JPS59175631A - Frictional engagement device - Google Patents

Abstract

PURPOSE:To provide possibility of using a frictional engagement device body commonly to many types of cars by dividing a piston member into a plurality of pieces, and by allowing one of the pieces to make contact with a frictional engagement element. CONSTITUTION:A piston member is divided into a restrictional part 12a and a working part 12b, and the restrictional part 12a is fixed to a drum tubing 11a while the working part 12b is set slidable in the axial direction and in contact with a frictional engagement element 14. Thereby a comparative large torque transmission capacity is formed as standard by other common parts than the piston member, and an appropriate combination of the two piston parts 12a, 12b is used accoding to the type of car used, to provide proper torque transmission capacity. Accordingly a single frictional engagement device body can be used commonly to many types of cars.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frictional engagement device, and more particularly to a piston for a frictional engagement device that can be used commonly in various vehicles.

The present invention has a general configuration including a cylinder member, a piston member fitted into an inner chamber of the cylinder member, a rotating body arranged to be rotatable relative to the cylinder member, and the rotating body and the cylinder member. The present invention relates to an improvement in a piston for use in a frictional engagement device comprising at least one set of frictional engagement elements disposed therebetween.

Generally, in the drive system of an automobile, IT continuous opening control of power transmission by a clutch is performed, but in this case, engagement shock occurs when the clutch is engaged.

For this reason, it is common practice to lower the oil pressure when engaging and gradually engage, thereby reducing the startup (initial) torque.

However, if the transmission and clutch parts are shared and used in a wide variety of car models, the clutch's engagement force will be excessive for engines with small outputs.
A situation arises in which the locking shock cannot be alleviated unless control is performed in a hydraulic pressure range that is further below the normal control range.

That is, as shown in FIG. 1, a conventional frictional engagement device, such as a clutch, includes a cylinder member 11 constituting a drum, a piston member 12 fitted into the inner chamber of the cylinder member, and a piston member 12 opposed to the cylinder member 12. Rotating body (hub) 1 arranged as
3, disposed between the hub 13 and the piston member 12,
It consists of at least one set of frictional engagement elements 14, one of which is spline-fitted to the hub 13 side and the other to the cylinder member 11 side. Hydraulic pressure is applied between the cylinder member 11 and the piston member 12, and the piston member 12 is moved in the axial direction against the spring pressing force.
The hub 13 rotates integrally with the hub 13, and torque transmission begins.

In this case, unless the torque transmission characteristics, that is, the change in torque transmission capacity with respect to the change in the control oil pressure, are not appropriate, the engagement of the flange will not be performed smoothly. For example, if the torque transmission capacity is large for a small engine and a latch is used, the initial engagement force of the clutch will be excessive and a locking shock will occur. Therefore, in order to obtain appropriate (initial)) torque transmission characteristics, it is conceivable to lower the oil pressure even further; for example, by 0.5K
At low oil pressures below g/cm', severe oil pressure control is required, which is difficult due to mechanical resistance, temperature changes, leakage, etc., and requires changes to the hydraulic control system or is complicated. The need arises to change the Therefore, there is a limit to what can be done by changing the oil pressure, and it is not a sufficient solution.

Thus, in the past, the drum diameter was generally changed or the number of engaging friction elements (friction members) was changed, but with the former method, the clutch itself had to be modified and could not be used in common with many different car models. The cost is high, and the latter method has the disadvantage that the number of friction surfaces is limited to an even number, a value corresponding to an odd number cannot be obtained, and it can only be varied in steps.

Therefore, an object of the present invention is to provide a novel frictional engagement device that solves the two drawbacks of the conventional method. In other words, the torque transmission characteristics can be made compatible with various engine outputs without changing the dimensions and configuration of the main body (drum, etc.) of the frictional engagement device (clutch, etc.) or the control oil pressure, and the frictional engagement can be adjusted to suit various vehicle models. The objective is to make it possible to share the main body of the combined device.

