JP7425023B2 - motor - Google Patents

Description

The present invention relates to a motor.

BACKGROUND ART Electric vehicles such as hybrid vehicles (HV) and electric vehicles (EV) are equipped with a motor as a driving source for driving. Permanent magnet synchronous motors (PMSM), which use permanent magnets that are ferromagnetic materials in their rotors, are widely used as motors.

When the motor is operating, heat is generated due to copper loss, iron loss, etc., so the motor needs to be cooled for continuous operation. An oil cooling method is used to cool the motor using oil (ATF: Automatic Transmission Fluid).

For example, a rotating shaft (rotor shaft) that is inserted through the center of the rotor has an axial oil passage and a radial oil that extends from the axial oil passage in the radial direction of the rotating shaft and is released on the circumferential surface of the rotating shaft. A road is formed. A rotor oil passage is formed in the rotor. The rotor oil passage is open at a position radially opposite to the open end of the radial oil passage on the inner circumferential surface of the rotor, and at a position close to the outer circumferential end on the end face of the rotor. By the action of the oil pump, oil collected at the bottom of the case housing the motor is supplied to the shaft oil passage, and the oil flows from the shaft oil passage to the radial oil passage. When the motor (rotor) rotates, centrifugal force causes oil flowing in the radial oil passage to be accepted into the rotor oil passage, oil to flow through the rotor oil passage, and oil to be discharged from the open end on the outer circumferential side of the rotor oil passage. Ru. The rotor is cooled by passing oil as a refrigerant through the rotor oil passage.

International Publication No. 2017/018067

However, in the conventional configuration, the pressure inside the rotor oil passage increases toward the outer circumferential side of the rotor, and there is a risk of oil leaking from the outer circumferential surface of the rotor, for example, between the rotor core and the end plate provided on the end surface of the rotor core. be. When oil leaks from the outer circumferential surface of the rotor, the oil enters the gap between the rotor and the stator, increasing drag resistance when the rotor rotates.

An object of the present invention is to provide a motor that can suppress leakage of refrigerant from the outer peripheral surface of the rotor.

In order to achieve the above object, a motor according to the present invention includes a rotor having a rotating shaft inserted through its center and rotatably provided integrally with the rotating shaft, and a stator surrounding the rotor. A refrigerant path through which refrigerant flows is provided between the inner circumferential portion and the outer circumferential portion, and the refrigerant path is provided with a non-filled portion in which the amount of refrigerant flowing out during rotation of the rotor is greater than the amount of refrigerant flowing in.

According to this configuration, a refrigerant path is provided between the inner circumference and the outer circumference of the rotor. As the refrigerant flows through the refrigerant path, heat exchange is performed between the rotor and the refrigerant, and the rotor is cooled.

A non-filled portion is provided in the refrigerant path. When the rotor is rotating, the amount of refrigerant flowing out from the unfilled portion is greater than the amount of refrigerant flowing into the unfilled portion, and the unfilled portion is not filled with refrigerant and a space is always created. Therefore, the influence of pressure from the part on the inner circumferential side (upstream side in the flow direction of the refrigerant) to the outer circumferential part can be blocked by the non-filled part, and the influence of pressure on the outer circumferential part from the non-filled part can be blocked. The increase in pressure can be suppressed. As a result, leakage of refrigerant from the outer peripheral surface of the rotor can be suppressed.

The refrigerant path includes a circumferential path extending in the circumferential direction of the rotor, an inner circumferential side path connected to the circumferential path and extending in the radial direction of the rotor on the inner circumferential side of the rotor with respect to the circumferential path, and a circumferential path. and an outer circumferential side passage connected to the circumferential passage and extending radially on the outer circumferential side of the rotor, and the connection point of the inner circumferential side passage and the connection point of the outer circumferential passage with respect to the circumferential passage are It may be shifted in the direction.

In this configuration, after the refrigerant flowing out from the inner circumferential side path flows in the circumferential direction in the circumferential direction, the refrigerant flows into the outer circumferential side path from the circumferential direction path. Since the refrigerant flows in the circumferential direction through the circumferential path, acceleration of the refrigerant in the radial direction due to centrifugal force is suppressed, and therefore it is possible to further suppress the pressure from increasing in the outer peripheral side than in the non-filled portion. As a result, leakage of refrigerant from the outer peripheral surface of the rotor can be further suppressed.

The refrigerant path may be provided with a small cross-sectional area having a smaller cross-sectional area than the unfilled part, adjacent to the unfilled part on the upstream side in the flow direction of the refrigerant.

