Motor cooling structure

Abstract

To provide a cooling structure of a motor capable of improving uniformity of cooling of a heating part.SOLUTION: In a radial view of a first cooling pipe 30A and a second cooling pipe 30B, the farther discharge ports 50 are positioned separating away from a rotation axis CL1, the larger diameters the discharge ports have, respectively. Therefore, the farther the discharge ports are positioned away from the rotation axis CL1, the more the discharge ports can discharge, respectively. In such a case, the first cooling pipe 30A and the second cooling pipe 30B are capable of securing supply amounts of coolant more for locations where the coolant is harder to flow.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cooling structure for an electric motor. [Background technology]

[0002] Patent Document 1 describes a cooling structure that supplies oil to an electric motor to cool it. The electric motor includes a rotating shaft extending along a rotation axis, a rotor provided on the rotating shaft, and a stator provided around the rotation axis relative to the rotor. The cooling structure includes a cooling pipe arranged above the stator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-217438 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described cooling structure for an electric motor, a cooling pipe is formed with multiple outlets, and the cooling medium is supplied to the heat-generating portion through the outlets. However, in the conventional cooling structure for an electric motor, there is a problem in that the cooling medium cannot be supplied uniformly to the heat generated. Therefore, there is a need to improve the uniformity in cooling the heat-generating portion.

[0005] An object of the present invention is to provide a cooling structure for an electric motor that can improve the uniformity of cooling of a heat-generating portion. [Means for solving the problem]

[0006] The cooling structure for an electric motor according to the present invention is a cooling structure for an electric motor that cools an electric motor that includes a rotating shaft extending along a rotating axis, a rotor provided on the rotating shaft, and a stator provided around the rotating axis relative to the rotor, and includes a first cooling pipe and a second cooling pipe that are arranged in parallel to extend in the axial direction above the stator, and a plurality of outlets that discharge the cooling medium circulating within the pipes are formed at predetermined axial positions of the first cooling pipe and the second cooling pipe, and when viewed radially, the outlets that are farther away from the rotating axis have larger diameters.

[0007] The cooling structure for an electric motor according to the present invention includes a first cooling pipe and a second cooling pipe arranged in parallel and extending in the axial direction above a stator. The first cooling pipe and the second cooling pipe each have a plurality of outlets formed at predetermined axial positions for discharging the cooling medium circulating therein. Therefore, the first cooling pipe and the second cooling pipe each discharge the cooling medium from the plurality of outlets, thereby supplying the cooling medium to a heat-generating component at multiple locations. When viewed radially from the first cooling pipe and the second cooling pipe, the outlets farther from the rotation axis have larger diameters. Therefore, the outlets farther from the rotation axis can discharge a larger amount. In this case, the first cooling pipe and the second cooling pipe can ensure a sufficient supply of cooling medium in locations where the cooling medium is less likely to flow. As a result, the uniformity of cooling of the heat-generating component can be improved.

[0008] At least three outlets may be formed in each of the first and second cooling pipes at predetermined axial positions, in which case the first and second cooling pipes can suitably adjust the supply of cooling medium to the heat-generating part by using the at least three outlets.

[0009] The outlets formed at predetermined axial positions of the first and second cooling pipes may be formed at different axial positions from adjacent outlets, which can prevent the strength of the first and second cooling pipes from decreasing due to the adjacent outlets being crowded together. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a cooling structure for an electric motor that can improve the uniformity of cooling of a heat-generating portion. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a view of a cooling structure according to an embodiment of the present invention as viewed from an axial direction; [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. [Figure 3] 2 is a view showing the electric motor in a state where a front retainer is removed from the state shown in FIG. 1. FIG. [Figure 4] FIG. 1 is a view of the space above the stator 6 as seen obliquely from below. [Figure 5] 2 is a cross-sectional view of the front retainer in the area indicated by "A" in FIG. 1. [Figure 6] FIG. 3 is a cross-sectional view taken at a different angle from FIG. 2. [Figure 7] FIG. 10 is a view of the front retainer as seen from the rear side. [Figure 8] FIG. 3 is a cross-sectional view taken at a different angle from FIG. 2. [Figure 9] FIG. 10 is a diagram showing the state of the discharge ports of the first cooling pipe and the second cooling pipe when viewed from the rotation axis. [Figure 10] FIG. 1(a) is a diagram schematically illustrating a first cooling pipe, a second cooling pipe, and a coil end to be cooled, and FIG. 1(b) is a diagram schematically illustrating an example of an oil supply mode. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0013] 1 to 3, the configuration of an electric motor 1 employing a cooling structure 100 according to an embodiment of the present invention will be described. FIG. 1 is a view of the cooling structure 100 according to the embodiment of the present invention as seen from the axial direction. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a view of the electric motor 1 in a state in which a front retainer has been removed from the state shown in FIG. 1. The direction in which a rotating axis CL1 of the electric motor 1 extends may be referred to as the "axial direction D1." One side of the axial direction D1 may be referred to as the "front" and the other side as the "rear." As shown in FIGS. 1 to 3, the electric motor 1 is a device that includes a mechanism for generating a rotational force inside a housing 2 and rotates a rotating shaft 3 with the generated rotational force. As shown in FIG. 2, the electric motor 1 includes a housing 2, a rotating shaft 3, a rotor 4, and a stator 6.

