JPH0483924A - Driving force transmission device - Google Patents

Abstract

PURPOSE:To prevent change of the viscous property or a viscous fluid and maintain the torque transmission property of a driving force transmission device by providing a communicating hole opened to the side of the housing chamber of a friction clutch to an annular groove with which a seal member that seals between a working piston and an outer rotary member liquid-tight is engaged. CONSTITUTION:An annular groove 13d is formed on the outer circumference of a working piston 13, and a seal ring 18 in a O-shape of elastic member is fitted there. And, a communicating hole 13f is formed to the working piston 13, with its one end is opened to the bottom part of one side wall 13e that constitutes the annular groove 13d and its another end is opened to a clutch housing chamber R1 communicating these annular groove 13d and clutch housing chamber R1 together. The seal ring 18 is pushed against an outer case 11 and positions in the annular groove 13d in the state of initial assembly, sealing between the outer circumference of the working piston 13 and the inner circumference of the outer case 11 liquid-tight. With these means, clutch oil does not return to the clutch housing chamber without being confined in it, eliminating lowering of the torque transmission property of the driving force transmission device in question.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a driving force transmission device that is interposed between coaxially supported rotating members and transmits torque between these two members.

(Prior Art) Such a driving force transmission device is interposed between two rotating members that are coaxially supported, and connects these two members so that torque can be transmitted to each other when the two members rotate relative to each other.
They are roughly divided into those used as a coupling mechanism for driving the driven side rotating member, and those used as a differential limiting mechanism for limiting the rotational difference between these two members. The former coupling mechanism is mainly installed in one of the power transmission lines in a real-time four-wheel drive vehicle, and the latter differential limiting mechanism is mainly installed in each differential in the vehicle.

However, as a conventional driving force transmission device,
As shown in Japanese Patent No. 240429, it is disposed between both inner and outer rotating members that are coaxially and relatively rotatably positioned,
a friction clutch that is actuated by the relative rotation of these two rotating members to generate a frictional engagement force that connects the two rotational members so that torque can be transmitted, and that increases or decreases the frictional engagement force in accordance with the applied axial pressing force; A pressing force generating means is provided for generating a pressing force in the axial direction according to the relative rotation of the two rotating members and applying the pressing force to the friction joint, and the pressing force generating means is arranged in a fluid-tight manner between the two rotating members. an actuating piston that is slidable in the axial direction and integrally rotatably assembled to the outer rotating member and faces one side of the friction clutch; a fluid chamber in which a viscous fluid is sealed; and a rotor having one or more vanes extending in the radial direction and integrally rotatably assembled to the inner rotating member in the fluid chamber. There is a driving force transmission device.

In this type of driving force transmission device, when relative rotation occurs between both rotating members, the working piston is attached to the outer rotating member so as to be integrally rotatable, and the rotor is attached to the inner rotating member so as to be integrally rotatable. Relative rotation occurs, and the viscous fluid within the fluid chamber is forced to flow by the vane portion of the rotor in the fluid chamber, and pressure is generated within the fluid chamber due to flow resistance or the like.

That is, a pressure corresponding to the differential rotation speed is generated in the pressing force generating means. This pressure pushes the actuating piston in the axial direction, causing the friction clutch to be pressed and generating a frictional engagement force in the clutch that connects both rotating members in a torque-transmitting manner. This frictional engagement force is proportional to the differential rotation speed, and a torque proportional to the differential rotation speed is transmitted between the two rotating members from one side to the other. Therefore, the driving force transmission device functions as a connection mechanism between the driving side rotating member and the driven side rotating member in one power transmission path of the four-wheel drive vehicle, and also functions as a connection mechanism between the driving side rotating member and the driven side rotating member, and between the driving side rotating member and the driven side rotating member. It also functions as a differential IJ limiting mechanism between rotating members or between both driven rotating members.

(Problems to be Solved by the Invention) By the way, in the above-mentioned type of driving force transmission device,
A friction clutch storage chamber located on the opposite side of the working piston from the fluid chamber and housing the friction clutch contains clutch oil that lubricates and cools the friction clutch. The viscosity properties of such clutch oil are significantly different from those of the viscous fluid stored in the fluid chamber, so if both of them coexist, the viscosity properties of the viscous fluid will change and the pushing force generated by the pushing force generating means will fluctuate. This results in fluctuations in the torque transmission characteristics of the driving force transmission device.

