Motor cooling device

Abstract

To provide a motor cooling device capable of improving cooling performance.SOLUTION: A motor cooling device is formed in a stator formed by stacking a number of steel plates, and has an oil passage that serves as a conduit for cooling oil, the oil passage is formed by oil holes formed in the number of steel plates overlapping in the stacking direction, and has an offset collision wall that is formed by the oil holes overlapping and shifted in a direction perpendicular to the stacking direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a motor cooling device. [Background technology]

[0002] Patent Document 1 describes a motor cooling system in which an oil passage through which cooling oil is introduced is formed in the teeth of a stator. The oil passage has a fixed shape in the direction in which the cooling oil flows. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Pat. No. 1,146,2957 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to improve the cooling performance of a motor cooling device.

[0005] The present disclosure has been made in consideration of the above, and has an object to provide a motor cooling device that can improve cooling performance. [Means for solving the problem]

[0006] The motor cooling device of the present disclosure is provided with an oil passage that serves as a conduit for cooling oil, which is formed in a stator formed by stacking a plurality of steel plates, and is formed by oil holes formed in the plurality of steel plates overlapping in the stacking direction, and has an offset collision wall that is formed by the oil holes overlapping and shifted in a direction perpendicular to the stacking direction. Effect of the Invention

[0007] According to the present disclosure, it is possible to realize a motor cooling device that can improve cooling performance. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of an oil passage of a motor cooling device according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining a steel plate of the motor cooling device shown in FIG. [Diagram 3] FIG. 3 is a diagram showing the heat transfer coefficient of the oil passage. [Figure 4] FIG. 4 is a diagram showing the magnetic flux density of a steel sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A motor cooling device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that components in the following embodiments include those that are easily replaceable by a person skilled in the art, or those that are substantially the same.

[0010] (Embodiment) Fig. 1 is a cross-sectional view showing a schematic configuration of an oil passage of a motor cooling device according to an embodiment. Fig. 1 is a cross-sectional view taken along a stacking direction D1 (left-right direction in Fig. 1) of steel plates of a stator S formed by stacking a plurality of steel plates, and the up-down direction in Fig. 1 corresponds to a radial direction D2 centered on the rotation axis of a rotor. As shown in Fig. 1, 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 hydraulic pressure, and an oil passage 4 that serves as a conduit for the cooling oil.

[0011] The motor cooling device 1 outputs cooling oil stored in an oil pan 2 at a predetermined oil pressure using an oil pump 3, and cools the motor by circulating the cooling oil inside an oil passage 4 formed in a stator S.

[0012] Fig. 2 is a diagram for explaining the steel plates of the motor cooling device shown in Fig. 1. The stator S is made up of multiple stacked steel plates P, but Fig. 2 shows only five steel plates P in order to explain the configuration of the steel plates P. In addition, the steel plates P have an annular shape centered on the rotation axis of the rotor, but Fig. 2 shows only a portion of the steel plates P including one tooth T.

[0013] Three oil holes 411, 412, 413 are formed in the steel plate P along the radial direction D2 from the inside to the outside. The radial direction D2 is longer than the circumferential direction D3 perpendicular to the radial direction D2. The stator S has teeth T protruding toward the inside in the radial direction D2, and the outermost oil hole 413 in the radial direction D2 is formed outside the teeth T in the radial direction D2, and the oil holes 411 and 412 other than the oil hole 413 are formed in the teeth T.

[0014] The oil passage 4 is formed by overlapping oil holes 411, 412, 413 formed in a plurality of steel plates P in the stacking direction D1. Cooling oil 5 is introduced into the oil passage 4 in the order of oil hole 411 located on the inside in the radial direction D2. That is, the cooling oil 5 is introduced into the oil passage 4 in the order of oil hole 411, oil hole 412, and oil hole 413.

[0015] Returning to Fig. 1, the oil passage 4 has an offset collision wall 41 formed by overlapping the oil holes 411, 412, 413 with a shift in a direction perpendicular to the stacking direction D1. Fig. 1 shows an example in which the offset collision wall 41 is formed by overlapping the oil holes 411, 412, 413 with a shift in the radial direction D2, but it is preferable that the offset collision wall 41 is formed by overlapping the oil holes 411, 412, 413 with a shift in the circumferential direction D3. The offset collision wall 41 is formed, for example, for every 30 stacked steel plates P, but the number of sheets is not particularly limited and can be set to any number of sheets equal to or greater than one.

[0016] Furthermore, 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 the cooling oil 5 introduced from one end in the stacking direction D1 is discharged from the other end in the stacking direction D1.

[0017] 2, the temperature is illustrated by the shade of hatching so that the hatching of the higher temperature parts is lighter. By introducing the cooling oil 5 sequentially from the oil holes 411 located on the inside in the radial direction D2 where the temperature of the steel sheet P is high, the high temperature parts of the steel sheet P can be efficiently cooled by the cooling oil 5 having a low temperature.

[0018] Fig. 3 is a diagram showing the heat transfer coefficient of the oil passage. In Fig. 3, the heat transfer coefficient is shown by the shade of hatching, so that the hatching of the parts with high heat transfer coefficient is lighter. As shown in Fig. 3, the heat transfer coefficient is large 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 disturbing the downstream flow, thereby improving the heat transfer coefficient between the cooling oil 5 and the wall surface of the stator S.