[0014] The housing 2 is a container that houses the rotating shaft 3, the rotor 4, the stator 6, and the cooling structure 100. The housing 2 includes a main body 11 and a front retainer 12. The main body 11 has a substantially cylindrical peripheral wall 13 that extends along the rotation axis CL1, and a substantially disc-shaped end wall 14 that closes an opening on the rear side of the peripheral wall 13. The front retainer 12 is a substantially disc-shaped member that closes an opening on the front end of the peripheral wall 13.

[0015] The rotating shaft 3 is a rod-shaped member extending along the rotation axis CL1. The rotating shaft 3 is a member that rotates due to the rotational force generated by the electric motor 1, thereby transmitting the force to external devices. The rotating shaft 3 extends inside the housing 2 along the axial direction D1. The front end of the rotating shaft 3 is supported by a front retainer 12, and the rear end is supported by an end wall portion 14. The front end of the rotating shaft 3 is rotatably supported by the front retainer 12 via a front bearing 16. An oil seal 17 is provided in front of the front bearing 16. The rear end of the rotating shaft 3 is rotatably supported by the end wall portion 14 via a rear bearing 18. A resolver 19 is provided behind the rear bearing 18. A resolver cover 20 is provided in a central position of the end wall portion 14, spaced rearward from the rotating shaft 3 and the resolver 19.

[0016] The rotor 4 is a cylindrical member that is attached to the rotating shaft 3 and rotates together with the rotating shaft 3. A permanent magnet is disposed inside the rotor 4 to form a rotor magnetic field. The rotor 4 rotates around the rotation axis CL1 in conjunction with the rotating shaft 3 due to the interaction between the rotor magnetic field formed by the rotor 4 and the stator magnetic field formed by the stator 6. Note that the rotor 4 and stator 6 are shown in simplified form in the drawings to facilitate understanding of the structure.

[0017] The stator 6 is a member provided around the rotation axis CL1 relative to the rotor 4. The stator 6 has a stator core 21 and coils 22. The stator core 21 is a member formed by stacking and welding electromagnetic steel sheets in the axial direction D1. The stator core 21 is disposed in the space between the peripheral wall portion 13 and the rotor 4. Coils 22 for forming a stator magnetic field are wound around the stator core 21. A coil end 22a, which is a part of the coil 22, is formed at the front end of the stator core 21, and a coil end 22b, which is a part of the coil 22, is formed at the rear end. The stator core 21 is fixed to the housing 2 at stator bolt fastening portions 24 formed by fastening stator bolts at multiple positions around the rotation axis CL1 on its outer periphery (see FIG. 3).

[0018] Next, the configuration of the cooling structure 100 according to this embodiment will be described. Fig. 4 is a view of the space above the stator 6 as seen from diagonally below. Fig. 4 shows the state as seen from the viewpoint indicated by "V1" in Fig. 2. As shown in Fig. 4, the cooling structure 100 includes a first cooling pipe 30A and a second cooling pipe 30B. The first cooling pipe 30A and the second cooling pipe 30B are arranged in parallel above the stator 6 and extend in the axial direction D1. The first cooling pipe 30A and the second cooling pipe 30B are arranged so as to sandwich the uppermost stator bolt fastening portion 24 in the circumferential direction (see also Fig. 3).