In this type of driving force transmission device, a zero-shaped seal member made of an elastic member that fits into an annular groove provided in the actuating piston provides a liquid-tight seal between the actuating piston and the outer rotating member. As a result, the fluid chamber and the clutch chamber are fluid-tightly isolated. In this state,
The sealing member is pressed and deformed between the actuating piston and the outer rotating member and fitted together.

5(a) to 5(d) schematically show the fitted state of the seal member I8, and the seal member 18 is initially assembled as shown in FIG. 5(a). Then, it is fitted into the annular groove 13d of the actuating piston 13 and is pressed and deformed by the actuating piston 13 and the outer rotating member 11. In this state, when the driving force transmission device operates and a pressing force is generated in the fluid chamber to push the actuating piston 13, the piston 13 and the sealing member 18 are separated as shown in FIG. 5(b).
At the same time, high pressure viscous fluid F2 is present in one example of the seal member 18, and clutch oil P is present in the other side.
i is located, and the sealing member work 8 is pressed by the viscous fluid pressure against the clutch housing chamber side wall work 3e in the annular groove 13d, as shown in FIG. 3(c). As a result,
Clutch oil Pi is placed at the bottom of the side wall 13e of the annular groove 13d.
is contained. When these conditions are repeated, the sealing member 18 loses its elasticity due to thermal and mechanical action, and eventually the pressure of the sealing member 18 against the annular groove 13d becomes lower than the pressure of the sealed clutch oil F1. , or when the operating state is canceled and the pressure in the fluid chamber decreases, the clutch oil F1 is reduced as shown in Fig. 5(d).
As shown by the arrow, the fluid flows to the viscous fluid F2 side and mixes. Therefore, the viscosity characteristics of the viscous fluid F2 change, impairing the torque transmission characteristics of the driving force transmission device. It is therefore an object of the present invention to address such problems.

(Means for Solving the Problems) In the driving force transmission device of the type described above, the present invention is provided on the outer periphery of the actuating piston to provide a fluid-tight connection between the actuating piston and the outer rotating member. The present invention is characterized in that a communication hole is provided at the bottom of the side wall of the annular groove into which a O-shaped seal member made of an elastic member for sealing is fitted, and which opens toward the housing chamber of the friction clutch.

(Operations and Effects of the Invention) In the driving force transmission device having such a configuration, the clutch oil trapped between the side wall of the annular groove and the seal member when the actuating piston is pushed is transferred to the clutch storage chamber through the communication hole provided in the actuating piston. It will not flow back and be contained,
Mixing of the clutch oil with the viscous fluid due to such containment does not occur, and the torque transmission characteristics of the drive force transmission device do not deteriorate.

(Example) Examples of the present invention will be described below based on the drawings.
The figure shows an embodiment of the driving force transmission device according to the present invention. As shown in FIG. 3, the driving force transmission device 10 is disposed in a rear wheel power transmission path of a real-time four-wheel drive vehicle.

In this vehicle, the front wheels are always driven and the rear wheels are driven when necessary. A transaxle 22 attached to one side of the engine 21 is equipped with a transmission/chiron and a transfer, and transmits power from the engine 21 to an axle shaft 23. The output drives the front wheels 24, and the first
Output to propeller Yaft 25. The first propeller/yaft 25 is connected via the drive power transmission device 10 to a second propeller shaft 26, both shafts 25, 26
When the torque can be transmitted, the power is output to the axle shaft 28 via the rear differential 27, and the power is transmitted to the rear wheels 2.
9 is driven.

Thus, the driving force transmission device 10 includes a pressing force generating means 10a and a friction clutch 10b in an annular working chamber consisting of an outer case 11 and an end cover 15, which are outer rotating members, and an inner shaft 12, which is an inner rotating member. There is.

