JPH1163162A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obviate a design change in output shafts, and restrain short a shaft directional dimension of a differential device which can transmit driving torque between the output shafts. SOLUTION: A differential device has a bevel gear type differential gear mechanism 17 to differentially distribute driving force of an engine inputted to a differential case 3 to respective output shafts 21 and 23 and first and second variable displacement oil pump/motors 51 and 53 arranged on first and second sub-shafts 35 and 37 respectively connected to the respective output shafts 21 and 23 through transmission mechanisms 45 and 47, and a suction port and a delivery port of the first oil pump/motor 51 are respectively connected to a delivery port and a suction port of the second oil pump/motor 53 through a passage 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a differential device capable of adjusting the distribution of driving force.

[0002]

2. Description of the Related Art As a conventional apparatus of this type, for example, an apparatus shown in FIG. 3 is described in Japanese Patent Application Laid-Open No. 63-125442.

[0003] In this device 401, left and right output shafts 405 and 407 of a differential mechanism 403 drive left and right wheels 405 and 407 via oil pumps / motors 409 and 411, respectively. If a driving resistance difference occurs between the wheels 413 and 415 during traveling, the oil pump / motor on the high-speed rotation side operates as a pump, and the oil pump / motor on the low-speed rotation side operates as a motor.

That is, for example, when the left wheel 413 slips on the road surface and the driving resistance (driving torque) decreases, the left wheel 413 rotates at a high speed by the action of the differential mechanism 403. At this time, the left oil pump / motor 409
Operate as a pump. Upon receiving the discharge oil pressure of the left oil pump / motor 409, the low-speed rotation side, that is, the right oil pump / motor 411 is driven.

Thus, even if the left wheel 413 slips and the driving torque is reduced, the right wheel 41 on the low-speed rotation side is driven.
5 is supplied with the drive torque by the above-mentioned discharge oil pressure and the torque for operating the left oil pump / motor 409, so that the traveling performance is improved.

[0006]

However, the left and right oil pumps / motors 409 and 411 have output shafts 405 and 40, respectively.
7, the output shafts 405 and 407 have to be greatly changed in design in order to install the oil pumps / motors 409 and 411.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to reduce the axial dimension of a differential device capable of transmitting drive torque between output shafts without requiring a design change of the output shaft.

[0008]

According to a first aspect of the present invention, there is provided a differential engine for differentially distributing an input driving force of an engine to output shafts arranged on both sides of a differential case. A dynamic gear mechanism, first and second countershafts respectively connected to the output shafts via transmission mechanisms, and first and second countershafts provided on the first and second countershafts, respectively. An oil pump / motor, wherein the suction port and the discharge port of the first oil pump / motor are respectively connected to the discharge port and the suction port of the second oil pump / motor via flow paths. It is characterized by.

Therefore, unlike the conventional example, since each oil pump / motor is not arranged on each output shaft, but is arranged on each sub shaft, a normal output shaft can be used as it is.
The axial dimension of the differential device can be reduced.

If a rotational speed difference occurs between the two output shafts, the oil pump / motor on one of the output shafts having the higher rotation speed becomes a pump and the oil pump / motor on the other side becomes a motor. The torque for driving the motor and the torque for driving the pump are transmitted to the low-speed output shaft by the discharge pressure, and the differential between the two output shafts, that is, the drive torque can be transmitted.

According to a second aspect of the present invention, in the differential device according to the first aspect, the first and second oil pumps / motors are arranged adjacent to one of the differential cases in an axially outer side. It is characterized by becoming.

Therefore, the same operation and effect as those of the first aspect of the invention can be obtained, and since both oil pumps / motors are arranged adjacent to each other, it is easy to form a flow path connecting them.

Further, it is easy to avoid interference with peripheral members.

According to a third aspect of the present invention, there is provided the differential device according to the first aspect, wherein the first and second countershafts are arranged substantially on the same axis, and the first and second oil shafts are arranged. A pump / motor is arranged adjacent to the opposing portion of the two countershafts.

Therefore, the same operation and effect as those of the first aspect of the invention can be obtained, and both oil pumps / motors can be arranged within a narrow range in the circumferential direction of the output shaft because both sub shafts are arranged substantially on the same axis. It is possible to dispose, and it is easy to avoid interference with peripheral members.

Further, since the two oil pumps / motors are arranged adjacent to each other, it is easy to form a flow path connecting the two oil pumps / motors.

