JPH05202963A - Drive force transmission device - Google Patents

Abstract

PURPOSE:To secure transmission of torque between both rotation members even if a cam means is damaged, in a drive force transmission device provided with the friction clutch for transmitting torque of both inner and outer rotation members, a pressing force generating means to produce a pressing force for pressing the friction clutch according to the differential rotation, and a cam means for locking up the friction clutch when a differential rotation between both rotation members becomes large. CONSTITUTION:A cam means 18 operated to generate a thrust when the relative rotation of both rotation members 11 and 13 reaches a specified value, and a transmission means 14 for transmitting a thrust from the cam means 18 to one of a friction clutch 10b are provided. Then the transmission means 14 is assembled slidably in axial direction with the transmission means 14 allowed to rotate by a specified amount relative to the inner rotation member 13 to always secure the connection of both rotation members 11 and 13 through the transmission member 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmission device which is interposed between a pair of coaxially supported rotary members to transmit torque between the rotary members.

[0002]

2. Description of the Related Art As one type of such driving force transmission device, as disclosed in Japanese Patent Laid-Open No. 63-240429,
The frictional engagement force is provided between the inner and outer rotary members coaxially and relatively rotatably arranged and actuated by the relative rotation of the both rotary members to generate a frictional engagement force for connecting the two rotary members so that torque can be transmitted. A friction clutch that increases or decreases the frictional engagement force according to the axial pressing force, and an axial pressing force that is disposed between the both rotary members and that corresponds to the relative rotation of the both rotary members to generate the same pressing force. There is a configuration including a pressing force generating means for applying one side to the friction clutch.

In this type of driving force transmission device,
When relative rotation (differential rotation) occurs between both rotary members, pressure corresponding to the differential rotation speed is generated in the pressing force generating means. This pressure presses the friction clutch, and generates a friction engagement force that couples both rotary members to the clutch so that torque can be transmitted. The frictional engagement force is proportional to the differential rotation speed, and torque proportional to the differential rotation speed is transmitted between the two rotary members from one to the other. Therefore, the driving force transmission device functions as a connecting mechanism between the driving side rotation member and the driven side rotation member in one driving force transmission system path of the four-wheel drive vehicle, and at the same time, between the driving side and driven side rotation members It also functions as a differential limiting mechanism between the side rotating members or between both driven side rotating members.

Further, in this type of drive force transmission device, when the relative rotation between the two rotary members is large, such as when the vehicle falls into a bad road, the friction heat generated in the friction clutch becomes high, and in this state. If it continues for a long time, the friction clutch may be burned out. Therefore, in order to prevent such a burnout of the friction clutch, a lock-up mechanism is provided to strengthen the engagement of the friction clutch and form a coupled state when the relative rotation of both rotary members reaches a predetermined value. A driving force transmission device is proposed in Japanese Patent Laid-Open No. 1-261553.

In the driving force transmission device of the above-mentioned type, the driving force transmission device is disposed between one of the rotating members and the friction clutch, and the relative rotation of the both rotating members reaches a predetermined value. Cam means for operating when it reaches and generating thrust and thrust transmitting means for transmitting thrust from the cam to the friction clutch,
Torque is transmitted between the rotating members through the thrust transmitting means and the friction clutch. Also,
The thrust transmitting means is rotatably and axially slidably mounted on one of the rotating members to face the friction clutch, and is configured to slide axially by the thrust from the cam means to press the friction clutch. ing.

[0006]

As described above, in the driving force transmission device described above, the torque transmission between the rotating members is performed through the cam means, the thrust transmission means and the friction clutch, and the thrust transmission means is provided. Since it is assembled to one rotating member so as to be rotatable and slidable in the axial direction, if the cam means is damaged by the generation of excessive torque, torque transmission between both rotating members becomes impossible. .. Therefore, it is an object of the present invention to address such issues.

