JPS63305030A - Drive force transmitting device for four-wheel drive car - Google Patents

Abstract

PURPOSE:To enable reduction of the weight of a device, by a method wherein an oil tank communicated to a differential pump and a hydraulic clutch is liquidtightly formed in a rotary housing. CONSTITUTION:A drive force transmitting device 20 comprises a rotary housing 21 and a rotary shaft 22 extended through the rotary housing 21 and rotatably pivotally supported. The device 20 includes a differential pump 23 actuated according to differential rotation between the rotary housing 21 and the rotary shaft 22 and a hydraulic clutch 24 actuated by means of pressure oil delivered from the differential pump 23. A space part in a hollow chamber 25 partitioned by an end cover 26 and a side plate 27 of the rotary housing 21 is formed as an oil tank 37 liquidtightly sealed by an oil seal 38 between the rotary housing 21 and the rotary shaft 22.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a four-wheel drive vehicle in which the rotational power of one of two drive shafts is transmitted to the other drive shaft via a hydraulic clutch. This invention relates to a force transmission device.

<Conventional technology> A four-wheel vehicle equipped with a hydraulic clutch for torque transmission and a differential pump that discharges oil according to the differential rotation of both drive shafts between the front drive shaft and the rear drive shaft. In a driving force transmission device for a drive vehicle, a housing and a rotating body connected to front and rear wheel drive shafts are rotatably supported at both ends of a fixed housing, and the inside of the fixed housing is configured as an oil tank. Pressure oil pumped up from an oil tank by a differential pump is supplied to a hydraulic clutch so that rotational power of one of the two drive shafts is transmitted to the other drive shaft.

<Problems to be Solved by the Invention> This type of driving force transmission device requires a fixed housing, which requires a large installation space, increases weight, and makes mounting difficult. There was also the problem of high costs.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned conventional problems, and includes a rotary housing coupled to one drive shaft,
A rotary shaft connected to the other drive shaft is rotatably supported in this rotary housing, and an oil tank communicating with a differential pump and a hydraulic clutch is formed in a fluid-tight manner within the rotary housing.

When the relative rotation speed of the two drive shafts is low and the amount of oil discharged from the differential pump is small, the pressure introduced into the oil chamber of the hydraulic clutch is low, but the relative rotation speed of the two drive shafts is low. When the number of pumps is high and the amount of oil discharged from the differential pump increases, the pressure introduced into the oil chamber of the hydraulic clutch also increases, and the rotational power of one of the two drive shafts drives the other through the hydraulic clutch. transmitted to the shaft.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 3, 10 is an engine, 11 is a transmission, 13 is a front wheel differential device, 14 is a rear wheel differential device, 15 is a front wheel drive shaft, 16 is a rear wheel drive shaft, 17 is a front wheel, 1 20 indicates a drive power transmission device installed between the front wheel drive shaft 15 and the rear wheel drive shaft 16. The output of the engine 0 is transmitted to the front wheel differential device 13 via the transmission 11. and drives the front wheels 17,
The rotation is transmitted to the front wheel drive shaft 15, and its rotation is transmitted to the rear wheel drive shaft 16 via the drive force transmission device 20, and the rotation is transmitted to the rear wheel drive shaft 16 through the drive force transmission device 20.
to drive.

As shown in FIG. 1, the driving force transmission device 20 includes a rotary housing 21, a rotary shaft 22 that extends vertically through the rotary housing 21 and is rotatably supported, and a rotary housing 21 and a rotary shaft 22. It is mainly composed of a differential pump 23 that is operated according to the differential rotation of the differential pump 23, and a hydraulic clutch 24 that is operated by the pressure oil discharged from the differential pump 23.

The front wheel drive shaft 1 is disposed at one end of the rotating housing 21.
A flange portion 15a formed at the shaft end of the rear wheel drive shaft 15 is integrally connected to the rotary shaft 22, and the rear wheel drive shaft 16 is spline-engaged within the rotating shaft 22.

