JPH03292423A - Viscous coupling - Google Patents

Abstract

PURPOSE:To secure speedy response at the time of transmission characteristic adjustment and reduce necessary operating force by installing the first plate which is engaged with one transmission member and the second plate which is engaged in shiftable manner in the axial direction with the other transmission member and deflected by a pressing means, in a working chamber filled with a viscous fluid. CONSTITUTION:A working chamber 45 filled with silicone oil having high viscosity is formed between a housing 23 and a pressing member 39, and the first and second plates 53 and 55 are accommodated in the working chamber 45. The first plate 53 is arranged in the spline groove 57 of a hub 25 in which the second plate 55 which is arranged in crossing with the inner periphery of the housing 23 is spline-fitted on a transmission shaft 27. Further, a flexible part 63 in the axial direction is formed of a slit 61 on the outer peripheral side of the plate 55, and the flexible part 63 is pressing-deflected through a pressing member 39 and a projection part 65 by the shift of the piston 73 of an actuator 79. Accordingly, the speedy response in the torque transmission characteristic adjustment can be obtained, and the necessary operation force can be reduced, and the dimension of the actuator 79 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a viscous coupling that transmits torque via a viscous fluid.

(Prior art) ``Liquid friction clutch'' is disclosed in Japanese Patent Application Laid-Open No. 61-65918.
is listed. This is a viscous coupling that transmits torque by using shear resistance of viscous fluid between plates that are individually engaged with a pair of transmission members.

(Problem to be Solved by the Invention) A disc spring is disposed between the plates, and when the plate is pressed in the axial direction by a pressing body, the disc spring is bent, all the plates move, and the spacing between the plates becomes narrower. Furthermore, when the pressing force is reduced, the plate spacing increases due to the biasing force of the disc spring. In this way, the torque transmission characteristics can be changed.

However, when moving in the axial direction, the plate receives great resistance from the viscous fluid. Poor response when adjusting characteristics.

Furthermore, since a large pressing force is required, the pressing means becomes large-sized.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a viscous coupling that has a quick response when adjusting torque transmission characteristics and requires a small operating force (pressing force) at that time.

[Structure of the Invention] (Means for Solving the Problems) The viscous coupling of the present invention includes a pair of transmission members arranged so as to be relatively rotatable, a working chamber in which a viscous fluid is sealed, and one side in the working chamber. A first plate that engages with a transmission member, and a first plate that is arranged alternately with this plate and engages with the other transmission member so as to be able to move in the axial direction, and deflects in the axial direction ζ under the pressure force, causing adjacent slits to move in the same direction. The present invention is characterized in that it includes a second plate having a flexible portion that opens, and a pressing means that bends the flexible portion via a pressing force transmission system.

(Function) When the flexible part is bent by the pressing means, the suri-soto is opened and a large amount of viscous fluid circulates, which applies thrust force to the flexible part, moves the second plate, and moves the first plate. The distance from the plate changes and the torque transmission characteristics change.

In this way, since the plate is smoothly moved by the thrust force, the response of torque transmission characteristic adjustment is quick and the required pressing force is small.

(Example) One embodiment will be explained with reference to FIGS. 1 to 5.

FIG. 5 shows the power system of a 4WD vehicle using this embodiment.

Hereinafter, the left and right directions are the left and right directions in FIG. 1, and the left side corresponds to the front of this vehicle (the upper part of FIG. 5). Note that members not numbered are not illustrated.

First, the configuration of the power system of this vehicle will be explained with reference to FIG. This power system consists of engine 1, transmission 3,
Front differential 5 (front wheel side differential device), left and right front wheels 7, 9, transfer 11, viscous coupling 13 of the example, propeller shaft 15, rear differential 1
7 (differential device on the rear wheel side), left and right rear wheels 19
．． It consists of 21 etc.

Next, the structure of the viscous coupling 13 will be explained with reference to FIGS. 1 to 4.

