JP2000304071A - Driving force transmitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the trailing resistance of a drive system to prevent the deterioration of fuel consumption by setting each material of an outer rotating member and a working piston so that the thermal expansion difference between the oil sealed in a clutch chamber and the fluid sealed in a working fluid chamber is absorbed by the thermal expansion difference between the outer rotating member and the working piston. SOLUTION: When a pair of propeller shafts is relatively rotated to cause a relative rotation between an outer case 10a and an inner shaft 10b, a fluid pressure is generated in the fluid chamber R2 of a pilot mechanism 10d, and a working piston 13 is axially pressed to engage a friction clutch 10c. At this time, the thermal expansion coefficient of the fluid sealed in the fluid chamber R2 is set larger than the oil sealed in a clutch chamber R1, and the linear expansion coefficient of the outer case 10a is also set larger than a working piston 13. Each material of the outer case 10a and the working piston 13 is set so that the thermal expansion difference between them is larger than the thermal expansion difference between the respective sealed oils in the fluid chamber R2 and the clutch chamber R1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmitting device.

[0002]

2. Description of the Related Art As one type of a driving force transmitting device, as disclosed in Japanese Utility Model Laid-Open No. 5-67826, an inner rotating member which is concentrically and rotatably fitted to an outer rotating member and the outer rotating member. A friction clutch disposed in a clutch chamber provided therebetween, and a pilot mechanism disposed between the two rotating members, wherein the pilot mechanism includes a side wall formed on one of the rotating members of the two rotating members. A working piston disposed between the rotating members between the side wall and the friction clutch so as to be movable in the axial direction and forming a working fluid chamber with the side wall; There is a driving force transmission device of a type constituted by a rotor which is integrally rotatably attached to the other rotating member of the member and rotates relative to the one rotating member.

The driving force transmitting device transmits a fluid pressure generated in accordance with the relative rotation of the two rotating members to the friction clutch via the operating piston, and operates the friction clutch to rotate the friction member. The clutch chamber is filled with hydraulic oil such as automatic transmission fluid (ATF), and the working fluid chamber is filled with high-viscosity fluid such as silicone oil. It is enclosed.

[0004] However, a driving force transmission device of this type is
For example, it is arranged on the rear wheel side power transmission path of the vehicle and constitutes a real-time four-wheel drive vehicle. In the four-wheel drive vehicle, one of the front and rear wheels is constantly driven, and When the differential rotation occurs, relative rotation occurs between the two rotating members, and a fluid pressure corresponding to the relative rotation is generated in the pilot mechanism to press the friction clutch, actuate the friction clutch and operate the two rotating members. A four-wheel drive state in which torque is transmitted between the two wheels to transmit driving force to the rear wheels to drive the rear wheels.

[0005]

Incidentally, when a vehicle equipped with a driving force transmission device of this type is driven at high speed under adverse conditions, for example, when there is a considerable air pressure difference between the front and rear wheels, or when one of the front and rear wheels When the vehicle is running at a high speed when the tires are considerably worn, relative rotation occurs continuously between the two rotating members, the pilot mechanism and the friction clutch operate continuously, and the driving force transmission device heats up. High temperature state.

As a result, in the driving force transmission device, the sealed oil in the clutch chamber and the sealed fluid in the working fluid chamber thermally expand. However, these sealed oils and sealed fluids are selected to have different characteristics in terms of their functions. Accordingly, the sealed fluid in the working fluid chamber has a larger thermal expansion than the sealed oil in the clutch chamber, and the internal pressure of the working fluid chamber becomes higher than the internal pressure of the clutch chamber due to the difference in thermal expansion. For this reason, the pressing force for operating the friction clutch is such that the pressure difference between the two chambers is added to the pressing force of the working piston corresponding to the relative rotation of both rotating members, and this becomes the drag resistance of the drive system. This can lead to poor fuel economy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving force transmission device of this type, which prevents the occurrence of drag resistance in a driving system to prevent deterioration of fuel efficiency.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a driving force transmitting device, and is provided in a clutch chamber provided between an outer rotating member and an inner rotating member which is concentrically and rotatably fitted to the outer rotating member. A friction clutch, and a pilot mechanism disposed between the two rotating members, the pilot mechanism, the side wall formed on one of the rotating members of the two rotating members, the said between the two rotating members A working piston disposed axially movably between the side wall and the friction clutch to form a working fluid chamber with the side wall; and the working fluid chamber integrally rotating with the other rotating member of the two rotating members. The one rotating member is assembled so as to be rotatable relative to the one rotating member, and a fluid pressure generated according to the relative rotation when the two rotating members are rotated relative to each other is forwardly adjusted via the working piston. Transmitted to the friction clutch, it is to be subject to format of the driving force transmission device which performs transmission of torque between the two rotary members by operating the same friction clutch.

