JPH03292425A - Viscous coupling - Google Patents

Abstract

PURPOSE:To secure the speedy adjustment of characteristic and reduce the dimension of an adjusting means by accommodating the first plate engaged with the first transmission member and the second and third plates which are arranged, having the first plate interposed, and are engaged with the second transmission member, and relatively shifted in the axial direction by an adjusting means, into a working chamber filled with a viscous fluid. CONSTITUTION:A working chamber 45 filled with silicone oil having high viscosity is formed between a hub 25 which is spline-fitted to a housing 23 and a transmission shaft 27 and a pressing member 39 which is connected through a bearing 91 on the piston 81 of an actuator 87. The first plate 55 is spline-engaged through a spacer ring 58 on the inner periphery of the housing 23, and one projecting part 63 is superposed on the other recessed part 65 on the inner edge side, having the first plate 55 interposed, and the second and third plates 59 and 61 having each slit 66 on the outer edge side are engaged with a groove 67 on the outer periphery of the hub 25 by a projection part 63. Further, the pieces 69 and 71 engaged with a groove 67 are penetration-arranged through a recessed part 65 on the other side, between each projection part 63, and the piece 71 of the third plate 61 is attached on a pressing member 39. Accordingly, the speedy adjustment of characteristic and the reduction of the dimension of an adjusting means can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) This invention relates to a viscous coupling that transmits torque through 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 arranged between the plates, and when the plate is pressed in the axial direction by a pressing body, the disc spring is bent and all the plates move, narrowing the gap between the plates. When the pressing force is reduced, the spacing between the plates increases due to the biasing force of the disc spring.

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

However, the movement stroke on the operating side becomes very long, as it is multiplied by the number of plates as the interval between the plates, and the plates are subjected to large resistance due to the viscous fluid during movement. Therefore, the response during characteristic adjustment is poor. This is noticeable when the plate spacing is widened using disc springs. Further, since the stroke is large, a large pressing force is required, and the pressing means becomes large.

SUMMARY OF THE INVENTION Accordingly, 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 for adjustment.

[Structure of the Invention] (Means for Solving the Problems) A viscous coupling of the present invention includes first and second transmission members arranged to be relatively rotatable, a working chamber filled with a viscous fluid, and a working chamber filled with a viscous fluid. a first plate that engages with the first transmission member within the operating chamber; second and third plates that are arranged to sandwich the first plate and engage with the second and third transmission members; It is characterized by comprising an adjusting means for relatively moving the second and third plates in the axial direction through force transmission.

(Function) The operating force from the adjusting means causes the second and third
By relatively moving the two plates and narrowing the distance between them and the first plate, the transmitted torque increases. Similarly, increasing this distance will reduce the transmitted torque. In this way, the torque transmission characteristics can be adjusted. The movement stroke of the plate at this time is only a few, even if there are many combinations of the first, second, and third plates, so the response when adjusting the characteristics is extremely fast, and the movement operation is easy. Since the force is small, the adjustment means can be made small.

(Example) An example will be explained with reference to FIGS. 1 to 5. Fifth
The figure shows the power system of a 4WD vehicle using this embodiment. Hereinafter, the left and right directions are the left and right directions in Figures 1 and 4,
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 (differential device on the front wheel side), left and right front wheels 7.9, L-transfer 11, viscous coupling 13 of the example, propeller shaft 15, rear differential 17 (differential device on the rear wheel side), left and right rear wheels 1
It consists of 9.21 etc.

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

The housing 23 (first transmission member) and the hub 25 (second 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 the 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 housing 23. The housing 23 is flange-connected to the transfer 11 side by bolts screwed into bolt holes 37, and the transmission shaft 27 is connected to the propeller shaft 15 side. A pressing member 3 is provided between the inner circumference of the housing 23 and the outer circumference of the transmission shaft 27.
A bearing 41 and a seal 43 are disposed between this member 39 and the housing 23.

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

In the working chamber 45, on the inner periphery of the housing 23, a first
A plate 55 is spline-connected so as to be movable in the axial direction. A wave washer 57 is arranged between the end plate 55 and the retaining ring 56. Each plate 55
A spacer ring 58 is provided between them to bias them so that the distance between them is kept constant. A second plate 59 is arranged on the left side of each plate 55, and a third plate 61 is arranged on the right side.

As shown in FIG. 2, the plates 59 and 61 are provided with alternately arranged protrusions 63 and recesses 65 on their inner edges, and slits 66 on their outer edges. As shown in FIG. 3, the outer periphery of the hub 25 is provided with an axial groove 67 in which the convex portion 63 can engage.
1, each convex portion 63 is engaged with this groove 67. As shown in FIGS. 4(a) and 4(b), the plate 59.
The convex portions 63 of both plates 61 face each other, and the convex portions 63 of one plate are engaged with the concave portions 65 of the other plate so as to face each other. Furthermore, as shown in the figure, cylindrical pieces 69, 71 that engage with the grooves 67 are arranged between the protrusions 63 of each play (59, 61) so as to pass through the recesses 65 on the other side. There is. In addition, FIG. 4 shows each piece 69.
71, in which pieces 69 and 71 are actually arranged on the same circumference. Further, the wave washer 57° and the spacer ring 58 are omitted.

