JP2603693Y2 - Friction clutch structure for automatic transmission - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a clutch for performing a shift by appropriately engaging and releasing an appropriate number of friction elements in an automatic transmission, particularly for an automatic transmission in which a return spring of a clutch piston for pressing a friction element is improved. The present invention relates to a friction clutch structure.

[0002]

2. Description of the Related Art Conventionally, as a friction clutch for an automatic transmission of this type, for example, there is a clutch as shown in FIG. In FIG. 4, a clutch 51 for an automatic transmission includes:
First, a clutch drum 52 is provided, and a shaft portion 52 a of an inner peripheral portion is rotatably supported on, for example, an output shaft 53. On the other hand, the drum portion 52b on the outer periphery of the clutch drum 52
Is provided with a multi-plate clutch 55 composed of a drive plate and a driven plate, for example, between the clutch and the planetary carrier 54.

In order to fasten the multi-plate clutch 55,
A clutch piston 56 having a seal member is provided in a cylinder portion formed between the drum portion 52b and the shaft portion 52a.
Are slidably supported in the axial direction. Then, if a pressurized fluid is introduced into a chamber 57 between the rear surface (left surface in FIG. 4) of the clutch piston 56 and the clutch drum 52, the clutch piston 56 moves toward the multiple disk clutch 55, and the multiple disk clutch 55 In the engaged state, the clutch drum 52 and the planetary carrier 54 are engaged.

In order to release the multi-plate clutch 55, a return spring 58 is provided between the right surface of the clutch piston 56 in FIG. 4 and a spring receiver 60 stopped by a snap ring 59 at the right end of the shaft 52a. . Since the space between the shaft portion 52a of the clutch drum 52 and the projecting portion of the planetary carrier 54 is narrow, the return spring 58 is a coil spring having a large coil diameter surrounding the output shaft 53 and the shaft portion 52a. ing.

When the pressurized fluid in the chamber 57 is drained to a fluid tank at atmospheric pressure or atmospheric pressure, the return spring 58
The clutch piston 56 is pushed back to the left in FIG. 4 by the urging force, so that the multiple disc clutch 55 is released, and the power transmission between the clutch drum 52 and the planetary carrier 54 is cut off.

[0006]

However, in order to engage and disengage the multiple disc clutch 55, the clutch piston 56
When the vehicle approaches or separates from the multi-plate clutch 55, the installation length of the return spring 58 is reduced or extended. However, since the return spring 58 is a coil spring having a large coil diameter, a torsional force acts to rotate the positions of both ends relative to the central axis as the coil is reduced or expanded.

[0007] Due to this torsional force, related parts,
For example, the return spring 58, the clutch piston 56, the spring receiver 6
0, the snap ring 59 and the like are worn. Further, since the spring receiver 60 is rotated, the snap ring 59 may come off. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a friction clutch structure for an automatic transmission in which parts related to the return spring 58 are prevented from being worn and parts are not disengaged in view of the above-mentioned conventional problems. .

[0008]

In order to achieve the above-mentioned object, the present invention makes it possible to move an appropriate number of friction elements in the axial direction.
In a friction clutch for an automatic transmission, which shifts by engaging and disengaging with a piston arranged in a clutch drum ,
The return spring of the piston moves the axis around which the clutch drum rotates.
It consists of two coil springs which are wound around and whose winding directions are opposite to each other, and these coil springs are arranged in series and connected via a spring fixing member provided in the middle.

[0009]

The clutch is engaged by moving the piston to press the friction element. At this time, the return spring is compressed. When the pressing force of the piston is released, the piston is pushed back by the urging force of the return spring, and the clutch is released. At this time, the return spring extends while weakening the urging force. Here, since the return spring is composed of two coil springs whose winding directions are opposite to each other with the spring fixing member interposed therebetween, even if the return spring is compressed or expanded,
The intermediate spring fixing member rotates with respect to the central axis, but both ends of the return spring do not rotate relatively. Therefore, parts in the clutch related to the return spring are not worn or dislodged.

