JP2000046071A - Return spring supporting structure of friction engaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a return spring supporting structure for friction engaging device, which abandons a retainer for supporting a return spring, reduces the number of parts and reduces cost. SOLUTION: A return spring 12 to energize a piston 10 to return in the axial direction is of wave spring type of such a structure that a leaf spring formed wavy is wound spirally in a plurality of turns so that the wave tops abut on one another, and a seat winding part 12b having a greater diameter than the other wave-form part is formed at one end of the return spring 12. The seat winding part 12b is supported directly by a snap ring 13 fitted on a drum 6 to allow omission of the use of any retainer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet multi-plate type friction engagement device used for an automatic transmission for a vehicle, and more particularly to a support structure for a return spring for urging a piston to return in an axial direction.

[0002]

2. Description of the Related Art Conventionally, a wet type multi-plate clutch or brake is provided with a return spring for urging a piston to return in the axial direction. As this return spring, a plurality of coil springs are often arranged annularly between a piston and a spring retainer.

[0003] However, in the case of the return spring having this structure, it is necessary to fix the coil spring to the spring retainer in order to prevent the coil spring from coming off due to centrifugal force.
Since the number of parts is increased, there is a disadvantage that the cost is increased.

[0004] Therefore, as a return spring, a clutch using a wave spring in which a single leaf spring formed into a waveform is spirally wound a plurality of times so that the peaks of the waves come into contact with each other has been known (see, for example, Japanese Patent Application Laid-Open No. H11-157556). 6-10226
No.).

[0005] In order to assemble such a return spring to the clutch, a retainer is necessary. However, as the number of parts increases, the assembling becomes troublesome. Accordingly, a large diameter retainer is fixed to the end turn portion on one end side of the return spring by spot welding or caulking, and the retainer is supported by a snap ring mounted on the drum to prevent the retainer from coming off.

[0006]

However, in the above-described structure, it is necessary to form a retainer separately from the return spring and fix it to the return spring by spot welding or caulking. However, there is a disadvantage that the cost is increased. Further, when a repeated load is applied, the joint between the return spring and the retainer may be disconnected, and there is a problem in terms of durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a return spring support structure for a friction engagement device that eliminates a retainer that supports a return spring, reduces the number of parts, and reduces costs.

[0008]

According to a first aspect of the present invention, there is provided a friction engagement device provided with a return spring for urging a piston to return in an axial direction. 1 shaped into a waveform
It is a wave spring in which a plurality of leaf springs are spirally wound a plurality of times so that the peaks of the waves come into contact with each other, and an end winding portion having a larger diameter or a smaller diameter than the other waveform portions is provided at one end of the return spring. The end winding part is formed and supported by a snap ring mounted on the drum. According to a second aspect of the present invention, in the frictional engagement device including a return spring for urging the piston to return in the axial direction, the return spring includes a single leaf spring formed into a wave shape and a wave peak. A wave spring wound spirally a plurality of times so as to abut each other, and a plurality of claws projecting from an inner diameter portion or an outer diameter portion of a snap ring mounted on a drum, and one end surface of the return spring. Is supported by the above-mentioned claw portions. Further, according to a third aspect of the present invention, in the first aspect, a plurality of claws are projected from an inner diameter portion or an outer diameter portion of the snap ring, and an end turn portion of the return spring is supported by the claw portions. is there.

According to the first aspect, the return spring is a wave spring, and an end turn is formed at one end of the end spring so as to protrude from the corrugated portion toward the outside diameter or inside diameter, and this end turn is directly supported by a snap ring. are doing. Therefore, the retainer can be abolished and the assemblability can be improved. Further, in the present invention, since the end turn portion and the corrugated portion functioning as a retainer are integrated, there is no possibility that the end turn portion is broken by a repeated load, and a return spring having excellent durability can be obtained. In claim 2,
The return spring is a wave spring, and a plurality of claws project from an inner diameter or an outer diameter of a snap ring mounted on the drum, and one end surface of the return spring is supported by the claws. That is, the retainer is abolished by adding the function of the retainer to the snap ring. Claim 3 further claims 1 and 2
Of the present invention. That is, the end spring portion is formed at one end of the return spring so as to protrude from the corrugated portion toward the outer diameter side or the inner diameter side, and the retainer is eliminated by supporting the end winding portion with the claw projecting from the snap ring. Things. In this case, even if the diameter of the snap ring and the diameter of the return spring are significantly different, it is absorbed by the amount of protrusion between the claw portion and the end turn portion, and the return spring can be directly supported by the snap ring.