The housing 23 (one transmission member) and the hub 25 (the other transmission member) are arranged to be relatively rotatable. hub 25
is spline-fitted to the transmission shaft 27, and a bearing 29 is disposed between the housing 23 and the transmission shaft 27. In order to fix this bearing 29 in the axial direction, a washer 31 and a lock nut 33 are attached to the transmission shaft 27, and a retaining ring 35 is attached to the /XX ring 47.

The housing 23 is flange-connected to the transfer 11 side by bolts screwed into bolt holes 37, and the housing 23 is connected to the transfer shaft 27 by a flange.
is connected to the propeller shaft 15 side.

Between the inner periphery of the housing 23 and the outer periphery of the transmission shaft 27, three pressing members are disposed so as to be movable in the axial direction and relatively rotatable. A seal 43 is arranged.

A working chamber 45 is formed between the housing 23, the tube 25, and the pressing member 39, and this working chamber 45 is filled with high-viscosity silicone oil (viscous fluid). There is an X between the housing 23 and the /
Rings 47, 49 (seals having an X-shaped cross section) are arranged, and an O-ring 51 is arranged between the hub 25 and the member 39 to keep the working chamber 45 liquid-tight.

Inside the working chamber 45, first and second plates 53 and 55 are arranged alternately, with the first plate 53
The plates 55 of the clause 2 are spline connected to the outer circumference of the hub 25, respectively.

As shown in FIG. 2, a spline groove 57 for connecting a plate 55 is provided on the outer periphery of the hub 25. or,
As shown in FIG. 3, the plate 55 is provided with spline teeth 59 that engage with the groove 57, and an axially flexible portion 63 is formed by a hook-shaped slit 61 on the outer peripheral side of the spline tooth 59. There is. As shown in FIGS. 1 and 4, protrusions 65 are provided on the left side of the flexible portion 63, and each protrusion 65 abuts the rear side of the protrusion 65 of the left plate 55. A similar protrusion 67 is also provided at the left end of the pressing member 39. Note that 68 is a stopper and 70 is a return spring.

On the right side of the housing 23, a ring-shaped cylinder member 69 fixed to the vehicle body side is arranged coaxially with the transmission shaft 27. A bearing 71 is arranged between the member 69 and the transmission shaft 27. A piston 73 is fitted into the cylinder member 69 so as to be movable in the axial direction, and the sliding portion of the member 69.73 is kept liquid-tight by O-rings 75.77. In this way, a hydraulic actuator 79 (pressing means) is configured.

Hydraulic pressure is supplied to the actuator 79 from a hydraulic source via a control valve device and a hydraulic boat 81.

The piston 73 is connected to the pressing member 39 via a bearing 83. When hydraulic pressure is supplied, actuator 7
9 presses each flexible portion 63 to the left via the pressing member 39 and the projection 65 of each plate 55 to bend it. The actuator 79 can be operated manually from the driver's seat or automatically depending on steering conditions and road surface conditions.

In this way, the viscous coupling 13 is constructed.

Next, the function of the viscous coupling 13 will be explained.

When the housing 23 rotates due to the driving force from the engine 1, this rotation is transmitted from the plate 53 to the plate 55 due to the shear resistance of the silicone oil, causing the hub 25 to rotate. At this time, if the rotational difference between the housing 23 and the hub 25 is large, the differential limiting force will be strong and a large torque will be transmitted, and if this rotational difference is small, the differential will be allowed and the transmitted torque will be small.

When no pressing force is applied from the actuator 79,
As shown in FIG. 1(b), the second plate 55 is located in the center of the first plates 53 on both sides, so the transmitted torque is minimum.

As shown in FIG. 4, when the flexible portion 63 of each plate 55 is bent due to the pressing force from the actuator 79, the slit 6 is bent.
1 is opened and silicone oil flows as shown by arrow 85.
The blade 55 moves to the side in response to a thrust force as indicated by an arrow 87, and comes into contact with the plate 53 as shown in FIG. 1(C). Therefore, the transmitted torque at this time is maximum.

In this way, the torque transmission characteristics can be adjusted.

