and is formed to extend in the axial direction on the outer circumferential surface 31a. In this embodiment, the second rib 36 is provided between the flange 34 and the flange 35, as shown in FIGS.

[0021] 5, the second rib 36 is provided such that the length L2 in the axial direction is longer than the length L1 in the axial direction of the first rib 32. In other words, the second rib 36 is formed so as to cover the outer periphery of the gap C where the first rib 32 is not provided.

[0022] Incidentally, in the rotating electric machine 100, vibrations in the circumferential direction may occur due to periodic twisting of the housing 3 in the circumferential direction accompanying the rotation of the rotor 2 and the shaft 7. When such vibrations occur, the vibrations and the noise caused by the vibrations may be transmitted to the inside of the vehicle, causing discomfort to the passengers.

[0023] In the rotating electric machine 100, a first rib 32 extending in the axial direction is provided to configure the cooling flow passage 4. The first rib 32 contributes to suppressing circumferential twisting of the housing 3 due to its rigidity. However, the rigidity of the first rib 32 alone is not sufficient to suppress circumferential twisting of the housing 3.

[0024] Therefore, in this embodiment, the second rib 36 is provided so as to extend in the axial direction on an extension line of the first rib 32 in the radial direction. By providing the second rib 36 in this manner, the first rib 32 and the second rib 36 can function in the same manner as a rib formed integrally with each other. This makes it possible to increase the rigidity against circumferential twisting, thereby suppressing circumferential twisting of the housing 3 and the occurrence of vibration in the housing 3.

[0025] Moreover, the second rib 36 is provided radially outside the gap C where the first rib 32 is not present, in other words, the second rib 36 is provided so as to overlap in the radial direction with the folded-back portion of the cooling flow passage 4. As a result, the second rib 36 is present radially outside the portion where the first rib 32 is not present, and therefore the circumferential rigidity at such a portion can be increased.

[0026] Here, a suitable height of the second rib 36 will be described with reference to Fig. 6. Fig. 6 is a graph showing the relationship between the ratio of the radial height H1 (see Fig. 4) of the first rib 32 to the radial height H2 (see Fig. 4) of the second rib 36 and the amount of twist in the circumferential direction of the housing 3. As shown in Fig. 6, when the height H2 of the second rib 36 is less than ⅓ of the height H1 of the first rib 32, the amount of twist becomes large, and vibration cannot be sufficiently suppressed.

[0027] Furthermore, as shown in FIG. 6, even if the height H2 of the second rib 36 is greater than or equal to the height H1 of the first rib 32 (H2 / H1 is 1 or greater), the effect of suppressing twisting is not as great as that obtained by increasing the amount of material and the difficulty of molding.

[0028] Therefore, it is preferable that the height H2 of the second rib 36 is equal to or greater than 1 / 3 of the height H1 of the first rib 32, which is the height H1 of the first rib 32. This makes it possible to effectively suppress vibration without increasing the amount of material used or making molding difficult.

[0029] In the above embodiment, the housing portion 31, the first rib 32, and the second rib 36 are integrally molded by casting, but the present invention is not limited to this and may be configured by combining two cylindrical members. In this case, the first rib 32 is fixed to the two cylindrical members by welding, adhesive, or the like, thereby integrating them.

[0030] Further, although the material of the housing 3 has been described as being an aluminum alloy, the material is not limited to this, and the material of the housing 3 may be other metal materials, resin, or the like.

[0031] In the above embodiment, the rotating electric machine 100 is described as being mounted on a vehicle, but the present invention is not limited to this and may be mounted on any type of device.

[0032] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0033] The rotating electric machine 100 has a stator 1, a rotor 2, and a housing 3 that accommodates the stator 1 and the rotor 2. The housing 3 is provided with a cylindrical accommodating portion 31 that accommodates the stator 1 and the rotor 2, a cooling flow path 4 that is provided in the accommodating portion 31 and cools the stator 1, a plurality of first ribs 32 that are provided in the cooling flow path 4 at intervals in the circumferential direction of the accommodating portion 31 and extend in the axial direction of the accommodating portion 31, and a second rib 36 that is provided on an outer circumferential surface 31a of the accommodating portion 31 and extends in the axial direction on an extension line of the first rib 32 in the radial direction of the accommodating portion 31. The axial length of the second rib 36 is longer than the length of the first rib 32.

