JPH0898464A - Hydraulic circuit of driver for electric automobile - Google Patents

Abstract

PURPOSE: To ensure sufficient quantity of motor cooling oil during high speed rotation by setting an appropriate quantity of lubricant in the torque transmission means of a driver for electric automobile where a motor is combined with the torque transmission means. CONSTITUTION: A driver 1 comprises a motor 2, means 3, 4 for transmitting the output torque from the motor 2 to driving wheels 9, an oil pump 5, a driving means 8 for the oil pump 5, a delivery circuit 71 being fed with oil delivered from the oil pump 5, and a lubrication circuit 72 coupled through a restrictor 74 with the delivery circuit 71 in order to introduce the oil to the torque transmission means 3, 4. The driver 1 further comprises a cooling circuit 73 coupled through a restrictor 75 with the delivery circuit 75 in order to introduce the oil to the motor 2, and a valve 76 for feeding the oil from the delivery circuit 71 to the cooling circuit 73 when the hydraulic pressure of the delivery circuit 71 exceeds a predetermined level. Since the valve 76 regulates the pressure to sustain a constant oil supply to the lubrication circuit 72 even during high speed rotation, oil supply to the cooling circuit 73 is increased as the r.p.m. increases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit used in an electric vehicle, and more particularly to a hydraulic circuit for lubricating and cooling the drive unit.

[0002]

2. Description of the Related Art Conventionally, as one type of drive device for an electric vehicle, there has been a combination of a motor and torque transmission means for transmitting output torque of the motor to drive wheels. In the drive device for an electric vehicle of the type described above, a hydraulic circuit that serves both lubrication and cooling is provided in order to lubricate each part of the torque transmission means and particularly to cool the motor at medium and high speeds. As such a hydraulic circuit, U.S. Pat. No. 4,418,777 discloses that oil discharged from an electric oil pump is once guided to a support portion through an oil passage in a case wall, and then divided to be divided there to form each portion of a torque transmission means. There is disclosed a hydraulic circuit for supplying a predetermined amount to a lubrication circuit for lubricating the motor and a cooling circuit for cooling the coil of the motor.

[0003]

By the way, in the above apparatus, it is sufficient to secure a certain amount of lubricating oil, and it is preferable to do so in order to prevent an increase in rotational resistance due to agitation of oil. On the other hand, the cooling oil amount needs to be increased with respect to the increase in the heat generation amount of the motor. However, in the hydraulic circuit having the above configuration, when the amount of oil discharged from the oil pump increases, the amount of oil supplied to the lubricating circuit and the cooling circuit also increases in proportion to each. Therefore, the mode
When a large amount of oil is required for cooling the motor, if the amount of oil discharged from the oil pump is increased accordingly, not only the amount of cooling oil for the motor but also the amount of lubricating oil for the torque transmission means increases, and the lubricating circuit Will be supplied with much more oil than is needed. The driving force for discharging the excess amount of oil causes a driving loss of the oil pump.

Therefore, according to the present invention, only the cooling oil amount of the motor is increased along with the increase of the discharge oil amount of the oil pump, thereby eliminating the consumption of the unnecessary lubricating oil amount to drive the oil pump. An object of the present invention is to provide a hydraulic circuit of a drive device for an electric vehicle, which is capable of efficiently cooling a motor while reducing loss.

[0005]

To achieve the above object, the present invention provides a motor, torque transmitting means for transmitting the output torque of the motor to a drive wheel, an oil pump, and the oil. A drive circuit for rotationally driving the pump, a discharge circuit to which the oil discharged from the oil pump is supplied, and a lubrication circuit connected to the discharge circuit via first throttle means and for guiding the oil to the torque transmission means. And a cooling circuit connected to the discharge circuit through a second throttle means for guiding oil to the motor, and when the hydraulic pressure of the discharge circuit becomes equal to or higher than a predetermined pressure, the cooling circuit is discharged from the discharge circuit. And a valve for supplying oil to. The drive means may be second torque transmission means for transmitting the output torque of the motor to the oil pump.

[0006]

In the hydraulic circuit configured as described above, when the amount of oil discharged from the oil pump is small, the lubricating oil is supplied to the torque transmitting means by the pump, the discharge circuit,
The first throttle means and the lubrication circuit are used to supply the cooling oil to the motor, and the pump, the discharge circuit, the second throttle means and the cooling circuit are used to supply the cooling oil. On the other hand, when the amount of oil discharged from the oil pump is large, the lubricating oil is supplied to the torque transmitting means and the cooling oil is supplied to the motor. For the supply of
When the hydraulic pressure of the discharge circuit becomes higher than a predetermined pressure, the valve opens and the surplus oil of the discharge circuit is supplied to the cooling circuit.Therefore, the supply of cooling oil that follows the route of the pump, the discharge circuit, the valve and the cooling circuit. Is added.

