JPH05122903A - Electric automobile driving apparatus - Google Patents

Abstract

PURPOSE:To cover a wide range of running conditions with a motor having a low rated output and realize a light weight and small size motor by changing quantity of circulating oil in accordance with heat generation of motor, keeping adequae quantity of oil for cooling a motor coil and effectively cooling the coil according to the output conditions of motor. CONSTITUTION:A driving apparatus is of an in-board type comprising a motor 1, a deceleration unit 2 coupled with the motor 1 and a case 3 for accommodating these elements. For the purpose of cooling the motor 1, an oil circulating means 6 consisting of an oil path and an oil pump 61 provided at the outside and inside of the case 3 and a cooling means 7 for cooling the circulating oil through the heat exchange. The oil circulating means 6 is provided with an oil pump motor 6A for changing quantity of circulating oil in accordance with heat generation of motor 1. Usually, the oil pump 61 is gear-driven for the oil circulation and the driving method is switched to the drive by the oil pump motor 6A in such a case that oil temperature is high but the number of rotations of motor 1 is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive system for an electric vehicle, and more particularly to a structure for cooling the motor of the drive system.

[0002]

2. Description of the Related Art Electric vehicles have attracted attention from the viewpoint of pollution prevention to prevent air pollution due to exhaust gas, and various development studies have been conducted. The drive system of a vehicle has a large load change depending on running conditions such as constant speed running, sudden start, and climbing, and it is necessary to generate torque according to these, but in an electric vehicle powered by a motor, the current supplied is Since the torque is adjusted depending on the size of the coil, the amount of heat generated by the coil increases when the current is large. In order to keep this heat generation amount properly even under heavy load and to prevent the temperature rise of the drive unit, it is sufficient to use a motor with a large rated output corresponding to it, but doing so makes the motor large and heavy, making it practical. Cannot be a driving device with good performance. Therefore, a motor having an appropriate rated output is selected in consideration of such a load fluctuation and a heat generation amount.

By the way, in electric vehicles, how to extend the mileage is a current issue. To this end, it is indispensable to reduce the size and weight of the power supply as well as the size of the drive unit. .. Therefore, conventionally, it has been proposed to cool a small motor with circulating oil to efficiently suppress heat generation of the coil when overloaded. In this proposal, a structure is adopted in which oil is circulated by driving an oil pump by a dedicated motor separately provided and cooled by heat exchange with the outside air.

[0004]

However, in the above-mentioned prior art, in order to secure the circulating oil amount at the time of heavy load, the oil pump motor must have a considerably large output, and the pump is constantly pumped. Must be driven, resulting in higher power consumption. Further, since the oil is cooled by heat exchange with the outside air, it is difficult to exert a sufficient cooling effect when the vehicle runs at low speed or is stopped.

In view of such circumstances, the present invention enables efficient coil cooling according to the output condition of the motor,
It is an object of the present invention to provide a drive device for an electric vehicle in which the motor has a small size and a light weight by enabling a small motor having a relatively low rated output to support a wide range of traveling conditions.

[0006]

In order to solve the above-mentioned problems, the present invention provides a motor comprising a rotor and a stator, a case for housing the motor, and an oil circulates in the case to cool the motor. In a drive device for an electric vehicle, comprising: an oil circulation means for causing the oil to circulate and a cooling means for cooling the circulating oil by heat exchange, the oil circulation means changes an oil circulation amount according to heat generation of the motor. It is configured to include means.

Further, the present invention is a drive for an electric vehicle comprising a motor comprising a rotor and a stator, a case for accommodating the motor, and an oil circulating means for circulating oil to cool the motor in the case. In the apparatus, the oil circulation means is an oil pump having two drive means mechanically connected to the motor and drive means capable of changing an oil circulation amount according to heat generation of the motor. Is configured.

[0008]

In the electric vehicle drive apparatus according to the present invention having such a structure, the oil circulation means includes the circulation amount changing means for changing the oil circulation amount according to the heat generation of the motor. The amount of oil that cools the motor is always kept proper by the operation of the means, and efficient coil cooling according to the output condition of the motor becomes possible.

Particularly, when the oil circulating means is provided with a mechanical driving means, reliable and reliable lubrication can be ensured in the speed reducer and the bearing, and the coil can be appropriately cooled by the oil pump motor. Together with this, a more reliable cooling effect can be achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the first embodiment shown in the drawings. As shown in the cross section of FIG. 1, the drive device of this example is an inboard type drive device including a motor 1, a speed reducer 2 composed of a planetary gear drivingly connected to the motor 1, and a case 3 for housing them. Has been done. As a configuration for cooling the motor 1, an oil circulating means 6 including an oil passage provided inside and outside the case 3 and an oil pump 61, and a cooling means 7 for cooling the circulating oil by heat exchange (see FIG. 1). 2) showing the II-II cross section), and the oil circulation means 6 is provided with a circulation amount changing means 6A for changing the oil circulation amount according to the heat generation of the motor 1.

