JPH0289822A - Viscous coupling - Google Patents

Abstract

PURPOSE:To regulate the overlap margin of a power transmission member or an axial distance and to perform rapid control of torque transmission characteristics by a method wherein a slidable shaft joint is located between a rotary member on the moving side and that on the outer side. CONSTITUTION:When a housing 39 is rotated by means of a drive force from an engine, rotation is transmitted from a cylinder 55 to a cylinder 57 to rotate a shaft member 45, and is transmitted to the rear wheel side through a bar field type joint 67 and propeller shaft 19. In this case, when a high rotation difference is produced between the housing 39 and the shaft member 45 by means of a drive force from an engine and drive resistance on the rear wheel side, the rotation difference is limited widely to transmit a high drive force. With an overlap margin L between the cylinders 55 and 57 increase through control of an actuator, differential control capacity is increased and transmission torque is increased. When the overlap margin L is decreased, differential control capacity is decreased and transmission torque is decreased.

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) A viscous clutch (viscous coupling) is described in JP-A-61-106130.

This device engages a plurality of cylinders arranged alternately in the radial direction within the working chamber formed between the housing and the sleeve, which are capable of relative rotation and relative axial movement, and engages the nozzing and the sleeve, respectively. The torque input from one of the housing and sleeve is transmitted to the other by the shear resistance of the viscous fluid. Further, the sleeve is spline engaged with the external shaft so as to be movable in the axial direction, and can be moved in the axial direction by a control device such as an actuator to change the overlapping margin of the cylinders and control the torque transmission characteristics.

In this manner, the sleeve and the shaft are engaged by spline, and since torque is applied to the spline portion during operation, sliding resistance is large and movement of the sleeve in the axial direction during operation is slow. Therefore, the torque transmission characteristics cannot be controlled quickly.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a viscous coupling that has low movement resistance in the axial direction and can quickly control torque transmission characteristics.

[Structure of the Invention] (Means for Solving the Problems) The viscous coupling of the present invention includes a working chamber filled with a viscous fluid, and an integral rotating member arranged to be able to rotate relative to each other and move relative to each other in the axial direction. vJ: a plurality of power transmission members arranged alternately in the radial direction within the working chamber and each rotating integrally with the rotating member; a slidable shaft coupling connecting one rotating member to an external shaft; The present invention is characterized by comprising a control means for controlling the overlapping margin or axial distance between the power transmission member on one side and the power transmission member on the other side by moving the rotation member in the axial direction with respect to the rotating member.

(Operation) Input torque from one rotating member is transmitted to the other rotating member by shear resistance of the viscous fluid.

At this time, if the rotation difference between these rotating members is large, this rotation difference is greatly restricted and a large torque is transmitted, and if the rotation difference is small, this rotation difference is allowed and the transmitted torque becomes small.

The torque transmission characteristics can be controlled by relatively moving the rotating members in the axial direction by the control means and changing the overlapping margin or axial spacing of the power transmission members.

Since a slidable shaft joint is interposed between the rotating member on the movable side and the external side, resistance to axial movement is small even when torque is applied. Therefore, it is possible to quickly adjust the overlapping margin or axial spacing of the power transmission members and control the torque transmission characteristics accordingly.

(Example) One embodiment will be explained with reference to FIG. 1 and FIG. 2.

FIG. 2 shows a vehicle using this embodiment. Note that in the following explanation, the left and right directions are the left and right directions in FIG. 1, and the left side corresponds to the front of the vehicle in FIG. 2.

First, the power transmission of this vehicle will be explained with reference to FIG.

The driving force of the engine 1 is shifted by the transmission 3 and transmitted to the front differential 5 (differential device on the front wheel side), and is transferred from the differential case 7 of the front differential 5 to the direction conversion gear set 11 housed in the transfer case 9 and the output. It is transmitted to the rear differential 21 (rear wheel side differential device) housed in the differential carrier 20 via the shaft 13, the viscous coupling 15 of this embodiment, and the propeller shaft 19 (external shaft). The transmitted driving force is differentially distributed by the front differential 5 to the left and right front wheels 27, 29 via the front axle 23.25, and then to the rear differential 21.
The left and right rear wheels 35.37 through the rear axle 31.33
differentially distributed.

Next, the configuration of the embodiment will be explained with reference to FIG.

The housing 39 (rotating member) is housed in the transfer case 9, and supports a shaft member 45 (rotating member) rotatably and axially movably at shaft supports 41 and 43. A needle bearing 47 and an X-ring (a sealing member having an X-shaped cross section) 49 are arranged on the shaft support 41, and an X ring 51 is arranged on the shaft support 43.

An annular working chamber 5 is provided between the housing 39 and the shaft member 45.
3 is formed, and silicone oil as a viscous fluid is sealed therein. Inside the working chamber 53, a plurality of cylinders 55, 57 serving as power transmission members having different diameters are alternately arranged in the radial direction and are attached to the left side wall 59 of the three housings and the flange portion 61 provided on the shaft member 45, respectively. It is fixed separately.

The housing 39 is connected to the output shaft 13.

Further, the shaft member 45 passes through the rear end of the transfer case 9 and also connects the needle bearing 63 and the seal ring 65.
The transfer case 9 is rotatably and axially movably supported via the transfer case 9.