The driving force transmitting device according to the present invention is the driving force transmitting device of the above-described type, wherein the difference between the thermal expansion of the sealed oil in the clutch chamber and the sealed fluid in the working fluid chamber is determined by the difference between the thermal expansion difference between the outside rotating member and The material of the outer rotating member and the material of the working piston are set so as to be absorbed by the difference in thermal expansion of the working piston.

In the driving force transmission device according to the present invention,
It is preferable that the coefficient of thermal expansion of the sealed fluid is set larger than the coefficient of thermal expansion of the sealed oil, and the coefficient of linear expansion of the outer rotating member is set larger than the coefficient of linear expansion of the working piston. In this case, it is preferable that the sealed oil is an automatic transmission fluid, the sealed fluid is a silicone oil, the outer rotating member is made of aluminum or an alloy thereof, and the working piston is made of iron.

[0011]

In the driving force transmission device according to the present invention, the difference in thermal expansion between the sealed oil in the clutch chamber and the sealed fluid in the working fluid chamber is absorbed by the difference in thermal expansion between the outer rotating member and the working piston. Is set to Therefore, when a vehicle equipped with the driving force transmission device travels at high speed under adverse conditions, the driving force transmission device is heated to a high temperature state,
The sealed oil in the clutch chamber and the sealed fluid in the working fluid chamber undergo thermal expansion, and the internal pressure of the working fluid chamber tends to be higher than the internal pressure of the clutch chamber due to the difference in thermal expansion. It is absorbed by the difference in thermal expansion between the rotating member and the working piston.

As a result, as for the pressing force for operating the friction clutch, the pressure difference between the two chambers is added to the pressing force of the working piston corresponding to the relative rotation of the two rotating members. It will decrease corresponding to the difference. That is, the difference in thermal expansion between the outer rotating member and the working piston corresponds to a decrease in the pressing force from the pilot mechanism, and there is no possibility that fuel consumption will deteriorate due to drag resistance of the drive system.

Such an effect of the driving force transmission device according to the present invention is achieved by setting the linear expansion coefficient of the outer rotating member to be larger than the linear expansion coefficient of the working piston. In this case, it is preferable that the filling oil is set to automatic transmission fluid, the filling fluid is set to silicone oil, the outer rotating member is made of aluminum or its alloy, and the working piston is set to iron.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 shows a driving force transmission device 10 according to an example of the present invention. The driving force transmission device 10 is shown in FIG.
As shown in the figure, the vehicle is mounted on a driving force transmission path to a rear wheel side of a four-wheel drive vehicle.

In the four-wheel drive vehicle, the torsion axle 21 integrally includes a transmission, a transfer, and a front differential, and the driving force of the engine 22 is transmitted to the two axle shafts 2 via the front differential 23 of the trans axle 21.
4a to drive the left and right front wheels 24b and output to the first propeller shaft 25 side. The first propeller shaft 25 is connected to the second propeller shaft 26 via the driving force transmission device 10, and when the first propeller shaft 25 and the second propeller shaft 26 are connected so as to be able to transmit torque, the first propeller shaft 25 is driven. The force is transmitted to the rear differential 27 and the rear differential 27
To both axle shafts 28a to drive the left and right rear wheels 28b.

As shown in FIG. 1, the driving force transmitting device 10 includes an outer case 10a, which is an outer rotating member.
The vehicle includes an inner shaft 10b, which is an inner rotating member, a friction clutch 10c, and a pilot mechanism 10d.

The outer case 10a includes a bottomed cylindrical front housing 11a and a rear housing 11b which is screwed into a rear end opening of the front housing 11a to cover the opening. In the outer case 10a, a first end is provided at a front end of the front housing 11a.
The propeller shaft 25 is connected to the rear end so as to be able to transmit torque.

The inner shaft 10b is inserted into the front housing 11a in a state where the inner shaft 10b penetrates the center of the rear housing 11b in a liquid-tight manner. 11b rotatably supported. The distal end of the second propeller shaft 26 is inserted into the inner shaft 10b, and is connected to transmit torque.