The present invention provides a friction engagement device having the general configuration described at the beginning, in which a piston member is divided into a plurality of mutually movable piston parts, at least one of which is movable in an axial direction, and the friction retention element is hydraulically moved. The rotating body is coupled to the cylinder member by engaging the cylinder member.

The present invention will be described in detail below based on preferred embodiments.

Preferably 2 or 3 pistons (4 or more in some cases)
The piston portion is divided concentrically into piston portions, and at least one (preferably one) having the desired action area is actuated hydraulically to apply force to the frictional engagement element, and the cylinder member and the counter rotating body (hub) are hydraulically actuated. Rotate as one unit. The remaining piston portion promptly restricts its movement and is preferably fixed to the cylinder member so that it exerts no force on the frictional engagement element.

The non-actuating piston portions can be located on one or both of the outer and inner diameters of the drum. The pressure-receiving area of the working piston portion can be variously selected by combining the divided piston portions, increasing the degree of freedom in torque transmission capacity. Moreover, parts other than the piston member do not need to be changed and can be shared, so there is an advantage that a low-cost frictional engagement device can be provided for a single vehicle of different types.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiment, the frictional engagement device is a clutch, but the frictional engagement device according to the present invention is not limited to a clutch, but can also be applied to a brake or the like. In addition, the piston part (actuating piston) that acts on the frictional engagement element is
- The shell is pressed in the direction of releasing the attachment via a spring or other elastic means, but means other than those shown in the embodiments (such as a disc spring) may also be used.

In FIG. 2, the clutch 10 includes a drum 11, which is a cylinder member spline-fitted to an engine output shaft (not shown), and a pair of piston parts 2 (J2a, 12b) fitted into the drum 11. , consisting of a hub 13 splined to an output shaft (not shown) and a friction engagement element 14 disposed between the hub and the piston section.

The drum 11 includes a central tubular portion 11a spline-fitted to an input shaft (not shown), a flange portion 11b extending radially from one end of the tubular portion 11a, and a central tubular portion 11a extending from the outer peripheral end of the flange portion 11b. A cylinder space in which the piston member 12 is fitted is formed between the tubular portion 11a and the outer wall portion 11c.

The piston member 12 comprises two annular concentric piston parts 1
2a and 12b, and the inner diameter side piston portion is restricted from moving to the right by a snap 15 on the drum tubular portion 11a, and a sealing material 16 is provided on the contact surface with the drum tubular portion 11a and the actuating piston 12b, respectively. is provided. The actuating piston portion 12b is arranged slidably in the axial direction between the regulating piston portion 12a and the inner surface of the drum outer wall portion 11c. A sealing material 17 is provided on the s% moving surface of the operating piston portion 12b with the drum outer wall portion lie to perform sealing. A check valve 18 is provided in the working piston portion 12b to control oil discharge during the piston return stroke. This working piston part 12b is provided with a return spring provided between the snap 15 on the drum tubular part 11a and the regulating piston part 12a, or held between the retainer 19 and a retainer 20 adjacent to the right end of the working piston part 12b. 21, it is constantly pressed to the left.

The frictional engagement element 14 includes at least a pair of drum-side friction disks 14b disposed on the drum outer wall portion lie so as to be movable in the axial direction and non-rotatable relative to the drum 11;
A hub-side friction disk 14a is disposed between the friction disks 14b and is disposed on the hub 13 so as to be movable in the axial direction and not to rotate relative to the hub 13 (for example, by spline fitting). , the disk on the opposite side from the operating piston part is attached to the snap 2 on the outer wall of the drum.
2 is prevented. The frictional engagement element 14 may be dry or wet (wet as shown), and if dry, typically includes a friction facing material on the driving surface.

In the above clutch, when hydraulic pressure is introduced into the space 24 defined by the /X tube 11 and the piston part 12 through the passage (not shown) in the input shaft and the through hole 23 of the hub tubular part 11a, the working piston part 12b begins to move toward the right against the return spring 21. The operating force at this time is equal to the oil pressure times the pressure receiving area of the movable piston 12b, and is smaller than the piston operating force of the conventional clutch shown in FIG. 1 by an amount corresponding to the pressure receiving area of the regulating piston portion 12a.

