JPH0226328A - Power transmission - Google Patents

Abstract

PURPOSE:To prevent any tight corner braking phenomenon from occurring by interposing a cam means between a first member and a second member, while setting up a friction clutch capable of restricting any relative rotation between a first rotating member and a second rotating member, and at the time of garaging, allowing this relative rotation between these first and second rotating members. CONSTITUTION:At the time of garaging or the like, relative rotation between a first rotating member 22 and a second rotating member 23 is allowed. In consequence, any tight corner braking phenomenon is prevented from occurring. Next, when a front wheel or a rear wheel is slipped during driving on a rough road, a cam means 27 works and a second member 18 is moved by action of this cam means 27, and a friction clutch 29 is pressed in the frictional force increment direction by this second member 18. Therefore an extent of torque being transmitted from the first rotating member 22 to the second rotating member 23 is suddenly enlarged, so that the front wheel or the rear wheel is quickly escapable from a state of being slipped.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a power transmission device that is incorporated into a power transmission system of a vehicle or the like and transmits power using a working fluid.

(Prior Art) As a conventional power transmission device, there is one shown in FIG. 5, for example. In the figure, 101 is a first rotating member connected to a driving shaft, and 102 is a second rotating member connected to a driven shaft.
The first rotating member 101 and the second rotating member 102 are rotating members, and the first rotating member 101 and the second rotating member 102 can rotate relative to each other. First rotating member 101
A sealed working chamber 103 is formed by the second rotating member 102 and the second rotating member 102.
is defined, and this working chamber 103 is filled with viscous fluid. A first resistance plate 104 and a second resistance plate 105 are housed in the working chamber 103, and the first resistance plate 104
and the second resistance plate 105 are respectively the first rotating member 101
and are mutually splined to the second rotating member 102.

This viscous coupling is interposed, for example, between a transfer and a propeller shaft of a four-wheel drive vehicle based on a front engine, front drive (FF), and the first rotating member 101 and the second rotating member 102 are each connected to a transfer shaft. and the propeller shaft. When the front wheels slip on a rough road with a low coefficient of friction, a large difference in rotational speed occurs between the front and rear wheels. For this reason, the first
The resistance plate 104 and the second resistance plate 105 rotate relative to each other to shear the viscous fluid. The shearing force of this viscous fluid is transmitted as torque to the rear wheels, which push the vehicle out of the slip state.

On the other hand, when you turn the steering wheel sharply at low speeds, such as when parking in a garage, there will be a difference in rotational speed between the front and rear drive shafts, as well as between the left and right wheels. This is absorbed by the coupling to prevent the so-called tight corner braking phenomenon from occurring.

(Problems to be Solved by the Invention) However, in such a conventional viscous coupling, the filling rate of the viscous fluid filled in the working chamber 103 was constant. Therefore, if the filling rate of viscous fluid is lowered in order to prevent the occurrence of tight corner braking, the shearing force of the viscous fluid will also be lowered, and if you slip while driving on a rough road, you can quickly recover from this slip state. In order to solve this problem, the present invention includes a first member and a second member movable with respect to the first member.
a second rotating member that is rotatable relative to the first rotating member; and an actuation device defined by the second rotating member and the first rotating member and filled with a working fluid. a chamber, a cam means is interposed between the first member and the second member, and a friction clutch capable of restricting relative rotation between the first rotating member and the second rotating member; When the relative rotation between the first rotating member and the second rotating member increases, the second member is moved by the action of the cam means, and the second member is configured to press the FIl friction hoe clutch in the direction of increasing friction force. It is something.

(Function) When the vehicle is parked in a garage, relative rotation between the first rotating member and the second rotating member is allowed, and tight corner braking phenomenon is prevented from occurring.

Next, when the front or rear wheels slip while driving on a rough road, the cam means acts, and the second member is moved by the action of the cam means, and the second member presses the friction clutch in the direction of increasing the friction force. do. Therefore, the torque transmitted from the first rotating member to the second rotating member suddenly increases, and the front wheel or the rear wheel can be quickly brought out of the slipping state.