In the present invention, the friction engagement device is
A clutch in which the drum rotates or a brake in which the drum is formed of a fixed member such as a transmission case may be used. The present invention is preferably used for a friction engagement device having a large outer diameter such as a brake of an automatic transmission.

[0011]

FIG. 1 shows a schematic structure of an automatic transmission using a friction engagement device according to the present invention. This automatic transmission includes a torque converter 1, an input shaft 2, to which engine power is transmitted via the torque converter 1, three clutches C1 to C3, two brakes B1, B2, a one-way clutch F, a Ravigneaux type planetary gear. Device 4, output gear 5,
An output shaft 7, a differential device 8, and the like are provided.

The forward sun gear 4a of the planetary gear set 4
And the input shaft 2 are connected via a C1 clutch.
The rear sun gear 4b and the input shaft 2 are connected via a C2 clutch. The carrier 4c is connected to the intermediate shaft 3,
The intermediate shaft 3 is connected to the input shaft 2 via a C3 clutch. The carrier 4c is a B2 brake and a carrier 4c.
and c is connected to the transmission case 6 via a one-way clutch F that allows only forward rotation (engine rotation direction). The carrier 4c supports two types of pinion gears 4d and 4e, the forward sun gear 4a meshes with a long pinion 4d having a long shaft length, and the rear sun gear 4b is connected to a long pinion 4 via a short pinion 4e having a short shaft length.
is engaged with d. The ring gear 4f that meshes with only the long pinion 4d is connected to the output gear 5. The output gear 5 is connected to a differential 8 via an output shaft 7. The automatic transmission implements four forward speeds and one reverse speed by operating the clutches C1, C2, C3, the brakes B1, B2, and the one-way clutch F.

FIG. 2 shows a specific structure of a B2 brake which is a friction engagement device. A piston 10 is arranged inside the transmission case 6 constituting the drum, and a hydraulic chamber 11 is formed between the piston 10 and the transmission case 6. A cylindrical guide 10a extending in the axial direction is integrally formed at the tip of the piston 10 (the right end in FIG. 2), and biases the piston 10 to the left of FIG. 2 around the outer periphery of the guide 10a. A return spring 12 is provided.

An inner spline groove 6a is formed on the inner peripheral surface of the transmission case 6, and a plurality of friction plates 14 are spline-engaged with the inner spline groove 6a, and the terminal surface (the right side surface in FIG. 2) is shifted. It is prevented from falling off by a snap ring 15 fitted on the inner peripheral surface of the machine case 6. Each friction plate 1
4, a friction disk 16 is arranged, and the inner diameter of the friction disk 16 is spline-engaged with the hub 17.

As shown in FIG. 3, the return spring 12 is composed of a wave spring formed by spirally winding a single leaf spring formed in a corrugated shape plural times so that the peaks of the waves come into contact with each other. I have. At one end of the return spring 12, a flat end turn portion 12b is formed at least one round, which gradually projects toward the outer diameter side from the other corrugated portion 12a. Also, on the other end side of the return spring 12,
A flat end winding portion 12c having the same diameter as the corrugated portion 12a is formed for at least one round. The large-diameter end turn portion 12b on one end side of the return spring 12 is directly supported by a snap ring 13 fitted on the inner peripheral surface of the transmission case 6, and the end end end portion 12b on the other end side is connected to the piston 10 Is in contact with The wave spring 12 has a property of easily bending in the radial direction. However, since the inner peripheral side is supported by the guide portion 10a provided on the piston 10, the bending can be restricted.

As described above, since the end turn portion 12b of the return spring 12 is directly supported by the snap ring 13, the retainer can be eliminated. Moreover, unlike the case where a separate retainer is fixed to the return spring 12 by welding or caulking, the end turn portion 12b having a retainer function is formed integrally with the return spring 12, so that even if a repeated load is applied, Return spring 1 with excellent durability without the risk of winding portion 12b being broken
It can be 2. In particular, in the case of a friction engagement device having a large diameter such as a B2 brake, the retainer is also a large diameter part,
Although the cost is increased, the weight can be reduced and the cost can be reduced by eliminating the retainer.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the present invention is applied to a clutch. A piston 21 is disposed inside the drum 20 movably in the axial direction, and an oil chamber 22 is formed between the drum 20 and the piston 21. A snap ring 23 is fitted on the inner diameter of the drum 20, and a return spring 24 made of a wave spring is disposed between the snap ring 23 and the piston 21. 25 is a hub, 26 is a plate that is spline-engaged with the drum 20,
Numeral 27 denotes a disk which is spline-engaged with the hub 25.