[0007]

According to the present invention, there is provided a friction clutch disposed in a clutch accommodating chamber provided between both inner and outer rotating members which are coaxially and relatively rotatable with each other, and a friction clutch disposed between the both rotating members. A pressing force generating means for generating an axial pressing force according to the relative rotation of these two rotating members and applying the same pressing force to the friction clutch is provided, and either one of the rotating members and the rotating member and The cam means is disposed between the friction clutches and is operated when the relative rotation of the two rotary members reaches a predetermined value to generate a thrust force, and a thrust transmission means for transmitting the thrust force from the cam means to the friction clutch. A driving force transmitting device for transmitting torque between the rotating members through the cam means, the thrust transmitting means, and the friction clutch, the thrust transmitting means being provided on the one rotating member. It is characterized in that to face to the friction clutch assembled slidably in the axial direction while restricting the rotation of the large predetermined amount than the amount of relative rotation means.

[0008]

In the driving force transmission device having such a structure, when the relative rotation of both rotary members is less than or equal to a predetermined value, the cam means is in the non-operating state, and the cam member responds to the relative rotation of both rotary members. Torque is generated between the rotating members through the friction clutch, the thrust transmitting means and the cam means. Further, when the relative rotation of both rotating members reaches a predetermined value, the cam means operates to generate thrust, and the thrust transmitting means slides in the axial direction by this thrust to press the friction clutch, thereby making the friction clutch firm. To lock up.

By the way, in the driving force transmitting device, the thrust transmitting means is mounted on one of the rotating members in a state in which the rotation of the rotating member is restricted by a predetermined amount or more, and is connected via a gap of a predetermined amount. Therefore, even if the cam means is damaged by the generation of excessive torque, torque transmission between both rotary members is performed through the friction clutch and thrust transmission means, and torque transmission between both rotary members does not become impossible.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a driving force transmission device according to the present invention. As shown in FIG. 5, the driving force transmission device 10 is arranged in a rear wheel side power transmission system path of a real-time four-wheel drive vehicle. In this four-wheel drive vehicle, the front wheels are always driven and the rear wheels are driven when necessary. The transaxle 22 mounted on one side of the engine 21 is equipped with a transmission and a transfer, and the power from the engine 21 is supplied to the axle shaft. 23 to drive the front wheels 24 and output to the first propeller shaft 25. The first propeller shaft 25 is the driving force transmission device 10.
When the two shafts 25, 26 can transmit torque, power is output to the axle shaft 28 via the rear differential 27 and the rear wheels 29 are driven.

The driving force transmission device 10 is provided with an outer casing 11 and an end cover 12 which are outer rotating members, and a pressing force generating means 10a and a friction clutch 10b in an annular working chamber which is composed of an inner shaft 13 which is an inner rotating member. There is. The outer case 11 is provided with an inward flange portion 11b at an inner end of a tubular portion 11a having a predetermined length, and an end cover 12 is fluid-tightly fitted to an outer end opening portion of the tubular portion 11a.
In the inner shaft 13, a pressure plate 14 is spline-fitted to the outer periphery of a middle portion of a stepped cylindrical portion 13a having a predetermined length, and the pressure plate 14 is formed with an outer spline 14a. The pressure plate 14 constitutes the thrust transmission means of the present invention and also functions as a support means for supporting the friction clutch 10b. The clutch plate 15a, which constitutes the friction clutch 10b, is fitted to the inner spline 11cb of the outer case 11 so as to be slidably mounted in the axial direction, and the clutch disc 15b.
Is fitted to the outer spline 14a of the pressure plate 14 and is slidably assembled in the axial direction. The pressing force generating means 10a is disposed between the bottom of the outer case 11 and one side of the friction clutch 10b.

In such an inner shaft 13, the second propeller shaft 26 is spline-fitted and fixed to an axially extending inner spline portion provided on the inner circumference of the inner end side of the tubular portion 13a, and the tubular portion 13a. The inner end and the second propeller shaft 26 are liquid-tightly and rotatably fitted and supported in the inner hole of the inward flange portion 11b of the outer case 11. A rear end of the first propeller shaft 25 is fixed to the outer case 11.