Further, the configuration of each part will be described in detail. The case 3 includes a center case 3a and two side cases 3b.
The center case 3a has a partition wall 31 at the center thereof.
It is divided into two by two, and two motor accommodating chambers 32a are provided on both sides thereof.
Are formed. Openings 33 at both ends of the center case 3a
The side case 3b that closes a includes a motor housing chamber 31b connected to the motor housing chamber 32a, a speed reducer chamber 32b that houses the speed reducer 2, and a shaft through hole 33b through which the output shaft 21 of the speed reducer 2 is inserted. ing. The rotary shaft 12 that supports the rotor 11 of the motor 1 has its inner end side supported by the partition wall 31a of the center case 3a via a ball bearing, and its outer end side in the shaft through hole 33b of the side case 3b. Also, the output shaft 21 of the reduction gear transmission 2 supported via the roller bearing is supported via the roller bearing.

As shown in FIGS. 1 and 3, the upper peripheral surface of the case 3 is a double wall, and the space surrounded by the outer wall and the inner wall constitutes an oil passage chamber 34 above the case. A circulation oil intake hole 35 is provided at the center of the uppermost part of the peripheral surface. The case 3 has a double wall extending from the one side lower peripheral surface to the side peripheral surface, and the lower portion of the outer wall is a horizontal wall slightly inclined outward, and the space surrounded by the inner and outer walls is located below the case. The oil sump 36 is configured. Partition wall 31a
Is cut out at its lower part so that the two chambers communicate with each other. An opening 37 (see FIG. 2) is provided in a side portion of the oil sump 36, that is, a vertical wall portion of the outer wall.

As shown in the sectional view of FIG.
A finned plate 7A that constitutes a cooling means so as to close the opening 37 is bolted together with the cover 3c to the outer wall of the outer wall of the plate with the cover 3c on the outer side thereof.
The finned plate 7A is a plate portion 7 that closes the opening 37.
A plurality of parallel fins 72 and 73 extending horizontally from 1 to the inside and outside of the case are provided. With this arrangement, the water cooling chamber 74 is defined between the plate 71 and the cover 3c. Reference numeral 75 indicates a drain plug.

The motor 1 is composed of a rotor 11 and a stator 13. The rotor 11 is fixed to the rotating shaft 12, a rotor body 11a part of which is spline-fitted to the outer periphery of the rotor body 11 and fixed to the outer periphery thereof, and the outer periphery thereof. And a permanent magnet 11b that has been formed. The stator 13 is composed of a core 13a and coils 13b projecting on both sides in the axial direction. Teeth forming the sun gear 22 of the speed reducer 2 are formed on the reduced diameter peripheral surface of the rotating shaft 12. Therefore,
In this example, the rotating shaft 12 also serves as a motor shaft and a sun gear 22 of a planetary gear.

The speed reducer 2 is provided with a pinion gear 23 that meshes with the sun gear 22 on the outer periphery thereof, and a ring gear 24 that meshes with the outer periphery of the pinion gear 23 internally. Ring gear 24 is case 3
It is supported by a peripheral wall of b by spline fitting to prevent rotation, and is snapped in a snap ring. The pinion shaft 25 that supports the pinion gear 23 is fixed to a carrier 26 that is integral with the output shaft 21. The shaft circumference of the output shaft 21 is case 3b through a ball bearing and a roller bearing.
It is supported on the inner circumference of the shaft through hole 33b.

The shaft end of the constant velocity joint 4 is fitted in the hollow stepped hole of the output shaft 21 by a spline coupling so as to prevent rotation. Axial circumference of constant velocity joint 4 and shaft through hole 3 of case 3b
The inner circumference of 3b is sealed with an oil seal.

In this drive device, the phase sensor 5 is provided so as to be supported by the case 3b. The phase sensor 5 is composed of a resolver driven by the rotation of a spur gear 51 that meshes with a spur gear 14 fixed to the circumference of a rotary shaft 12 via a shaft 53 supported by ball bearings 52a and 52b. .. The resolver body is attached to the outside of the case 3b. The oil circulating means 6 meshes with the spur gear 51, and the roller bearing 65 and the thrust washer 66.
A pump shaft 64 connected to the rotary shaft 12 via a spur gear 62 supported by a and 66b and a one-way clutch 63, and the pump shaft 64 constitutes a circulation amount changing means attached to the outside of the case 3b. It is also connected to the oil pump motor 6A. The oil discharged from the pump 61 passes through the oil passage formed in the case and the external pipe, and becomes upward when mounted on the vehicle. The oil passage chamber 34 and the oil passages 38, 40, It is supplied to each part such as the speed reducer 2 via 41, and finally collected in an oil sump 36 formed by the outer wall of the case 3.

