JPH01169132A - Driving force transmission device - Google Patents

Abstract

PURPOSE:To secure torque transmission by communicating a sealed chamber with an oil chamber which has a means for changing the volume thereof according to a volume expansion of a clutch lubricating oil in the sealed chamber due to a temperature-rise. CONSTITUTION:The temperature of a clutch lubricating oil in a sealed chamber 3 is increased by friction heat between an outer plate 5 and an inner plate 6. The volume of the clutch lubricating oil expands due to the temperate-rise, thereby a piston 13 retreats against the pressing force of a spring 15, and the volume of an oil chamber 10 is increased according to the volume expansion of the clutch lubricating oil. The volume expansion of the clutch lubricating oil generated in the sealed chamber 3 is adsorbed accordingly, the hydraulic pressure therein is prevented from rising, repressing of an operation piston 7 which presses a multi-plate clutch 18 in a connection direction is prevented. Thus, torque transmission can be secured.

Description

[Detailed description of the invention] <Industrial application> The present invention provides a driving force transmission system that transmits the rotational power of the input shaft to the output shaft when differential rotation occurs between the input shaft and the output shaft. It is related to the device.

<Prior art> In a torque transmission device for a four-wheel drive vehicle, torque is transmitted between a front wheel drive shaft (input shaft) and a rear wheel drive shaft (output shaft) within a sealed chamber formed between the two shafts. A multi-disc clutch is arranged, and an operating piston is provided that controls the transmission torque of the multi-disc clutch by the hydraulic pressure of a hydraulic pressure generating means that generates a hydraulic pressure corresponding to differential rotation between a front wheel drive shaft and a rear wheel drive shaft. A driving force transmission device is known, for example, from Japanese Patent Laid-Open No. 60-252026.

The hydraulic pressure generating means of this device incorporates a plunger-type or vane-type oil pump that discharges hydraulic pressure in accordance with the differential rotation of both shafts between the front wheel drive shaft and the rear wheel drive shaft, and the hydraulic pressure is discharged from this oil pump. The pressurized oil is introduced into a cylinder chamber on one side of the actuating piston through a pressure introduction path formed on one of both shafts, and the multi-disc clutch is pressed in the engaging direction by the actuating piston.

Further, as the hydraulic pressure generating means, a limited axial clearance is provided on the side of the working piston between the cylinder housing that houses the working piston, and a wall thickness approximately the same as that of the clearance is provided in the axial clearance. A thin-walled rotor is housed, the rotor is connected to either the front wheel drive shaft or the rear wheel drive shaft, the cylinder housing is connected to the other, and a plurality of blades are provided on the circumference of the rotor, and these rotors are connected to one of the front wheel drive shaft and the rear wheel drive shaft. The applicant of the present application has proposed a structure in which the space is divided into a plurality of spaces on the circumference by a blade and high viscosity oil is sealed in each of these spaces in Japanese Patent Application No. 75240/1982.

<Problems to be Solved by the Invention> In the driving force transmission device equipped with the hydraulic pressure generating means having any of the above configurations, clutch lubricating oil is sealed in the sealed chamber in which the multi-plate clutch is disposed.

The temperature of this clutch lubricating oil increases due to the frictional heat of the clutch when the multi-disc clutch is continuously operated differentially. This temperature rise causes the clutch lubricating oil to expand in volume, and this volumetric expansion pushes back the actuating piston.As a result, the pressing force of the multi-disc clutch by the actuating piston is reduced and the transmitted torque is reduced.

Means for Solving the Problems> The present invention has been made in view of the above problems, and has a structure in which a clutch lubricating oil is placed between the input shaft and the output shaft in a sealed chamber. a multi-disc clutch that transmits torque between both shafts; a hydraulic pressure generating means that generates hydraulic pressure according to the differential rotation between the input shaft and the output shaft; A driving force transmission device including an actuating piston that controls transmission torque of a clutch,
The oil chamber is connected to the sealed chamber and includes a means for changing the volume of the clutch lubricating oil in accordance with the volume expansion of the clutch lubricating oil due to an increase in the temperature of the clutch lubricating oil in the sealed chamber.

