JPH0348030A - Driving force transmission device - Google Patents

Abstract

PURPOSE:To prevent fine particles of metal from being produced by interposing a pressing member, by which a rotor is repulsively pressed so as to be abutted on an abrasion resistance member, between one side surface of the rotor and an inside rotating member, so that a minute clearance can be formed between respective side surfaces. CONSTITUTION:In a driving force transmission device 10, a rotor 14 is energized by a dish spring 18b constituting a retaining means so that it is always maintained in such a condition that it is abutted on a thrust washer 18a. Therefore, both side surfaces 14c, 14d of the rotor 14, and respective side surfaces 13b, 15b of an operation piston 13 and a retainer 15 are kept in a parallel state in which a minute clearance is always maintained between respective side surfaces, so that shaving-off of the rotor 14 itself, that of the operation piston 13, the retainer 15 or the like due to the inclination of the rotor 14 can be prevented. Accordingly, fine particles of metal can be prevented from being produced in the inside of a fluid chamber. Thus, variation in torque transmission characteristics attributable to the change in viscosity due to the mixture of fine particles of metal into a viscous fluid, variation in the sliding resistance of the operation piston 13, or the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a driving force transmitting device which is disposed between both inner and outer rotating members that are coaxially and relatively rotatably located, and which transmits torque between these two members. Regarding equipment.

(Prior Art) Such a driving force transmission device is disposed between a driving side rotating member and a driven side rotating member, and connects these two members so that torque can be transmitted to each other when these two members rotate relative to each other, so that the driven side rotation A connecting mechanism that is used as a coupling mechanism to drive members, and a mechanism that is disposed between a driving side and a driven side rotating member, between a re-driving side rotating member, or between both driven side rotating members, and when these two members rotate relative to each other. These two members are broadly classified into those used as differential limiting mechanisms that limit the rotational difference between these two members by connecting them to each other so as to transmit torque. The former coupling mechanism is mainly disposed on one power transmission path in a real-time four-wheel drive vehicle, and the latter differential limiting mechanism is mainly disposed on 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 an axial pressing force corresponding to the relative rotation of the two rotating members and applying it to the friction clutch, and the pressing force generating means is arranged between the two rotating members in a fluid-tight manner in the axial direction. A shaft is provided between an actuating piston that is slidably attached to the outer rotating member and is integrally rotatable with the outer rotating member and faces the friction clutch, and an actuating piston that is integrally or integrally rotatably provided with the outer rotating member. a retainer forming a fluid chamber in which a viscous fluid is sealed at a predetermined interval in the direction; and one or more vanes extending in the radial direction, the retainer being integrally assembled to the inner rotating member in the fluid chamber. There is a driving force transmission device configured with a rotor.

In this type of driving force transmission device, when relative rotation occurs between both rotating members, an actuating piston and a retainer are assembled to be integrally rotatable with the outer rotating member, and a rotor is integrally assembled with the inner rotating member. During this period, relative rotation occurs, and the viscous fluid within the enclosure chamber is forced to flow by the vane portion of the rotor in the fluid chamber, and pressure is generated within the enclosure 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 coupling 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. It also functions as a differential limiting mechanism between rotating members or between both driven rotating members. Therefore, in such a driving force transmission device, the rotor must be assembled so that both sides of the rotor and each side of the operating piston and the retainer are always maintained in a parallel state. As shown, annular guide portions 1a and 2a that slightly protrude toward the fluid chamber are provided on the inner circumferential side of the actuating piston 1 and the retainer 2, and the rotor 3 It is conceivable that there is a means for maintaining the holder in a predetermined upright position.

(Problem to be Solved by the Invention) In the above-described type of driving force transmission device, when all or part of the operating piston, rotor, retainer, etc. are made of aluminum alloy, etc., if the above-mentioned holding means is adopted, the rotor There is a risk that the rotor will be worn out due to mutual sliding between the rotor, the working piston, and the retainer, and the minute gaps between both side surfaces of the rotor and each side of the working piston and retainer will increase, causing the rotor to tilt. When the rotor tilts, at least one of the rotor, the actuating piston, and the retainer is scraped, and metal fine powder is generated in the fluid chamber, causing a change in the viscosity of the viscous fluid. In addition, some of the metal fine powder migrates to the outer circumferential side of the fluid chamber due to the action of centrifugal force during high-speed rotation of both rotating members, and then passes through the minute gap between the contact surfaces of the operating piston and the retainer to the outer rotating member. and the outer circumference of the working piston, and the sliding resistance of the working piston against the outer rotating member increases and fluctuates. For this reason, there is a risk that the generation of the metal fine powder described above may lead to an unstable state such as a decrease in torque transmission characteristics, and there is also a risk that the sealing performance for the seal portion of the operating piston may be reduced. It is therefore an object of the present invention to address such problems.