As a result, when the rotor rotates, the amount of refrigerant flowing into the unfilled portion is greater than the amount of refrigerant flowing out from the unfilled portion, and it is possible to satisfactorily create a state in which the unfilled portion is not filled with refrigerant.

It is preferable that the unfilled portion is provided at the outermost side of the refrigerant path.

Thereby, it is possible to suppress the pressure at the outermost portion of the refrigerant path from increasing, and it is possible to effectively suppress leakage of the refrigerant from the outer peripheral surface of the rotor.

The refrigerant inlet that allows the refrigerant to flow into the refrigerant path is opened on the inner circumferential surface of the rotor, and the rotating shaft has an axial path that extends on the center axis and a radial path that extends from the axial path in the radial direction of the rotating shaft. A radial passage opened at a position radially opposite to the refrigerant inlet on the circumferential surface may be formed.

In this configuration, when the rotor and the rotating shaft are rotated together while the refrigerant is supplied to the axial path of the rotating shaft, the refrigerant flows from the axial path to the radial path due to centrifugal force. Oil flowing out from the open end is received at the refrigerant inlet of the rotor, and the refrigerant flows through the refrigerant path of the rotor. Therefore, the refrigerant can be well supplied to the refrigerant path.

According to the present invention, leakage of refrigerant from the outer peripheral surface of the rotor can be suppressed.

FIG. 1 is a sectional view of a motor according to an embodiment of the present invention. It is a figure showing the inner surface of the end plate of a rotor. FIG. 3 is a cross-sectional view of the rotor taken along the section line III-III shown in FIG. 2; FIG. 3 is a diagram showing the relationship between the rotation speed of the rotor 2 and the oil flow rate (ATF flow rate) at points A, B, C, D, and E.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<Motor>
FIG. 1 is a sectional view of a motor 1 according to an embodiment of the present invention.

The motor 1 is installed in an electric vehicle such as a hybrid vehicle or an electric vehicle as a driving source or generator for running. The motor 1 is a permanent magnet synchronous motor and includes a rotor 2 and a stator 3. The rotor 2 and stator 3 are housed in a case (not shown).

The rotor 2 includes a rotor core 11 formed by stacking a large number of annular electromagnetic steel plates, and end plates 12 that sandwich the rotor core 11 from both sides in the centerline direction. A rotor shaft 13 is inserted through the center of the rotor core 11 so that it cannot rotate relatively. The rotor shaft 13 is rotatably held in the case. Thereby, the rotor 2 is provided so as to be rotatable integrally with the rotor shaft 13 with the rotor shaft 13 as a fulcrum.

The stator 3 is provided around the rotor 2 and surrounds the rotor 2. The stator 3 includes a stator core 14 formed by stacking a large number of annular electromagnetic steel plates. The stator core 14 includes a cylindrical stator yoke having a width in the radial direction centered on the rotational axis of the rotor 2, and is provided at equal angular intervals inside the stator yoke, and extends from the inner peripheral surface of the stator yoke to the rotational axis of the rotor 2 ( The stator yoke has teeth extending toward the center line of the stator yoke. A coil is wound around the teeth.

<Oil channel configuration>
An axial oil passage 21 is formed on the center line of the rotor shaft 13 . Further, a plurality of radial oil passages 22 are formed in the rotor shaft 13 . The radial oil passage 22 extends from the axial oil passage 21 in the radial direction of the rotor shaft 13 and is open at the outer peripheral surface of the rotor shaft 13 .

FIG. 2 is a diagram showing the inner surface of the end plate 12 of the rotor 2. As shown in FIG. FIG. 3 is a cross-sectional view of the rotor 2 taken along the section line III--III shown in FIG.

As shown in FIG. 2, on the inner surface of the end plate 12 of the rotor 2 (the surface on the rotor core 11 side), a circular tubular groove (recess) centered on the rotation axis is provided in the radial center. It is formed as a channel 31.

Furthermore, on the inner surface of the end plate 12, a plurality of (for example, eight) inner circumferential oil passages 32 are formed radially at equal angular intervals around the rotation axis on the inner circumferential side with respect to the circumferential oil passage 31. ing. Each inner circumferential oil passage 32 is a groove extending in the radial direction, and one end is connected to the circumferential oil passage 31, and the other end is opened as an oil inlet 33 on the inner circumferential surface of the end plate 12. The same number of radial oil passages 22 of the rotor shaft 13 as the inner oil passages 32 are provided, and the open end of each inner oil passage 32 faces the open end of the radial oil passage 22 in the radial direction. .