With the above configuration, when the clutch lubricating oil expands in volume due to a rise in temperature, the volume of the oil chamber communicating with the sealed chamber changes greatly in accordance with the volumetric expansion, and the volumetric expansion of the clutch lubricating oil is transferred to the oil chamber. It is absorbed by

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In Fig. 1, 1 is a cylindrical housing, which also serves as an output shaft to which a rear wheel drive shaft is connected.
Ill! Only one side is opened, and a cap 2 is attached to that opening.
are tightly fitted to form a sealed chamber 3.

An input shaft 4 is rotatably supported on the housing 1 and the cap 3, concentrically with the housing 1. One end of a front wheel drive shaft is coupled to the input shaft 4.

Clutch lubricating oil is sealed in the sealed chamber 3, and a plurality of outer plates 5 are arranged in parallel on the inner periphery of the housing 1 to be engaged in the rotational direction by splines and movable in the axial direction. There is.

On the other hand, on the outer periphery of the input shaft 4, a plurality of inner plates 6 are engaged with each other in the rotational direction by splines, and are arranged side by side so as to be movable in the axial direction, and these outer plates 5 and inner plates 6 are arranged alternately, So-called multi-plate clutch 18
is formed.

An actuating piston 7 is slidably fitted in the housing 1 between the multi-disc clutch 18 and the cap 2, and the actuating force of the actuating piston 7 is transmitted to the multi-disc clutch 18.

A slight axial clearance 8 is provided between the operating piston 7 and the cap 2 on the side thereof, and a thin-walled rotor 9 having approximately the same wall thickness as the clearance 8 slides into this clearance 8. possible storage.

As shown in FIG. 3, this rotor 9 has blades formed in the diametrical direction, and the center portion thereof is engaged with the outer periphery of the input shaft 4 by a spline. Note that the rotor 9 may be connected to the housing 1 side instead of to the input shaft 4 side, and its outer periphery may be spline-engaged to the inner periphery of the housing 1, and high viscosity oil such as silicone oil may be filled in the gap 8. has been done.

Furthermore, an oil chamber 10 is formed within the input shaft 4 and communicates with the sealed chamber 3 through a passage 11. Therefore,
This oil chamber 10 is also filled with the clutch lubricating oil sealed in the sealed chamber 3. The oil chamber 10 is provided with means for changing the volume in accordance with the volume expansion of the clutch lubricating oil due to an increase in the temperature of the clutch lubricating oil. In the first embodiment, as shown in FIG. 1, a cylinder 12 communicating with the oil chamber 10 is provided in the input shaft 4, and a piston 13 is fitted into the input shaft 4 so as to be able to move forward and backward. Further, a nut 14 is screwed into the opening of the cylinder 12 that opens at the rear of the piston 13, and a spring 15 is interposed between the nut 14 and the piston 13.
The piston 13 is always pressed in the forward direction. Note that a through hole 16 is formed in the nut 14 to communicate the inside of the cylinder 12 behind the piston 13 with atmospheric pressure, thereby performing a breathing action that allows the piston 13 to move forward and backward.

With the above configuration, when the input shaft 4 and the housing 1, which also serves as the output shaft, are not rotating relative to each other, no internal pressure is generated due to high viscosity oil in the gap 8 where the rotor 9 is housed.
No actuation force is generated to push the actuation piston 7 toward the multi-disc clutch 18.

Therefore, the outer plate 5 and the inner plate 6 slip and no torque is transmitted, resulting in 2Va drive of the front or rear drive wheels in a four-wheel drive vehicle.

