JPH05331452A - Non-asbestos friction material - Google Patents

Abstract

PURPOSE:To obtain a friction material having good squeal preventing performance in a non-asbestos friction material used in a disk brakes and drum brakes, etc., of automobiles. CONSTITUTION:In a friction material containing a fiber component other than asbestos, a thermosetting resin component such as phenol resin and a filler powder component such as graphite or barium sulfate, the objective friction material is divided into two layers mutually different in these friction material components or contents of these components.

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 as a brake pad, a brake lining, a clutch facing of an automobile, which does not contain asbestos as a fiber component and is excellent in fade resistance and squealing performance. It relates to asbestos-based friction materials.

[0002]

2. Description of the Related Art Conventionally, asbestos is often used as a base material for friction materials used for automobile brake pads, brake linings, clutch facings, etc.
The use of asbestos is being regulated as a result of the fact that dust is harmful to the human body, and there is an increasing demand for friction materials that do not use asbestos.

Therefore, many proposals have been made for non-asbestos-based friction materials that do not use asbestos, but most of them use heat-resistant organic fibers, glass fibers, and metal fibers as fiber components, and phenol resin as a binder. The above thermosetting resin is used as a filler powder component such as graphite, barium sulfate, and alumina.

[0004]

There are disc brakes and drum brakes in a braking system of an automobile. The former has a structure in which a disc pad is pressed from both sides of a disc rotor that rotates with wheels to perform braking, and the latter is The brake lining is pressed against the inner surface of the drum that rotates with the wheels for braking.

At present, the above-mentioned non-asbestos type friction materials are often used for both disc brakes and drum brakes, but one of the problems is that an unpleasant noise called squeal is generated during braking.

It is considered that the cause of the squeal is mainly due to the frictional vibration of the friction material and the disk rotor and the drum at the time of braking. A composite friction material provided in a part of the material and a friction material in which the hardness distribution on the surface of the friction material has been devised so that friction vibration does not easily occur have been considered, but there are problems such as high manufacturing cost. ..

Therefore, the problem to be solved by the present invention is
It is an object of the present invention to provide a friction material having excellent squealing performance without impairing frictional wear performance, face-to-face aggression and the like in the above non-asbestos friction material, and further, without increasing manufacturing cost.

[0008]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and its constitution is a fiber component other than asbestos, a thermosetting resin component such as phenol resin, graphite, In a friction material containing a filler powder component such as barium sulfate, first of all, two or more friction material constituent components are different from each other in parallel to the friction surface, or the content ratio of the friction material constituent components is different from each other. Consists of
Secondly, at least a part of the friction material layer in contact with the back metal contains rubber particles, and thirdly, the thermosetting resin as a binder is the same in each layer.

That is, the inventors of the present invention have conducted repeated studies for the purpose of obtaining a non-asbestos-based friction material having excellent squealing performance. As a result, the friction material has a constitution of at least rubber particles and is in contact with the backing metal. It has been found that the above object can be achieved by dividing into two layers, a layer (hereinafter abbreviated as P layer) and a friction material layer (hereinafter abbreviated as Q layer) including a friction surface with a structure different from that of the P layer, Was achieved.

The P layer has a structure sandwiched between the Q layer and the back metal, and its thickness is preferably 10% or more of the total thickness of the friction material, and 10% or less is less effective. Further, the rubber particles contained in the P layer are 1 with respect to the total amount of the friction material components constituting the P layer.
0 to 30% is desirable, and less than 10%, the effect is small.
If it is 0% or more, the strength decreases. Furthermore, it is desirable that the thermosetting resins used as the binders for the P layer and the Q layer are the same, and when different thermosetting resins are used,
The strength of the interface between the P layer and the Q layer decreases.

The fibers used in the present invention include organic fibers such as aramid fibers, inorganic fibers such as glass fibers, rock wool and ceramic fibers,
Examples include metal fibers such as copper, bronze, aluminum, and brass. As the binder, phenol resin, urea resin,
Thermosetting resins such as melamine resins or modified resins thereof, and heat resistant resins such as polyacetal, aromatic polyimide resins, fluororesins, etc. are mentioned, and the filler is graphite,
Examples include metal powder, molybdenum disulfide, cashew dust, etc., which have a lubricating action, barium sulfate, calcium carbonate, and the like.

[0012]

The friction material of the present invention is a non-asbestos friction material, and the squealing performance is obtained by dividing it into two layers, a P layer which contains rubber particles and is in contact with the back metal, and a Q layer which has a friction surface and has a different structure from the P layer. Is improved.

[0013]

EXAMPLES Next, examples of the present invention will be described. Aramid fiber, glass fiber, rock wool as fiber base material,
Ceramic fibers, phenol resin as a binder, nitrile rubber and isoprene rubber as rubber particles, cashew dust, calcium carbonate, barium sulfate, graphite as a filler powder component, and a friction modifier are uniformly mixed using a mixer. The friction material was used for the P layer and the Q layer shown in FIG.
In addition, the numerical value in a table shows volume%. Next, the P layer and the Q layer are combined as shown in Table 2 at room temperature and a pressure of 100 kg / cm ²
Pre-molding is performed at a temperature of 150 ℃ and pressure of 200.
The material was heat-pressed and molded at kg / cm ² for 10 minutes, and then heat-treated at 200 ° C. for 5 hours to obtain a friction material for a brake lining for a medium-sized truck of the example. The thicknesses of P and Q layers are all 1: 4
And Similarly, a friction material for a brake lining for medium-duty trucks of a comparative example using only the friction material for the Q layer was obtained.

A friction test (JASO C406-82, inertia 40 kgms ² ) of the friction materials of Examples and Comparative Examples produced by the above-mentioned method with a full size dynamo tester was carried out and the squealing state was examined. Show. In the table, ◎ means no squeaking, ○ means tiny squeaking, △ means slightly squeaking, and × means squeaking.

[0015]

INDUSTRIAL APPLICABILITY As described above, the non-asbestos friction material of the present invention which does not contain asbestos as a fiber base material is composed of two friction material layers having different structures in parallel to the friction surface, as shown in the examples. As a result of including rubber particles in some of the components of the friction material layer on the side that contacts the back metal, the squealing performance can be improved as described above, so friction materials used for automobile disc brakes, drum brakes, clutch facings, etc. Is suitable as

[0016]

[Table 1]

[0017]

[Table 2]

Claims (4)

[Claims] 1. A friction material containing a fiber component other than asbestos, a thermosetting resin component such as a phenol resin, and a filler powder component such as graphite and barium sulfate, wherein the friction material constituent component is at least parallel to the friction surface. A non-asbestos-based friction material, characterized by comprising two or more layers different from each other or having different content ratios of friction material constituents. 2. The composition of the friction material layer on the side in contact with the backing which is one of the two friction material layers contains 10 to 30% by volume of rubber particles with respect to the total amount of the friction material layer. The non-asbestos friction material according to claim 1. 3. The non-asbestos-based friction material according to claim 1, wherein the thermosetting resin used as a binder is the same in the two-layer friction material. 4. A fiber component other than asbestos is an organic fiber such as aramid fiber, an inorganic fiber such as glass fiber, rock wool, ceramics fiber, or a metal fiber such as copper, bronze, aluminum or brass. The non-asbestos friction material according to claim 1.