JPH02120531A - Driving force transmission - Google Patents

Abstract

PURPOSE:To automatically control transmitting torque characteristic according to differential rotation by providing a spring between a working piston and a cylinder housing, and fitting a sub-working piston to the working piston so as to be relatively slidable and movable in one body. CONSTITUTION:In the case of small differential rotating speed, the generated pressure cannot move a working piston 36 against the spring 50 force in the direction to a multiple disc clutch 40. Meanwhile, a sub-working piston 51 is actuated by pressure in proportion to pressure receiving area from a pressure through hole and pushably presses the clutch 40. However, as the pressure receiving area of the piston 51 is smaller than that of the piston 36, transmitting torque is small at small differential rotation. In the case of large differential rotating speed, the generated pressure accordingly becomes large over the spring 50 force acting on the piston 36, the piston 36 moves in the direction to the clutch 40, pushably presses the clutch 40 with a big force through the piston 51, and transmitting torque becomes large.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a driving force transmission device that transmits rotational power between two relatively rotatable shafts when differential rotation occurs between the two shafts. It is related to.

<Prior Art> Generally, in a four-wheel drive drive force transmission device that transmits torque between the front and rear wheels, or a drive force transmission device for differential restriction that transmits torque between the left and right wheels, etc. , a clutch means for transmitting torque, a piston that operates the clutch means, and a pressure generating section that generates pressure according to the differential rotation of the front and rear wheels or the left and right wheels, and the generated pressure is applied to the piston. The clutch means is actuated to frictionally engage the clutch means.

By the way, with the main purpose of reducing the size and weight of the driving force transmission device 17, a space filled with a high viscosity fluid is provided on the side of the piston, a blade is housed in this space, and the space is expanded by the differential rotation. By relatively rotating the blades within the unit, a high viscosity fluid is forcibly moved between two close surfaces, and the viscous friction of the high viscosity fluid generates pressure corresponding to the differential rotation.1 This pressure is applied to the piston. The applicant of the present invention has previously provided a driving force transmission device in which a clutch means is engaged by a driver (Japanese Patent Application No. 75240/1986).

<Problem to be solved by the invention> In this type of driving force transmission device, the transmitted torque capacity can be freely changed by changing the axial dimension of the space or the radial length of the blade. If the torque capacity is increased, there is a problem of tight corner braking, and conversely, if the transmitted torque capacity is decreased, there is a problem of poor stall escape performance.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems, and its characteristic configuration is that the invention is arranged between two relatively rotatable shafts, In a driving force transmission device comprising a clutch means for transmitting torque between the clutch means and an actuation piston for controlling the transmission torque of the clutch means, a cylinder housing accommodating the actuation piston is connected to one of the two shafts. , a rotating shaft rotatably supported by the cylinder housing is connected to the other side, a space is provided in the cylinder housing on the side of the working piston, and the end face of the working piston on the side of the space, or this end face is connected to the other end. A blade stored in the space on the opposing end face of the cylinder housing is connected to either one of the two shafts, a high viscosity fluid is sealed in the space, and the blade is actuated between the actuating piston and the cylinder housing. A spring is provided for restricting the movement of the piston toward the clutch means, and a sub-operating screw 1 that contacts the clutch means is fitted to the operating piston so as to be able to slide relative thereto and move integrally with the operating piston, The operating piston is provided with a pressure hole that communicates the rear end surface of the sub-actuating piston with the space.

Effects> The present invention has the above-described configuration, so that the actuating piston is not actuated until a pressure is generated that overcomes the spring force, and during that time, a pressure proportional to the pressure-receiving area of the sub-actuating piston acts,
The pressing force of this auxiliary actuating piston presses the clutch means and transmits a small torque.

When the differential rotation speed exceeds a certain value and the generated pressure becomes greater than the spring force, the actuating piston operates and presses the clutch means with a larger pressing force to achieve large transmission torque characteristics.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, 30 is a driving force transmission device. 32 is a cylinder housing to which one end of the input shaft is connected. Reference numeral 31 denotes a housing cap that is integral with the cylinder housing 31, and the inside of the cylinder housing 32 is sealed thereby.

This cylinder housing 32 and housing cap 31
A rotating shaft 33 is rotatably supported concentrically with the cylinder housing 32. One end of an output shaft is coupled to the rotating shaft 33 .

A clutch lubricating oil 27 is sealed inside the cylinder housing 32, and the cylinder housing 3
A plurality of outer plates 37 are arranged on the inner periphery of the outer plate 2 so as to be engaged with each other in the rotational direction by splines and to be movable in the axial direction.

On the other hand, a plurality of inner plates 38 are provided on the outer periphery of the rotating shaft 33.
are engaged in the rotational direction by a spline and are arranged in parallel so that they can move in the axial direction. These outer plates 37 and inch plates 38 are arranged alternately to constitute a multi-plate clutch 40 as clutch means. Inside the cylinder housing 32, there is a housing cap 31 between the multi-disc clutch 4G and the cylinder housing 32 (in the illustrated example, a housing cap 31
) between the actuating piston 36 and the cylinder housing 32
The actuating force of this actuating piston 36 is transmitted to the arm plate clutch 40.

A space 44 consisting of an axial gap is provided on the side of the actuating piston 36 between it and the housing cap 31 (or between it and the cylinder housing 32). A diametrical blade 42 having a wall thickness of 44 and 2 hours is housed. This blade 42 is splined to the rotating shaft 33. The space 44 is filled with a highly viscous fluid such as silicone oil.

