JPH0772572B2 - Squeal prevention shim for disc brake - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disc brake used in an automobile or the like, and a disc interposed between a caliper and a friction pad in order to prevent a squeaking noise. Regarding anti-squeal shims for brakes (anti-squeal shim).

[Conventional technology]

Disc brakes widely used in automobiles and the like have a structure in which a pair of friction pads are pressed by hydraulic cylinders from both sides of a disc integrated with a wheel to brake the disc. Here, the friction pad is
It is supported by the caliper so that it can move slightly not only in the direction perpendicular to the disc plate but also in the plane parallel to the disc. When the friction pad is strongly pressed against the disk by the hydraulic cylinder, at the same time, one of the pads is pressed against the caliper. At this time, the pad slightly moves in a plane parallel to the disk. Friction occurs between the and caliper, and a squeaking noise is generated.

For this reason, conventionally, a squeal preventing shim is interposed between the pad and the caliper in order to prevent the generation of such a squeaking noise. Conventionally, as this type of shim, a layer of synthetic rubber alone is coated on both sides of a steel sheet to a thickness of about 100 μ on one side, and then the surface of these rubber layers is subjected to graphite treatment in order to reduce the friction coefficient. What I did was used a lot.

[Problems to be solved by the invention]

In the conventional anti-squeal shim, the rubber layer flows laterally and is easily peeled off when strongly pressed by the caliper. Also,
The frictional heat generated on the sliding surface between the friction pad and the disc is transferred to the shim through the friction pad, but the heat resistance temperature of the rubber layer is low (the heat resistance temperature of synthetic rubber is about 150 ° C), so the rubber heats up due to the heat. The layers tended to age and tatter in a relatively short period of time. Therefore, the conventional anti-squeal shim has poor durability, and as a result, the anti-squeal effect is considerably reduced in a relatively short period of time.

In addition, recently, in view of the adverse effect of asbestos on the human body, the movement to ban the use of asbestos is intensifying. Especially, when asbestos is used for friction materials such as brakes, fine asbestos is scattered around and the adverse effect is large. Therefore, as for disc brakes, so-called deasbestos products that do not use asbestos have been recently developed, and some of them are already in use. And
In such asbestos-free disc brakes, metal fibers with good heat conduction are generally used in place of asbestos in the composition of the friction pad, so shims can be made from the sliding surface between the friction pad and the disc through the pad. The thermal load that is applied is much more severe, exceeding 200 ° C,
Under such an environment, the durability of the conventional shim is further reduced.

In addition, the situation of such asbestos-free disc brakes also increases the thermal load on the oil in the hydraulic cylinder,
The deterioration of oil, the decrease in viscosity of hot water, etc. are promoted, and the durability of the hydraulic system itself of the brake system has become a concern.

[Object of the Invention]

The present invention has been made to solve the above-mentioned conventional problems. The coating layer does not flow laterally and is peeled off, and the heat-resistant temperature is high, the durability is excellent, and the squeaking is stable over a long period of time. A disc that can provide a preventive effect and that also has heat insulation properties, reduces heat transfer to oil in the hydraulic cylinder of the disc brake, and improves the reliability of the hydraulic system of the brake system. It is intended to provide a squeal prevention shim for a brake.

[Means for solving problems]

The anti-squeal shim for disc brakes according to the present invention is coated on both sides of a metal plate with a thin layer of a compound obtained by mixing a heat-resistant non-metal fiber other than asbestos, a filler and an elastomer such as rubber, and further coating these. The surface of the compound layer is coated with a layer containing graphite as a main component.

[Operation] In the squeal prevention shim according to the present invention, the coating layers (compound layers) provided on both sides of the metal plate are not rubber alone, but a heat-resistant non-metal fiber is blended.
Even if the friction pad is strongly pressed by the caliper, no lateral flow occurs, so that no peeling occurs. Further, since the heat resistant non-metal fiber is mixed, the heat resistant temperature of the compound layer can be increased to about 350 ° C., for example, so that the compound layer is never deteriorated by the friction heat between the friction pad and the disk. Therefore, the durability is excellent, and the stable squeal preventing effect can be obtained over a long period of time.

In addition, the coating layer (compound layer) contains not only rubber but also heat-resistant non-metallic fibers with poor thermal conductivity, so it also has heat insulating properties, so it can be applied to oil inside the hydraulic cylinder of the disc brake. It reduces heat transfer and improves the reliability of the hydraulic system of the brake system.

〔Example〕

 Hereinafter, the present invention will be described based on embodiments shown in the drawings.

FIG. 1 is a sectional view of an embodiment of a squeal prevention shim for a disc brake according to the present invention. The shim 1 of the present embodiment includes a base material fiber made of a heat-resistant non-metal inorganic fiber other than asbestos or a heat-resistant organic fiber or both, a rubber material, and a rubber chemical on both surfaces of a metal plate 2 such as a steel plate. A thin layer 3 of a compound made of an inorganic filler is coated, and the surface of the compound layer 3 is coated with a graphite layer 4. In this example, the compound layer 3 is 100 μm on each side, and the graphite layer 4 is 2 μm on each side.
It is set to ~ 3μ. The graphite layer 4 is
Instead of 100% graphite, it contains additives necessary for fixing the graphite layer 4 to the compound layer 3.

Examples of the inorganic fibers that form the base fibers in the compound layer 3 include glass fibers, ceramic fibers, rock wool,
Mineral cotton, fused quartz fiber, chemically treated high silica fiber, fused silicate alumina fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, alkali titanate fiber, whiskers, boron fiber and the like can be used.

