JPH01303328A - Driving force transmitting device - Google Patents

Abstract

PURPOSE:To prevent wear of a tire and deterioration of fuel consumption by interposing a release spring for pushing an operating piston 7 in the direction reverse to the pushing direction of a clutch means, between the operating piston and a housing. CONSTITUTION:Between an operating piston 7 and a housing 1, there is interposed a non-linear release spring 10 for energizing the operating piston 7 in the direction reverse to the pushing direction of a multi-plate type clutch 18. When there occurs micro-differential rotation due to the effective diameter difference of the tire or air pressure difference so as to generate a small internal pressure in a gap 8, the operating piston 7 is pushed back by a release spring 10. This prevents the pressurization between an outer plate 5 and inter plate 6 so as to prevent the torque transmission. Thus, it is possible to prevent wear of the tire and deterioration of fuel consumption.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is an 11μ power transmission system that transmits rotational power between two relatively rotatable shafts when differential rotation occurs between the two shafts. It is related to the device.

<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 multi-disc clutch is normally provided for torque transmission, and this multi-disc clutch is operated by an actuating piston to which pressure is applied depending on the differential rotation of the front and rear wheels or the left and right wheels. It is designed to be frictionally engaged.

<Problems to be Solved by the Invention> In this type of driving force transmission device, clutch lubricating oil is sealed in a sealed chamber in which the multi-disc clutch is arranged, and the multi-disc clutch is lubricated. A small differential rotation is always generated between the front and rear wheels or the left and right wheels due to the effective diameter difference between the left and right tires, the air pressure difference, etc., and the pressure generated by this differential rotation causes a large amount of The plate clutch is always frictionally engaged. Therefore, if the connection between the two axles is strong, it will cause tire wear and worsen fuel efficiency.Furthermore, it will be impossible for the clutch lubricating oil to enter the friction surface l\, which will worsen the lubricity and cause the multi-disc clutch to There are problems in that durability is significantly impaired due to wear and seizure due to overheating.

Means for Solving the Problems The present invention has been made in view of the above problems, and consists of a clutch means disposed between two relatively rotatable shafts and transmitting torque between the two shafts. and a driving force transmission device comprising: a pressure generating means for generating pressure according to the differential rotation of the two shafts; and an actuating piston for controlling the transmission torque of the clutch means by a torque of the pressure generating means. Between the working piston and the housing that houses the working piston, there is one non-linear release spring that presses the working piston in the opposite direction to the pressing direction of the first stage of the clutch.
A non-linear release spring is inserted which presses in a direction opposite to the pressing direction of the interposed plate clutch.

<Operation> With the above configuration, while the differential rotation is small, the release spring pushes back the actuating piston to open the clutch means, thereby increasing the lubricity of the clutch lubricating oil.

In addition, by making the release spring non-linear,
The increased deflection of the release spring reduces the load, reducing torque transmission loss in areas with large differential rotation.

<Example> Hereinafter, an example of the present invention applied to a 4'[H motion will be described based on the drawings. In FIG. 1, reference numeral 1 denotes a cylindrical housing, 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 into the opening 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 provided on the inner periphery of the housing 1.
are engaged in the rotational direction by a spline and are arranged side by side so as to be movable in the axial direction.

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, A multi-plate clutch 18 is formed as clutch means.

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

An axial gap 8 is provided between the actuating piston 7 and the cap 2 on all four sides thereof, and a rotor 9 having a wall thickness and a gap 8 is slidably housed in the gap 8. ing. As shown in FIG. 2, this rotor 9 has blades 11 formed in the diametrical direction, the center of which is engaged with the outer periphery of the input shaft 4 by a spline. 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.

Further, a non-linear release spring 10 is interposed between the actuating piston 7 and the housing 1 to urge the actuating piston 7 in a direction opposite to the pressing direction of the multi-disc clutch 18.

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 due to high viscosity oil is generated in the gap 8 where the 17-taper 9 is housed, and the operating piston 7 toward the multi-disc clutch 18 side is not generated.

When differential rotation occurs between the input shaft 4 and the housing 1,
The high viscosity oil sealed in the gap 8 is forcibly moved between the two closely spaced surfaces by the blades 11 of the rotor 9 at a flow rate corresponding to the rotational speed difference, and due to viscous friction between the cap 2 and both end surfaces of the actuating piston 7. Generates internal pressure according to differential rotation.