(Example) This IfJM will be explained below based on the drawings.

1 to 4 are diagrams showing an embodiment of a viscous coupling as a power transmission device according to this explanation.

This embodiment is an example in which a viscous coupling is interposed between the front wheel drive shaft and the rear wheel drive shaft of an FF-based four-wheel drive vehicle.

First, the configuration will be explained. In Fig. 1, 1 is an internal combustion engine, and the torque output from the internal combustion [Ql] is the clutch 2.
is transmitted to the transmission 3 via. Torque is transmitted from the drive gear 4 of the transmission 3 to the front wheel differential gear mechanism 6 via the ring gear 5, allowing differential rotation between the left wheel drive shaft 7a and the right wheel drive shaft 7b of the front wheel drive shaft 7. communicated. Differential case 8 of differential gear mechanism 6
The torque transmitted to is transmitted to the power transmission gear 9 and direction-changed by the direction-changing gear set 10 at right angles. The torque redirected at right angles is transferred to the viscous coupling 11
is transmitted to the propeller shaft 12 via the drive pinion 13 to the rear wheel differential gear mechanism 15 via the ring gear 14, and is transmitted to the left wheel drive shaft 1 of the rear wheel drive shaft 16.
6a and the right wheel drive shaft 16b, differential rotation is allowed and transmitted.

The viscous coupling 11 will be explained with reference to FIG.

Reference numeral 17 denotes a first member having a substantially bottomed cylindrical shape to which torque is input from the direction conversion gear 10, and a second member 18 is movably housed in the first member 17. The second member 18 includes a cylindrical portion 19 and a first end wall member 20 and a second end wall member 21 provided at both ends of the cylindrical portion 19, respectively.

The first member 17 and the second member 18 constitute a first rotating member 22, and the inner peripheral side of the first rotating member 22 has a substantially cylindrical shape that is relatively rotatable and that outputs torque to the propeller shaft. A second rotating member 23 having a shape is provided. A working chamber 24 is defined by the second member 18 and the second rotating member 23, and this working chamber 24 is filled with silicone oil, which is a highly viscous fluid, as a working fluid. The filling rate of silicone oil should be kept low to prevent the occurrence of tight corner braking phenomena. In addition, the working chamber 2
4 includes a first resistance plate 25 and a second resistance plate 2 which are spline-connected to the second member 18 and the second rotating member 23, respectively.
6 is included.

Here, a cam means 27 is interposed between the first member 17 and the second member 18, and this cam means 27 is attached to each of the first member 17 and the second member 18 as shown in FIG. It consists of cam surfaces 17a and 18b that are substantially trapezoidal in plan view. Further, there is a second member between the second member 18 and the first member 17.
A return spring 28 is provided that constantly urges the member 18 toward the cam means 27. The first member 17 and the second member
A friction clutch 29 is interposed between the member 18 and the member 18 . That is, a substantially annular interlocking member 30 is spline-connected to the cylindrical portion 23a of the second rotating member 23, and a first friction plate 31 is spline-connected to the interlocking member 30. Two friction plates 32 are arranged in parallel, and this second
The friction plate 32 is connected to the first member 17 by a spline.

A side wall member 33 is fixed to the first member 17 on the right side of the first and second friction plates 31 and 32 in FIG. It is rotatably supported.

Next, the effect will be explained.

When turning the steering wheel sharply at low speeds, such as when parking a garage, a differential rotational speed ΔN occurs between the front wheel drive shaft 7 and the rear wheel drive shaft 16, and the first rotating member 22 and the second rotating member 23 are relative to each other. Rotate. When the differential rotational speed difference ΔN at this time is in the A region lower than 20 to 3Q rpl as shown in FIG. 4, the transmitted torque between the third member 18 and the second rotating member 23 is small. Therefore, the second member 18 is pressed to the left in FIG. Relative rotation between the first rotating member 22 and the second rotating member 33 is allowed while shearing the silicone oil with a low filling rate by the two resistance plates 26. Therefore, occurrence of tight corner braking phenomenon when parking the vehicle is prevented.

