Motor cooling device

Abstract

The invention provides a motor cooling device capable of improving cooling performance. The motor cooling device is provided with an oil passage which is formed in a stator formed by stacking a plurality of steel plates, serves as a conduit for cooling oil, and is formed by overlapping oil holes formed in the plurality of steel plates in the stacking direction. The oil passage has an offset collision wall formed by overlapping the oil holes in a staggered manner in a direction orthogonal to the stacking direction.

Description

Technical Field

[0001] The present disclosure relates to an electric motor cooling device. Background Art

[0002] Patent Document 1 describes a motor cooling system in which an oil passage for introducing cooling oil is formed in the teeth of a stator. The oil passage has a constant shape in the direction in which the cooling oil flows.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent No. 11462957 Summary of the invention

[0006] Problems to be solved by the invention

[0007] It is desirable to improve the cooling performance of a motor cooling device.

[0008] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a motor cooling device capable of improving cooling performance.

[0009] Means for solving problems

[0010] The electric motor cooling device disclosed herein has an oil circuit, which is formed in a stator formed by stacking a plurality of steel plates, serving as a conduit for cooling oil, and is formed by overlapping oil holes formed in the plurality of steel plates in a stacking direction, and the oil circuit has an offset collision wall formed by staggered overlapping of the oil holes in a direction orthogonal to the stacking direction.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to realize a motor cooling device capable of improving cooling performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view showing a schematic structure of an oil passage of the motor cooling device according to the embodiment.

[0014] Figure 2 It is used to illustrate Figure 1 Figure 1. Steel plate of an electric motor cooling device.

[0015] Figure 3 It is a graph showing the heat transfer coefficient of the oil circuit.

[0016] Figure 4 It is a graph showing the magnetic flux density of a steel plate. DETAILED DESCRIPTION

[0017] The motor cooling device according to the embodiment of the present disclosure will be described with reference to the drawings. It should be noted that the components in the following embodiment include components that can be easily replaced by those skilled in the art, or components that are substantially the same.

[0018] (Implementation Method)

[0019] Figure 1 It is a cross-sectional view schematically showing the structure of an oil passage in the motor cooling device according to the embodiment. Figure 1 The stator S is formed by stacking a plurality of steel plates, and the stator S is formed by stacking a plurality of steel plates along the stacking direction D1 ( Figure 1 The cross-sectional view of Figure 1 The up and down direction corresponds to the radial direction D2 centered on the rotor's rotation axis. Figure 1 As shown, the motor cooling device 1 includes an oil pan 2 that stores cooling oil, an oil pump 3 that outputs the cooling oil at a predetermined oil pressure, and an oil passage 4 that serves as a conduit for the cooling oil.

[0020] The motor cooling device 1 outputs cooling oil stored in an oil pan 2 at a predetermined hydraulic pressure by an oil pump 3 , and the cooling oil circulates inside an oil passage 4 formed in a stator S, thereby cooling the motor.

[0021] Figure 2 It is used to illustrate Figure 1 The stator S is composed of a plurality of stacked steel plates P, but Figure 2 In order to explain the structure of the steel plate P, only five steel plates P are shown. In addition, the steel plate P is in a circular ring shape with the rotation axis of the rotor as the center, but Figure 2 Only a portion of the steel plate P including one tooth T is shown in the figure.

[0022] Three oil holes 411, 412, and 413 are formed on the steel plate P from the inside to the outside in the radial direction D2. The oil holes 411, 412, and 413 are longer in the radial direction D2 than in the circumferential direction D3 orthogonal to the radial direction D2. In addition, the stator S has teeth T protruding toward the inside of the radial direction D2, and the outermost oil hole 413 in the radial direction D2 is formed at a position outside the tooth T in the radial direction D2, and the oil holes 411 and 412 other than the oil hole 413 are formed in the tooth T.

[0023] The oil passage 4 is formed by overlapping the oil holes 411, 412, and 413 formed in the plurality of steel plates P in the stacking direction D1. In the oil passage 4, the cooling oil 5 is introduced sequentially from the oil hole 411 located on the inner side in the radial direction D2. That is, the cooling oil 5 is introduced in the order of the oil hole 411, the oil hole 412, and the oil hole 413.