The pressing force generating means 10a is a working piston 16
And the rotor 17, and the friction clutch 10b is provided on the side.
To form a clutch housing chamber R1. The operating piston 16 is located at the bottom of the outer case 11
Is integrally and liquid-tightly rotatable with respect to the inner shaft 13 and axially slidable with respect to the inner shaft 13. It faces one side of the friction clutch 10b.
As shown in FIGS. 1 and 2, the rotor 17 is provided with two vane portions 17b extending in the radial direction at positions 180 ° apart from each other on the outer periphery of the annular boss portion 17a.
Is fitted to the outer circumference of the cylindrical portion 13a of the inner shaft 13,
The shaft 13 is assembled so as to be integrally rotatable. The rotor 17 is formed to have a thickness substantially the same as the depth of the annular recess 16a provided on one side of the working piston 16 and is fitted in the annular recess 16a. With the bottom of 11 rotor 1
It forms a fluid chamber in which 7 is located. A highly viscous fluid such as silicone oil is enclosed in this fluid chamber, and the rotor 17 has an annular recess 16a on the outer periphery of its vane portion 17b.
Liquid-tightly contact with the inner circumference of the fluid chamber to create two retention chambers R
It is divided into 2.

In the driving force transmission device 10, the pressure plate 14 is assembled so as to be slidable in the axial direction as shown in FIGS. 3 and 4, and is spline-fitted onto the inner shaft 13. A fitting gap L1 that is larger than the relative rotation amount between the pressure plate 14 and the cam plate 18, which will be described later, is secured, and the arm portion 14b is in contact with the other side of the friction clutch 10b (see FIG. 1). A cam plate 18 is spline-fitted on the inner shaft 13 so as to be slidable in the axial direction. The cam plate 18 has a predetermined fitting gap L.
2 is secured, and both fitting gaps are set to satisfy the relationship of L1> L2. In these plates 14 and 18, the pressure plate 14 is formed with a fitting groove 14c into which the ball 19a is fitted, and the cam plate 18 is formed with a V-shaped cam groove 18a. 14
A ball 19a is fitted between c and 18a.

A disc spring 19b is provided between the cam plate 18 and the end cover 12, and a support cylinder 1 for supporting the disc spring 19b.
9c is provided, and the support cylinder 19c is the end cover 1
It is rotatably supported with respect to 2 and supports the disc spring 19b. With the disc spring 19b being in the applied state, the cam plate 18
Is urged toward the pressure plate 14 side via the ball 19a. Pressure plate 14, cam plate 1
8, the ball 19a, the disc spring 19b, and the support cylinder 19c constitute the cam means of the present invention. When the relative rotation between the pressure plate 14 and the cam plate 18 is less than a predetermined value, it is in a non-operating state, Pressure plate 14
Is rotatably held integrally with the cam plate 18 and the inner shaft 13, and when the relative rotation becomes a predetermined value or more, it is operated to generate a thrust force, and this thrust force causes the pressure plate 14 to slide in the axial direction. Friction clutch 10b
Is pressed in the axial direction.

In the driving force transmission device 10 having such a configuration, torque is transmitted when relative rotation occurs between the first and second propeller shafts 25 and 26. That is,
When relative rotation occurs between these shafts 25 and 26,
An outer case 11, an end cover 12, and an operating piston 16 that are integrally rotatably assembled to the first propeller shaft 25, and an inner shaft 13 and a rotor 17 that are integrally rotatably assembled to the second propeller shaft 26. Relative rotation occurs between.

Therefore, in the fluid chamber of the pressing force generating means 10a, the viscous fluid in the retention chamber R2 is forced to flow at a speed proportional to the relative rotational speed, and the retention chamber R2 sequentially moves relative to the circumferential direction. Due to the flow resistance, a pressure distribution in which pressure is gradually increased from the downstream end of the vane portion 17b toward the upstream end of the next vane portion 17b is generated therein. The pressure-increased portion of this pressure distribution increases in proportion to the differential rotation speed, and presses the working piston 16 in the axial direction. As a result,
The working piston 16 presses the friction clutch 10b to frictionally engage each clutch plate 15a with the clutch disc 15b through the clutch oil.