[0019] As shown in FIG. 2 , the first cooling pipe 30A extends parallel to the axial direction D1 from the front retainer 12 to the end wall portion 14 in the space above the stator 6 within the internal space of the housing 2. A front end of the first cooling pipe 30A is connected to an insertion port in the front retainer 12. A rear end of the first cooling pipe 30A is connected to an insertion port in the end wall portion 14 of the housing 2. The first cooling pipe 30A is supported near its front end by a support member 36 provided on the peripheral wall portion of the housing 2. The first cooling pipe 30A is supported near its rear end by a support member 37 provided on the peripheral wall portion of the housing 2.

[0020] The first cooling pipe 30A has a plurality of discharge ports 50 formed at a plurality of predetermined positions in the axial direction D1, through which the oil (coolant) flowing through the pipe is discharged. This allows the first cooling pipe 30A to cool the stator 6 (the coil ends 22a, 22b and the stator core 21) by injecting oil onto the stator 6. The configuration of the discharge ports 50 will be described in detail later. Like the first cooling pipe 30A, the second cooling pipe 30B also extends from the front retainer 12 to the end wall portion 14. The first cooling pipe 30A has a plurality of discharge ports 50 formed at a plurality of predetermined positions in the axial direction D1, through which the oil (coolant) flowing through the pipe is discharged.

[0021] Here, with reference to FIG. 5, how oil is supplied to the first cooling pipe 30A and the second cooling pipe 30B will be described. FIG. 5 is a cross-sectional view of the front retainer 12 in the area indicated by "A" in FIG. 1. An oil passage 31A for the first cooling pipe 30A and an oil passage 31B for the second cooling pipe 30B are formed in the upper part of the front retainer 12. The oil passage 31A extends from the outer surface of the front retainer 12 to an insertion port 32A to which the front end of the first cooling pipe 30A is connected. The oil passage 31B extends from the outer surface of the front retainer 12 to an insertion port 32B to which the front end of the second cooling pipe 30B is connected. The oil passages 31A and 31B intersect with each other inside the front retainer 12, and the intersection is connected to an inlet oil passage 33 extending downward from the upper surface of the front retainer 12. First, oil is pumped by an oil pump (not shown) to inlet oil passage 33, and the oil passes through oil passages 31A and 31B and is supplied to outlets 32A and 32B, respectively. As a result, the oil is supplied to cooling pipes 30A and 30B via outlets 32A and 32B, respectively.

[0022] As shown in FIGS. 6 and 7, the cooling structure 100 has a lubrication structure 110 that supplies oil to the front bearing 16 and the oil seal 17. FIG. 6 is a cross-sectional view taken at a different angle from FIG. 2. FIG. 7 is a view of the front retainer 12 as seen from the rear. As shown in FIG. 6, the front retainer 12 has a thick portion 41 formed at its center that protrudes into the housing 2. The thick portion 41 has a communication portion 43 that communicates from the outer peripheral side surface 41a to the inner peripheral side surface 41b. The communication portion 43 opens at the inner peripheral side surface 41b into a space SP1 between the oil seal 17 and the front bearing 16. The front retainer 12 also has a plurality of reinforcing ribs 42 that extend radially from the thick portion 41 toward the outer peripheral side (see FIG. 7). Each reinforcing rib 42 extends radially from the thick portion 41 toward the outer peripheral side while protruding into the housing 2.

[0023] With the above-described configuration, some oil ATF leaks from the insertion ports 32A, 32B at the top of the front retainer 12 and flows along the reinforcing ribs 42 to the thick portion 41 (see FIG. 7). The oil ATF then flows along the outer peripheral side surface 41a of the thick portion 41 into the communication portion 43. As a result, the oil ATF is supplied from the communication portion 43 to the space SP1, thereby lubricating the oil seal 17 and the front bearing 16.