A second plate 59 is arranged on the leftmost side, and a pressure receiving ring 73 is attached to the hub 25 on the left side thereof. Further, a third plate 61 is arranged on the oldest side, and a piece 71 is also arranged on the right side thereof, and this piece 71 is in contact with the pressing member 39. Moreover, each plate 59 separated by the plate 55
．． A wave washer 75 is arranged between the 61 pairs on the radially outer side of the pieces 69 and 71. As described above, the second plate 59 is restricted from moving to the left by the pressure receiving ring 73, and the third plate 61 is movable left and right.

On the right side of the housing 23, a ring-shaped cylinder member 77 fixed to the vehicle body side is arranged coaxially with the transmission shaft 27. A bearing 79 is arranged between the member 77 and the transmission shaft 27. A piston 81 is fitted into the cylinder member 77 so as to be movable in the axial direction. The sliding parts of the cylinder member 77 and piston 81 are kept liquid-tight by O-rings 83, 85. In this way, a hydraulic actuator 87 (adjustment means) is configured. Hydraulic pressure is supplied to the actuator 87 from a hydraulic source via a control valve device and a hydraulic boat 89. The piston 81 is connected to the pressing member 39 via a bearing 91.

When supplied with hydraulic pressure, the actuator 87 presses the third plate 61 to the left via such an operating force transmission system. The actuator 87 can be operated manually from the driver's seat, or automatically so as to stop operating depending on steering conditions, road surface conditions, or during braking.

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 55 to the plates 59, 61 due to the shear resistance of the silicone oil, and the hub 25
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 87,
The second and third
The plates 59, 61 and the first plate 55 are in the positions shown in FIG. 1(b) and FIG. 4(a). In this position, the plates 59 and 61 between the plates 55 are in contact and the distance between them and the plate 55 is maximum. Therefore, the transmitted torque is minimized.

When the actuator 87 presses the third plate 61 to the left, the plate 61 presses and moves the plate 55 on the left side of each plate 61 as shown in FIG. 1(C) and FIG.
Contact the five plates on the left side as shown in b). In this state, the plates 59, 61 are in contact with the plate 55 from the left and right sides. Therefore, the transmitted torque becomes maximum.

When the pressing is stopped, the wave washer 57.
75, each plate returns to the state where the transmitted torque is minimum.

By adjusting the pressing force, the transmitted torque can be arbitrarily adjusted between the maximum and minimum values. Further, since the stroke of the plate is small and the pressing force is small, the response when adjusting the torque transmission characteristics is extremely quick and the adjusting means can be made compact, unlike the conventional example. Also, wave washer 57,7
5 has a longer stroke than the disc spring used in the conventional example, and the spring constant can be reduced. For this reason as well, the pressing force can be reduced and the adjustment means can be made smaller. Since the stroke of the plate is extremely small, wave washers with these advantages can be used without affecting response.

Next, the function of the viscous coupling 13 in accordance with the power performance 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 7.9, and from the transfer 11 to the viscous coupling 13,
It is transmitted to the propeller shaft 15 and the rear differential air, and is dividedly output 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 7.9 spin on rough roads and there is a difference in rotation between the front and rear wheels, the rear wheels 19.21
The driving force is transmitted to the side, providing high running performance. Further, since the small rotational difference that occurs between the front and rear wheels when turning is absorbed by the viscous coupling 13, 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.
Tight corner braking phenomenon is prevented.

If the transmission torque of the viscous coupling 13 is increased, the driving force sent to the rear wheels when the front wheels are idling will be increased, and the running performance will be further improved. Furthermore, by reducing the transmission torque of the viscous coupling 13 during braking and cutting off communication between the front and rear wheels, interference between the braking forces of each side can be prevented, and for example, locking on the - side can be prevented from spreading to the other side. ABS function is not inhibited. As mentioned above, since the characteristic adjustment response is quick, it is possible to respond quickly to sudden braking and protect the ABS function.

In addition, in this invention, the adjustment means is provided with a pair of moving means, one of which moves the second plate, and the other moves the third plate to adjust the distance between these and the first plate. It's okay.

Further, the housing side may have a double plate configuration.

[Effects of the Invention] The viscous coupling of the present invention has a double plate configuration with the plates on one transmission member side, and moves these plates relatively by a movement operation of a small stroke to reduce the distance between the plates on the other transmission member side. Since it is constructed so that the characteristics can be adjusted quickly, the adjustment means can be made compact.

[Brief explanation of the drawing]

FIG. 1(a) is a sectional view of one embodiment, and FIGS. 1(b) and 1(c) are (a) of this embodiment at the minimum and maximum transmission torque, respectively.
Figure 2 is a plan view of the plate, Figure 3 is a sectional view of the hub, and Figures 4 (a) and 4 (b) are expanded to show the cross section of the bridge. FIG. 5 is an enlarged sectional view of main parts showing the maximum state, and a skeleton mechanism diagram showing the power system of a vehicle using this embodiment. 23... Housing (first transmission member) 25... Hub (second transmission member) 45... Working chamber 55... First plate 59... Second plate 61... third plate

Claims (1)

[Claims] a first and a second transmission member arranged to be relatively rotatable; a working chamber in which a viscous fluid is sealed; a first plate that engages with the first transmission member within the working chamber; a second transmission member disposed to sandwich the plate and engaged with the second transmission member;
A viscous coupling comprising: a third plate; and adjusting means for relatively moving the second and third plates in the axial direction through transmission of an operating force.