[0024] return Figure 1The oil passage 4 has an offset collision wall 41 formed by overlapping the oil holes 411, 412, and 413 in a staggered manner in a direction perpendicular to the stacking direction D1. Figure 1 , an example is shown in which the offset collision wall 41 is formed by overlapping the oil holes 411, 412, and 413 in a staggered manner in the radial direction D2, but the offset collision wall 41 is preferably formed by overlapping the oil holes 411, 412, and 413 in a staggered manner in the circumferential direction D3. The offset collision wall 41 is formed by stacking, for example, 30 steel plates P each, but the number of sheets is not particularly limited and can be set to any number of sheets greater than 1 sheet.

[0025] The oil passage 4 has a turn portion 42 that turns back in the stacking direction D1. The oil passage 4 has two turn portions 42, and discharges the cooling oil 5 introduced from one end in the stacking direction D1 from the other end in the stacking direction D1.

[0026] exist Figure 2 In the figure, the temperature is illustrated by using the shade of the shadow so that the shadow of the high temperature portion becomes lighter. By sequentially introducing the cooling oil 5 from the oil hole 411 located on the inner side of the radial direction D2 where the temperature of the steel plate P is high, the high temperature portion of the steel plate P can be efficiently cooled by the low temperature cooling oil 5.

[0027] Figure 3 is a graph showing the heat transfer coefficient of the oil circuit. Figure 3 In the figure, the heat transfer coefficient is illustrated by using the shade of the shadow so that the shadow of the part with high heat transfer coefficient becomes lighter. Figure 3 As shown, the heat transfer coefficient increases near the offset collision wall 41. This is because the cooling oil 5 flowing in the oil passage 4 collides with the offset collision wall 41, generating turbulence and disrupting the downstream flow, thereby increasing the heat transfer coefficient between the cooling oil 5 and the wall surface of the stator S.

[0028] Figure 4 is a graph showing the magnetic flux density of a steel plate. Figure 4 In the figure, the magnetic flux density is illustrated by the shade of the hatching so that the shadow of the part with high magnetic flux density becomes lighter, and the magnetic lines of force are illustrated. Figure 4 As shown, it can be seen that Figure 4 The case where the oil holes 411, 412, 413 are not formed in the steel plate P shown in (a) is different from Figure 4 In the case where the oil holes 411 , 412 , and 413 are formed in the steel plate P shown in (b), there is no significant difference in the distribution of the magnetic flux density.

[0029] In addition, Figure 4 (c) shows Figure 4In the partial enlarged view of (b), the outermost oil hole 413 in the radial direction D2 is formed at a position outside the tooth T in the radial direction D2, and the oil holes 411 and 412 other than the oil hole 413 are formed in the tooth T. By setting such a structure, the change in magnetic flux density caused by forming the oil holes 411, 412, and 413 in the steel plate P can be reduced.

[0030] According to the motor cooling device 1 described above, since the oil passage 4 has the offset collision wall 41 , the cooling performance can be improved by reducing the pressure loss even at a small flow rate, and a small and low-cost motor cooling device 1 can be provided.

[0031] In addition, the offset collision wall 41 is formed by overlapping the oil holes 411, 412, and 413 in a staggered manner in the circumferential direction D3. Specifically, the offset collision wall 41 can be formed by alternately stacking two types of steel plates P with different shapes every 30 sheets. Therefore, the increase in the types of steel plates P with different shapes can be suppressed, and the increase in man-hours and costs can be suppressed. It should be noted that by flipping a steel plate P and using it as a steel plate P with different shapes, the increase in the types of steel plates P with different shapes can be further suppressed.

[0032] In addition, the oil holes 411, 412, 413 are longer in the radial direction D2 than in the circumferential direction D3, and the offset collision wall 41 is formed by overlapping the oil holes 411, 412, 413 in a staggered manner in the circumferential direction D3. As a result, the offset collision wall 41 is formed on the long side of the oil holes 411, 412, 413, and the area of ​​the offset collision wall 41 can be increased, so that the cooling performance is improved and the increase in pressure loss can be suppressed.

