JPH08337661A - Friction material for vehicle - Google Patents

Abstract

PURPOSE: To reduce the time required for smoothing the surface of a friction material formed with a resin mold without increasing the kinds of raw materials or production steps by forming, on the surface of the friction material, a surface layer having a resin content lower than that of the friction material. CONSTITUTION: A friction material 12 obtd. by preforming a mixture contg. a phenol resin, various kinds of fibers, an org. agent, a metal, an abrasive, a lubricant, etc., is placed on a backing plate 11. A surface layer 13 having a resin content of 10-50wt.% of that of the friction material 12 and preformed independently of the friction material 12 is placed on the surface of the friction material 12 and thermally press molded together with the friction material 12 to be integrally fixed to the plate 11. Thus the surface layer 13 can be formed on the surface of the friction material 12 without increasing the kinds of materials or production steps. Moreover, since the surface layer 13 is quickly worn away, the friction area becomes large and a desired friction force is obtd. from the early stage of the use, enabling a large decrease in the time required for smoothing the surface in comparison with a conventional friction material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material used for vehicle clutches and brakes.

[0002]

2. Description of the Related Art For example, as shown in FIG. 4, a brake pad 1 for a disc brake, which is a kind of vehicle friction material.
The friction material 3 fixed to the back plate 2 is formed by a resin mold in which various raw materials such as phenol resin, various fibers, organic agents, metals, abrasives, lubricants and the like are pressure-thermoformed.

By the way, a friction material of this type has a high surface smoothness in a new state, so that a predetermined friction force cannot be obtained in the initial stage of use due to a lack of a friction area. It is necessary to make a so-called hit to obtain a predetermined frictional force by increasing the friction area.

In order to shorten the hitting time, for example, as disclosed in Japanese Patent Laid-Open No. 50-18845,
There is one in which cork powder, wood powder, cork sheet or the like is attached to the surface of the friction material to increase the friction area of the surface so that a predetermined friction force can be obtained from the initial stage of use.

[0005]

However, in the above-mentioned structure, since a different material is attached to the surface of the friction material, the number of materials is increased and an attachment step is required.

Therefore, an object of the present invention is to provide a friction material for a vehicle in which the time required for hitting is shortened without increasing the number of materials or the manufacturing process.

[0007]

In order to achieve the above-mentioned object, the present invention is, in the invention of claim 1, a vehicle friction material in which a friction material slidingly contacting a slidable member is formed by a resin mold. A surface layer having a resin content lower than that of the friction material is formed on the surface of the friction material formed by the resin mold. In the invention of claim 2, the resin content of the surface layer is It is characterized in that it is 10 to 50% by weight of the resin content of the formed friction material.

[0008]

[Operation] In the structure of claim 1, since the resin content of the surface layer is low, the surface layer is rapidly worn, so that the friction area becomes large and a predetermined frictional force can be obtained from the beginning of use. The time required can be shortened.

Further, according to the second aspect of the present invention, the time required for hitting can be more effectively shortened and the change in frictional force can be suppressed to a low level.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a brake pad of a disc brake will be described below with reference to FIGS.

In the brake pad 10, a friction material 12 formed by a resin mold is fixed to a back plate 11, and a surface layer having a resin content lower than that of the friction material 12 is formed on the surface of the friction material 12 formed by the resin mold. 13 is formed.

The friction material 12 is prepared by mixing various raw materials such as phenol / resin, various fibers, organic agents, metals, abrasives, lubricants, etc., pre-forming them and arranging them on the back plate 11 and press-heat molding. It is fixedly attached to the back plate 11.

The surface layer 13 has a lower resin content than the friction material 12, and the surface layer 13 has a resin content of the friction material 1
10 to 50% by weight of the resin content of 2, the friction material 12
Separately from the above, it is preformed, is placed on the surface of the preformed friction material 12, and is fixed to the back plate 11 integrally with the friction material 12 by pressure thermoforming.

Therefore, the surface layer 13 can be applied to the surface of the friction material 12 without increasing the number of materials or the manufacturing process.

Brake pad 10 constructed as described above
When the change in the friction coefficient between the conventional brake pad and the conventional brake pad was tested, as shown in FIG. 2, the friction coefficient A of the brake pad 10 was much shorter than the friction coefficient B of the conventional brake pad. A predetermined friction coefficient is obtained at.

This is because the surface layer 13 is rapidly worn, so that the frictional area becomes large and a predetermined frictional force can be obtained from the beginning of use, and the time required for the hitting can be greatly shortened as compared with the conventional case. .

FIG. 3 shows the friction coefficient when the resin content of the surface layer 13 is variously changed with respect to the resin content of the friction material 12. The friction coefficient C of the surface layer 13 is the surface layer. When the resin content of 13 is 10 to 50% by weight based on the resin content of the friction material 12, the friction coefficient of the friction material 12 is within the range of ± 30%, and the surface layer 13 is worn and the friction material 12 Also, the number of brakings until the sliding contact with the sliding member is short.

When the resin content of the surface layer 13 is 50% by weight or more, the number of times of braking until the friction material 12 comes into sliding contact with the sliding member due to wear of the surface layer 13 is long, and the resin content of the surface layer 13 is contained. When the amount is 10% by weight or less, the friction coefficient C of the surface layer 13 becomes -30% or more of the friction coefficient of the friction material 12, and the formability of the surface layer 13 has a problem.

Therefore, the resin content of the surface layer 13 is preferably 10 to 50% by weight of the resin content of the friction material 12. Within this range, the time required for hitting can be more effectively shortened and the friction can be reduced. Changes in force can be kept low.

In the above embodiment, the present invention is applied to the brake pad of the disc brake.
The same effect can be obtained by applying it to the brake shoe of the drum brake or the facing of the clutch.

[0021]

As described above, in the friction material for a vehicle of the present invention, the surface layer having a resin content lower than that of the friction material is formed on the surface of the friction material formed by the resin mold. Wears quickly and the friction area becomes large so that a predetermined friction force can be obtained from the beginning of use, the time required for hitting can be shortened, and the surface layer of the friction material can be changed without increasing the number of materials or the manufacturing process. Can be applied to.

Further, the resin content of the surface layer is 10 to 50 of the resin content of the friction material formed by the resin mold.
By setting the weight percentage, the time required for hitting can be more effectively shortened and the change in frictional force can be suppressed low.

[Brief description of drawings]

FIG. 1 is a sectional view of a brake pad of a disc brake to which the present invention is applied.

FIG. 2 is a graph showing changes in the friction coefficient of the brake pad of the present invention and the conventional brake pad depending on the number of times of braking.

FIG. 3 is a graph showing a change in friction coefficient when the resin content of the surface layer is variously changed with respect to the resin content of the friction material.

FIG. 4 is a sectional view of a brake pad of a conventional disc brake.

[Explanation of symbols]

10 ... Brake pad, 11 ... Back plate, 12 ... Friction material formed by resin mold, 13 ... Surface layer

Claims (2)

[Claims] 1. A friction material for a vehicle, wherein a friction material slidingly contacting a sliding member is formed by a resin mold. A surface layer having a resin content lower than that of the friction material is formed on the surface of the friction material formed by the resin mold. A friction material for vehicles, characterized in that 2. The resin content of the surface layer is 10 to 50 of the resin content of a friction material formed by a resin mold.
The friction material for vehicles according to claim 1, wherein the friction material is wt%.