JP2557083B2 - Driving force transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a driving force transmission in which rotational power of an input shaft is transmitted to an output shaft when differential rotation occurs between the input shaft and the output shaft. It relates to the device.

<Prior Art> In a torque transmission device for a four-wheel drive vehicle, a torque is generated between a front wheel drive shaft (input shaft) and a rear wheel drive shaft (output shaft) in a sealed clutch chamber formed between the shafts. A multi-disc clutch for transmitting the torque is arranged, and an operating piston for controlling the transmission torque of the multi-disc clutch by the hydraulic pressure of hydraulic pressure generating means for generating hydraulic pressure according to the differential rotation between the front wheel drive shaft and the rear wheel drive shaft. A driving force transmission device provided with is disclosed in, for example, JP-A-60-25.
It is known from Japanese Patent No. 2026.

The hydraulic pressure generating means of this one incorporates a plunger type or vane type oil pump for discharging hydraulic pressure between the front wheel drive shaft and the rear wheel drive shaft according to the differential rotation of both shafts, and discharges from this oil pump. The pressure oil is introduced into a cylinder chamber on one side of the working piston through a pressure introducing passage formed in one of both shafts, and the multi-plate clutch is pressed by the working piston in the joining direction.

Further, as the hydraulic pressure generating means, an axial gap limited between the working piston and the cylinder housing is provided on the side of the working piston, and the axial gap has a thickness substantially equal to that of the gap. A thin rotor is housed, this rotor is connected to one of the front wheel drive shaft and the rear wheel drive shaft, and the other is connected to the cylinder housing, and a plurality of blades are provided on the circumference of the rotor. The above-mentioned space is divided into a plurality of parts on a circumference by a blade, and a high-viscosity oil is sealed in each of these spaces, which is provided by the applicant of the present invention in Japanese Patent Application No. 62-75240.

<Problems to be Solved by the Invention> In any of the driving force transmission devices provided with the hydraulic pressure generating means having any of the above configurations, clutch lubricating oil is enclosed in a closed clutch chamber in which a multi-plate clutch is arranged. .

The temperature of the clutch lubricating oil rises due to frictional heat of the clutch when the multi-plate clutch is continuously operated. In this case, if the amount of air in the clutch chamber is too small, the clutch lubricating oil thermally expands (volume expands) at high temperature and pushes back the working piston, and as a result, the pressing force of the multi-plate clutch by the working piston is eliminated. , The transmission torque decreases. Further, if the amount of air is too large, the lubrication effect of the multi-plate clutch 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 between an input shaft and an output shaft is sealed in a closed clutch chamber. A multi-plate clutch that is arranged to transmit torque between both shafts, a hydraulic pressure generating unit that generates hydraulic pressure according to the differential rotation between the input shaft and the output shaft, and the multi-pressure clutch by the hydraulic pressure of the hydraulic pressure generating unit. In a driving force transmission device including an actuating piston for controlling the transmission torque of a plate clutch, the air filling rate in the clutch chamber is set to 20 to 30% of the clutch chamber volume.

<Operation> In the present invention, the amount of air filled in the clutch chamber is set to 20 to 30% of the clutch chamber volume, so that the thermal expansion of the clutch lubricating oil at high temperature is suppressed and the lubricity of the multi-plate clutch is secured. To do.

<Examples> Examples of the present invention will be described below with reference to the drawings. First
In the figure, reference numeral 1 denotes a cylindrical auging, which also serves as an output shaft to which a rear wheel drive shaft is coupled. This housing 1
Is open only on one side, and a cap 2 is tightly fitted in the opening to form a closed clutch chamber 3.

An input shaft 4 is rotatably supported by the housing 1 and the cap 2 concentrically with the housing 1. The input shaft 4
One end of a front wheel drive shaft is coupled to the.

Clutch lubricating oil is sealed in the clutch chamber 3, and a plurality of outer plates 5 are arranged side by side on the inner circumference of the housing 1 so as to engage with each other by a spline in the rotational direction and axially movable. ing.

On the other hand, on the outer periphery of the input shaft 4, a plurality of inner plates 6 are arranged side by side so as to engage with each other by a spline in the rotational direction and movably in the axial direction. The outer plates 5 and the inner plates 6 are alternately arranged. So-called multi-disc clutch 18
Is formed.