[0024] As shown in FIG. 8, the cooling structure 100 has a lubrication structure 120 that supplies oil to the rear bearing 18. FIG. 8 is a cross-sectional view taken at a different angle from FIG. 2. The end wall portion 14 of the housing 2 is formed with an insertion port 38A of the first cooling pipe 30A and an oil passage 47 that communicates with the insertion port 38A and extends radially inward. The oil passage 47 communicates with a space SP2 between the resolver 19 and the resolver cover 20. Therefore, the oil ATF flows from the first cooling pipe 30A through the insertion port 38A to the oil passage 47. The oil ATF then flows through the oil passage 47 and is supplied to the space SP2, where it accumulates. The oil ATF that has accumulated in the space SP2 overflows from the gap between the rotating shaft 3 and the housing 2, reaches the rear bearing 18, and lubricates it.

[0025] Between the inlet 38A and the oil passage 47, a throttle section 48 having a smaller diameter than the inlet 38A is formed. This limits the amount of oil ATF flowing to the rear bearing 18. Therefore, the internal pressure of the first cooling pipe 30A can be maintained high, and the discharge pressure of the discharge port 50 can be ensured. A similar inlet and oil passage are provided in the second cooling pipe 30B, but no throttle section is formed therein.

[0026] Next, the configuration of the discharge ports 50 of the first cooling pipe 30A and the second cooling pipe 30B will be described. As shown in Fig. 4, three discharge ports 51A, 52A, and 53A are formed at predetermined positions in the axial direction D1 of the first cooling pipe 30A. Three discharge ports 51B, 52B, and 53B are formed at predetermined positions in the axial direction D1 of the second cooling pipe 30B. Note that combinations of discharge ports 51A, 52A, 53A, 51B, 52B, and 53B are formed at multiple locations in the axial direction D1 in the cooling pipes 30A and 30B.

[0027] Here, the arrangement and diameters of the discharge ports 51A, 52A, 53A, 51B, 52B, and 53B will be described with reference to FIG. 9. FIG. 9 is a diagram showing the appearance of the discharge ports 51A, 52A, 53A, 51B, 52B, and 53B when viewed from the rotation axis CL1. Specifically, a reference line SL is set that passes through the center of the first cooling pipe 30A and the center of the second cooling pipe 30B when viewed from the axial direction D1. A viewing direction D2 is set that is perpendicular to the reference line SL when viewed from the rotation axis CL1. This viewing direction D2 is one of the radial directions. FIG. 9 is a schematic diagram of the first cooling pipe 30A and the second cooling pipe 30B when viewed from the viewing direction D2.

[0028] As shown in FIG. 9, when the first cooling pipe 30A and the second cooling pipe 30B are viewed in the radial direction (viewing direction D2 in FIG. 2), the diameter of the discharge ports 50 increases as they are located farther from the rotational axis CL1. In the first cooling pipe 30A, discharge ports 51A, 52A, and 53A are formed in order from the closest to the rotational axis CL1. Therefore, the diameters of the discharge ports 51A, 52A, and 53A increase in this order, and the oil discharge rates also increase in this order. In this case, the discharge ports 51A, 52A, and 53A are formed with diameters that increase as they are farther from the stator bolt fastening portion 24 (see FIG. 3). In the second cooling pipe 30B, discharge ports 51B, 52B, and 53B are formed in order from the closest to the rotational axis CL1. Therefore, the diameters of the discharge ports 51B, 52B, and 53B increase in this order, and the oil discharge rates also increase in this order. In this case, discharge ports 51A, 52A, and 53A are formed with diameters that increase with increasing distance from stator bolt fastening portion 24 (see FIG. 3). The distance from rotation axis CL1 is defined by the distance from rotation axis CL1 in direction D3 perpendicular to rotation axis CL1.

[0029] The multiple discharge ports 51A, 52A, and 53A formed at predetermined positions in the axial direction D1 of the first cooling pipe 30A are formed at different positions in the axial direction D1 from the other adjacent discharge ports. In this embodiment, the discharge port 52A is formed at a position forward of the adjacent discharge port 51A in the axial direction D1. The discharge port 53A is formed at a position rearward of the adjacent discharge port 52A in the axial direction D1. The discharge ports 51A and 53A that are not adjacent to each other are arranged at the same position in the axial direction D1. In this manner, the discharge ports 51A, 52A, and 53A are arranged alternately in the axial direction D1. However, the discharge port 51A and the discharge port 53A may be arranged at different positions from each other in the axial direction D1. The amount of deviation in the axial direction D1 may be adjusted within a range of, for example, about 2 mm. The positional relationship between the outlet 51B, the outlet 52B, and the outlet 53B in the axial direction D1 is the same as that between the outlet 51A, the outlet 52A, and the outlet 53A.

