JP2001190047A - Electric motor rotor cooling device - Google Patents

Abstract

[PROBLEMS] To provide an electric motor 1 and a rotor shaft 11 of the electric motor.
In the electric drive unit including the power transmission device 2 connected to the power transmission device, the rotor 12 of the electric motor can be efficiently cooled by the lubricating oil for the power transmission device. A cooling oil passage is formed in a yoke portion of a rotor. Casing 20 of power transmission device 2
An oil pump 3 for sucking lubricating oil from the inside is provided, and the lubricating oil from the oil pump 3 is supplied to a cooling oil passage 1 through an oil supply passage 4.
The lubricating oil supplied to the cooling oil passage 22 and passed through the cooling oil passage 122 is returned into the casing 20 via the return oil passage 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor cooling device for an electric motor used in an electric drive unit including an electric motor and a power transmission device connected to a rotor shaft of the electric motor.

[0002]

2. Description of the Related Art Conventionally, there has been known an electric drive unit of this type in which a water cooling jacket is formed in a motor housing of an electric motor, and the motor is cooled by a coolant flowing through the jacket.

[0003]

In the above-mentioned prior art, the stator mounted on the inner surface of the motor housing can be cooled, but the rotor of the electric motor cannot be cooled, which is a problem in increasing the output of the electric motor. I have.

[0004] In view of the above, it is an object of the present invention to provide a rotor cooling device capable of efficiently cooling a rotor of an electric motor using lubricating oil for a power transmission device.

[0005]

Means for Solving the Problems In order to solve the above problems,
The present invention relates to a rotor cooling device for an electric motor used for an electric drive unit including an electric motor and a power transmission device connected to a rotor shaft of the electric motor, the cooling device being provided on a yoke portion of a rotor of the electric motor. An oil passage, an oil pump that sucks up the lubricating oil in the casing of the power transmission device, an oil supply passage that supplies the lubricating oil from the oil pump to the cooling oil passage, and a lubricating oil that passes through the cooling oil passage into the casing. And a return oil passage.

According to the present invention, the lubricating oil in the casing of the power transmission device is circulated between the casing and the cooling oil passage through a path of an oil pump → an oil supply passage → a cooling oil passage → a return oil passage. Thus, the rotor can be efficiently cooled, and the output of the electric motor can be increased. In addition, since the lubricating oil is heated by heat exchange with the rotor when passing through the cooling oil passage, it is possible to raise the temperature of the lubricating oil at a low temperature at an early stage, and the friction of the power transmission device due to the viscosity of the lubricating oil is increased. Loss can be reduced.

[0007]

FIG. 1 shows an electric drive unit for a vehicle comprising an electric motor 1 and a power transmission device 2 for transmitting the power of the electric motor 1 to left and right wheels (not shown) of the vehicle. ing.

[0008] The power transmission device 2 includes a rotor shaft 11 of the electric motor 1 in a casing 20 connected to one end (left end in the illustrated example) of the motor housing 10 of the electric motor 1 in the axial direction.
, An input shaft 21 connected to the left end, a differential gear 22 disposed parallel to the input shaft 21, and a transmission mechanism 23 connecting the input shaft 21 and the differential gear 22. I have. The input shaft 21 is rotatably supported on the casing 20 via a bearing 210 at the left end, and is spline-fitted to the left end of the rotor shaft 11 at the right end.

The differential gear 22 includes a pair of left and right side gears 222, 222 in a gear case 221 that is supported in the casing 20 via bearings 220, 220 at both left and right ends.
And a plurality of pinions 223 meshing with both side gears 222, 222.
2, 222 are connected to constant velocity joints 224, 224 for transmitting power to the left and right wheels of the vehicle.

The transmission mechanism 23 includes an intermediate shaft 2 that is supported in the casing 20 via bearings 230 at the right and left ends.
31, a large-diameter first reduction gear 232 meshing with the input gear 211 formed on the input shaft 21, and a small-diameter second reduction gear 233 meshing with a final gear 225 attached to the gear case 221 of the differential gear 22. And a power reduction gear train provided with the input shaft 21.
, And is transmitted to the differential gear 22 at a reduced speed. The intermediate shaft 23
1 is provided with a parking gear 234 located between the first and second reduction gears 232 and 233.