Further, on the inner surface of the end plate 12, a plurality (eight, for example) of outer circumferential oil passages 34 are formed on the outer circumferential side with respect to the circumferential oil passage 31. One end of each outer circumferential oil passage 34 is arranged at equal angular intervals around the rotation axis, and is offset in the circumferential direction from the connection point between the inner circumferential oil passage 32 and the circumferential oil passage 31. Each outer circumferential oil passage 34 includes a first oil passage 35, which is a groove extending from the circumferential oil passage 31 to the outer circumferential side, and a first oil passage 35, which extends in the circumferential direction from the outer circumferential end of the first oil passage 35 to one side in the circumferential direction. The second oil passage 36 is a groove. The first oil passage 35 is inclined toward one side in the circumferential direction with respect to the radial direction, that is, the side on which the second oil passage 36 extends. The tip of the second oil passage 36 is bent radially outward and is opened via an oil outlet 37 that penetrates between the bottom surface of the second oil passage 36 and the outer surface of the end plate 12 (the surface opposite to the rotor core 11 side). There is.

The circumferential oil passage 31 has a groove width larger than the inner oil passage 32 and the outer oil passage 34 over its entire length, and the inner oil passage 32 and the outer oil passage 34 are approximately Each groove has the same width over its entire length. Further, the second oil passages 36 of the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34 have substantially the same groove depth, each having a constant groove depth over the entire length, and The first oil passage 35 of the side oil passage 34 has a groove depth smaller than that of the second oil passage 36 of the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34 over its entire length. Therefore, the first oil passage 35 has a smaller cross-sectional area than the circumferential oil passage 31, the inner circumferential oil passage 32, and the second oil passage 36 over its entire length.

<Oil distribution>
The motor 1 is arranged in a unit case together with a differential gear, and has the form of a transaxle. Furthermore, in electric vehicles, an oil cooling method is adopted in which the motor 1 is cooled with oil (ATF). An oil pump is housed in the unit case, and the oil collected at the bottom of the unit case is sucked up by the oil pump, and the sucked oil is supplied to the axial oil passage 21 of the rotor shaft 13. .

When the rotor 2 rotates, oil flows from the axial oil passage 21 to the radial oil passage 22 due to the action of the oil pump and centrifugal force, and is discharged from the open end of the radial oil passage 22. The oil discharged from the open end of the radial oil passage 22 is received by the open end of the inner oil passage 32 radially opposite to the open end, and due to centrifugal force, the oil is moved around the inner oil passage 32 in the circumferential direction. It flows toward the oil path 31. The oil flowing through the circumferential oil passage 31 flows into the outer oil passage 34 and is discharged from the oil outlet 37 to the outside in the rotational axis direction with respect to the end plate 12 through the outer oil passage 34. Oil passes through the inner oil passage 32, circumferential oil passage 31, and outer oil passage 34 between the inner surface of the end plate 12 and the rotor core 11, and at this time, heat exchange occurs between the rotor core 11 and the oil. By performing this, the rotor core 11 is cooled.

<Oil path flow rate>
FIG. 4 is a diagram showing the relationship between the rotational speed of the rotor 2 and the oil flow rate (ATF flow rate) at points A, B, C, D, and E.

While the rotor 2 is rotating, the ATF flow rate at a point A (see FIG. 1) in the axial oil passage 21 of the rotor shaft 13 is the largest. Further, in a range where the rotational speed of the rotor 2 is equal to or higher than a predetermined rotational speed R (rpm), the ATF flow rate at point E (see FIG. 2) in the oil outlet 37 is the next largest than the ATF flow rate at point A. The cross-sectional area of the first oil passage 35 of the outer oil passage 34 is smaller than the cross-sectional area of the circumferential oil passage 31, the inner oil passage 32, and the second oil passage 36 of the outer oil passage 34; Since the ATF flow rate is throttled at the first oil passage 35, which is the cross section, the ATF flow rate at point C (see FIG. 2) in the first oil passage 35 is lower than that at point B in the inner oil passage 32 and the second oil passage. less than the ATF flow rate at each point D in path 36. As a result, the inner oil passage 32 and the first oil passage 35 are filled with oil, and the second oil passage 36, where the amount of oil flowing out is greater than the amount of oil flowing in, is not filled with oil. , space is always occurring.

<Effect>
As described above, the rotor 2 of the motor 1 is provided with the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34 through which oil as a refrigerant flows. As the oil flows through the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34, heat exchange occurs between the rotor 2 (rotor core 11) and the oil, and the rotor 2 is cooled. Ru.