Examples of the organic fiber that constitutes the base fiber include aramid fiber (aromatic polyamide fiber), polyamide fiber, polyolefin fiber, polyester fiber,
Polyacrylonitrile fiber, polyvinyl alcohol fiber, polyvinyl chloride fiber, polyurea fiber, polyurethane fiber, polyfluorocarbon fiber, phenol fiber, cellulose fiber and the like can be used.

Then, the base fiber is, for example, in the compound layer 3
About 30-80% is blended.

Examples of the rubber material forming the compound layer 3 include nitrile rubber (NBR), styrene-butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), butyl rubber (II).
R), ethylene-propylene rubber (EPM), fluorine rubber (FPM), silicone rubber (Si), chlorosulfonated polyethylene (CSM), ethylene vinyl acetate (EVA), polyethylene chloride (CPE), butyl chloride rubber (CIR), Shrimp chlorohydrin rubber (ECO), nitrile isoprene rubber (N
IR) can be used. Also, other types of elastomers can be used in place of rubber.

Examples of the rubber chemicals that compose the compound layer 3 include sulfur, zinc oxide, magnesium oxide, peroxides, fluting agents such as dinitrorebenzene, and thiazole compounds, polyamine compounds, sulfenamide compounds. A vulcanization accelerator such as a dithiocarbamate compound, an aldehyde amine compound, a guanidine compound, a thiourea compound or a xanthate compound can be used.

Further, as the filler constituting the compound layer 3, for example, clay, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripolystone, wollastonite, etc. can be used.

FIG. 2 is an exploded perspective view showing an example of a disc brake using the shim 1 of this embodiment, and FIG. 3 is a sectional view showing a shim interposition part in the brake. In these figures, 5a and 5b are left and right caliper members, and one caliper 5 is configured by being integrated by bolts (not shown). A hydraulic cylinder (not shown) is formed on each of the caliper members 5a and 5b. 6 is a piston fitted in the cylinder, 7 is a piston seal, 8 is a cylinder boot, and 9 is a set ring. Ten
Is a friction pad, which is formed by fixing a friction material 10b containing a metal fiber or the like on one surface of a steel plate 10a. 11 is a with hole pin, 12 is a clip, and 13 is an anti-rattle spring, and these parts are used for assembling the friction pad 10 and the shim 1 to the caliper 5.

In FIG. 3, reference numeral 14 is a disk, and the caliper 5 is arranged over the disk. Also, a pair of friction pads 10 are arranged on both sides of this disc 14,
Ten friction members 10b are opposed to the disk 14. In addition,
The friction pad 10 is supported by the caliper 5 so that it can be slightly moved not only in a direction perpendicular to the disc 14 but also in a plane parallel to the disc 14. Each shim 1 is interposed between the steel plate 10 a of each friction pad 10 and the caliper 5.

In the shim 1 of the present invention, since the coating layers (compound layers 3) provided on both sides of the metal plate 2 contain not heat-resistant rubber but heat-resistant non-metal fibers, the friction pad 10 strongly presses the caliper 5. Even if it is done, no lateral flow occurs, so no peeling occurs. Further, since the heat-resistant non-metal fiber is blended, the heat-resistant temperature of the compound layer 3 can be increased to about 350 ° C., so that the compound layer 3 is never deteriorated by the friction heat between the friction pad 10 and the disk 14. There is no. Therefore, it is possible to obtain a squeal preventing effect that is excellent in durability and stable for a long period of time. FIG. 4 demonstrates such an effect, and shows the relationship between the mileage and the squealing sound ratio between the shim 1 of the present invention and the conventional shim. It can be seen that the sound rate significantly increases with the traveling distance, whereas when the shim of the present invention is used, the increase in the squealing rate is very small even if the traveling distance increases.

Further, since the coating layer (compound layer 3) contains not heat-resistant rubber but heat-resistant non-metal fiber having poor heat conduction, the shim 1 of the present invention also has heat insulating properties. Therefore, heat transfer from the friction pad 10 to the oil in the hydraulic cylinder via the shim 1 is reduced, and the reliability of the hydraulic system of the brake system is also improved.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the anti-squeal shim for disc brakes according to the present invention has the following characteristics: (a) The coating layer does not flow laterally and is peeled off; A preventive effect can be obtained.

(B) It also has a heat insulating property, so that it is possible to reduce the heat transfer to the oil in the hydraulic cylinder of the disc brake and improve the reliability of the hydraulic system of the brake system.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a squeal preventing shim for a disc brake according to the present invention, FIG. 2 is an exploded perspective view showing an example of a disc brake using the shim of the embodiment, and FIG.
FIG. 4 is a cross-sectional view showing a shim interposed portion in the disc brake, and FIG. 4 is a characteristic diagram showing a relationship between a running distance and a squealing sound rate in the shim of the present invention and the conventional shim. 1 ... squeal prevention shim, 2 ... metal plate, 3 ... compound layer,
4 ... Graphite layer.

Claims (1)

[Claims] 1. A squeal prevention shim for a disc brake, which is interposed between a caliper and a friction pad for preventing squeaking noises in a disk brake, wherein a heat-resistant non-metal other than asbestos is provided on both sides of a metal plate. An anti-squeal shim for disc brakes, which is formed by coating a thin layer of a compound formed by mixing fibers, a filler, and an elastomer, and further coating the surface of these compounds with a layer containing graphite as a main component.