(Means for Solving the Problems) The present invention provides a driving force transmission device of the type described above, in which the rotor is assembled to the outer periphery of the inner rotating member so as to be slidable only in the axial direction, and A wear-resistant member is interposed between the other side surface of the rotor facing the side surface, and the rotor is elastically pressed between one side surface of the rotor and the inner rotating member to abut against the wear-resistant member. The present invention is characterized in that a pressing member is interposed therebetween to form a minute gap between the respective side surfaces.

(Operations and Effects of the Invention) According to this configuration, the rotor is moved by the action of the pressing member.
Since it is held in contact with the wear-resistant member, the working piston and each side surface of the retainer are always in a parallel state with a small gap maintained between them.

This causes the rotor to tilt, causing the rotor itself, the working piston,
The retainer etc. will not be scraped. Therefore, metal fine powder is not generated, viscosity changes due to metal fine powder mixed into the viscous fluid, fluctuations in torque transmission characteristics caused by fluctuations in the sliding resistance of the working piston, etc. are prevented, and the seal portion of the working piston is prevented from changing. This prevents the sealing performance from deteriorating.

(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. 5, 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 and a transfer, and outputs the driving force from the engine 21 to an axle shaft 23. The power is output to the first propeller shaft 25 and drives the front wheels 24 . The 110th spatula shaft 25 is connected to the second propeller shaft 26 via the drive force transmission device 10, and both shafts 25.2
6 is capable of transmitting torque, the driving force is output to the axle shaft 28 via the rear differential 27, and the rear wheels 29 are 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 made up of an outer case 11 and an inner shaft 12.

The outer case 11 includes an inward flange portion 11b at one end of a cylindrical portion 11a having a predetermined length, the other end of the cylindrical portion 11a is open, and a threaded portion 11c is formed on the inner periphery of the other end. The inner shaft 12 has a stepped cylindrical portion 12a having a predetermined length.
An outer spline portion 12b is formed on the outer periphery of the intermediate portion of the flange portion 12b, and an outer spline portion 12C extending in the axial direction is formed on the outer periphery of the flange portion 12b. A spline portion 12d is formed. In such an inner shaft 12, the cylindrical portion 12
One end of a is rotatably fitted into the inner hole of the inward flange portion 11b of the outer case 11 in a liquid-tight manner, and the cylindrical portion 1
Pushing force generating means 10, which will be described later, is assembled on the outer periphery of the other end of 2a.
It is rotatably supported by the outer case 11 via the component a. 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 is fixed to the outer case 1.
1 is fixed to the rear end of the 110th bell shaft 25.

The pressing force generating means 10a includes an operating piston 13 and a rotor 14.
and a retainer 15, and a friction clutch 10b
The clutch is of a wet type multi-plate clutch type and consists of 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 lid 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, is located between each clutch plate 16, and is assembled to the shaft 12 so as to be rotatable and movable in the axial direction. It is being

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 is slidable in the axial direction. They are respectively attached to the outer periphery thereof in a liquid-tight manner so as to be rotatable and slidable in the axial direction, and their negative side surface 13a abuts against 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 14b extending in the radial direction at positions 180° apart from each other on the outer periphery of the annular boss portion 14a. is spline-fitted to the outer periphery of the cylindrical portion 12a of the inner shaft 12 and assembled so as to be slidable in the axial direction,
It is held by a holding means that will be described later. Such a rotor 1
4 is formed to have approximately the same thickness as the depth of the annular recess 15b provided on one side of the retainer 15, and is fitted into the annular recess 15b. The retainer 15 has a threaded portion 15a on the outer periphery of the other end, is fitted to the outer periphery of the other end of the cylindrical portion 12a of the inner shaft 12 so as to be slidable and rotatable in the axial direction in a fluid-tight manner, and is fitted to the outer case 11. For the screw part 15
a is screwed into the threaded portion 11c of the outer case 11 so that it can move forward and backward, and is liquid-tight. In this retainer 15, the position of the outer case 1 is adjusted in the axial direction.
1 by caulking means, and the annular outer edge surface 1 on the negative side thereof.
5c contacts the other side surface 13b of the working piston 13, and the negative side surface 15b and the other side surface 13b of the working piston 13 form a fluid chamber in which the rotor 14 is located. A predetermined amount of highly viscous fluid such as silicone oil is sealed in this fluid chamber, and the rotor 14 has its vane portion 14. The outer periphery of the annular recess 15b is brought into liquid-tight contact with the inner periphery of the annular recess 15b, thereby dividing the fluid chamber into two retention chambers R2.