The motor housing 10 has a peripheral wall 100
And end wall portions 101 and 102 at both left and right ends, and a bearing mounting hole 10 at the center of both end wall portions 101 and 102.
The rotor shaft 11 is supported by rotor bearings 110 and 111 mounted on 1a and 102a. As shown in FIG. 3, a plurality of permanent magnets 120 are provided on the rotor 12 on the rotor shaft 11.
Is attached, and the peripheral wall 1 of the motor housing 10 is mounted.
The armature coil 130 is mounted on the stator 13 on the inner surface of the motor 00 to form a permanent magnet type motor. Then, a water-cooled jacket 100a is formed on the peripheral wall portion 100, and the stator 13 can be cooled by a cooling liquid flowing through the jacket 100a.

In the permanent magnet motor, the temperature of the permanent magnet 120 rises due to the influence of the rotating magnetic field of the stator 13, and when the temperature reaches the demagnetization temperature, the electric motor 1
Output performance is lowered. Therefore, in the present embodiment, the yoke portion 121 of the rotor 12 composed of a large number of laminated plates
In addition, a cooling oil passage 122 extending in the axial direction is formed near each permanent magnet 120. Then, the oil pump 3 that sucks up the lubricating oil in the casing 20, the oil supply path 4 that supplies the lubricating oil from the oil pump 3 to the cooling oil path 122, and the lubricating oil that has passed through the cooling oil path 122 And a return oil passage 5 for returning the permanent magnet 120 to lubrication oil.

More specifically, as shown in FIG. 2, side plates 123 and 124 made of a cast product are attached to both right and left end surfaces of the rotor 12 so that both side plates 123 and 124 are attached to the rotor 12. Are fixed to the rotor 12 by fastening bolts 125 penetrating through the yoke portion 121, and the oil passages 123a, 124a radially formed in the side plates 123, 124 are communicated with the cooling oil passages 122. In addition, packings 123b and 124b are attached to joints of the outer circumferences of the side plates 123 and 124 with the rotor 12 in order to prevent oil leakage from between the cooling oil passage 122 and the oil passages 123a and 124a. I have.

At the right end of the rotor shaft 11, a sealing member 1 is provided.
An oil passage 112 in the shaft partitioned by 12a is formed. The oil passage 112 communicates with the oil passage 124a in the right end side plate 124, and communicates with the oil chamber 112 through the input shaft 21 and the rotor shaft 11. Refueling pipe 4a
And the discharge side of the oil pump 3 is connected to the oil supply pipe 4a. Thus, the refueling pipe 4a and the oil passage 112
And the oil passage 124a in the right end side plate 124 constitutes the oil supply passage 4. An oil seal 11 for sealing a gap between the rotor bearing 111 and a right end side plate 124 located axially inside the bearing mounting hole 102a of the right end wall portion 102 of the motor housing 10.
1a, and an oil seal 111b located outside the rotor bearing 111 in the axial direction.
An oil passage 124a in the side plate 124 communicates with a gap between the first oil passage 1 and the side plate 124, and the oil passage 1
12 also communicates with the gap between the rotor bearing 111 and the oil seal 111b. According to this, the oil passage 112
Is supplied to the oil passage 124a via the rotor bearing 111, and the rotor bearing 111 is lubricated with the lubricating oil.

Also, an oil passage 113 in the shaft is formed at the left end of the rotor shaft 11 by a seal member 113a.
This oil passage 113 communicates with an oil passage 123a in the left end side plate 123, and the oil passage 11
An axial oil passage 212 communicating with the third oil passage 3 is formed. Thus, the return oil passage 5 is constituted by the oil passage 123a, the oil passage 113, and the oil passage 212 in the left end side plate 123, and the final gear 225 and the second reduction gear 233 are formed from the oil passage 212.
The lubricating oil is supplied to the meshing portion of the bearing and the bearing 210. An oil seal 110a located axially inside the rotor bearing 110 is mounted in the bearing mounting hole 101a of the left end wall portion 101 of the motor housing 10, and a gap between the rotor bearing 110 and the oil seal 110a is provided. Oil passage 1 in the gap
13 are communicated. According to this, a part of the lubricating oil returned to the oil passage 113 is returned into the casing 20 via the rotor bearing 110, and the rotor bearing 110 is lubricated with the lubricating oil. In the figure, reference numeral 20a denotes an oil sump provided in an upper portion in the casing 20, and lubricating oil scooped up in the casing 20 receives an input including an engagement portion between the input gear 211 and the first reduction gear 232 via the oil sump 20a. The oil is supplied to a lubrication point around the shaft 21.