The friction clutch 10c is a wet multi-plate type friction clutch, and includes a number of clutch plates (an inner clutch plate 12a, an outer clutch plate 12a).
b) is provided in the clutch room R1 on the back wall side of the front housing 11a. Friction clutch 10
c, each inner clutch plate 12a is spline-fitted to the outer periphery of the inner shaft 10b and is mounted so as to be movable in the axial direction, and each outer clutch plate 12b is spline-fitted to the inner periphery of the front housing 11a. It is assembled so that it can move in the axial direction. The respective inner clutch plates 12a and the respective outer clutch plates 12b are alternately positioned, abut against each other and frictionally engage with each other, and are separated from each other to be in a free state.

The pilot mechanism 10d includes the working piston 1
3, the rotor 14, and the rear housing 11b. The working piston 13 is connected to the friction clutch 10c.
On one side between the front housing 11a and the inner shaft 10b so as to be movable in the axial direction. In the pilot mechanism 10d, the outer case 10a
Corresponds to one rotating member of the present invention, and the rear housing 11b corresponds to a side wall formed on the one rotating member of the present invention.

However, the working piston 13 is assembled to the front housing 11a so as to be liquid-tight and integrally rotatable, and to the inner shaft 10b so as to be liquid-tight and relatively rotatable. Thereby, the working piston 1
Reference numeral 3 denotes a fluid chamber R2 in which a high-viscosity fluid as a working fluid is sealed together with the rear housing 11b. The rotor 14 is located in the fluid chamber R2 in a state of being integrally rotatably mounted on the outer periphery of the inner shaft 10b. The rotor 14 includes a plurality of vanes 14a extending to the outer peripheral side, and the fluid chamber R2 is partitioned into a plurality of pressure chambers by each vane 14a.

In the pilot mechanism 10d, when the outer case 10a and the inner shaft 10b rotate relative to each other,
The rotor 14 includes the working piston 13 and the rear housing 1
1b, into each pressure chamber of the fluid chamber R2,
A pressure corresponding to the relative rotation is generated, and the generated pressure is applied to the working piston 13 as a thrust.

In the driving force transmission device 10, when the relative rotation occurs between the two propeller shafts 25 and 26 and the relative rotation occurs between the outer case 10a and the inner shaft 10b, the driving force transmission device 10 enters the fluid chamber R2 of the pilot mechanism 10d. Fluid pressure is generated, and this fluid pressure pushes the working piston 13 in the axial direction to frictionally engage the friction clutch 10c. As a result, the friction clutch 10c connects the two propeller shafts 25, between the outer case 10a and the inner shaft 10b.
The torque is transmitted in accordance with the relative rotation between the vehicle 26 and the vehicle is brought into a four-wheel drive state in real time.

Thus, in the driving force transmission device 10, the automatic transmission fluid (ATF) is sealed in the clutch chamber R1 and the fluid chamber R2
Is filled with silicone oil. On the other hand, both the front housing 11a and the rear housing 11b are made of an aluminum alloy, and the working piston 13 and the rotor 14 are made of iron. In this configuration, the coefficient of thermal expansion of each component is such that the oil sealed in the clutch chamber R1 (ATF: 0.7 × 10 ⁻³ cc / cc / ° C.) <The fluid sealed in the fluid chamber R2 (silicone oil: 0.94 × 1
0 ⁻³ cc / cc / ° C.), and the thermal (linear) expansion coefficient of each component is outer case 10 a (aluminum alloy: 22 × 10 ⁻⁶ mm / mm / ° C.)> Working piston 13
(Iron: 11 × 10 ⁻⁶ mm / mm / ° C.).

Therefore, in the driving force transmission device 10, the thermal expansion coefficient of the sealed fluid in the fluid chamber R2 is larger than the thermal expansion coefficient of the sealed oil in the clutch chamber R1, and
The linear expansion coefficient of the outer case 10a is set to be larger than the linear expansion coefficient of the working piston 13. The materials of the outer case 10a and the working piston 13 are set such that the difference in thermal expansion between these two members is larger than the difference in thermal expansion between the sealed fluid in the fluid chamber R2 and the sealed oil in the clutch chamber R1.

As a result, the difference in thermal expansion between the sealed oil in the clutch chamber R1 and the sealed fluid in the working fluid chamber R2 can be absorbed by the difference in thermal expansion between the outer case 10a and the working piston 13. For this reason, the vehicle equipped with the driving force transmission device 10 travels at high speed under adverse conditions, and the outer case 10a
When the relative rotation occurs continuously between the drive force transmission device 10 and the inner shaft 10b, the driving force transmission device 10 is heated to a high temperature state and the sealed oil in the clutch chamber R1 and the working fluid chamber R2
The sealed fluid inside expands thermally, and the internal pressure of the working fluid chamber R2 becomes higher than the internal pressure of the clutch chamber R1 due to the thermal expansion difference.