The outer case 11 includes an inward flange portion 11b at one end of a cylindrical portion 11a having a predetermined length, and an end cover 15 is screwed onto the opening at the other end of the cylindrical portion 11a. Inner shaft 12
is provided with an outward flange portion 12b on the outer periphery of the intermediate portion of a stepped cylindrical portion 12a of a predetermined length, an outer spline portion 12c extending in the axial direction is formed on the outer periphery of the flange portion 12b, and an inner spline portion 12c on one end side of the cylindrical portion 12a is formed on the outer periphery of the flange portion 12b. An internal spline portion 12d extending in the axial direction is formed on the periphery. Inner shirt) 12
In this case, one end of the cylindrical portion 12a is connected to the outer case 11.
The end cover 15 is fluid-tightly and rotatably fitted into the inner hole of the inwardly directed 7 flange portion 11b, and the other end thereof is supported in the inner hole of the end cover 15. The inner shaft 12 is fixed at its inner spline portion 12d by fitting into the spline 26a at the tip of the second propeller shaft 26, and the outer case 11 is fixed to the rear end of the first propeller shaft 25.

The pressing force generating means 10a includes an operating piston 13 and a rotor 14, and the friction clutch 10b is of a wet type multi-plate clutch type, and includes a large number of clutch plates 16 and clutch discs 17. Each clutch plate 16 has a spline portion on its outer periphery fitted into a spline portion lie provided on the inner periphery of the outer case 11, and is assembled to the case 11 so as to be integrally rotatable and movable in the axial direction. Each clutch disk 17 has a spline portion on its inner circumference fitted into an outer spline portion 12c of the inner shaft 12, and is positioned between each clutch plate 16.
It is assembled to be rotatable and movable in the axial direction. A predetermined amount of clutch oil and gas are sealed in the storage chamber R1 of the clutch plate 16 and the clutch disc 17.

The actuating piston 13 constituting the pressing force generating means 10a is rotatable integrally with the inner periphery of the other end side of the cylindrical portion 11a of the outer case 11 in a fluid-tight manner and slidable in the axial direction, They are respectively assembled to the outer periphery so as to be rotatable and slidable in the axial direction in a liquid-tight manner, and the other side surface 13a is in contact with the clutch plate 16 at the rightmost end in the figure. As shown in FIGS. 1 and 2, the rotor 14 includes two vane portions t4b extending in the radial direction at positions 180° apart from each other on the outer periphery of the annular boss portion 14a. It is fitted onto the outer periphery of the space 12a of the inner shaft 12, and is assembled to be able to rotate integrally with the shaft 12. Such a rotor 14 is a working piston 13
It is formed to have approximately the same thickness as the depth of the annular recess 13b provided on one side of the annular recess 13b, and is fitted into the annular recess 13b. The end cover 15 is fluid-tightly fitted to the outer periphery of the other end side of the cylindrical portion 12a of the inner/yield shell 12 so as to be slidable and rotatable in the axial direction, and is screwed onto the outer case 11 so as to be movable forward and backward. , and is liquid-tight. In such an end cover 15, the position of the outer case 1 is adjusted in the axial direction.
1 by caulking means, its side surface 15a abuts one side annular outer edge surface 13c of the working piston 13, and the rotor 14 is positioned between the side surface 15a and the annular recess 13b of the working piston 13. A fluid chamber is formed.

This fluid chamber is filled with a highly viscous fluid such as silicone oil, and the rotor 14 has the outer periphery of its vane portion 14b in liquid-tight contact with the inner periphery of the annular recess 13b, and the fluid chamber is divided into two retention chambers. It is divided into R2.

In this embodiment, an annular groove 13d is formed on the outer periphery of the actuating piston 13 as shown in FIGS. 18 are fitted. In addition, the working piston 1
3 is formed with a communication hole 13f. One end of the communication hole 13f opens at the bottom of one side wall 13e constituting the annular groove 13d, and the other end opens into the clutch housing chamber R1, thereby communicating the annular groove 13d and the clutch housing chamber R1. . When the seal ring 18 is initially assembled, as shown in FIG. outer periphery and outer case 1
1 and the inner periphery thereof is liquid-tightly sealed.

In the driving force transmission device IO having such a configuration, torque is transmitted when relative rotation occurs between the first and second propeller shafts 25,26. That is, when relative rotation occurs between these two shafts 25 and 26, the outer case 11. Relative rotation occurs between the working piston 13 and the end cover 15, and the inner shaft 12 and rotor 14, which are integrally rotatably assembled to the second propeller shaft 26. 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 viscous fluid in the retention chamber R2 moves relative to each other sequentially in the circumferential direction. Due to the resistance, a pressure distribution is generated in which the pressure is gradually increased from the downstream end of the vane section 14b to the upstream end of the next vane section 14b. The increased pressure portion of this pressure distribution increases in proportion to the differential rotation speed, and presses the actuating piston 13 in the axial direction.