A hollow chamber 25 is formed in the rotating housing 21 concentrically with the rotating shaft 22, and one end of the hollow chamber 25 is closed with an end cover 26. A side plate 27 is fitted into the hollow chamber 25, and a cam ring 28 is fitted and fixed between the side plate 27 and the side wall of the hollow chamber. Inside the cam ring 28 is a rotor 29 housing a vane 29a.
is accommodated, and this rotor 29 is spline engaged with the rotating shaft 22. On the other hand, a piston 30 is slidably fitted into the hollow chamber 25 on the back side of the side plate 27, and a plurality of separate plates 33 forming the hydraulic clutch 24 are connected between the piston 30 and the end cover 26. Friction plates 34 are arranged alternately. Thus, the separate plate 33 is attached to the inner circumference of the rotating housing 21, and the flexible plate 34 is attached to the rotating shaft 21.
are engaged with the outer peripheries of the two, and rotational torque is transmitted through frictional engagement between the two. An oil chamber 35 is formed between the piston 30 and the side plate 27, and both plates 33, 34 are inserted into this oil chamber 35 via the piston 21.
A bias torque spring 36 is inserted to press in the direction of frictional engagement. Further, oil discharged from the differential pump 23 is introduced into the oil chamber 35 as will be described later.

A space within the hollow chamber 25 divided by the end cover 26 and the side plate 27 is configured as an oil tank 37 that is liquid-tightly sealed between the rotation housing 21 and the rotation shaft 22 by an oil seal 38 or the like. , hydraulic oil is stored in this oil tank 37.

A pair of suction and discharge boats 41 and 41 are formed on the end wall of the rotary housing 21, and these suction and discharge boats 1-41
．． 41 communicates with a discharge passage 43 via a check valve 42. Further, the suction and discharge boats 41, 41 are communicated with the oil tank 37 via a check valve 44. As a result, when the rotor 29 is rotated forward or reverse relative to the cam ring 28, hydraulic oil is sucked from the oil tank 37 into one suction and discharge port 41 via the check valve 44, and from the other suction and discharge port 41 in the reverse direction. Hydraulic oil is discharged into the discharge passage 43 via the stop valve 42 . As shown in FIGS. 2 and 4, the discharge passage 43 has a valve hole 45 formed in the rotary housing 21.
The other end of this valve hole 45 communicates with the oil tank 37. A clutch pressure switching valve 47 is slidably fitted in the valve hole 45.
A throttle passage 48 is formed in 7, and both end chambers of the valve hole 45 communicate with each other via this throttle passage 48.

Two control passages 49.50 are opened in the valve hole 45, spaced apart in the sliding direction of the clutch pressure switching valve 47, and these control passages 49.50 communicate with the oil chamber 35 of the hydraulic clutch 24. Clutch pressure switching valve 47 is normally operated by spring 5.
1, one of the control passages 49 is pushed to the left in the figure, and in this state, one control passage 49 opens to the right end side of the valve hole 45.
is closed by the clutch pressure switching valve 47, and the oil chamber 35 of the hydraulic clutch 24 is communicated with the oil tank 37. However, due to the differential pressure before and after the throttle passage 48, the clutch pressure switching valve 45
When the valve is slid against the spring 51, the other control passage 50 opened on the left end side of the valve hole 45 is closed by the switching valve 47, and the oil chamber 35 of the hydraulic clutch 24 is connected to the discharge of the differential pump 23. communicated to the side.

Note that 53 indicates a pressure relief valve communicated with the discharge side of the differential pump 23, and the upper limit of the discharge pressure of the differential pump 23 is regulated by this pressure relief valve 53.

Next, the operation in the above configuration will be explained.

The rotational power of the engine 10 is transmitted to the front wheel differential device 13 via the transmission 11 to drive the front wheels 17, and is also transmitted to the front wheel drive shaft 15. The rotation transmitted to the front wheel drive shaft 15 is transmitted to the rotation housing 21, but in a state where the front wheel drive shaft 15 and the rear wheel drive shaft 16 are rotating almost integrally, the differential pump 2
3 does not operate, and no oil pressure is introduced into the oil chamber 35 of the hydraulic clutch 24. Therefore, the separate plate 33 and the friction plate 34 of the hydraulic clutch 24 are lightly (frictionally engaged) only by the spring force of the bias torque spring 36. Ru.