[0030] Next, the oil ejection direction from each outlet of the first cooling pipe 30A and the second cooling pipe 30B will be described with reference to Fig. 10. Fig. 10(a) is a diagram schematically showing the first cooling pipe 30A, the second cooling pipe 30B, and the coil end 22a to be cooled. In Fig. 10(a), a reference line SL2 is set that passes through the rotation axis CL1 and extends in the vertical direction. In addition, a reference line SL3 is set that passes through the rotation axis CL1 and the center of the first cooling pipe 30A. In addition, a reference line SL4 is set that passes through the rotation axis CL1 and the center of the second cooling pipe 30B.

[0031] The first cooling pipe 30A is disposed at a position where the reference line SL3 forms an angle, for example, in the range of 17 to 21 degrees (19 degrees here) with respect to the reference line SL2. The second cooling pipe 30B is disposed at a position where the reference line SL4 forms an angle, for example, in the range of 5 to 9 degrees (7 degrees here) with respect to the reference line SL2.

[0032] The angles of the jetting directions JD1, JD2, and JD3 of the discharge ports 51A, 52A, and 53A of the first cooling pipe 30A will be described. The jetting direction JD1 of the discharge port 51A is set to an arbitrary angle, for example, in the range of 39 to 47°, more preferably, for example, in the range of 41 to 45° (here, 43°), with respect to the reference line SL3. The jetting direction JD1 of the discharge port 51A is preferably set to a direction that intersects with the reference line SL2. The jetting direction JD2 of the discharge port 52A is set to an arbitrary angle, for example, in the range of 3 to 11°, more preferably, for example, in the range of 5 to 9° (here, 7°), with respect to the reference line SL3. The jetting direction JD3 of the discharge port 53A is set to an arbitrary angle, for example, in the range of 50 to 54°, more preferably, for example, in the range of 51 to 53° (here, 52°), with respect to the reference line SL3.

[0033] The angles of the jetting directions JD1, JD2, and JD3 of the discharge ports 51B, 52B, and 53B of the second cooling pipe 30B will be described. The jetting direction JD1 of the discharge port 51B is set to an arbitrary angle, for example, in the range of 18 to 26°, more preferably, in the range of 20 to 24° (here, 22°), with respect to the reference line SL4. The jetting direction JD1 of the discharge port 51B is preferably set to a direction that intersects with the reference line SL2. The jetting direction JD2 of the discharge port 52B is set to an arbitrary angle, for example, in the range of 31 to 39°, more preferably, in the range of 33 to 37° (here, 35°), with respect to the reference line SL4. The jetting direction JD3 of the discharge port 53B is set to an arbitrary angle, for example, in the range of 52 to 56°, more preferably, in the range of 53 to 55° (here, 54°), with respect to the reference line SL4.

[0034] In order to change the cooling performance of the object to be cooled (the coil end 22a) in the axial direction D1, the spray directions JD1, JD2, and JD3 of the discharge ports 30A, 30B of the cooling pipes on the welding side and the non-welding side may be different. For example, for the second cooling pipe 30B, when the spray direction JD3 of the discharge port on the non-welding side in the axial direction D1 is set to 54° with respect to the reference line SL4, the spray direction JD3 of the discharge port on the welding side in the axial direction D1 may be set to 57° with respect to the reference line SL4 (for example, any angle in the range of 55 to 59°, more preferably, 56 to 58°). This allows oil to be sprayed over a wider area of ​​the coil end 22a on the welding side than on the non-welding side, thereby providing better cooling. The spray directions can be adjusted similarly for the other cooling pipes and other discharge ports.

[0035] FIG. 10(b) is a diagram showing a schematic example of an oil ATF supply mode. Only the supply mode of the second cooling pipe 30B is shown in FIG. 10(b). As shown in FIG. 10(b), the second cooling pipe 30B can supply oil ATF to a wide supply area PE1 of the heat generating portion on the front side of the reference line SL2. The second cooling pipe 30B can also supply oil ATF to a supply area PE2 of a portion of the heat generating portion on the opposite side of the reference line SL2.