[0034] Since the housing 3 includes a plurality of first ribs 32 extending in the axial direction of the accommodating portion 31, and a second rib 36 provided on the outer circumferential surface 31a of the accommodating portion 31 and extending in the axial direction on an extension line of the first ribs 32 in the radial direction of the accommodating portion 31, the circumferential rigidity of the housing 3 can be increased. Furthermore, since the second rib 36 is provided on an extension line of the first rib 32 in the radial direction of the accommodating portion 31, the first rib 32 and the second rib 36 function in the same manner as a rib formed integrally with each other. This can further increase the circumferential rigidity, and thus the circumferential vibration of the rotating electric machine 100 can be further suppressed.

[0035] Furthermore, in the rotating motor 100, the axial length L2 of the second rib 36 is longer than the length L1 of the first rib 32, so that the second rib 36 can increase the rigidity of the outer peripheral portion of the gap C where the first rib 32 is not provided.

[0036] In the rotating electric machine 100, the cooling passage 4 is configured to meander in the circumferential direction by displacing adjacent first ribs 32 from each other in the axial direction. The second ribs 36 are provided to overlap the folded portions of the cooling passage 4 in the radial direction.

[0037] In this configuration, the second rib 36 is provided so as to overlap in the radial direction with the folded-back portion of the cooling flow passage 4. As a result, the second rib 36 is present radially outside a portion where the first rib 32 is not present, and therefore the circumferential rigidity can be increased in such a portion.

[0038] In the rotating electric machine 100, the height H2 in the radial direction of the second rib 36 is equal to or greater than ⅓ the height H1 in the radial direction of the first rib 32 and is equal to or less than the height H1 in the radial direction of the first rib 32.

[0039] By setting the height H2 of the second rib 36 to be at least 1 / 3 of the height H1 of the first rib 32, which is the height H1 of the first rib 32, vibration can be effectively suppressed without increasing the amount of material or making molding difficult.

[0040] In the rotating electrical machine 100, the housing portion 31, the first rib 32, and the second rib 36 are integrally formed.

[0041] In this configuration, by integrally forming the housing portion 31, the first rib 32, and the second rib 36, it is possible to omit operations such as assembly and welding.

[0042] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments and the respective modified examples merely represent some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0043] For example, the outer circumferential surface 31a of the housing portion 31 may be provided with a rib extending in the circumferential direction.

[0044] In the above embodiment, the cooling flow passage 4 is partitioned in a meandering manner by displacing the adjacent first ribs 32 from each other in the axial direction, but the present invention is not limited to this. For example, a gap may be provided at both ends of the first rib 32 in the axial direction, and the refrigerant may pass through the gap. In addition, the cooling flow passage 4 does not need to be provided so as to cover the entire circumference of the accommodation portion 31, and may be configured so as to cover a part of the accommodation portion 31. [Explanation of symbols]

[0045] 100 Rotating Electric Machine 1 Stator 2 Rotors 3. Housing 4 Cooling Channel 31 Storage unit 31a Outer surface 32 First Rib 36 Second Rib

Claims

[Claim 1] A rotating electric machine having a stator, a rotor, and a housing that accommodates the stator and the rotor, The housing includes: a cylindrical housing portion that houses the stator and the rotor; a cooling passage provided in the housing portion and configured to cool the stator; a plurality of first ribs provided in the cooling passage at intervals in a circumferential direction of the housing portion and extending in an axial direction of the housing portion; a second rib provided on an outer peripheral surface of the housing portion and extending in the axial direction on an extension line of the first rib in the radial direction of the housing portion; The length of the second rib in the axial direction is longer than the length of the first rib, The cooling flow passage is configured to meander in the circumferential direction by displacing adjacent first ribs from each other in the axial direction, The second rib is provided so as to overlap a folded portion of the cooling flow passage in the radial direction, The storage portion, the first rib, and the second rib are integrally formed, The height of the second rib in the radial direction is equal to or greater than 1 / 3 of the height of the first rib in the radial direction and is equal to or less than the height of the first rib in the radial direction. Rotating electric motor.

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