Thus, according to the hydraulic circuit of the present invention, when the hydraulic pressure in the discharge circuit becomes equal to or higher than the predetermined pressure, the valve opens and the surplus oil in the discharge circuit is supplied to the cooling circuit. The amount of oil is kept constant regardless of the amount of oil, and a constant amount of oil from the lubricating circuit is supplied to the torque transmitting means via the first throttle means. On the other hand, since the oil supplied to the cooling circuit via the valve is an excess of the oil supplied from the discharge circuit to the lubricating circuit, a large amount of oil is generated when the heat generation amount of the motor increases. The required amount of cooling oil for the motor can be supplemented with surplus oil in the discharge circuit. Therefore, an unnecessary amount of oil is not supplied to the torque transmission means, and an extra drive loss of the oil pump can be reduced accordingly. Moreover, the amount of cooling oil for the motor can be increased as compared with the discharge amount of the oil pump by using the excess oil for cooling the motor, and as a result, the purpose of cooling the motor and lubricating the torque transmission means can be increased. It is possible to reliably secure the amount of oil according to.

A second means for transmitting the output torque of the motor to the oil pump by the drive means for rotationally driving the oil pump.
When the torque transmission means is used, the oil pump can be rotationally driven by the output torque of the motor, and the electric vehicle drive device can have a simple configuration. further,
Since the running resistance of the vehicle increases as the vehicle speed increases,
In an electric vehicle, the motor frequently produces a large output as the vehicle speed increases, and the average heat value of the motor also increases as the vehicle speed increases. By rotating the oil pump, the amount of oil discharged from the oil pump can be increased in accordance with the increase in vehicle speed, and the cooling oil amount in the motor can be increased in accordance with the increase in vehicle speed, and cooling can be performed efficiently. You can Further, since the oil pump can be driven to rotate without consuming electric power when the motor is driven, the amount of lubricating oil to the torque transmitting means and the amount of cooling oil to the motor can be reliably secured even when the motor is driven. be able to.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments. As conceptually shown in FIG. 1, an electric vehicle drive device 1 according to the present invention includes a motor 2 and torque transmission means 3, 4 for transmitting output torque of the motor 2 to drive wheels 9.
An oil pump 5, a drive means 8 for rotationally driving the oil pump 5, a discharge circuit 71 to which the oil discharged from the oil pump 5 is supplied, and a connection to the discharge circuit 71 via a first throttle means 74. The lubricating circuit 72 that guides oil to the torque transmitting means 3 and 4 and the second throttle means 75 in the discharge circuit 71.
And a cooling circuit 73 for guiding oil to the motor 2
And a valve 76 for supplying oil from the discharge circuit 71 to the cooling circuit 73 when the hydraulic pressure of the discharge circuit 71 exceeds a predetermined pressure.
It has and.

As the driving means 8 shown in the figure, the oil pump 5 may be rotationally driven by the second torque transmitting means 81 to 85 which rotationally drive the oil pump 5 by the motor 2, or may be separately driven by the oil pump. And a control means for controlling the motor are provided to detect the torque command value of the motor, the vehicle speed of the electric vehicle, the temperature of the coil end, the oil temperature, etc., and when the torque command value of the motor is large, the The oil pump driving motor may be controlled to increase the amount of oil discharged from the oil pump 5 when the vehicle speed is high, the coil end temperature is high, and the oil temperature is high.

Next, each of these parts will be described in more detail with reference to the more specific drawings. As shown in the cross section in FIG. 2, the electric vehicle drive device 1 includes a case 1 divided into a motor case 10m and a gear case 10g.
Stator 21 fixed to the 0m motor case 10m side
And a rotor 22 arranged radially inside the stator 21.
And a pair of ball bearings 16 and 18 which are spline-connected to the rotor 22 and support radial and thrust forces.
A motor 2 having a rotor shaft 23 rotatably supported by the motor case 10m and a rotor shaft 23 coaxially arranged on the gear case 10g side, and constituting torque transmitting means for decelerating and outputting the rotation of the motor 2. Planetary gear 3
In this example, the output of the planetary gear 3 is transmitted through the rotor shaft 23, and the other is directly transmitted to the left and right drive wheels of the vehicle.
It consists of and.

