KR20110096485A - Dry friction lining for a clutch, in particular for a motor vehicle - Google Patents

Abstract

Dry friction linings for clutches, in particular automotive applications, which comprise a friction material fixed on a thin metal backing or "foil", which is formed with coaxial annular grooves 32, angularly and with respect to one another. Substantially radial grooves are formed which are formed of several parts 34, 36, 38, 40 which are circumferentially offset.

Description

DRY FRICTION LINING FOR A CLUTCH, IN PARTICULAR FOR A MOTOR VEHICLE}

The present invention relates in particular to dry friction linings for clutches, for automotive applications.

In FR 2 706 556 A1, for example, these friction linings are formed by press compression, and the friction material on a thin metal backing, referred to as a "foil" whose thickness is usually approximately 0.1 to 1 mm. Techniques for curing are known and the metal backing is prepared in advance by shot blasting, sand blasting or chemical treatment and will probably contain an adhesive coat to fix the friction material.

The purpose of this metal backing is essentially to reduce the deflection and creep of the friction material and thereby cause an incidence phenomenon (gradual engagement areas of the clutch disc or blades to penetrate the friction material). To reduce the clutch during operation. According to this, it is also possible to improve the resistance of the lining to dispersion by centrifugal force action.

Since these linings are sensitive to thermal deformation due to thermal expansion differences between the friction material and the thin metal backing, the friction material on the opposite side to the thin metal backing is formed with annular and radial grooves that divide it into blocks, and the radial groove Deeper.

However, this has the disadvantage that the friction linings are weak in these radial grooves where the base can be deformed or broken during the handling or use of the linings.

It is an object of the present invention, in particular, to provide a simple, effective and economical solution to this problem.

To this end, the present invention is a dry friction lining for clutches, in particular for automotive applications, comprising a friction material fixed on a thin metal backing or "foil" and having a substantially radial rib formed thereon. In order to increase the bending stiffness of the lining, the substantially radial groove proposes a dry friction lining for the clutch, characterized in that it has a non-linear shape between the inner and outer circumferences of the lining.

In one embodiment of the invention, the substantially radial grooves are formed of several parts that are angularly or circumferentially offset with respect to each other.

The substantially radial grooves are for example made zigzag.

In a variant, the substantially radial grooves may be formed of staggered portions.

Advantageously, the friction material also comprises an annular groove which cuts said substantially radial groove and interconnects the various different portions of said substantially radial groove.

Typically, the thickness of the friction material at the base of the substantially radial groove is 0 to 1 mm, preferably 0 to 0.5 mm.

The thickness of the foil is generally 0.1 to 1 mm, preferably 0.1 to 0.5 mm.

The present invention also proposes a clutch disc, in particular for automotive use, comprising a friction lining of the type described above.

According to the present invention, it is generally possible to increase the bending stiffness of the dry friction lining fixed on the foil, which reduces the risk of bending deformation or breakage during the handling of the lining and its use in the clutch.

Thus, according to the present invention, it is also possible to produce linings with radial grooves having a base of minimum thickness, which makes these linings less susceptible to thermal expansion differences between the friction material and the foil.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood by reading the following description, which is illustrated with reference to the accompanying drawings, and its features, details and advantages will become more apparent.
1 and 2 are partial schematic perspective and cross-sectional views of prior art dry friction linings.
3, 4 and 5 are partial schematic views showing grooves of a dry friction lining according to the invention.

First, reference is made to FIGS. 1 and 2 showing a dry friction lining 10 of the prior art comprising a friction material 12 fixed on a metal foil 14.

In the conventional manner, the foil 14 is first prepared by shot blasting, sand blasting, heat treatment, etc., and will probably be glued by laminating a thin layer of suitable adhesive, after which the friction material is laminated in a thick layer on the foil The assembly is then placed in the press to cure under pressure.

After curing, the assembly is grounded, then subjected to post-cure treatment, and the lining is perforated.