In this case, both propeller shafts 25, 26
If the relative rotation between them is less than a predetermined value, the cam means is inactive. Therefore, the friction clutch 10b is frictionally engaged only by receiving the pressing force from the working piston 16, and the torque proportional to the differential rotation speed is applied from the outer case 11 to the friction clutch 10b, the pressure plate 14 constituting the cam means, and the ball. It is transmitted to the inner shaft 13 through 19a and the cam plate 18, and the vehicle is in the four-wheel drive state. Further, in this four-wheel drive state, differential rotation of the front and rear wheels is allowed, and the occurrence of the tight corner braking phenomenon is prevented.

On the other hand, when the relative rotation between the propeller shafts 25 and 26 becomes a predetermined value or more and the transmission torque in the friction clutch 10b overcomes the spring force of the disc spring 19b, the pressure plate 14 and the cam plate 18 move relative to each other. The cam means actuate to rotate and generate thrust. Due to this thrust, the pressure plate 14 is slid in the axial direction and presses the friction clutch 10b against the working piston 16. As a result, the friction clutch 10b is firmly friction-engaged and coupled, and the outer case 11 and the inner shaft 13, and thus both the propeller shafts 25 and 26 are integrally coupled, and the escapeability from a bad road of the vehicle is improved. Let

By the way, in the driving force transmission device 10, the pressure plate 14 constituting the thrust transmission means.
Is spline-fitted to the inner shaft 13 with a predetermined fitting gap L1 secured, the pressure plate 14 and the inner shaft 13 form a reliable connection state when the fitting gap disappears. To do. Therefore, even if the cam means is damaged by the generation of excessive torque, torque transmission between the outer shaft 11 and the inner shaft 13 is performed through the friction clutch 10b and the pressure plate 14, and the torque between the outer shaft 11 and the inner shaft 13 is increased. Communication is not lost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a driving force transmission device according to an embodiment of the present invention.

FIG. 2 is a front view of a rotor that constitutes the driving force transmission device.

FIG. 3 is a partial cross-sectional view showing a cam means constituting the driving force transmission device.

FIG. 4 is a partial cross-sectional view (a) showing a fitting gap of a cam plate with respect to an inner shaft adopted in the same driving force transmission device, and a partial cross-sectional view (b) showing a fitting gap of a pressure plate with respect to the inner shaft. ..

FIG. 5 is a schematic configuration diagram of a four-wheel drive vehicle that employs the same driving force transmission device.

[Explanation of symbols]

10 ... Driving force transmission device, 10a ... Pressing force generating means, 10
b ... Friction clutch, 11 ... Outer case, 12 ... End cover, 13 ... Inner shaft, 14 ... Pressure plate, 16 ... Working piston, 17 ... Rotor, 17b ... Vane part, 18 ... Cam plate, 19a ... Ball, 19b
... disc springs, 19c ... supporting cylinders, 25,26 ... propeller shafts, R1 ... clutch accommodating chamber, R2 ... retaining chamber (fluid chamber).

Claims (1)

[Claims] 1. A friction clutch disposed in a clutch accommodating chamber provided between both inner and outer rotating members coaxially and relatively rotatable with each other, and a friction clutch disposed between the both rotating members for relative rotation of the both rotating members. The frictional clutch is provided with a pressing force generating means for generating a pressing force corresponding to the axial direction and applying the pressing force to the friction clutch, and is disposed between one of the rotating members of the rotating members and the friction clutch. Cam means for operating when the relative rotation of both rotary members reaches a predetermined value to generate thrust and thrust transmitting means for transmitting the thrust from the cam to the friction clutch;
In a driving force transmission device that transmits torque between the rotating members through a thrust transmitting means and a friction clutch, the thrust transmitting means allows the one rotating member to rotate a predetermined amount larger than the relative rotation amount of the cam means. And a driving force transmission device which is assembled so as to be slidable in the axial direction and faces the friction clutch.