The planetary gear 3 is composed of a sun gear 31 connected to the rotor shaft 23 and a ring gear 32 fixed to the gear case 10g so as to allow radial play.
And a carrier 34 that is rotatably supported by a support on the side of the motor case 10m, rotatably supports a pinion 33 that meshes with the sun gear 31 and the ring gear 32, and is coupled to the differential device 4. The sun gear 31 is the rotor shaft 2
3, the end portions of which are in contact with each other, and are connected to each other by a spline fitting by a sleeve 81.

The differential gear 4 is a pair of differential gears arranged in a differential gear case 40 which is composed of a portion integrated with the carrier 34 of the planetary gear 3 and a separate bolted portion. A large gear 41 and a plurality of differential small gears 43 meshing with these and loosely fitted on a differential small gear shaft 42 pinned to the differential case 40 (only one of which is shown in the figure).
And one of the outputs of the differential device 4 is passed through the rotor shaft 23 through the shaft hole of the one differential large gear 41.
The end portion of the drive shaft 11 that transmits to one drive wheel via a (shown by an imaginary line) is spline-fitted and snap ring-fastened, and the differential large gear 41 has a differential in its shaft hole. A yoke shaft 12b, which also functions as a drive shaft for directly transmitting the other output of the device 4 to the other drive wheel, is spline-fitted and snap ring-fastened. The shaft portion formed on one portion of the differential gear case 40 has a ball bearing 15
The other part, which is supported by the support part of the outer end wall of the gear case 10g via the carrier and is integrated with the carrier 34, has a shaft part formed on the carrier 34 through the ball bearing 13 and a support part on the side of the motor case 10m. Supported by.

In FIG. 2, reference numeral 19 indicates a connecting sleeve for spline-connecting the drive shaft 11 to the yoke shaft 12a. The outer periphery of the sleeve 19 is connected to the outer end of the motor case 10m via a ball bearing 17. Is supported by the lid, and the outer circumference of the inner end side is supported by the inner circumference of the rotor shaft 23 via the needle bearing 20.
Further, reference numeral 101 is an oil pan of an oil sump for collecting lubrication and cooling oil in the drive device, 24 is a power cable for supplying three-phase AC power to the motor 2, and 5 is a case 10 for lubrication and cooling oil of each part of the drive device. An oil pump geared to the sleeve 81 of the parking gear 82 to circulate in the interior of the engine, 6 a resolver connected to the oil pump shaft to detect the rotational position of the rotor 22, and 7 an oil strainer and a relief valve type valve. A valve body incorporating 76, a parking gear 82, and a motor case 10
The cooling fins are formed in a large number on the outer peripheral surface of m and allow the heat of the motor to escape directly to the atmosphere.

Particularly in this example, since the second torque transmitting means for transmitting the output torque of the motor 2 to the oil pump 5 is used as the driving means 8, the driving means 8 is formed at the end of the sleeve 81. Gear 83 meshing with the outer peripheral teeth 811 and a small diameter gear 8 meshing with the driven gear 85 which is superposed on the gear 83 and integrally formed with the oil pump shaft.
And a second torque transmission means composed of an intermediate gear consisting of 4 and 4. The intermediate gears 83 and 84 have one end supported by the center support of the motor case 10m and the other end supported by the oil pump housing.

In the electric vehicle drive device 1 configured as described above, the rotation of the rotor 22 of the motor 2 is caused by the rotation of the rotor shaft 2.
3 is transmitted to the sun gear 31 by utilizing the sleeve 81 of the parking gear 82 as a connecting means. The rotation transmitted to the sun gear 31 is taken out to the carrier 34 as the revolution of the pinion 33 that takes a reaction force of the rotation to the ring gear 32 fixed to the gear case 10g to rotate, and the differential case 40 integrated with it is rotated. . Differential case 4
The rotation of 0 passes through the differential small gear shaft 42 and the differential small gear 43 loosely fitted thereto, and is the rotation of the drive shaft 11 spline-fitted from the large differential gear 41 on one side, and the differential on the other side. The yoke shaft 12b, which is spline-fitted through the large gear 41, is rotated, and finally transmitted to the left and right driving wheels (not shown) to be used as the driving force of the vehicle.