In the drive device according to the above embodiment, the motor 1
Rotation of the rotor 11 is input to the reduction gear 2 from the sun gear 22 that is integral with the rotation shaft 12, and the reduced rotation of the carrier 26 due to the revolution of the pinion gear 23 that uses the ring gear 24 as a reaction force is output to the output shaft 21 that is integral with it. It is transmitted to the wheel via the quick joint 4. Due to the rotation of the rotary shaft 12, the rotation of the spur gear 14 fixed to the rotary shaft 12 via the rotor 11 is transmitted to the oil pump shaft 64 via the spur gear 51 of the phase sensor 5 and the pump shaft gear 62.
By engaging the one-way clutch 63, the oil pump 61
Rotates at a speed according to the rotation of the motor 1.

The oil discharged by the rotation of the pump 61 is supplied to the oil passage chamber 34 from the hole 35 at the top of the case through a pipe (not shown) arranged outside the case, passes through the oil holes 39a and 39b, and is coiled. Run down to 13b. The oil that has flowed down flows circumferentially and downward along the guide walls 31c and 32c of the case 3, falls below the case while being heated by heat exchange with the coil 13b, and finally collects in the oil sump 36 via the notch. To be done. It should be noted that part of the oil passes through an oil passage (not shown) formed in the case to the oil passage 41, and also via the oil passage 38, the other oil passage 4 is formed.
0, is applied to lubrication of the speed reducer 2 and each bearing portion, and is similarly collected in the oil sump 36.

The oil returned to the oil sump 36 comes into contact with the cooling fins 73 arranged therein, and when flowing toward the suction port 68 of the oil pump 61, the cooling fins 73 cooled by the fluid on the outside Heat is exchanged between the two and they are sufficiently cooled before being sucked. Oil is pumped from the suction port 68 through the strainer 67 to the pump 6
1, and the above cycle is repeated.

Normally, the oil circulation is performed by the gear drive as described above, but when the oil temperature is high and the motor 1 is stopped, such as when the vehicle suddenly stops, the oil pump as a circulation amount changing means. The motor 6A is operated. At this time, the spur gear 62 is separated from the pump shaft 64 by the operation of the one-way clutch 63. It should be noted that control of the operation timing and the number of revolutions of the oil pump motor 6A is not particularly disclosed, but the number of revolutions may be controlled according to the oil temperature by a detection signal of an oil temperature sensor, for example.
An increase in oil temperature may be predicted and controlled in advance according to the output status of the motor 1, and the operation time may be constant,
It may be necessary.

Next, a second embodiment of the present invention will be described with reference to FIG. 4, which schematically shows the construction thereof. This example is based on the first
In order to reduce the drag loss of the oil pump motor 6A when the circulation amount changing means of the embodiment is not in operation or at a rotation speed lower than the gear side input, the configuration of that portion is changed so that the oil pump motor 6A and the oil pump 61 are separated from each other. In addition, a one-way clutch 69 is additionally provided. With this arrangement, the oil pump motor 6A is driven when the gear 62 is driven.
Since the rotor of is separated from the pump shaft 64, the pump drive loss can be further reduced.

FIG. 4 shows a third embodiment of the present invention.
In this example, the heat exchange surfaces of the finned plate 7A are intertwined with each other. By doing so, the heat exchange area per space can be increased, and the cooling effect can be further improved. The shape of the cooling fins is not limited to these, and may be of any configuration as long as it allows the oil flowing down in the case to flow into the pump suction port.

Although the present invention has been described in detail based on the three embodiments, the specific configurations of the respective portions can be modified as mentioned in the respective relevant portions, and further within the scope of the claims. It can be changed appropriately.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view of a case of the first embodiment.

FIG. 4 is a schematic side view showing a second embodiment in which the circulation amount changing means is modified.

FIG. 5 is a sectional view of a portion similar to FIG. 2, showing a third embodiment in which the cooling fin portion is changed.

[Explanation of symbols]

 1 Motor 3 Case 6 Oil Circulation Means 6A Oil Pump Motor (Circulation Amount Change Means) 7 Cooling Means 11 Rotor 61 Oil Pump

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[Procedure amendment]

[Submission date] November 12, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 4]

[Figure 1]

[Figure 3]

[Figure 5]

Claims (2)

[Claims] 1. A motor comprising a rotor and a stator, a case for housing the motor, an oil circulating means for circulating oil to cool the motor in the case, and a cooling for cooling the circulating oil by heat exchange. In the driving apparatus for an electric vehicle, the oil circulating means includes a circulation amount changing means for changing an oil circulation amount according to heat generation of the motor. 2. A drive device for an electric vehicle, comprising: a motor composed of a rotor and a stator; a case accommodating the motor; and an oil circulating means for circulating oil in the case to cool the motor. The oil circulation means is an oil pump having two drive means mechanically connected to the motor and drive means capable of changing the oil circulation amount according to heat generation of the motor. Drive system for electric vehicles.