The friction material 12 is formed with annular grooves 16 and radial grooves 18 by compression in the press described above, which grooves are adjacent blocks interconnecting the friction material by the bases of the grooves 16, 18. Divided into 20, which suppresses deformation due to thermal expansion difference between the friction material and the foil 14 in use.

The radial grooves 18, which extend from the inner circumference to the outer circumference of the lining and are usually about 0 to 1 mm, preferably 0 to 0.5 mm, with a small or almost no base thickness, make the lining very flexible and therefore There is a risk of deformation and destruction during the handling of and during its use in the clutch.

The lining according to the invention, shown schematically in FIGS. 3 to 5, is characterized in that the radial grooves are not linear along their entire length between the inner and outer circumferences of the lining, but are angularly or circumferentially offset relative to one another. It has the same characteristics as the linings of FIGS. 1 and 2, except that it is formed of four linear portions. These grooves are formed by press compression, like the grooves of the previous lining. In a variant, these grooves may be formed by machining.

The friction material of the lining 22 schematically shown in FIG. 3 comprises at least one annular groove 24 and substantially radial grooves formed from several angularly offset portions 26, 28. The first portion 26 of each radial groove extends from the inner circumferential portion of the lining to the annular groove 24, and the second portion 28 of the groove extends from the annular groove 24 toward the outer circumference of the lining. .

The lining 30 in FIG. 4 comprises three annular grooves 32 coaxial and different in diameter, and four portions radially offset circumferentially in a staggered arrangement with respect to each other. The first and third portions 34, 38 of these grooves are radially aligned, and the second and fourth portions 36, 40 of these grooves are also radially aligned.

In FIG. 5, the friction material of the lining comprises radial grooves formed of three parts 44, 46, 48 interconnected in a zigzag form. These radial grooves are regularly distributed with respect to the axis of the lining, and annular grooves (not shown) can be formed in the friction material to cut the zigzag grooves, and these annular grooves are for example shown in FIGS. 1, 3 or It is of the same type as shown in FIG.

For example, the bending stiffness gain of the friction lining of the type shown in FIG. 4 is in the form of a mold in which the friction material comprises fibers, fillers and resins, Its thickness is 2 mm and is approximately 10 when the base thickness of the radial groove is almost zero and the thickness of the foil is 0.4 mm.

10 dry friction lining 12 friction material
14 foil 16: annular groove
18: radial groove 20: block
22, 30: lining 24, 32: annular groove
26, 28: radial grooves 34, 36, 38, 40: annular groove
44, 46, 48: radial groove

Claims (8)

Dry friction linings for clutches, in particular for automotive applications, comprising a friction material fixed on a thin metal backing or foil 14 and having a substantially radial groove formed therein,
In order to increase the bending stiffness of the linings 22, 30, 42, the substantially radial grooves have a non-linear shape between the inner and outer circumferences of the linings.
Dry friction lining for clutch. The method of claim 1,
The substantially radial grooves are characterized in that they are formed of several parts 26, 28, 34, 36, 38, 40, 44, 46, 48 that are angularly or circumferentially offset with respect to each other.
Dry friction lining for clutch. The method according to claim 1 or 2,
Characterized in that the substantially radial grooves 44, 46, 48 are zigzag in shape.
Dry friction lining for clutch. The method according to claim 1 or 2,
The portions 34, 36, 38, 40 of the substantially radial groove are offset in a staggered arrangement.
Dry friction lining for clutch. The method according to any one of claims 1 to 4,
A variety of different portions of the substantially radial groove are characterized in that they are interconnected by annular grooves 24, 32.
Dry friction lining for clutch. 6. The method according to any one of claims 1 to 5,
Characterized in that the thickness of the friction material at the base of the substantially radial groove is 0 to 1 mm, in particular 0 to 0.5 mm.
Dry friction lining for clutch. The method according to any one of claims 1 to 6,
The foil has a thickness of 0.1 to 1 mm, in particular 0.1 to 0.5 mm.
Dry friction lining for clutch. A friction lining as claimed in claim 1, in particular for automotive use.
Clutch disc.

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