FIG. 3 shows the hydraulic circuit of the drive system 1 for the electric vehicle in an undeveloped part which does not clearly appear in FIG. 2, and a valve body 7 having the strainer and the valve 76 built in is provided below the gear case 10g. Is installed.
The valve body 7 and the oil pump 5 are connected by a suction circuit 70 and a discharge circuit 71. In this example, the discharge circuit 71 is divided into three branches in the valve body 7 as shown in FIG. 4, and the first oil passage 71a is provided with an orifice which constitutes the first throttle means 74. The downstream side of the orifice is the first lubricating oil passage 72a. This oil passage 72a passes through the inside of the end wall of the gear case 10g, reaches the shaft of the differential gear case 40 at the support portion, and from there, 2
One of the branches branches to the inside of the pinion support shaft 341 of the carrier 34 through the oil passage in the case wall of the differential case 40,
It terminates in a radial oil hole in the shaft. The other is the yoke shaft 12
It opens in the differential gear case 40 through the oil passage in b, and further ends in two oil holes 112 and 113 in the radial direction via the oil passage 111 in the drive shaft 11.

The second oil passage 71b, which is branched into three in the valve body 7, is provided with an orifice constituting the second throttle means 75, and the downstream side of the orifice is shown in FIG. 4 in this example. As described above, it is branched into two, and one side serves as the second lubricating oil passage 72b. This oil passage 72b is shown in FIG.
As shown in FIG. 6, it passes through the peripheral wall of the motor case 10m, is squeezed by the third squeezing means 78 in the lid, that is, an orifice, and reaches the support portion of the lid on the outer end side of the motor case 10m. And the rotor shaft 23 are opened and terminated. The other circuit with two branches is
In this example, the cooling circuit 73 is configured, and is connected to one of the pair of nozzle blocks 107a mounted on the upper part of the motor case 10m via the connection pipe 73p arranged in the motor case 10m shown in FIG. The nozzle blocks 107a and 107b are connected by an oil passage 73c at the top of the motor case 10m. Each of the nozzle blocks 107a and 107b is formed with a large number of fourth throttle means 79a and 79b functioning as nozzles directed to the coil 211 of the stator 21 of the motor 2.

As shown in FIG. 4, in the third oil passage 71c which is branched into three in the valve body, in this embodiment, when the hydraulic pressure of the discharge circuit 71, that is, the primary pressure becomes a predetermined pressure or more, a spring load is applied. A direct-acting relief valve type valve 76, which opens the valve against the pressure and releases the oil from the discharge circuit 71 to the cooling circuit 73, is interposed. The secondary side, that is, the discharge side, of the valve is a branch circuit 77. Is connected to the second lubricating oil passage 72b and the cooling circuit 73.

Thus, according to the driving device of the above embodiment,
The oil sucked up by the pump 5 through the strainer 70s once returns to the valve body 7 through the discharge circuit 71, and then reaches the oil passage branched into three as described above. The flow rate of the oil in the first oil passage 71a is regulated by the orifice 74, reaches the shaft support portion on the end wall side of the gear case 10g, and passes through the oil groove of the support portion of the differential case 40 to the gear case 10g, One passes between the yoke shaft 12b and the shaft portion of the differential gear case 40, and is guided from an oil hole in the wall of the differential gear case 40 to the oil passage 341 in the pinion support shaft of the carrier 34.
This oil is discharged from a radial oil hole continuing to the oil passage 341 to lubricate the needle bearing and the thrust washer. On the other hand, the oil that has entered the oil passage in the yoke shaft 12b reaches the inside of the differential gear case 40 and meshes with the differential gear, the sliding surface between the differential gear 41 and the differential gear case 40, and the differential gear. Lubricate the spline fitting portion between the large gear 41 and the drive shaft 11 and the yoke shaft 12b, the sliding surface between the differential small gear 43, the differential small gear shaft 42, and the differential device case, and further drive the drive shaft 1
The oil is discharged from the radial oil holes 112 and 113 through the oil passage 111 in the No. 1, and the meshing surface of the sun gear 31 and the pinion 33, the bearing 14 and the ball bearing 13, and the sleeve 81 connect the rotor shaft 23 and the sun gear 31. The spline fitting portion, the ball bearing 18, the spline fitting portion of the drive shaft 11 and the sleeve 19, the needle bearing 20 and the like are lubricated. The oil that has been lubricated scatters in the case, travels down the case wall, flows down to the lowermost portion, and is eventually collected in the oil sump.

The flow rate of the oil entering the second oil passage 71b is regulated by the third throttle means 78 and flows to the support portion constituted by the lid on the outer end side of the motor case 10m, and the ball bearing 16 and the ball. After lubricating the bearing 17, etc., it also travels down the case wall, flows down to the lowermost part thereof, and is eventually collected in the oil sump.

On the other hand, the oil that has entered the cooling circuit 73 passes through the connecting pipe 73p and the nozzle block 107a,
It reaches 107 b, and is sprayed onto the coil 211 of the stator 21 from a large number of nozzle holes provided in the block.
Similarly, after cooling the coil 211, this oil also flows down to the lowermost portion thereof directly or along the case wall and is collected in the oil reservoir through the opening below the support portion of the motor case 10m.