A fourth aspect of the present invention is the differential device according to any one of the first to third aspects, wherein the first and second oil pumps / motors are both variable displacement oil pumps / motors. It is characterized by being.

Therefore, the same operation and effect as those of the first to third aspects of the invention can be obtained, and the capacity between the first and second oil pumps / motors can be varied by changing the capacity of the first and second oil pumps / motors. The drive torque can be positively transmitted.

That is, in addition to the differential-limited drive torque transmission from the high-speed output shaft to the low-speed output shaft, the oil pump / motor connected to the low-speed output shaft via a power transmission mechanism is also provided. By increasing the capacity (in this case, operating as a pump) and reducing the capacity of the oil pump / motor connected to the high-speed output shaft via a transmission mechanism (in this case, operating as a motor) ), It is possible to positively transmit the driving torque from the output shaft on the low rotation side to the output shaft on the high rotation side.

The displacement of the first and second oil pumps / motors is changed by an actuator according to the running state of the vehicle, and the attitude of the vehicle can be positively controlled by using the differential device of the present invention. The turning performance and running stability of the vehicle are improved.

A fifth aspect of the present invention is the differential device according to any one of the first to fourth aspects, wherein the differential gear mechanism is a bevel gear type differential gear mechanism.

Therefore, with a differential device using a bevel gear type differential gear mechanism, the same operation and effect as those of any of the first to fourth aspects of the invention can be obtained.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a skeleton diagram of a rear differential device (hereinafter abbreviated as a differential device) of the present embodiment.

The differential device 1 of this embodiment is rotatably supported in a differential carrier (not shown), and the differential carrier has an oil reservoir. A ring gear 5 is fixed to the differential case 3, and a drive pinion 7 meshing with the ring gear 5 is provided.
The driving force of the engine is input to the differential case 3 via the. In the differential case 3, a pinion gear 11 is rotatably supported on a pinion shaft 9, and the driving force is distributed to left and right output side gears 13 and 15 that mesh with the pinion gear 11. Thus, the differential gear mechanism 17 is configured.

Left and right output shafts 21 and 23 are respectively connected to the side gears 13 and 15, and a driving force is transmitted to the left and right rear wheels 25 and 27 via the output shafts 21 and 23. Gears 31 and 33 are fixed on the output shafts 21 and 23, respectively.
5, 37 are engaged with the gears 41, 43 fixed thereon. Transmission mechanisms 45 and 47 are constituted by these gears 31 and 41 and gears 33 and 43.

The first and second sub shafts 35 and 37 (hereinafter simply referred to as sub shafts 35 and 37) respectively have variable capacity first
And second oil pumps / motors 51 and 53 (hereinafter simply referred to as pumps / motors 51 and 53). Each housing (not shown) of the pump / motor 51, 53 is fixed to a differential carrier on the vehicle body side (fixed system). Each rotor of the pump / motor 51, 53 is
5,37. Pump / motor 51, 53
Each of the housings can be displaced by an actuator such as an electric motor to adjust and change the internal capacity of the pump / motors 51 and 53. In the present embodiment, details of the pumps / motors 51 and 53 are not shown, but the pumps / motors 51 and 53 are axial-plunger type oil pumps / motors. The oil capacity is made variable by adjusting. The plunger and the cylinder (rotor) are connected to the respective countershafts 35 and 37, and the swash plate is installed on the housing side so that the inclination can be adjusted.

The suction ports (not shown) of the pumps / motors 51 and 53 and the discharge ports (not shown) on the other side are connected by a hydraulic flow path (flow path) 55. Hydraulic flow path 5
5 is a closed circuit as a circulation channel.

Next, the operation of the differential device 1 will be described.

When the vehicle is traveling straight, both pumps / motors 51,
Since the change in volume of 53 is zero, suction and discharge hydraulic pressures are not generated, and the driving force of the engine is equally distributed to the left and right rear wheels 25, 27.

That is, the swash plates of both pumps / motors 51 and 53 are in an upright state with respect to the axis of both sub shafts 35 and 37, and the inclination angles of both the swash plates are 0 degrees. Therefore, there is no capacity difference between the two pumps / motors 51 and 53 (no suction and discharge operations are performed), and both the sub shafts 35 and 37 are idle.