This internal pressure forces the actuating piston 7 against the release spring 10.

However, even if a minute relative rotation (differential rotation) occurs due to the difference in effective diameter of the tires, the difference in air pressure, etc., and a small internal pressure is generated in the gap 8 due to high viscosity oil, the release spring 10 It overcomes the push toward the plate clutch 18 and pushes back the operating piston 7. Therefore, since the outer plate 5 and the inner plate 6 are not in n-contact and no torque is transmitted, 41! In a l-drive vehicle, the vehicle has two-wheel drive, either the front wheels or the rear wheels.

As the differential rotation between the input shaft 4 and the housing 1 increases, the pressure acting on the actuating piston 7 also increases, so that the actuating piston 7 overcomes the spring force of the release spring 10 and the multi-disc clutch 18 Press
The rotational driving force of the human power shaft 4 is transmitted to the housing 1 through this multi-disc clutch 18, resulting in 4@drive.

By the way, the nonlinear release spring 10 has a third
It has the characteristics shown in the figure. In other words, in the case of a linear spring, the spring load 1' increases linearly in proportion to the deflection of the spring, as shown by line D in Figure 3.
In the case of a nonlinear spring, as shown in line A in Figure 3, the spring load increases as the spring deflection increases, but once the spring deflection increases to a certain point, even if the deflection increases beyond that point, the spring load will increase. The load decreases. Utilizing this characteristic, a nonlinear release spring 10 is created with ε shown in FIG. Set it to the mounting position.

As a result, as shown in FIG. 4, the transmission torque characteristic based on the differential rotation has a characteristic indicated by cMA. That is, in a region where the differential rotation is small, no transmission torque is generated, and in a region where the differential rotation is large, characteristics shown by line D, which are close to those without the spring, are obtained. Further, when a linear spring is used, the characteristic will be the characteristic of the E line in FIG. 4, and when this is compared to the characteristic of the present invention of the C line, a transmission torque loss of only '■' can be prevented.

In the above embodiment, the actuating piston 7 is connected to the multi-disc clutch 1.
The pressure generating means for pressing in the welding direction of 8 has a structure using a blade 11 that rotates within the gap 8 filled with high viscosity oil, but the present invention can also be applied to a plunger type or vane type differential pump type. The invention can also be applied to control the pressing force of the clutch means without relying on differential rotation.

<Effects of the Invention> 4. As described above, the present invention has a non-linear release spring interposed between the actuating piston and the housing, which presses the actuating piston in a direction opposite to the pressing direction of the clutch means. Because of this structure, a slight differential rotation is always generated between the two shafts due to the difference in effective diameter of the tires, the difference in air pressure, etc., and even if pressure is generated in the pressure generating means, it is activated by the release spring force. Since the piston is pushed back and the clutch means is not engaged, torque transmission to the two shafts is reliably interrupted. Therefore, tire wear and fuel efficiency will not deteriorate.

In addition, the clutch lubricating oil effectively enters the friction surfaces of the clutch means, improving lubricity, preventing overheating of the clutch means, and improving durability.

Furthermore, the non-linear release spring allows the spring load to be large in the micro-differential rotation region and to be reduced in the large differential rotation region, thereby reducing the transmission torque loss and achieving high transmission torque characteristics. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a sectional view of the driving force transmission device, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a spring load characteristic of a nonlinear spring and a linear spring. FIG. 4 is a comparison diagram of transmission torque characteristics based on differential rotation in the case of the present invention, without a spring, and in the case of using a linear spring. DESCRIPTION OF SYMBOLS 1... Housing, 2... Cap, 4... Input shaft, 5... Outer plate, 6... Inner plate, 7... Operating piston, 9... Rotor, 10...
Release spring, 11...Blade, 18...
clutch means. Patent applicant: Toyoda Machine Machinery Co., Ltd. Agent: Mr. Hirai
Part drawing figure 2

Claims (1)

[Claims] A clutch means disposed between two relatively rotatable shafts and transmitting torque between the two shafts, a pressure generating means generating pressure according to the differential rotation of the two shafts, and a pressure generating means generated by the pressure generating means. In a driving force transmission device comprising an actuation piston that controls transmission torque of the clutch means, the actuation piston is moved in a direction opposite to the pressing direction of the clutch means between the actuation piston and a housing that accommodates the actuation piston. A driving force transmission device characterized by interposing a nonlinear release spring that presses the force.