FIG. 7 shows the distribution of the oil distributed to the respective parts with respect to the oil pump discharge flow rate. The discharge flow rate naturally rises in proportion to the vehicle speed which reflects the rotation speed of the motor, but is shown in FIG. The amount of oil supplied to the first lubricating oil passage 72a (indicated as "lubrication 1" in the figure) is made constant by the relief action of the valve 76 of the hydraulic pressure of the discharge circuit 71, and the first throttle means 7
Since the absolute amount is regulated by No. 4, it does not increase at a vehicle speed exceeding the relief pressure (the bending point of the line showing the flow rate in the figure hits this). On the other hand, the second lubricating oil passage 7
The amount of oil supplied to 2b (indicated as lubrication 2 in the figure) is finally regulated by the third throttle means 78, but a circuit between the second throttle means 75 and the third throttle means 78. Along with the increase in the secondary pressure supplied via the valve 76, the pressure slightly increases as the vehicle speed increases. On the other hand, the cooling circuit 7
The amount of oil supplied to No. 3 is the remainder of the discharge flow rate that increases in proportion to the vehicle speed, and therefore increases as the vehicle speed increases. Thus, according to the circuit of the above embodiment, the amount of oil supplied to the lubrication circuit 72 becomes substantially constant regardless of changes in vehicle speed.
Any excess oil produced by doing so can be used for cooling. As a result, it becomes possible to avoid an increase in the rotational resistance of the torque transmission means due to excessive supply to the lubrication circuit, which is conventionally required. On the other hand, by supplying the cooling circuit with the amount of oil that was conventionally supplied to the lubricating circuit more than necessary,
When viewed as the entire flow rate, the drive loss of the oil pump can be reduced by the amount of surplus oil.

In summary, in the hydraulic circuit of the above embodiment, the oil circulating through the device by the oil pump 5 is optimally distributed by the orifice for lubrication and coil cooling respectively, and the pressure of the valve 76 is adjusted. The amount of oil distributed to lubrication by the action is made constant regardless of the speed, and the rest is used for coil cooling. Further, in this example, fins 102 are provided on the motor case 10m to improve cooling efficiency. This prevents a rapid increase in temperature due to the heat capacity of the motor body, fins, etc. at low speeds and high loads, and at the time of medium and high speeds, the cooling oil is injected to the coil as much as possible to eliminate the local temperature rise. Cooling can be performed efficiently.

Although the present invention has been described above based on the embodiments, the present invention is not limited to this structure, and the specifics of each part are appropriately specified within the scope of the claims. It can be implemented by changing various configurations.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of a drive device for an electric vehicle having a hydraulic circuit structure of the present invention.

FIG. 2 is a sectional view of a drive device for an electric vehicle according to an embodiment of the present invention.

FIG. 3 is a circuit connection diagram showing a connection relationship in which a hydraulic circuit in the electric vehicle drive device is partially developed.

FIG. 4 is a circuit diagram showing a part of a hydraulic circuit according to an embodiment of the present invention.

FIG. 5 is a view taken in the direction of arrows VV in FIG. 2;

6 is a VI-VI arrow view of FIG. 2. FIG.

FIG. 7 is a graph showing the relationship between the vehicle speed and the oil pump discharge flow rate in the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric vehicle drive device 2 Motor 3 Planetary gear (torque transmission means) 4 Differential device (torque transmission means) 5 Oil pump 8 Drive means 9 Drive wheel 71 Discharge circuit 72 Lubricating circuit 73 Cooling circuit 74 First throttle means 75 Second throttle means 76 Valve

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[Procedure amendment]

[Submission date] October 3, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. A motor, a torque transmitting means for transmitting an output torque of the motor to a drive wheel, an oil pump, a driving means for rotationally driving the oil pump, and a discharge from the oil pump. A discharge circuit to which oil is supplied, a lubrication circuit connected to the discharge circuit via a first throttle means, and guiding oil to the torque transmission means, and a discharge circuit connected to the discharge circuit via a second throttle means. An electric circuit comprising a cooling circuit for guiding oil to the motor, and a valve for supplying oil from the discharge circuit to the cooling circuit when the hydraulic pressure of the discharge circuit exceeds a predetermined pressure. Hydraulic circuit for automobile drive unit. 2. The hydraulic circuit for a drive device for an electric vehicle according to claim 1, wherein the drive means is second torque transmission means for transmitting the output torque of the motor to the oil pump.