JPH01234624A - Driving power transmission device - Google Patents

Abstract

PURPOSE:To restrain thermal expansion due to the temperature rise of sealed clutch lube oil and prevent a drop in transmission torque by keeping an air filling rate within a clutch amber for housing a multi-disc clutch at a specific ratio for chamber capacity. CONSTITUTION:A lubricating oil is sealed in a chamber 3 where a multi-disc clutch 18 is housed, and an air filling rate is kept at 20-30% of the capacity of the chamber 3. When the multi-disc clutch 18 is continuously operated with a working piston 7, the temperature of lubricating oil is raised with the frictional heat of an outer plate 5 and an inner plate 6. The thermal expansion of lubricating oil, however, is restrained as much as possible with air filled in the chamber 3 up to 20-30% thereof, and a lubricating effect for the multi- disc plate 18 is maintained. It follows, therefore, that the drop of transmission torque due to the thermal expansion is avoided as much as possible and a lubricating effect is maintained, thereby ensuring durability.

Description

[Detailed Description of the Invention] <Industry> Field of Application The present invention provides a driving force 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. The present invention relates to a transmission device.

<Prior art> 4. In a torque transmission device for a drive vehicle, torque is transmitted between the front wheel drive shaft (input shaft) and the rear wheel drive shaft (output shaft) in a sealed clutch chamber formed between the two shafts. an operating piston 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 the differential rotation between the front wheel drive shaft and the rear wheel drive shaft; A driving force transmission device equipped with
It is publicly known from the No. 2026 publication.

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. A configuration in which the pressurized oil is introduced into the cylinder chamber on one side of the operating screws 1 to 1 through a pressure introduction path formed on one of both shafts, and the multi-disc clutch is pushed in the engaging direction by the operating piston. Further, as the hydraulic pressure generating means, an operating screw 1 is used to maintain a limited axial clearance between the hydraulic pressure generating means and the cylinder housing that accommodates the operating piston.
A thin-walled rotor having a wall thickness approximately the same as that of the gap is housed in the axial gap, and this rotor is connected to either the front wheel drive shaft or the rear wheel drive shaft, and The cylinder housing is connected to the other side, a plurality of blades are provided on the circumference of the rotor, the space is divided into a plurality of parts on the circumference by these blades, and high viscosity oil is sealed in each of these spaces. The applicant filed a patent application for the composition in 1986.
No. 2-75240.

<Problems to be Solved by the Invention> Even in a driving force transmission device equipped with a hydraulic pressure generating means having a top-circuit configuration, clutch lubricating oil is sealed in a closed clutch chamber in which a multi-disc clutch is disposed. There is.

When the multi-disc clutch is continuously operated, the temperature of this clutch lubricating oil increases due to the frictional heat of the clutch. in this case,
If the amount of air in the clutch chamber becomes too small, the clutch lubricating oil will thermally expand (volume expansion) at high temperatures, causing the operating screw 1 to
As a result, the pressing force of the multi-disc clutch by the actuating screws 1 to 1 is reduced, and the transmission power and torque are reduced. Furthermore, when the amount of air increases, the lubrication effect of the multi-disc clutch decreases.

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 chamber between an input shaft and an output shaft is filled with clutch lubricating oil. 1 between the two axes
- a multi-disc clutch that transmits torque, a hydraulic pressure generating means that generates hydraulic pressure according to the differential rotation between the input shaft and the output shaft, and a hydraulic pressure of the hydraulic pressure generating means that transmits torque of the multi-disc clutch; In the driving force transmission device, the air filling rate in the clutch chamber is set to 20 to 30% of the clutch chamber volume.

Kusaku Kawa> The present invention suppresses the thermal expansion of the clutch lubricating oil at high temperatures and ensures the lubricity of the multi-disc clutch by setting the air filling amount in the clutch chamber to 20 to 30% of the clutch chamber volume. do.

<Example> Hereinafter, an example of the present invention 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 clutch 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 clutch chamber 3, and a plurality of outer plates 5 are arranged in parallel on the inner periphery of the housing 1 and are engaged in the rotational direction by splines and are movable in the axial direction. ing.