In addition, since the operating force required at this time is only a slight pressing force to move the flexible portion 63 while bending it, the actuator 79 can be made smaller. Since the plate 55 is automatically moved by the above-mentioned thrust force, the response of characteristic adjustment is quick.

Further, if the plates 53 and 55 are configured to be in contact with each other when not operated, and the gap between these plates is widened when the actuator 79 is operated, the viscous coupling 13 can be quickly brought into the disconnected state. Further, if the flexible portion 63 is configured to be bent not only in one direction but also in both directions in the axial direction, the movement and return can be quickly performed by the thrust force as described above.

Next, the function of the viscous coupling 13 in accordance with the power characteristics of the vehicle shown in FIG. 5 will be explained.

The rotation of the engine 1 is shifted by the transmission 3 and divided and output from the front differential 5 to the left and right front wheels 7.
The signal is transmitted to the propeller shaft 15 and the rear differential 17, and is divided into outputs to the left and right rear wheels 19.21.

When the rotation difference between the front and rear wheels is small, such as when driving on a good road, the characteristics of the viscous coupling 13 cause the rear wheel to
Almost no driving force is transmitted to the sides. Therefore, the vehicle becomes substantially a two-wheel drive state with front-wheel drive, and fuel efficiency improves.

When the front wheels 7 and 9 spin on rough roads and a rotation difference occurs between the front and rear wheels, the rear wheels 19 and 21 are connected to each other via the viscous coupling 13.
The driving force is transmitted to the side, providing high running performance. Further, a small rotational difference that occurs between the front and rear wheels when turning is absorbed by the viscous coupling 13, so that smooth turning can be achieved.

Even when making low-speed sharp turns such as parking or making a U-turn, the difference in rotation between the front and rear wheels is absorbed by the viscous coupling 13, thereby preventing tight corner braking.

When the transmission torque of the viscous coupling 13 is increased by the above-described operation, the driving force sent to the rear wheels increases when the front wheels are idling, and the running performance is further improved. In addition, if the configuration is such that the transmission torque of the viscous coupling 13 becomes smaller when the viscous coupling 13 is operated, the viscous coupling 1
3, the connection between the front and rear wheels can be cut off. This will prevent interference between the braking forces on each side of the front and rear wheels during braking, and, for example, locking on the negative side will not spread to the other side.
ABS function is not inhibited. Since the response of characteristic adjustment is quick, it can respond quickly to sudden braking and protect the ABS function.

In addition, the present invention may be configured such that the movable plate is composed of two groups: a plate having a protrusion and a plate having a flexible portion that is pushed by the protrusion, and the former is moved by a pressing means. Further, the moving plate may be provided on the housing side.

[Effects of the Invention] The viscous coupling of the present invention is configured such that the plate is provided with a flexible portion and the plate is moved by applying thrust force applied to the flexible portion from the viscous fluid, so that torque transmission characteristics can be adjusted. The response is fast. Further, the required operating force is small, so the pressing means can be made compact.

[Brief explanation of drawings]

Figure 1 (a) is a cross-sectional view of one embodiment, Figures (b) and (C) are enlarged cross-sectional views showing the plate positions at maximum and minimum transmission torque, respectively. 3 is a plan view of the second plate, FIG. 4 is a side view showing the main parts of the plate, and FIG. 5 is a skeleton mechanism diagram showing the power system of a vehicle using this embodiment. 23... Housing (one transmission member) 25... Hub (other transmission member) 45... Working chamber 53... First plate 55... Second plate 63... Flexible Part 65...
・Protrusion

Claims (1)

[Claims] A pair of transmission members disposed to be relatively rotatable, a working chamber filled with viscous fluid, a first plate engaged with one transmission member within the working chamber, and a first plate arranged alternately with the other transmission member. a second plate having a flexible portion that engages with the member in an axially movable manner and deflects in the axial direction in response to a pressing force to open adjacent slits in the same direction; A viscous coupling characterized in that it is equipped with a pressing means for bending the viscous coupling.