[0019] Fig. 4 is a diagram showing the magnetic flux density of a steel sheet. In Fig. 4, the magnetic flux density is illustrated by the shade of hatching so that the hatching of the parts with high magnetic flux density is lighter, and the magnetic field lines are also illustrated. As shown in Fig. 4, it can be seen that there is no significant difference in the distribution of magnetic flux density between the case where the oil holes 411, 412, and 413 are not formed in the steel sheet P shown in Fig. 4(a) and the case where the oil holes 411, 412, and 413 are formed in the steel sheet P shown in Fig. 4(b).

[0020] 4(c) shows a partially enlarged view of Fig. 4(b), and the outermost oil hole 413 in the radial direction D2 is formed outside the teeth T in the radial direction D2, and the oil holes 411 and 412 other than the oil hole 413 are formed in the teeth T. With this configuration, it is possible to reduce the change in magnetic flux density caused by forming the oil holes 411, 412, 413 in the steel plate P.

[0021] According to the motor cooling device 1 described above, since the oil passage 4 has the offset collision wall 41, the cooling performance is improved with low pressure loss even at a small flow rate, and a small-sized, low-cost motor cooling device 1 can be provided.

[0022] The offset collision wall 41 is formed by overlapping the oil holes 411, 412, 413 with a shift in the circumferential direction D3. Specifically, the offset collision wall 41 can be formed by alternately stacking every 30 sheets of two types of steel plates P having different shapes. This makes it possible to suppress an increase in the types of steel plates P having different shapes, and suppress an increase in labor and costs. Note that an increase in the types of steel plates P having different shapes may be further suppressed by inverting one type of steel plate P and using it as a steel plate P having a different shape.

[0023] Furthermore, the oil holes 411, 412, and 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, and 413 while being shifted in the circumferential direction D3. As a result, the offset collision wall 41 is formed on the long sides of the oil holes 411, 412, and 413, and the area of ​​the offset collision wall 41 can be increased, improving the cooling performance and suppressing an increase in pressure loss.

[0024] Furthermore, three oil holes 411, 412, 413 are formed in the steel plate P along the radial direction D2. As a result, the oil holes 411, 412, 413 are formed side by side along the magnetic field lines of the teeth T, which makes it possible to suppress an increase in magnetic resistance and a resulting decrease in motor torque.

[0025] In addition, the oil passage 4 has a turn portion 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 speed, the area of ​​the wall surface of the oil passage 4 that comes into contact with the oil passage 4 can be increased, improving the cooling performance. Furthermore, turbulence is also generated in the turn portion 42, improving the heat transfer coefficient and the cooling performance.

[0026] In addition, 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 faces, so they do not get in the way of the coil ends and mutual interference can be prevented.

[0027] In addition, the cooling oil 5 is introduced into the oil passage 4 in order from the oil holes 411 located on the inside in the radial direction D2. As a result, the cooling oil 5, which has a low temperature, can efficiently cool the inner parts of the teeth T, where the temperature of the steel plate P is high.

[0028] Furthermore, the outermost oil hole 413 in the radial direction D2 is formed outside the teeth T in the radial direction D2, and the oil holes 411 and 412 other than the oil hole 413 are formed in the teeth T. As a result, it is possible to suppress a reduction in the magnetic path and a resulting reduction in motor torque.

[0029] Furthermore, an inlet coil end cooling oil hole for cooling the coil end may be formed before the inlet of the oil passage 4. This makes it possible to cool the coil end and improve the insulation of the coil end.

[0030] Furthermore, an outlet coil end cooling oil hole for cooling the coil end may be formed after the outlet of the oil passage 4. This makes it possible to cool the coil end and improve the insulation of the coil end.

[0031] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0032] 1 Motor cooling device 2 Oil pan 3. Oil pump 4 Oil road 5 Cooling oil 41 Offset impact wall 42 Turn section 411, 412, 413 oil hole P steel plate S stator T Teeth

Claims

1. An oil passage that serves as a conduit for cooling oil is formed in a stator formed by laminating a plurality of steel plates, The oil holes formed in the plurality of steel plates are formed by overlapping in the stacking direction, A motor cooling device comprising an oil passage having an offset collision wall formed by overlapping the oil holes in a direction perpendicular to the stacking direction.

2. The oil hole is longer in a radial direction about the rotation axis of the rotor than in a circumferential direction perpendicular to the radial direction, The motor cooling device according to claim 1 , wherein the offset collision wall is formed by overlapping the oil holes with a deviation in the circumferential direction.

3. a plurality of oil holes are formed in the steel plate along a radial direction centered on a rotation axis of the rotor, The motor cooling device according to claim 1 , wherein the oil passage has a turn portion that turns back in the stacking direction.

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

5. The motor cooling device according to claim 3 , wherein the cooling oil is introduced into the oil passage in order from the oil holes located radially inward.

6. The stator has teeth protruding radially inward, the radially outermost oil hole is formed radially outward from the teeth, The motor cooling device according to claim 3 , wherein the oil holes other than the radially outermost oil holes are formed in the teeth.

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