[0010]

FIG. 1 shows a first embodiment of the present invention. In a clutch 1 for an automatic transmission, a clutch drum 2 having a shaft portion 2a on an inner peripheral portion and a drum portion 2b on an outer peripheral portion is rotatably supported by, for example, an output shaft 3 on the shaft portion 2a. A multi-plate clutch (clutch) 5 is provided in the drum portion 2b between itself and, for example, a protrusion 4a of the planetary carrier 4.

The multi-plate clutch 5 includes a plurality of driven plates 6 engaged with splines provided on the inner periphery of the drum portion 2b, and a drive engaged with splines provided on the outer periphery of the projecting portion 4a of the planetary carrier 4. The retaining plate 7 and the snap ring 8 fixed to the inner circumference of the drum portion 2b prevent the plate 9 from coming off.

A cylinder portion formed between the drum portion 2b and the shaft portion 2a for fastening the multi-plate clutch 5 includes:
A clutch piston 12 sealed by a seal member 11 is provided slidably in the axial direction. Then, when pressurized fluid is introduced into the chamber 13 between the rear surface of the clutch piston 12, the left surface in FIG. 1, and the clutch drum 2, the clutch piston 12 moves in the direction of the multi-plate clutch 5.

A pressing portion 12a is provided on the clutch piston 12 on a side facing the multiple disc clutch 5, and a dish plate 10 made of a spring steel material is provided between the clutch piston 12 and the pressing portion 12a. ing. The movement of the clutch piston 12 causes the dish plate 10, the driven plate 6, and the drive plate 9 of the multi-plate clutch 5 to be pressed and pressed between the retaining plate 7 and the multi-plate clutch 5 in succession. Will be concluded.

In order to release the multi-plate clutch 5,
Snap ring 1 on clutch piston 12 and shaft 2a
A return spring 16 is provided between the spring support 15 and the spring receiver 15. The return spring 16 is connected to the output shaft 3
And two coil springs having a large coil diameter and having opposite coil directions so as to surround the shaft portion 2a, for example, a right-handed right-handed coil spring 17 and a left-handed left-handed coil spring 18 in FIG. , And are connected in series via a spring fixing member 19.

The first embodiment is constructed as described above. First, when the pressure fluid is introduced into the chamber 13, the driven plate 6 and the drive plate 9 of the multi-plate clutch 5 become the retaining plate 7 and the clutch piston 12 The multi-plate clutch 5 is brought into the engaged state by friction, so that the planetary carrier 4 and the clutch drum 2 are connected. At this time, the mounting size of the return spring 16 is reduced between the clutch piston 12 and the spring receiver 15 and compressed.

Next, when the pressure fluid in the chamber 13 is drained by a switching valve (not shown), the clutch piston 12 is pushed back by the urging force of the return spring 16, so that the engagement of the multi-plate clutch 5 is released. At this time, the mounting size of the return spring 16 is increased between the clutch piston 12 and the spring receiver 15 and extended.

Looking at the state of the end of the return spring at the time of compression and extension, as described above, both mounting ends of each spring have a characteristic of rotating relatively to the central axis. However, the return springs 16 are coil springs 17 and 18 whose winding directions are opposite to each other.
Are assembled in series with the spring fixing member 19 interposed therebetween. Therefore, the rotation of the contact end of the coil spring 17 with the spring holder 15 with respect to the contact end of the coil spring 17 with the spring receiver 15, and the clutch piston 12 of the coil spring 18 with the clutch piston 12 The rotation of the contact end of the spring fixing member 19 with respect to the contact end of the contact member is the same in the direction in which the spring fixing member 19 is turned and the rotation angle. Therefore, even if the return spring 16 as a whole is compressed / extended, only the spring fixing member rotates, and both end surfaces do not relatively rotate.