[0033] Furthermore, three oil holes 411, 412, 413 are formed along the radial direction D2 in the steel plate P. As a result, since the oil holes 411, 412, 413 are arranged along the magnetic lines of force of the teeth T, an increase in magnetic resistance and a decrease in motor torque caused thereby can be suppressed.

[0034] In addition, the oil passage 4 has a bend 42 that turns back in the stacking direction D1. As a result, even if the cooling oil 5 has the same flow rate and flow velocity, the area of ​​the wall surface of the oil passage 4 in contact can be increased, and the cooling performance can be improved. In addition, turbulence is also generated in the bend 42, so the heat transfer coefficient is improved, and the cooling performance is improved.

[0035] The oil passage 4 discharges the cooling oil 5 introduced from one end in the stacking direction D1 from the other end in the stacking direction D1. As a result, the inlet and outlet of the cooling oil 5 are located on opposite end surfaces, so that the coil ends are not blocked and mutual interference can be prevented.

[0036] Furthermore, the cooling oil 5 is sequentially introduced from the oil holes 411 located inside in the radial direction D2 into the oil passage 4. As a result, the inner portion of the teeth T of the steel plate P with a high temperature can be effectively cooled by the cooling oil 5 with a low temperature.

[0037] The outermost oil hole 413 in the radial direction D2 is formed outside the tooth T in the radial direction D2 , and the oil holes 411 and 412 other than the oil hole 413 are formed in the tooth T. As a result, the reduction in magnetic path and the resulting reduction in motor torque can be suppressed.

[0038] In addition, an inlet-side coil end cooling oil hole for cooling the coil end may be formed before the inlet of the oil passage 4. This can cool the coil end and improve the insulation of the coil end.

[0039] In addition, an outflow-side coil end cooling oil hole for cooling the coil end may be formed after the outflow port of the oil passage 4. This can cool the coil end and improve the insulation of the coil end.

[0040] Those skilled in the art can easily derive further effects and variations. Therefore, the broader aspects of the present invention are not limited to the specific detailed and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the attached claims and their equivalents.

[0041] Description of Reference Numerals

[0042] 1 Motor cooling device

[0043] 2 Oil pan

[0044] 3 Oil pump

[0045] 4 Oil circuit

[0046] 5. Cooling oil

[0047] 41 offset collision wall

[0048] 42 Turning section

[0049] 411, 412, 413 oil holes

[0050] P Steel Plate

[0051] S-Stator

[0052] T-tooth.

Claims

1. A motor cooling device, comprising an oil circuit, This oil passage is formed in a stator formed by stacking a plurality of steel plates, and serves as a conduit for cooling oil. The oil holes formed in the plurality of steel plates are overlapped in the stacking direction. The oil passage has an offset collision wall formed by overlapping the oil holes in a staggered manner in a direction orthogonal to the stacking direction.

2. The motor cooling device according to claim 1, The oil hole is longer in the radial direction centered on the rotating axis of the rotor than in the circumferential direction orthogonal to the radial direction. The offset collision wall is formed by overlapping the oil holes in a staggered manner in the circumferential direction.

3. The motor cooling device according to claim 1, The steel plate is provided with a plurality of oil holes along a radial direction centered on the rotating shaft of the rotor. The oil passage has a turning portion that turns back in the stacking direction.

4. The motor cooling device according to claim 3, The steel plate is provided with three oil holes along the radial direction. The oil passage has the two turning portions, and discharges the cooling oil introduced from one end in the stacking direction from the other end in the stacking direction.

5. The motor cooling device according to claim 3, The cooling oil is introduced into the oil passage in sequence from the oil hole located on the inner side in the radial direction.

6. The motor cooling device according to claim 3, The stator has teeth protruding toward the inner side in the radial direction, The outermost oil hole in the radial direction is formed at a position further outward in the radial direction than the teeth. The oil holes other than the outermost oil holes in the radial direction are formed in the teeth.

Images