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

A slight axial gap 8 is provided between the actuating piston 7 and the cap 2 on the side of the cap 2, and a thin roller 9 having substantially the same thickness as the gap 8 can slide in the gap 8. It is stored in. As shown in FIG. 2, a blade is formed in the rotor 9 in the diameter direction, and the central portion of the rotor 9 is spline-engaged with the outer circumference of the input shaft 4. The rotor 9 is
The outer circumference may be spline-engaged with the inner circumference of the housing 1 on the housing 1 side instead of the input shaft 4 side. Then, a highly viscous oil such as silicone oil is enclosed in the gap 8.

According to the present invention, in the above structure, the air filling rate in the clutch chamber 3 is set to 20 to 30% of the capacity of the clutch chamber 3.

With the above configuration, when the input shaft 4 and the housing 1 also serving as the output shaft do not rotate relative to each other, the internal pressure due to the highly viscous oil is not generated in the gap 8 in which the rotor 9 is housed, and the working piston 7 is No actuating force for pushing the multi-disc clutch 18 side is generated. Therefore, the outer plate 5 and the inner plate 6 do not slip and torque is not transmitted, and in a four-wheel drive vehicle, two-wheel drive of the front wheels or the rear wheels is performed.

However, when the input shaft 4 and the housing 1 rotate differentially and the rotor 9 rotates in the gap 8, the high-viscosity oil sealed in the gap 8 causes a difference in rotational speed between the two surfaces approached by the blade of the rotor 9. Is forcedly moved at a flow velocity corresponding to, and an internal pressure is generated by viscous friction between the cap 2 and both end surfaces of the working piston 7. Due to this internal pressure, the operating piston 7 presses the multi-plate clutch 18 in the joining direction, the rotational power of the input shaft 4 is transmitted to the housing 1, and four-wheel drive is performed.

When the multi-plate clutch 18 is continuously operated in this way, the temperature of the clutch lubricating oil in the clutch chamber 3 rises due to the frictional heat between the outer plate 5 and the inner plate 6, but the air filled in the clutch chamber 3 is increased. Since the amount is 20 to 30% of the volume of the clutch chamber 3, the amount of air is not too small or too large, the thermal expansion of the clutch lubricating oil due to the temperature rise is suppressed as much as possible, and the multiple disc clutch is used.
Holds the lubrication effect of 18.

It is effective to increase the air filling rate in terms of the reduction of the transmission torque due to the thermal expansion of the clutch lubricating oil at high temperature.However, as a result of experimental research, the durability of the clutch due to the air filling rate and the lubricating action of the multi-plate clutch 18 is As shown in Fig. 3, when the air filling rate is 30% or more, the clutch lubrication effect decreases, and the durability of the multi-plate clutch 18 rapidly deteriorates.
20-30% was found to be the optimum rate. In the above-described embodiment, the hydraulic pressure generating means for pressing the working piston 7 based on the differential rotation between the input shaft 4 and the housing 1 in the connecting direction of the multi-plate clutch is the rotor 9 rotating in the gap 8 filled with high-viscosity oil. However, the present invention can also be applied to a plunger type or vane type oil pump type.

<Effects of the Invention> As described above, according to the present invention, a multi-plate clutch controlled by an operating piston is provided in a closed clutch chamber between an input shaft and an output shaft, and clutch lubricating oil is provided in the closed chamber. In the enclosed driving force transmission device, since the air filling rate in the closed clutch chamber is set to 20 to 30% of the volume of the clutch chamber, the clutch lubricating oil at high temperature due to too little air amount The effect of ensuring the transmission torque and the durability of the multi-disc clutch by suppressing the thermal expansion, preventing the reduction of the transmission torque, and preventing the deterioration of the lubrication effect of the multi-disc clutch due to the excessive air amount. have.

[Brief description of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a sectional view of a driving force transmission device, Fig. 2 is a sectional view taken along line II-II of Fig. 1, and Fig. 3 shows a relationship between air filling rate and clutch durability. It is a curve figure shown. 1 ... Housing, 2 ... Cap, 3 ... Clutch chamber, 4 ... Input shaft, 5 ... Outer plate, 6 ...
Inner plate, 7 ... Working piston, 18 ... Multi-plate clutch.

Claims (1)

(57) [Claims] 1. A multi-plate clutch, which is arranged in a closed clutch chamber in which clutch lubricating oil is sealed between an input shaft and an output shaft, and transmits torque between the both shafts, and the input shaft and the output shaft. In the driving force transmission device, there is provided a hydraulic pressure generating means for generating hydraulic pressure according to the differential rotation of the clutch, and an operating piston for controlling the transmission torque of the multi-disc clutch by the hydraulic pressure of the hydraulic pressure generating means. A drive force transmission device characterized in that the air filling rate in the interior is 20 to 30% of the clutch chamber volume.