When the front wheel drive shaft 15 and the rear wheel drive shaft 16 rotate relative to each other, the differential pump 23 is activated and hydraulic oil is sucked from the oil tank 37. Pressure oil is discharged from the differential pump 23 in accordance with the differential rotation. This pressure oil is drained into the oil tank 37 via the throttle passage 48 of the clutch pressure switching valve 47, and a pressure corresponding to the outflow resistance due to the throttle passage 4 is generated on the discharge side of the differential pump 23. At this time, when the differential rotation is small and the discharge amount from the differential pump 23 is small, the differential pressure generated before and after the throttle passage 48 is small, so the clutch pressure switching valve 47 is slid by the spring force of the spring 51. It is held at the moving end. As a result, the oil chamber 35 of the hydraulic clutch 24 is communicated with the oil tank 37, so no oil pressure is generated in the oil chamber 35 while the differential rotation is small, which prevents tight corner braking when the car turns. It becomes like this.

However, when the differential rotation between the front drive shaft 15 and the rear drive shaft 16 increases due to wheel slip when driving on a low μ road, the amount of pressure oil discharged from the differential pump 23 increases, and accordingly. As a result, the differential pressure across the throttle passage 48 increases. When the differential pressure becomes larger than the spring force of the spring 51, the clutch pressure switching valve 47 is slid against the spring 51, switching the oil chamber 35 of the hydraulic clutch 24 to the discharge side of the differential pump 23. Therefore, the pressure in the oil chamber 35 of the hydraulic clutch 24 increases in accordance with the discharge amount of the differential pump 23, that is, the differential rotation between the front wheel drive shaft 15 and the rear wheel drive shaft 16, and 34 and is frictionally engaged with the rigid to control direct four-wheel drive. Therefore, stable driving can be achieved even when driving on a low μ road. FIG. 5 shows a change in the torque T transmitted between the front wheel drive shaft 15 and the rear wheel drive shaft 16 with respect to the differential rotation speed N between the two wheels.

<Effects of the Invention> As described above, the present invention rotatably supports a rotating shaft coupled to the other drive shaft in a rotating housing coupled to one of the two drive shafts, and a rotary shaft coupled to the other drive shaft is rotatably supported within the rotating housing. By forming the oil tank in a liquid-tight manner, the structure eliminates the need for a fixed housing, making it possible to reduce the weight of the drive power transmission device, as well as making it easy to mount as it does not take up much space.
Moreover, it has the effect of contributing to cost reduction.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a driving force transmission device for a four-wheel drive vehicle, and FIG.
3 is a schematic diagram of a four-wheel drive vehicle, FIG. 4 is a hydraulic system diagram, and FIG. 5 is a diagram showing the relationship between differential rotation speed and transmission torque. Work 5...Front wheel side drive shaft, 16...Rear wheel side drive shaft, 2
1... Rotating housing, 22... Rotating shaft, 23...
・Differential pump, 24... Hydraulic clutch, 30... Piston, 35... Oil chamber, 37... Oil tank. Figure 1 Figure 3

Claims (1)

[Claims] (1) A hydraulic clutch that transmits torque between the front drive shaft and the rear drive shaft, and a differential that discharges oil according to the differential rotation speed of the two drive shafts. Install a pump,
In a driving force transmission device for a four-wheel drive vehicle, the rotational power of one of the two drive shafts is transmitted to the other drive shaft by applying oil discharged from a differential pump to a hydraulic clutch, wherein the one A rotary housing is coupled to the drive shaft of the rotary housing, a rotary shaft coupled to the other drive shaft is rotatably supported on the rotary housing, and an oil tank communicating with the differential pump and the hydraulic clutch is arranged in the rotary housing. A driving force transmission device for a four-wheel drive vehicle that is densely formed.