When the front wheels slip when the vehicle is traveling on a rough road with a small road surface friction coefficient, the resistance of the front wheels, which are directly driven by the engine, is low, so that the rotational speed of the front wheel drive shaft 7 is transmitted to the front wheels. Only a small amount of torque is exerted. Here, the engine side rotation speed of the rear wheel (front wheel drive shaft)
Since it rotates less, the second
The rotating member 23 rotates less than the first rotating member 23. Therefore, there is a distance of 30 mm between the front wheel drive shaft 7 and the rear wheel drive shaft 16, that is, between the first rotating member 22 and the second rotating member 23.
A large differential rotational speed ΔN of ~2 Orpm or more occurs and these rotate relative to each other.

Therefore, the first resistance plate 25 and the second resistance plate 26 shear the silicone oil at high speed. The shearing force of this silicone oil is transmitted to the rear wheels as a torque as shown by the broken line in FIG. 4, and the rear wheels push the vehicle out, causing the front wheels to escape from the slipping state.

Here, the first rotating member 22, that is, the second part 18 and the second part
When the rotating member 23 and the rotating member 23 rotate largely relative to each other, the first member 17
and the second member 18 begin to rotate relative to each other because the second member 18 side receives the viscous resistance of the silicone oil. Therefore, as shown in FIG. 3, the cam surface 17a of the first member 17 and the cam surface 18a of the second member 18 slide up against each other, generating a thrust force as shown by the arrow. This thrust force causes the second member 18 to engage the am clutch 29! fl Press in the direction of increasing friction force (to the right in Figure 2). [When the first clutch 29 is pressed and fastened, the first rotating member 22 and the second rotating member 33 are almost directly connected, and FIG. 4 shows a region B where the differential rotation speed ΔN is 20 to 30 rt+n+ As shown by the solid line, the torque suddenly rises, and the torque transmitted from the first rotating member 22 to the second rotating member 23 suddenly increases.

Therefore, the rear wheels can forcefully push the vehicle, allowing the front wheels to quickly escape from the slipping state.

[Effects of the Invention] As explained above, according to the present invention, the cam means is interposed between the first member and the second member, and the relative rotation between the first rotating member and the second rotating member is restricted. Since a possible friction clutch is provided, relative rotation of the first rotating member and the second rotating member is allowed when the vehicle is parked in a garage, thereby preventing the occurrence of tight corner braking. Furthermore, when one of the wheels slips while driving on a rough road, the second member is moved by the action of the cam means, and this second member presses the friction clutch in the direction of increasing the frictional force. The torque transmitted from the member to the second rotating member suddenly increases,
It is possible to quickly escape from a slipping situation.

[Brief explanation of the drawing]

1 to 4 are diagrams showing one embodiment of a power transmission device according to the present invention, and FIG. 1 shows a power transmission device installed between a front wheel drive shaft and a rear wheel drive shaft of a four-wheel drive vehicle. A schematic overall view, FIG. 2 is a sectional view of this power transmission device, FIG. 3 is a plan view showing the action of the cam means, and FIG. 3 is a graph showing the torque transmitted to. FIG. 5 is a sectional view showing a conventional viscous coupling. 17...First member 18...Second member 22...First rotating member 23...Second rotating member 24...Operation seedling 27...Cam means 29...Friction crutch 2nd Figure tIN =20~3Orpm →MuN

Claims (1)

[Claims] A first rotating member consisting of a first member and a second member movable relative to the first member; a second rotating member rotatable relative to the first rotating member; a working chamber defined by a first rotating member and filled with working fluid, a cam means interposed between the first member and the second member, and a working chamber defined by a first rotating member and a second rotating member; A friction clutch capable of restricting the relative rotation of the members is provided, and when the relative rotation between the first rotating member and the second rotating member increases, the second member is moved by the action of the cam means, and the friction is reduced by the second member. A power transmission device characterized in that a clutch is pressed in a direction of increasing frictional force.