The working piston portion 12b thus moved to the right,
The right end protrusion 25 presses the friction engagement element 14, and the friction disks 14a, 14b become integrated. Second drum 11
and the hub 13 begin to rotate together, and torque is transmitted from the input shaft to the output shaft.

In the illustrated example, there is an advantage that the restriction piston portion is restricted by snapping the retainer 19 of the return spring 21. In the case of using another blocking means, by setting the fixing position outside the sliding range of the piston member, it can be used for various purposes. Note that the relationship between the input and output axes can also be reversed.

FIG. 3 shows an embodiment different from the embodiment of FIG. This embodiment has the following points: the regulating piston portion 12a is located on the outer diameter side, the operating piston portion 12b is located on the inner diameter side, and one retainer 20 for the return spring 21 is not required. This is different from the embodiment shown in FIG. In this case as well, the moving force of the actuating piston portion 12b is reduced by the pressure receiving area of the restriction piston portion 12a, but the overall circumference can be made longer by providing the restriction piston portion on the outer diameter.
Even a member with a small radial width can have a large pressure receiving area, and the pressing force on the actuating piston can be greatly reduced. Although not shown, in the present invention, in addition to the above, it is also possible to provide regulating piston members on both the inner and outer diameter portions, thereby further expanding the permissible adjustment range of the torque transmission capacity.

As described above, the frictional engagement device according to the present invention is configured as a standard with a relatively large torque transmission capacity due to common parts other than the piston member, and the regulating piston part and the operating piston part are configured depending on the vehicle model. Appropriate torque transmission capacity can be obtained by appropriately combining these. In this way, the expensive latch drums and frictional engagement elements can be manufactured in large quantities to the same specifications, so the cost of the entire device can be significantly reduced. Furthermore, the present invention completely eliminates the limitation of stepwise adjustment of the frictional engagement force by increasing or decreasing the number of disc pairs of the frictional engagement elements.

Furthermore, by dividing the piston member into piston parts, a new sliding surface is created between adjacent piston parts, so in this case, the machining accuracy of the inner surface of the drum (cylinder member) can be reduced.

The non-actuating piston portion may be allowed some deformation due to hydraulic pressure. Therefore, lightweight materials or low-grade materials such as synthetic resins and composite materials can be used, and the overall cost can be further reduced and the need for weight reduction can be met.

It should be noted that the present invention does not exclude modifications that are obvious to those skilled in the art, such as changes or additions to known means, to the embodiments described above.
These naturally belong to the protection scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a conventional frictional engagement device, FIG. 2 is a partial sectional view showing an embodiment of the frictional engagement device according to the present invention, and FIG. 3 is different from FIG. 2. FIG. 3 is a partial sectional view showing the upper half of the embodiment. 11. Cylinder member (drum) 12 Piston member 1
2a, , , , , , , regulation piston portion 12
b, , , , , , , , , working piston portion 13,
, , , , , , , , , , Rotating body (hub) 14 , ,
, , , , , , , , Frictional engagement element 21 , , , , ,
,,,,,,,,Return Spring Applicant Aisin Seiki Co., Ltd. Aisin Warner Co., Ltd. Agent Patent Attorney Asa Kato Road Figure 1 Figure 2 ~ η 14c ゝ To 1 η - Figure 3 Difference 2 degrees

Claims (1)

[Claims] a cylinder member, a piston member fitted into an inner chamber of the cylinder member, a rotating body arranged to be rotatable relative to the cylinder member, and at least one pair arranged between the rotating body and the cylinder member. In a frictional engagement device comprising a frictional engagement element, the piston member is divided into a plurality of piston portions that can move freely (with respect to each other), at least one of which is movable in the axial direction, and the frictional engagement element is engaged by hydraulic pressure. A frictional engagement device characterized in that the rotating body is coupled to the cylinder member by moving the rotating body.