In this embodiment, the return spring 24
The end turn portion 24a formed at one end of the end portion is formed to have a smaller diameter than the corrugated portion 24b, and the small end turn portion 24a is supported by the snap ring 23. Also, return spring 2
Since the guide portion 21a supporting the inner peripheral surface of the piston 4 is formed integrally with the piston 21, the radial deflection of the return spring 24 due to the centrifugal force can be restricted by the guide portion 21a.

FIG. 5 shows a third embodiment of the present invention. The same parts as those in FIG. In this embodiment, as in the first embodiment, as the snap ring mounted on the inner peripheral surface of the drum 6, a snap ring 13 having a plurality of claws 13a protruding from the inner diameter as shown in FIG. The claw portion 13a supports one end surface of the return spring 12 made of a wave spring. In the return spring 12 of this embodiment, the end turns 12b and 12c at both ends are formed to have the same diameter as the corrugated portion 12a. In this embodiment, the snap ring 13
Since the claw portion 13a functions as a retainer, the retainer can be eliminated. Since the portion 13b of the snap ring 13 other than the claw portion 13a is formed narrow, the elasticity in the radial direction is not impaired.

The present invention is not limited to the first to third embodiments. For example, in the third embodiment, the snap ring 13 having the plurality of claw portions 13a on the inner diameter portion is used.
As in the second embodiment, a snap ring having a plurality of claws on its outer diameter may be used as the snap ring mounted on the outer peripheral surface of the drum.

Further, the first embodiment and the third embodiment may be combined. That is, the end turn portion 12b on one end side of the return spring 12 has a large diameter.
b may be supported by a snap ring 13 having a claw portion 13a on the inside diameter as shown in FIG. In this structure, the mounting position of the return spring 12 and the snap ring 13
Can be supported even when the mounting position is separated in the radial direction.

Further, as in the second embodiment, a snap ring having a plurality of claws on its outer diameter may be used for supporting the return spring 24 having a small diameter end turn 24a on one end.

[0023]

As is apparent from the above description, claim 1
According to the invention described in (1), an end turn portion protruding from the corrugated portion to the outer diameter side or the inner diameter side is formed at one end of the return spring, and the end turn portion is directly supported by the snap ring, so that the retainer can be eliminated. At the same time, assembly becomes easy. Further, since the end turn portion and the corrugated portion functioning as a retainer are integrated, there is no possibility that the end turn portion is broken by a repeated load, and a return spring having excellent durability can be obtained. According to the second aspect of the present invention, a plurality of claws are protruded from the inner diameter or the outer diameter of the snap ring mounted on the drum, and one end surface of the return spring is supported by the claws. The retainer can be eliminated, and it is only necessary to process the claw portion on the snap ring, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an example of an automatic transmission for a vehicle using a friction engagement device according to the present invention.

FIG. 2 is a detailed sectional view of a part of the automatic transmission of FIG.

FIG. 3 is a perspective view of a return spring.

FIG. 4 is a sectional view of a second embodiment of the present invention.

FIG. 5 is a sectional view of a third embodiment of the present invention.

FIG. 6 is a front view of a snap ring.

[Explanation of symbols]

 B2 Friction engagement device 6 Transmission case (drum) 10 Piston 12 Return spring 12a Corrugated portion 12b End turn portion 13 Snap ring 13a Claw portion

Claims (3)

[Claims] In a frictional engagement device provided with a return spring for urging a piston to return in the axial direction, the return spring is formed by a single leaf spring formed into a corrugated shape so that wave peaks abut each other. A snap ring formed by spirally winding a plurality of turns, forming an end turn having a larger diameter or a smaller diameter than one of the other wave portions at one end of the return spring, and attaching the end turn to a drum. A return spring support structure for a friction engagement device, wherein the return spring support structure is supported by: 2. A friction engagement device having a return spring for urging a piston to return in the axial direction, wherein the return spring is formed by a single leaf spring formed into a corrugated shape so that peaks of the waves come into contact with each other. A plurality of spirally wound wave springs. A plurality of claws project from an inner diameter or an outer diameter of a snap ring mounted on a drum, and one end surface of the return spring is supported by the claws. A return spring support structure for a friction engagement device. 3. The snap ring according to claim 1, wherein a plurality of claws project from an inner diameter portion or an outer diameter portion of the snap ring, and an end turn portion of the return spring is supported by the claws. Return spring support structure for friction engagement device.