A second oil passage 36 is provided in the outer peripheral oil passage 34 . When the rotor 2 is rotating, the amount of oil flowing out from the second oil passage 36 is greater than the amount of oil flowing into the second oil passage 36, and the second oil passage 36 is not filled with oil, leaving a space. It's happening all the time. Therefore, the second oil passage 36 can block the influence of pressure from the inner circumference side (upstream side in the oil flow direction) to the outer circumference side of the second oil passage 36. It is possible to suppress an increase in pressure at a portion on the outer peripheral side. As a result, oil leakage from the outer peripheral surface of the rotor 2 can be suppressed.

The connection point of the inner circumferential oil passage 32 and the connection point of the outer circumferential oil passage 34 to the circumferential oil passage 31 are shifted in the circumferential direction. Therefore, after the oil flowing out from the inner circumferential oil passage 32 flows in the circumferential oil passage 31 in the circumferential direction, the oil flows from the circumferential oil passage 31 into the outer circumferential oil passage 34. Since the oil flows in the circumferential direction through the circumferential oil passage 31, acceleration of the oil in the radial direction due to centrifugal force is suppressed, so that it is possible to further suppress an increase in pressure in a portion on the outer circumferential side of the second oil passage 36. As a result, oil leakage from the outer peripheral surface of the rotor 2 can be further suppressed.

A first oil passage 35 having a smaller cross-sectional area than the second oil passage 36 is provided on the upstream side of the second oil passage 36 in the oil distribution direction. As a result, when the rotor 2 rotates, the amount of oil flowing into the second oil passage 36 is greater than the amount of oil flowing out from the second oil passage 36, and the second oil passage 36 is prevented from being filled with oil. can be caused to occur.

The second oil passage 36 which is not filled with oil is provided at the outermost side of the oil passage consisting of the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34. As a result, the pressure at the outermost portion of the oil passage can be suppressed from increasing, and leakage of oil from the outer circumferential surface of the rotor 2 can be effectively suppressed.

<Modified example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the embodiment described above, the depth of the groove of the first oil passage 35 of the outer circumferential oil passage 34 is constant over its entire length, and is smaller than the depth of the groove of the circumferential oil passage 31. However, the depth of the groove of the first oil passage 35 may become smaller toward the downstream side in the oil flow direction, and may be smaller than the depth of the groove of the circumferential oil passage 31 over its entire length. Further, the depth of the groove of the first oil passage 35 is the same as the depth of the groove of the circumferential oil passage 31, and the groove width of the first oil passage 35 is smaller than the groove width of the circumferential oil passage 31. The cross-sectional area of the first oil passage 35 of the outer circumferential oil passage 34 may be smaller than the cross-sectional area of the circumferential oil passage 31.

In addition, the second oil passage 36, which is a non-filled part, is provided at the outermost side of the oil passage consisting of the circumferential oil passage 31, the inner oil passage 32, and the outer oil passage 34. It may be provided in the middle of the oil passage.

In addition, various design changes can be made to the above-described configuration within the scope of the claims.

1: Motor 2: Rotor 3: Stator 31: Circumferential oil path (circumferential path)
32: Inner circumference side oil path (inner circumference side path)
34: Outer periphery side oil path (outer periphery side path)
35: First oil passage (small cross section)
36: Second oil passage (unfilled part)

Claims (1)

a rotor having a rotating shaft inserted through its center and rotatably provided integrally with the rotating shaft;
a stator surrounding the rotor;
The rotor includes a rotor core and end plates that sandwich the rotor core from both sides in the axial direction of the rotating shaft,
A refrigerant path through which refrigerant flows is provided on a surface of the end plate on the rotor core side ,
The refrigerant path is
a circumferential path extending in the circumferential direction of the rotor;
One end is connected to the circumferential path and extends in the radial direction of the rotor on the inner circumferential side of the rotor with respect to the circumferential path, and the other end is connected to the inner circumferential surface of the end plate to allow a coolant to flow when the rotor rotates. an inner circumferential side passage that is open as a refrigerant inlet to receive the refrigerant;
a first outer peripheral side path extending from the circumferential path to the outer peripheral side of the end plate;
a second outer periphery that extends in the circumferential direction from an end on the outer periphery side of the first outer periphery side passage to one side in the circumferential direction, and whose tip end is opened via a refrigerant outlet that discharges the refrigerant when the rotor rotates; having a side road;
The first outer peripheral side path has a smaller cross-sectional area than the circumferential path, the inner peripheral side path, and the second outer peripheral side path .

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