As shown in FIG.
2e so as to be slidable in the axial direction, and is held by a holding means consisting of a thrust washer 18a, a disc spring 18b, and a snap ring 18c. Thrust washer 1
8a is made of a wear-resistant material with a low coefficient of friction, and retainer 1
The disc spring 18b is fitted into the annular recess 15d of No. 5 and protrudes toward the fluid chamber by a predetermined amount. The thrust washer 18a is pressed against the thrust washer 18a. As a result, both sides 14c and 14d of the rotor 14
and each side 13b of the actuating piston 13 and retainer 15.
, 15b, and these side surfaces 13b, 14c, 14d, and 15b are parallel to each other.

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 25,26. That is, when relative rotation occurs between these two shafts 25 and 26, the outer case 11, the operating piston 13, and the retainer 15, which are assembled to the first propeller shaft 25 so as to be integrally rotatable, and the second
Relative rotation occurs between the inner shaft 12 and the rotor 14, which are assembled to the propeller shaft 26 so as to be able to rotate together. 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 10b to bring each clutch plate 16 and clutch disk 17, which constitute the friction clutch 10b, into frictional engagement via the 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.

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

By the way, in the driving force transmission device 10, the rotor 1
4 is biased by a disc spring 18b constituting a holding means and is always held in contact with the thrust washer 18a, so that both side surfaces 14c and 14d of the rotor 14, and each side surface 13b of the actuating piston 13 and the retainer 15, 15b, the rotor 14 is always in a parallel state with a small gap maintained, and the rotor 14 itself, the actuating piston 13, and the retainer 15 are tilted.
Therefore, metal fine powder is not generated in the fluid chamber. Therefore, fluctuations in torque transmission characteristics caused by changes in viscosity due to the mixing of fine metal powder into the viscous fluid, fluctuations in sliding resistance of the working piston 13, etc., are prevented, and the working piston 13, outer case 11, and inner shaft 12 are prevented from changing. It is possible to prevent the sealing performance of the sealing member interposed between the parts from being deteriorated.

In the above embodiment, the thrust washer 18a is used as the holding means for the rotor 14, but a needle bearing 18d can be used instead of the thrust washer 18a as shown in FIG. Further, in the above embodiment, a fluid chamber is formed between the actuating piston 13 and the retainer 15, and the rotor 1 is provided in the fluid chamber.
4, a fluid chamber is formed between the inner wall of the outer case 11 and the actuating piston, and the rotor 14 is disposed in the fluid chamber, and a friction clutch 10b is provided between the actuating piston and the retainer 15. may be placed.

[Brief explanation 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 cross-sectional view taken in the direction of arrows - ■ in FIG.
The figure is an enlarged sectional view of the main part of the device, FIG. 4 is a sectional view showing a modified example of the rotor holding means, FIG. 5 is a schematic diagram of a vehicle adopting the same device, and FIG. 6 is the rotor holding means. FIG. 4 is a sectional view corresponding to FIG. 3 showing a comparative example. Explanation of symbols 10... Drive force transmission device, 10a... Pressing force generation means, 10b... Friction clutch, 11... Outer case, 12... Inner shaft, 13... Working piston, 14... Rotor, 14b... Vane part, 15...
- Retainer, 15b, 15d... recess, 16... clutch plate, 17... clutch disc, 18a
... Thrust washer, 18b... Belleville spring, 18d
. Needle bearing, 25.26...propeller shaft.

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, The pressing force generating means is configured to include an actuating piston that is slidable liquid-tightly in the axial direction between the two rotary members and integrally rotatable with the outer rotary member and faces the friction clutch; a retainer that is integrally or rotatably provided with the actuating piston and forms a fluid chamber in which a viscous fluid is sealed, having a predetermined spacing between the retainer and the actuating piston; and one or more vanes extending in the radial direction. and a rotor integrally rotatably assembled to the inner rotating member in the fluid chamber, the rotor sliding around the outer periphery of the inner rotating member only in the axial direction. A wear-resistant member is interposed between one side of the retainer and the other side of the rotor opposite to the same side, and the rotor is elastically attached between one side of the rotor and the inner rotating member. A driving force transmission device characterized in that a pressing member is interposed to press against the wear-resistant member, and a minute gap is formed between each of the side surfaces.