A spring 50 is interposed between the actuating piston 36 and the cylinder housing 32, and movement in the direction of the multi-disc clutch 40 is restricted by the spring 50. The set load of the spring 50 is set to restrict the movement of the actuating piston 36 until the pressure of the hydraulic pressure generating means is reached when the differential rotation speed exceeds a certain value.

Further, a sub-actuating piston 51 that contacts the multi-disc clutch 40 is fitted into the actuating piston 36 so as to be capable of relative sliding and movement together with the actuating piston 36, and the rear end surface of the sub-actuating piston 51 and the space 44 A pressure passage 652 is provided which communicates with the

With the above configuration, when the cylinder housing 32 and the rotating shaft 33 differentially rotate, the high viscosity fluid sealed in the space 44 is forced by the blade 42 between the two closely spaced surfaces at a flow rate corresponding to the rotational speed difference. As the cylinder housing 32 moves, internal pressure is generated due to viscous friction with the end face of the cylinder housing 32. That is, for example, in FIG.
On the other hand, when the blade 42 rotates clockwise, internal pressure is generated with a high pressure distribution on the A1 and A2 surfaces of the blade 42 and a low pressure distribution on the B1.82 surface.

The pressure generated in this space 44 is proportional to the rotation speed of the blade 42, that is, the differential rotation speed. Therefore, at a small differential rotation speed, the generated pressure overcomes the force of the spring 50 and prevents the actuating piston 36 from moving toward the multi-disc clutch 40, thereby restricting its movement.

On the other hand, pressure is applied to the rear end surface of the sub-actuating piston 51 from the pressure through hole 52 in proportion to the pressure receiving area, thereby pressing the multi-disc clutch 40 . However, the actuating piston 36
Since the pressure-receiving area of the sub-actuating piston 51 is smaller than that of
As shown by curve A in the figure, when the differential rotation ΔN is small, the transmitted torque T is small.

When the differential rotation speed is large, the generated pressure increases accordingly, and when this exceeds the elastic limit of the actuating piston 36 by the spring 50, the actuating piston 36 moves toward the multi-disc clutch 40, and the sub-actuating piston 51 The multi-disc clutch 40 is pressed with a large force via the multi-disc clutch 40 to increase the transmitted torque T as shown by the curve A in FIG.

Further, when the cylinder housing 32 and the rotating shaft 33 are not differentially rotated, no internal pressure is generated due to the high viscosity fluid in the space 44 consisting of the axial gap in which the blade 42 is housed, and the multi-plate Clutch 40 does not perform any torque transmission action.

In the embodiment L, the clutch means is a multi-plate clutch 40.
However, it is not necessarily limited to the multi-disc clutch 40.

<Effects of the Invention> As described above, the present invention provides a high viscosity fluid on the side of the actuating piston that controls the clutch means that transmits torque between two relatively rotatable shafts by differential rotation between the two shafts. An enclosed space is provided, and the actuating piston is brought into pressure contact with the clutch means by the internal pressure caused by the high viscosity fluid generated in the space by the rotation of the blade housed in the space, wherein the actuating piston is brought into pressure contact with the clutch means by a certain constant value. A spring is used to restrict the elastic force so that the hydraulic pressure generated by the differential rotation as described above operates, and a sub-actuating piston, which operates by the pressure generated by the small differential rotation, is provided on the operating piston so that it can slide relative to the operating piston and move together with it. Because of this configuration, the transmitted torque is suppressed when the differential rotation is low, ensuring maneuverability when turning at low speeds, and the transmission torque is large when the differential rotation is high, which requires four-wheel drive. This has the effect of automatically changing and controlling the transmission torque characteristics according to the differential rotation.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Figure 1 is a sectional view of the driving force transmission device, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 shows the difference between the conventional and the present invention. FIG. 4 is a characteristic diagram of transmission torque due to dynamic rotation. 31... Housing cap, 32... Cylinder housing, 33... Rotating shaft, 36... Operating piston, 40... Multi-disc clutch, 42... Blade, 44
...Space, 50...Spring, 57...Sub-actuating piston, 52...Pressure through hole. Patent applicant Toyota Machinery Co., Ltd. Agent Hirai, Radical Figure 2 Section 1 Figure 3 ΔN Differential rotation

Claims (1)

[Claims] A driving force transmission device comprising a clutch means disposed between two relatively rotatable shafts and transmitting torque between the two shafts, and an actuating piston controlling the transmission torque of the clutch means. A cylinder housing that accommodates the working piston is connected to the other side, and a rotating shaft rotatably supported on the cylinder housing is connected to the other side, and a space is provided in the cylinder housing on the side of the working piston, and a space is provided in the cylinder housing on the side of the working piston. A blade stored in the space is connected to either one of the two shafts on an end face on the side of the space, or an end face of the cylinder housing opposite to this end face, and a high viscosity fluid is sealed in the space, A spring is provided between the actuating piston and the cylinder housing to restrict movement of the actuating piston toward the clutch means, and a sub-actuating piston that abuts the clutch means is caused to slide relative to the actuating piston and the actuating piston. A driving force transmission device, which is fitted so as to be integrally movable, and has a pressure hole in the actuating piston that communicates the rear end surface of the sub-actuating piston with the space.