The shaft member 45 is connected to the propeller shaft 19 via a Barfield type sliding joint 67 (slidable shaft joint). The Barfield type joint 67 consists of an outer cylinder member 69, an inner member 71, and balls 73 that are removably engaged with grooves provided in each of the outer cylinder member 69 and an inner member 71. Transmits torque while absorbing movement. Therefore, the resistance to axial movement of the shaft member 45 due to the transfer of the balls 73 of the Barfield type joint 67 is small.

A ring 75 is fixed on the shaft member 45, seven forks are slidably engaged in a cylindrical groove 77 provided in the ringer 5, the seven forks are connected to an operating rod 81, and the operating rod 81 is a transfer member. It is supported by the case 9 so as to be slidable in the axial direction.

The operating rod 81 is connected to an actuator (control means, not shown).

By operating the actuator, the operating rod 81° and the fork 79. The shaft member 45 moves from side to side via the ring 75, and the overlap of the cylinders 55, 57 changes. The actuator can be operated manually from the driver's seat, or automatically depending on steering conditions, road surface conditions, etc.

Next, the functions of this embodiment will be explained.

When the housing 39 rotates due to the driving force from the engine 1, this rotation is transmitted from the cylinder 55 to the cylinder 57 due to the shear resistance of the silicone oil, rotating the shaft member 45 and connecting the Barfield type joint 67 and the propeller shaft 19. The signal is transmitted to the rear wheels 35 and 37 through the transmission line. At this time, if a large rotational difference occurs between the housing 39 and the shaft member 45 due to the driving force from the engine 1 and the driving resistance on the rear wheels 35, 37 side, this rotational difference is greatly limited and a large driving force is transmitted. . Furthermore, if the rotation difference is small, this rotation difference is allowed and the transmitted driving force becomes small.

If the overlapping amount of the cylinders 55, 57 is increased by operating the actuator, the differential limiting ability will increase and the transmitted torque will increase, and if the overlapping amount is decreased, the differential limiting ability will become smaller and the transmitted torque will decrease. In this way, the torque transmission characteristics can be changed.

Next, functions corresponding to the performance of the vehicle shown in FIG. 2 will be explained.

For example, when the rotation difference between the front and rear wheels is small, such as when driving on a good road, the driving force transmitted to the rear wheels 35, 37 via the viscous coupling 15 is small. Therefore, the vehicle becomes in a driving force distribution state substantially equivalent to that of a two-wheel drive vehicle with front wheel drive, and such vehicle characteristics are obtained, and fuel efficiency is improved compared to a four-wheel drive vehicle. Furthermore, by operating the actuator to reduce the torque transmitted by the viscous coupling 15, a substantially two-wheel drive state can be achieved regardless of the rotational difference between the front and rear wheels.

If the front wheel 27.29 side slips on a rough road, the difference in rotation at the viscous coupling 15 will increase.
A large driving force is transmitted to the rear wheels 35 and 37 via the viscous coupling 15, and the vehicle can maintain smooth running without becoming stuck. In this way, the ability to escape from rough roads (drivability), etc. is improved. Furthermore, if the actuator is operated to increase the transmission torque of the viscous coupling 15, a large driving force will be transmitted to the rear wheels 35, 37 with a slight difference in rotation, and the ability to escape from a rough road will be significantly improved.

Furthermore, the difference in rotation that occurs between the front and rear wheels during a low-speed sharp turn, such as when parking the vehicle, is absorbed by the viscous coupling 15, so that tight corner braking does not occur.

Since the Barfield type joint 67 is used to connect the shaft member 45 and the propeller shaft 19, resistance to movement in the axial direction under torque load is small. Therefore, the torque transmission characteristics can be changed quickly, and the actuator can also be small. Furthermore, compared to the conventional example in which the sleeve and the shaft are engaged by spline, the structure around the shaft member 45 is simpler and can be stored in the transfer case 9, making it easier to mount it on the vehicle body.

In addition to being housed in the transfer case 9 as in the above embodiment, the viscous coupling 15 is also housed in the rear differential 21.
It may be stored in the differential carrier 20.

Further, the shaft joint is not limited to the Barfield type sliding joint 67, but may be a tripod type sliding joint, for example.

[Effects of the Invention] As described above, the viscous coupling of the present invention can transmit torque while controlling (limiting and allowing) the rotation difference, and can also change the torque transmission characteristics. Further, since the movement resistance in the axial direction during control is small, the torque transmission characteristics can be controlled quickly. Furthermore, it is also possible to downsize actuators and the like for control.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of part A in FIG. 2 showing the configuration of an embodiment;
FIG. 2 is a skeleton mechanism diagram showing power transmission in a vehicle using this embodiment. 39... Housing (rotating member) 45... Shaft member (rotating member) 53... Working chamber 5
5.57...Cylinder

Claims (1)

[Claims] a working chamber in which a viscous fluid is sealed; a pair of rotating members arranged to be able to rotate relative to each other and move relative to each other in the axial direction; A power transmission member, a slidable shaft coupling that connects one rotating member and an external shaft, and a sliding shaft coupling that moves the rotating member in an axial direction relative to the other rotating member to transmit power between the one side of the power transmission member and the other side. A viscous coupling characterized by comprising a control means for controlling an overlapping margin with a member or an axial distance.