As a result, the radial space between the shaft portion 2a and the protruding portion 4a is so small that a large number of coil springs having a small diameter cannot be arranged in the circumferential direction of the shaft portion 2a. When using the spring 16,
The related components around the return spring 16, that is, the clutch piston 12, the seal member 11, the spring receiver 15, and the snap ring 14 are prevented from friction and wear, and have an effect of improving durability. Further, there is no danger that the spring receiver 15 and the snap ring 14 will be disengaged by being turned, so that there is an effect that reliability is improved.

When there is a slight space between the return spring 16 and the shaft portion 2a, a plurality of springs are provided on both sides as shown in FIG. Spring fixing member 20 having locking claw 20a
By using, even if an unexpected shock in the direction perpendicular to the axis is received, the position of the coil springs 17 and 18 with respect to the axis is reliably maintained and the reliability is improved.

FIG. 3 is an explanatory sectional view of a main part of a second embodiment of the present invention. This embodiment is effective when the space for arranging the return spring has little room in the length direction and some room in the radial direction. That is, the return spring 22
For example, a left-handed coil spring 23 having one end in contact with the clutch piston 12 and a coil spring 2
For example, a right-handed coil spring 25 having a coil diameter larger than 3
Are used. The coil springs 23 and 25 are connected in the axial direction by a hat-shaped spring fixing member 26 having a stepped cross section.

That is, the end of the small-diameter coil spring 23 is accommodated in the inner concave portion of the hat-shaped cylindrical portion 27, and the end of the large-diameter coil spring 25 is
And abuts against the outer flange 28, whereby the coil springs 23 and 25 are connected in series while overlapping in the axial direction. In addition, pawls 26a are further provided upright on the hat concave portion and the outer periphery of the flange to further securely maintain the position of the coil spring 23. Other configurations are the same as those of the first embodiment, and the same effects can be obtained by this.

[0022]

[Effect of the invention] As described above, according to the present invention, as the return spring of the piston of engagement and disengagement of the friction element, clutch
Since two coil springs, which surround the axis around which the drum rotates and are wound in opposite directions, are connected in series via a spring fixing member provided in the middle, the return spring compresses and expands as the piston moves. Even if it does, both mounting ends will not rotate relative to the central axis. Therefore, the related parts around the return spring do not wear due to the rotation, so that there is an effect that the durability is improved.
In addition, since there is no possibility that the related components come off due to the rotation of the return spring, the reliability is improved.

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main part showing a modification of the first embodiment.

FIG. 3 is an explanatory diagram of a main part showing a second embodiment.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clutch 2 Clutch drum 3 Output shaft 4 Planetary carrier 5 Multiplate clutch (clutch) 12 Clutch piston 13 Chamber 14 Snap ring 15, 24 Spring receiver 16, 22 Return spring 17, 18, 23, 25 Coil spring 19, 20, 26 spring fixing member 20a, 26a spring stopper claw 27 cylindrical portion 28 flange 51 clutch 52 clutch drum 53 output shaft 54 planetary carrier 55 multi-plate clutch (clutch) 56 clutch piston 57 chamber 58 return spring 59 snap ring 60 spring receiver

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 63/30 F16D 25/0638 F16H 63/12

Claims (2)

(57) [Scope of request for utility model registration] 1. A method for arranging an appropriate number of friction elements so as to be movable in an axial direction .
In a friction clutch for an automatic transmission in which a gear is engaged and released by a piston disposed in a latch drum to shift gears, a return spring of the piston is a shaft on which the clutch drum rotates.
Automatic transmission, wherein two coil springs are wound around each other and the winding directions of the coil springs are opposite to each other, and the coil springs are arranged in series and connected via a spring fixing member provided therebetween. Friction clutch structure for machine. 2. The two coil springs have different coil diameters from each other, the spring fixing member has a hat shape, and the coil springs overlap in the axial direction. Item 3. A friction clutch structure for an automatic transmission according to Item 1.