On the other hand, on the outer periphery of the input shaft 4, a plurality of inner plates 1-6 are arranged in parallel so as to be engaged with each other in the rotational direction by splines and to be movable in the axial direction, and these outer plates 5 and inner plates 6 are arranged alternately. The so-called multi-disc clutch 1
8 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 gap 8 is provided between the actuating piston 7 and the cap 2 on the side of the cap 2, and a thin rotor 9 having a substantially concave wall thickness is formed in this gap 8. is slidably housed.

As shown in FIG. 2, 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 spline-engaged with the inner circumference of the housing 1 on the housing 1 side instead of on the input shaft 4 side. A highly viscous oil such as silicone oil is sealed in the gap 8.

In the above configuration, the present invention sets the air filling rate in the clutch chamber 3 to 20 to 3() of the volume of the clutch chamber 3.
%.

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 in which 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 1-6 slip, and 1-luke transmission is performed, resulting in two-wheel drive with the front or rear drive shaft 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 or the blades of the rotor 9 cause the two to approach each other.
The fluid is forcibly moved between the surfaces at a flow rate corresponding to the difference in rotational speed, and internal pressure is generated due to viscous friction between the cap 2 and both end surfaces of the actuating screws 1 to 7. Due to this internal pressure, the operating screw 1hen 7 presses 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 operated continuously in this way, the temperature of the clutch lubricating oil in the clutch chamber 3 rises due to the frictional heat between the outer plays 1 to 5 and the inner plays 1 to 6, but the temperature of the clutch lubricating oil in the clutch chamber 3 increases. Since the amount of air is 20 to 30% of the volume of the clutch chamber 3, the amount of air is not too small or too large, and the thermal expansion of the clutch lubricating oil due to the temperature rise is suppressed as much as possible. Maintains the lubricating action of the clutch 18.

It is more effective to increase the air filling rate in order to reduce the transmission torque due to heat PM of the clutch lubricating oil at high temperatures. However, as a result of experimental research, we found that the clutch Looking at the durability, as shown in Figure 3, when the air filling rate exceeds 30%, the clutch lubrication effect decreases, and the durability of the multi-disc clutch 18 deteriorates rapidly. It turns out that there is something.

In the above embodiment, the hydraulic pressure generating means for pressing the actuating piston 7 in the multi-disc clutch engagement direction based on the differential rotation between the input shaft 4 and the housing 1 is the rotor 9 rotating within 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, in the present invention, a multi-plate clutch controlled by an actuating piston is installed in a sealed clutch chamber between an input shaft and an output shaft, and a clutch is installed in the sealed chamber. In driving force transmission devices that contain lubricating oil,
Since the air filling rate in the sealed clutch chamber is set to 20 to 30% of the volume of the clutch chamber,
An appropriate amount of air to suppress the thermal expansion of the clutch lubricating oil at high temperatures due to a small gap in the amount of air, prevent a decrease in transmission torque, and prevent a decrease in the lubrication effect of a multi-disc clutch due to a large gap in the amount of air. This has the effect of maintaining the transmission torque and the durability of the multi-disc clutch.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; 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 shows the relationship between air filling rate and clutch durability. FIG. ■... Housing, 2... Cap, 3... Clutch chamber, 4... Input shaft, 5... Outer play 1-16... Inner plate, 7... Operating screw 1~
18...Multi-disc clutch.

Claims (1)

[Claims] Clutch between input shaft and output shaft A multi-disc clutch is placed in a sealed clutch chamber filled with lubricating oil and transmits torque between both shafts, and differential rotation between the input shaft and output shaft is achieved. In the driving force transmission device, the driving force transmission device includes a hydraulic pressure generating means that generates a corresponding hydraulic pressure, and an operating piston that controls the transmission torque of the multi-disc clutch by the hydraulic pressure of the hydraulic pressure generating means. A driving force transmission device characterized in that the volume of the clutch chamber is 20 to 30% of the clutch chamber volume.