As described above, according to the present embodiment, the permanent magnet 120 of the rotor 12 can be efficiently cooled with the lubricating oil for the power transmission device 2, and the output of the electric motor 1 can be increased. The lubricating oil is heated by the heat from the permanent magnets 120, so that the temperature of the lubricating oil at a low temperature can be quickly raised, and the friction loss of the power transmission device 2 due to the viscosity of the lubricating oil can be reduced. Also, grease-enclosed bearings generally used as the rotor bearings 110 and 111 have a relatively low rotational use limit and are restricted in use in a high rotation range of the electric motor 1. By lubricating with lubricating oil, it can withstand use in a high rotation range.

FIG. 4 shows a second embodiment, and the same members as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, the oil passage 21 in the input shaft 21
2, the discharge side of the oil pump 3 is connected, and the oil passage 113 on the left end side in the rotor shaft 11 communicating with the oil passage 212 is communicated with the oil passage 123a in the left end side plate 123.
The oil passage 212, the oil passage 113, and the oil passage 123a constitute the oil supply passage 4. The oil passage 113 is also communicated with a gap between the left end rotor bearing 110 and an oil seal 110a axially inside the same, as in the first embodiment. Is supplied to the rotor bearing 110. Further, the right end side oil passage 112 in the rotor shaft 11 communicating with the oil passage 124a in the right end side plate 124 is communicated with a gap between the right end rotor bearing 111 and an axially outer oil seal 111b. Along with
An oil passage 102b is formed in a right end wall portion 102 of the motor housing 10 so as to communicate with the gap, and the oil passage 102b is formed in a peripheral wall portion 100 of the motor housing 10.
00b and the left end wall portion 101 of the motor housing 10.
And the oil passage 101b communicates with the inside of the casing 20 via the oil passage 101b.
02b, the oil passage 100b, and the oil passage 101b constitute the return oil passage 5. The water-cooled jacket 10 of the peripheral wall portion 100
0a is formed avoiding the portion where the oil passage 100b is formed.

Thus, also in the second embodiment, the permanent magnet 120 of the rotor 12 can be efficiently cooled with the lubricating oil for the power transmission device 2, and the lubricating oil can be quickly heated at a low temperature. The rotor bearings 110 and 111 can be lubricated with lubricating oil.

In the second embodiment, the rotor 12 is fixed on the rotor shaft 11 via a tubular member 126 mounted on the inner periphery of the rotor 12, and both ends of the tubular member 126 are caulked to form side plates at both ends. 123 and 124 are fixed to the rotor 12.

By the way, in both the first embodiment and the second embodiment, the oil pump 3 is
The motor 12 is electrically driven so that the rotor 12 can be cooled even when the vehicle is stopped. Note that the oil pump 3 may be always driven by the power from the input shaft 21 and may be driven by the motor 3a when the vehicle stops.

Further, in the above embodiment, the electric motor 1 is a permanent magnet type motor in which the permanent magnet 120 is mounted on the rotor 12, but a motor in which a field coil or an armature coil is mounted on the rotor, or a conductor is mounted on the rotor. The present invention can be similarly applied to a case where an induction motor to be mounted is used.

[0022]

As is apparent from the above description, according to the present invention, the rotor can be efficiently cooled by the lubricating oil for the power transmission device, and the output of the electric motor can be increased.
It is possible to raise the temperature of the lubricating oil at a low temperature at an early stage, thereby reducing the friction loss of the power transmission device due to the viscosity of the lubricating oil.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of an electric drive unit including the device of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of a rotor.

FIG. 3 is a cross-sectional view of the rotor cut along the line III-III in FIG. 2;

FIG. 4 is a longitudinal sectional view of a second embodiment of the electric drive unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 11 Rotor shaft 12 Rotor 121 Yoke part 122 Cooling oil path 2 Power transmission device 20 Casing 3 Oil pump 4 Oil supply path 5 Return oil path

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H609 BB19 PP01 PP02 PP05 PP06 PP07 PP08 PP10 QQ04 QQ05 QQ13 QQ18 QQ23 RR12 RR27 RR33 RR35 RR37 RR40 RR42 RR43 RR46 RR63 RR69 RR73

Claims (1)

[Claims] 1. A rotor cooling device for an electric motor used in an electric drive unit comprising an electric motor and a power transmission device connected to a rotor shaft of the electric motor, comprising: a cooling unit formed in a yoke of a rotor of the electric motor. Oil passage, an oil pump that sucks lubricating oil in the casing of the power transmission device, an oil supply passage that supplies lubricating oil from the oil pump to the cooling oil passage, and a lubricating oil that passes through the cooling oil passage inside the casing. And a return oil passage for returning to the rotor.