As a result, the actuating piston 13 presses the friction clutch lOb, and each clutch plate 16 and clutch disc 17
are frictionally engaged via clutch oil. As a result, in the friction clutch 10b, torque proportional to the differential rotation speed is transmitted from the outer case 11 to the inner shaft 12, and the vehicle enters a four-wheel drive state.

Further, in this four-wheel drive state, differential rotation between the front and rear wheels is allowed, and occurrence of tight corner braking is also prevented.

By the way, in the driving force transmission device 10, the sill ring 18 is in the state shown in FIG. The piston 13 slides to the left in the figure to the state shown in FIG.
8 is pressed by the high-pressure viscous fluid F2 in this state, and becomes the state shown in FIG. 8(e). In such a state, the seal ring 18 forms an annular groove! It is in pressure contact with the side wall 13e of 3d,
The clutch oil Fl is tried to be contained between the side wall 13e and the same side wall 13e. However, there is no communication hole in the containment area.
3f is open, the pressure in the fluid chamber becomes low and the actuating piston 13 closes to the seal ring 1 as shown in FIG.
8, the clutch oil F1 will not flow back into the clutch storage chamber R1 and be contained. Therefore, even if the seal ring 18 deteriorates due to long-term use and its elasticity decreases, the clutch oil PI will not be mixed in the viscous fluid F2, and the torque transmission characteristics will not deteriorate due to such mixture. Nothing happens.

In the above embodiment, the rotor 14 is disposed between the operating piston 13 and the end cover 15, but the rotor 14 may be disposed between the bottom wall of the outer case 11 and the operating piston I3. , a friction clutch lOb may be disposed between the actuating piston 13 and the end cover 15.

[Brief explanation of the drawing]

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 cross-sectional view taken in the direction of arrow nn in Fig. 1, and Fig. 3 is a schematic diagram of a vehicle employing the same device. Figure, Figure 4(a)~
(d) is an enlarged sectional view of the fitting portion of the seal ring which is the main part of the present invention, and FIGS. 5(a) to 5(d) are FIGS. It is an enlarged sectional view corresponding to (d). Explanation of symbols 10... Drive force transmission device, loa... Pressing force generation means, 10b... Friction clutch, 11... Outer case, 12... Inner shaft, 13... Working piston, 13d... Annular groove, 13f... Communication hole, 13e... Side wall, 14... Rotor,
14b... Vane part, 15... End cover,
16...Clutch plate, 17...Clutch disc, 1B...Seal ring, 25.26...Propeller shaft, R1...Clutch housing chamber, R2...
Retention chamber (fluid chamber), F2...viscous fluid, Fl...clutch oil.

Claims (1)

[Claims] It is disposed between the inner and outer rotating members that are coaxially and relatively rotatably positioned, and is actuated by the relative rotation of these rotating members to generate and apply a frictional engagement force that connects the two rotating members so that torque can be transmitted. A friction clutch that increases or decreases the friction engagement force in accordance with an axial pressing force, and a pressing force generating means that generates an axial pressing force in accordance with the relative rotation of both rotating members and applies it to the friction clutch, an actuating piston in which the pressing force generating means is slidable fluid-tightly in the axial direction between the two rotary members and integrally rotatably assembled with the outer rotary member, and is opposed to one side of the friction clutch;
a fluid chamber formed between the outer rotating member and the actuating piston, having a predetermined interval in the axial direction, and enclosing a viscous fluid;
A driving force transmission device comprising: a rotor having one or more vane portions extending in a radial direction and integrally rotatably assembled to the inner rotating member in the fluid chamber; An O-shaped sealing member made of an elastic member provided on the outer periphery of the piston to fluid-tightly seal between the actuating piston and the outer rotating member opens at the bottom of the side wall of the annular groove into which the friction clutch is fitted. A driving force transmission device characterized in that a communication hole is provided that opens to the storage chamber side.