When the swash plates of both pumps / motors 51 and 53 are adjusted to have the same swash plate inclination angle and 180 degrees out of phase, the capacities of both pump / motors 51 and 53 become equal and one of the two pumps / motors 51 and 53 becomes the same. The discharge stroke on one side is synchronized with the suction stroke on the other side. If a difference in rotation occurs between the left and right rear wheels 25, 27 in this state, for example, if the left rear wheel 25 slips on the road surface and the driving torque decreases, the driving torque of the right rear wheel that does not slip with a normal differential device is Although the drive torque is equal to the reduced drive torque of the left rear wheel that has slipped, in the differential device 1, the pump / motor 51 that is connected via the transmission mechanism 45 to the left rear wheel 25 that has become high-speed due to the slip is transmitted.
Is larger than the suction amount of the pump / motor 53 connected to the right rear wheel 27 (low rotation side), the pump / motor 51 on the left rear wheel 25 acts as a pump, and the right rear wheel The pump / motor 53 on the 27 side acts as a motor.

At this time, the discharge amount of the pump 51 and the motor 5
A discharge hydraulic pressure is generated in accordance with the difference between the intake hydraulic pressure and the suction pressure of No. 3 and the drive torque of the motor 53 by the discharge hydraulic pressure is transmitted to the right rear wheel 27 (low rotation side). At the same time, the pump 51 on the left rear wheel 25 side
Is distributed to the right rear wheel 27 by the differential gear mechanism 17. Thus, the driving torque of the right rear wheel 27 increases, and the traveling performance is improved.

Conversely, when the right rear wheel 27 slips, the roles of the pumps / motors 51 and 53 are reversed.

On the other hand, when positive drive torque transmission is performed, the inclination angle of only one of the swash plates of both pump / motors 51 and 53 is reduced from the same state. That is, the stroke of the plunger is reduced to reduce the capacity of the pump / motor.

When the right rear wheel 27 of the left and right rear wheels 25 and 27 rotates rapidly (the vehicle makes a left turn), the right rear wheel 27
When the inclination angle of the swash plate of the pump / motor 53 on the left side is reduced, the capacity of the pump / motor 51 on the left rear wheel 25 side becomes larger, so that the pump / motor 51 functions as a pump and the pump / motor 53 functions as a motor. I do.

Therefore, more driving torque can be transmitted to the right rear wheel 27 on the outer wheel side, and the yaw moment in the turning direction is applied to the vehicle to control the vehicle attitude and improve the left turning performance.

Conversely, in the case of a right turn, the pump / motor 51 on the outer side of the turn is made to have a smaller swash plate inclination angle, and the roles of the pumps / motors 51 and 53 are reversed. The performance is improved.

The two pumps / motors 5 of the present embodiment
1, for example, when a spare tire house (not shown) is arranged at the lower part of the trunk of the vehicle behind the differential device 1 (below in FIG. 1), the right side of the tire house This is a part that can avoid interference with the space part, and can also avoid interference with a muffler disposed on the left side of the differential gear mechanism 17.

Thus, according to the present embodiment, the pump /
Since the motors 51 and 53 are not disposed on the output shafts 21 and 23, there is no need to change the design of the output shaft, and the axial size of the differential device can be reduced.

Since the pumps / motors 51 and 53 are disposed adjacent to each other, the length of the hydraulic passage 55 can be reduced, and the operation response of the pumps / motors 51 and 53 is good.

Also, pump / motors 51, 5 of variable capacity
3, the driving torque can be positively transmitted from the differentially limited driving torque transmission to the vehicle attitude control.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a skeleton diagram of a rear differential device (hereinafter abbreviated as a differential device) of the present embodiment.

The differential device of the present embodiment differs from the first embodiment in the location of the oil pump / motor, and is otherwise the same. Therefore, this difference will be described, and redundant description will be omitted.

In the differential device 101 of this embodiment, the gear 1
Transmission mechanisms 145 and 147 are constituted by 31, 141 and gears 133 and 143. And the first and second
Are arranged coaxially, and the first and second
Oil pumps / motors 51 and 53 (hereinafter simply referred to as pumps / motors)
Motors 51 and 53) are disposed adjacent to the opposing portions of the countershafts 135 and 137.

The two pumps / motors 5 of the present embodiment
The arrangement parts 1 and 53 in FIG. 2 are parts that can avoid interference with a spare tire house (not shown), for example, when the spare tire house (not shown) is arranged in another part, not below the trunk of the vehicle.

Thus, according to the present embodiment, the first
The same operation and effect as those of the embodiment can be obtained, and the length of both the countershafts 135 and 137 can be reduced.