However, when the input shaft 4 and the housing 1 rotate differentially and the rotor 9 rotates within the gap 8, the high viscosity oil sealed in the gap 8 is brought closer by the blades of the rotor 9.
It is forcibly moved between the surfaces at a flow rate corresponding to the rotational speed difference, and internal pressure is generated due to viscous friction between the cap 2 and both end surfaces of the actuating piston 7. This internal pressure causes the actuating piston 7 to press the multi-disc clutch 18 in the engaging direction, transmitting the rotational power of the input shaft 4 to the housing 1, resulting in four-wheel drive.

When the multi-plate clutch 18 is continuously differentially operated in this way, the temperature of the clutch lubricating oil in the sealed chamber 3 increases due to the frictional heat between the outer plate 5 and the inner plate 6. Due to this temperature rise, the Kura-Tsuchi lubricating oil expands in volume, and this volumetric expansion force causes the piston 13 to move backward against the pressing force of the spring 15, increasing the volume of the oil chamber 10 in accordance with the volume expansion. do. This absorbs the volume expansion of the clutch lubricating oil that occurs in the sealed chamber 3, suppresses the rise in oil pressure in the sealed chamber 3, prevents the actuating piston 7 that presses the multi-disc clutch 18 in the engagement direction from being pushed back, and transmits torque. ensure that

In addition to the first embodiment, the means for changing the volume of the oil chamber 10 includes a second embodiment shown in FIG. Diaphragm 17 due to volumetric expansion force
The volume expansion of the oil chamber 10 can be increased by changing the volume of the oil chamber 10 to absorb the volume expansion.

Further, in the first and second embodiments, the oil chamber 10 provided with the volume changing means is provided on the input shaft 4, but it is also possible to provide it on the housing 1 or the like in addition to the input shaft 4. Furthermore, the first
In the embodiment shown in Fig. 2 and Fig. 2, the hydraulic pressure generating means for pressing the operating piston 7 in the multi-disc clutch engagement direction based on the differential rotation between the input shaft 4 and the housing 1 rotates within a gap 8 filled with high viscosity oil. j by the rotor 9? Although it is of fA construction, the present invention can also be applied to plunger type or vane type oil pump types.

<Effects of the Invention> As described above, the present invention includes a multi-disc clutch controlled by an actuating piston in a sealed chamber between an input shaft and an output shaft, and clutch lubricating oil is sealed in the sealed chamber. In the driving force transmission device, an oil chamber communicating with the sealed chamber is provided, and the volume of the oil chamber is changed in accordance with the volume expansion of the clutch lubricating oil due to a temperature rise of the clutch lubricating oil in the sealed chamber. Since the structure is equipped with means, the clutch lubricating oil is
Even if it expands, it is absorbed by the oil chamber, and the clutch lubricating oil can push back the actuating piston that controls the multi-disc clutch, eliminating the effect of reducing the clutch pressing force.As a result, a decrease in transmitted torque can be prevented. There are advantages to doing so.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a cross-sectional view of a driving force transmission device, FIG. 2 is a cross-sectional view showing a modification of the same design, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. 1. . DESCRIPTION OF SYMBOLS 1... Housing, 2... Cap, 3... Sealed chamber, 4... Input shaft, 5... Outer plate, 6...
・Inner plate, 7... Operating piston, 10...
Oil chamber, 11... Passage, 13... Piston, 15... Spring, 17... Diaphragm, 1
8...Multi-plate clutch.

Claims (1)

[Claims] A multi-disc clutch between an input shaft and an output shaft that is arranged in a sealed chamber filled with lubricating oil and transmits torque between both shafts, and a multi-disc clutch that transmits torque between the two shafts, and a multi-disc clutch that is arranged in a sealed chamber filled with lubricating oil. In a driving force transmission device comprising a hydraulic pressure generating means for generating pressure and an operating piston for controlling the transmission torque of the multi-disc clutch by the hydraulic pressure of the hydraulic pressure generating means, due to a temperature rise of the clutch lubricating oil in the sealed chamber A driving force transmission device comprising an oil chamber that communicates with the sealed chamber, the oil chamber having a means for changing the volume according to the volume expansion of clutch lubricating oil.