[0036] Next, the operation and effect of the cooling structure 100 for the electric motor according to this embodiment will be described.

[0037] The cooling structure 100 for the electric motor 1 according to this embodiment includes a first cooling pipe 30A and a second cooling pipe 30B arranged in parallel and extending in the axial direction D1 above the stator 6. The first cooling pipe 30A and the second cooling pipe 30B each have a plurality of outlet ports 50 formed at predetermined positions in the axial direction D1, through which the cooling medium circulating therethrough is discharged. Therefore, the first cooling pipe 30A and the second cooling pipe 30B each discharge the cooling medium from the plurality of outlet ports 50, thereby supplying the cooling medium to a heat-generating component at multiple locations. When viewed radially from the first cooling pipe 30A and the second cooling pipe 30B, the outlet ports 50 located farther from the rotation axis CL1 have larger diameters. Therefore, the outlet ports located farther from the rotation axis CL1 can discharge a larger amount of cooling medium. In this case, the first cooling pipe 30A and the second cooling pipe 30B can ensure a sufficient supply of cooling medium to locations where the cooling medium is less likely to flow. As a result, the uniformity of cooling of the heat generating portion can be improved.

[0038] For example, in the case of EVs and FCVs, the motor is the main power source, and the amount of heat generated by the motor is large. Therefore, if the heat-generating parts inside the motor cannot be cooled uniformly, there is a problem that motor performance (continuous output) will decrease. In contrast, in this embodiment, by improving the uniformity of cooling of the heat-generating parts, the range of use of the motor can be expanded, and power consumption / fuel efficiency and vehicle driving performance can be improved.

[0039] At least three outlets 50 may be formed at predetermined positions in the axial direction D1 of the first cooling pipe 30A and the second cooling pipe 30B, respectively. In this case, the first cooling pipe 30A and the second cooling pipe 30B can suitably adjust the supply mode of the cooling medium to the heat-generating part by using the at least three outlets 50.

[0040] The plurality of outlet ports 50 formed at predetermined positions in the axial direction D1 of the first cooling pipe 30A and the second cooling pipe 30B may be formed at positions in the axial direction D1 that are different from other adjacent outlet ports 50. In this case, it is possible to prevent the strength of the first cooling pipe 30A and the second cooling pipe 30B from decreasing due to the adjacent outlet ports 50 being closely spaced.

[0041] The present invention is not limited to the above-described embodiments.

[0042] For example, the shape, size, and arrangement of the outlets are not limited to those in the above-described embodiment. The number of outlets formed in one location may be more than three, or may be two, instead of three as in the embodiment. [Explanation of symbols]

[0043] 1...electric motor, 2...housing, 3...rotating shaft, 4...rotor, 6...stator, 30A...first cooling pipe, 30B...second cooling pipe, 50, 51A, 52A, 53A, 51B, 52B, 53B...discharge port.

Claims

1. A cooling structure for an electric motor that cools an electric motor including: a rotating shaft extending along a horizontally disposed rotation axis; a rotor provided on the rotating shaft; and a stator having a coil and provided around the rotation axis relative to the rotor on the outside of the rotor, a first cooling pipe and a second cooling pipe arranged in parallel above the stator so as to extend in an axial direction on a plane vertical to the rotation shaft; a plurality of discharge ports are formed in the first cooling pipe and the second cooling pipe at predetermined positions in the axial direction, the discharge ports discharging the cooling medium flowing through the pipes toward coil ends of the coil, the discharge ports being closely spaced in the axial direction; a cooling structure for an electric motor, wherein, when viewed in the axial direction, the first cooling pipe and the second cooling pipe are arranged so that the spray angle of the discharge port on the welding side of the coil end is wider than the spray angle of the discharge port on the anti-welding side, and when viewed in the radial direction, the discharge ports farther away from the rotating shaft have larger diameters.

2. 2. The cooling structure for an electric motor according to claim 1, wherein at least three of the discharge ports are formed at predetermined positions in the axial direction of the first cooling pipe and the second cooling pipe.

3. 3. The cooling structure of an electric motor according to claim 1, wherein the plurality of discharge ports formed at predetermined positions in the axial direction of the first cooling pipe and the second cooling pipe are formed at different positions in the axial direction relative to other adjacent discharge ports.

Images