In this case, the working piston 13 moves toward the friction clutch 10c due to a change in the internal pressure between the clutch chamber R1 and the working fluid chamber R2, but the amount of movement is the thermal expansion of the outer case 10a and the working piston 13. Absorbed by the difference.

As a result, the pressing force for operating the friction clutch 10c is reduced by the outer case 10a and the inner shaft 10a.
b to the pressing force of the working piston 13 corresponding to the relative rotation of
Although the pressure difference between the clutch chamber R1 and the working fluid chamber R2 is added, the pressure difference is reduced according to the difference in thermal expansion between the outer case 10a and the working piston 13. Therefore, the outer case 10a and the inner shaft 10
The transmission torque between the points b and b decreases in accordance with the difference in thermal expansion between the outer case 10a and the working piston 13.

That is, a decrease in the transmission torque between the outer case 10a and the inner shaft 10b due to the friction clutch 10c due to a difference in thermal expansion between the outer case 10a and the working piston 13 corresponds to a decrease in the pressing force. In addition, the fuel economy does not deteriorate due to the drag resistance of the drive system.

FIG. 3 shows the relationship between the temperature and the transmission torque when a predetermined relative rotation is given between the outer case 10a and the inner shaft 10b of the driving force transmission device 10. Graph A shows the relationship between transmission torque and temperature when an iron working piston is used in the driving force transmission device 10, and Graph B shows an aluminum alloy working piston in the driving force transmission device 10. 4 shows the relationship between the transmission torque and the temperature in the case of adopting.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a driving force transmission device according to the present invention.

FIG. 2 is a schematic configuration diagram of a four-wheel drive vehicle equipped with the driving force transmission device.

FIG. 3 is a graph showing a relationship between a transmission torque and a temperature when a predetermined relative rotation is given.

[Explanation of symbols]

Reference numeral 10: driving force transmission device, 10a: outer case, 10b
... Inner shout, 10c ... Friction clutch, 10d ... Pilot mechanism, 11a ... Front housing, 11b ...
Rear housing, 12a ... inner clutch plate, 1
2b: outer clutch plate, 13: working piston,
14 ... rotor, 14a ... vane, 21 ... transaxle, 22 ... engine, 23 ... front differential, 24a ... axle shaft, 24b ... front wheel, 25,
26 ... propeller shaft, 27 ... rear differential, 28a ... axle shaft, 28b ... rear wheel, R1 ...
Clutch chamber, R2 ... fluid chamber.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masato Okamoto 1-1-1, Asahi-cho, Kariya-shi, Aichi F-term in Toyota Koki Co., Ltd. 3D043 AA01 EA18 EB00 EC01

Claims (3)

[Claims] A friction clutch disposed in a clutch chamber provided between an outer rotating member and an inner rotating member concentrically and rotatably fitted to the outer rotating member; and a friction clutch disposed between the two rotating members. Equipped with a pilot mechanism,
A side wall formed on one of the rotating members of the two rotating members,
An operating piston disposed between the two rotating members so as to be movable in the axial direction between the side wall and the friction clutch and forming a working fluid chamber together with the side wall; The one rotating member is configured to be integrally rotatable with the other rotating member and a rotor that rotates relative to the other rotating member. Fluid pressure generated according to the relative rotation when the two rotating members rotate relative to each other is configured. In a driving force transmitting device that transmits torque to the friction clutch via the operation piston and operates the friction clutch to transmit torque between the two rotating members, the sealed oil in the clutch chamber and the sealed fluid in the working fluid chamber The material of the outer rotating member and the material of the working piston are set so as to absorb the difference in thermal expansion between the outer rotating member and the working piston. That the driving force transmission apparatus. 2. The driving force transmitting device according to claim 1, wherein a coefficient of thermal expansion of the sealed fluid is larger than a coefficient of thermal expansion of the sealed oil, and a coefficient of linear expansion of the outer rotating member is set to A driving force transmission device characterized in that the driving force transmission device is set larger than the linear expansion coefficient of the working piston. 3. The driving force transmission device according to claim 1, wherein the sealed oil is an automatic transmission fluid, the sealed fluid is a silicone oil, and the outer rotating member is made of aluminum or an alloy thereof, and is used for the operation. A driving force transmission device wherein the piston is made of iron.