The variable displacement oil pump / motor is not limited to the axial plunger type as described above, but may be a radial plunger type or a vane type.

Further, since the oil pump / motor involves a leakage loss, it is conceivable to provide a reservoir passage and a reservoir tank for replenishing oil.

[0049]

As is apparent from the above description, according to the first aspect of the present invention, unlike the conventional example, the first and second oil pumps / motors are not disposed on each output shaft. In addition, since they are arranged on the first and second countershafts, respectively, the ordinary output shaft can be used as it is, and the axial dimension of the differential device can be reduced.

In the case where a rotational speed difference occurs between the two output shafts, the oil pump / motor on one of the output shafts having a higher rotation speed becomes a pump and the oil pump / motor on the other side becomes a motor. The torque for driving the motor and the torque for driving the pump are transmitted to the low-speed output shaft by the discharge pressure, and the differential between the two output shafts, that is, the drive torque can be transmitted.

In particular, when the differential device according to the first aspect is used between the left and right wheels, a normal output shaft can be used, so that the suspension stroke of each wheel can be sufficiently secured as usual.

According to the invention described in claim 2, according to claim 1
The same effect as that of the first invention can be obtained, and since the first and second oil pumps / motors are arranged adjacent to each other, it is easy to form a flow path connecting them.

Further, the flow path resistance is reduced because the flow path is easily formed, and the response of the driving force transmission is improved.

Further, it becomes easy to avoid interference with peripheral members such as a spare tire arrangement space, suspension-related members, and a vehicle frame.

According to the third aspect of the present invention, the first aspect is provided.
The same effect as that of the invention can be obtained, and the two oil pumps / motors can be arranged in a narrow range in the circumferential direction of the output shaft because both sub shafts are arranged substantially on the same axis. It is easy to avoid interference with peripheral members such as a vehicle frame and a spare tire space.

Further, since the two oil pumps / motors are arranged adjacent to each other, it is easy to form a flow path connecting the two oil pumps / motors.

Further, the flow path resistance is reduced because the flow path is easily formed, and the response of driving force transmission is improved.

According to the invention set forth in claim 4, according to claim 1
The same effect as any one of the inventions of (1) to (3) is obtained,
Since the first and second oil pumps / motors are of variable displacement types, the operation of changing the capacity of each oil pump / motor in accordance with the running state of the vehicle is performed, whereby the differentially limited drive torque transmission between output shafts is performed. In addition, for example, the driving torque can be positively transmitted to, for example, the necessary wheels according to the traveling state of the vehicle. In this way, the vehicle attitude can be positively controlled, and the turning performance and running stability of the vehicle are improved.

According to the fifth aspect of the present invention, there is provided a differential device using a bevel gear type differential gear mechanism.
The same effect as any of the first to fourth aspects of the invention can be obtained.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of a first embodiment.

FIG. 2 is a skeleton diagram of a second embodiment.

FIG. 3 is a skeleton diagram of a conventional example.

[Explanation of symbols]

3 Differential case 11 Pinion gear 13, 15 Side gear 17 Differential gear mechanism 21, 23 Output shaft 25, 27 Rear wheel 31, 33, 41, 43, 131, 133, 141, 1
43 gear 35,135 first sub shaft 37,137 second sub shaft 45,47,145,147 transmission mechanism 51 first oil pump / motor (variable displacement oil pump / motor) 53 second oil Pump / motor (variable displacement oil pump / motor) 55 Hydraulic flow path (flow path)

Claims (5)

[Claims] 1. A differential gear mechanism for differentially distributing an input driving force of an engine to output shafts disposed on both sides of a differential case, and a first gear connected to each of the output shafts via a transmission mechanism. , A second countershaft, and first and second oil pumps / motors provided on the first and second countershafts, respectively. A differential device characterized in that an outlet is connected to a discharge port and a suction port of a second oil pump / motor via respective flow paths. 2. The differential device according to claim 1, wherein the first and second oil pumps / motors are arranged adjacent to one of the differential cases in an axially outer side. Differential device. 3. The differential device according to claim 1, wherein said first and second countershafts are arranged substantially on the same axis, and said first and second oil pumps / motors are connected to said two countershafts. A differential device, which is arranged adjacent to a shaft opposing portion. 4. The differential device according to claim 1, wherein said first and second oil pumps / motors are both variable displacement oil pumps / motors. Differential device. 5. The differential device according to claim 1, wherein the differential gear mechanism is a bevel gear type differential gear mechanism.