JPH07102246A - Nonasbestos friction material - Google Patents

Abstract

PURPOSE:To improve the brake feeling at a high humidity of a nonasbestos friction material which contains a thermosetting resin component and a filler component by incorporating a specific granulated aluminum into the material as at least a part of the filler component. CONSTITUTION:This friction material contains a fiber component (e.g. an aramid fiber or a rock wool), a thermosetting resin component (e.g. a phenol resin, a urea resin, or a melamine resin), and a filler component (w.g. graphite, barium sulfate, or alumina), and the filler component at least contains 0.1-20vol.% (based on the material) granulated aluminum having a void content of 5-30vol.%. The premolding, thermal press forming, and thermal treatment of the material can be done by conventional methods without any specific limitation. The material, contg. the granulated aluminum which absorbs water easily, gives a good brake feeling even after being long left at a high humidity.

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, etc. of an automobile or an industrial machine, which is a non-asbestos-based material having an excellent brake feeling at high humidity. It relates to a friction material.

[0002]

2. Description of the Related Art Most non-asbestos friction materials that do not use asbestos use heat-resistant organic fibers, glass fibers, metal fibers, etc. as fiber components, and thermosetting resins such as phenol resins as fillers as binders. Graphite, barium sulfate, alumina, etc. are used. When these friction materials are left in a high humidity state for a long time, the effectiveness of the first few braking operations is enhanced, which is called morning effect. Therefore, it is necessary to continue driving with a bad brake feeling for a while after starting driving the vehicle. It is thought that the cause is that a thin film of water is formed on the surface of the brake pad or lining, which raises the friction coefficient.

A method of repelling water or absorbing water can be considered as a method of alleviating morning effects. However, the method of repelling water requires the friction material to contain a material having a high water-repellent effect, which is often not preferable in terms of friction and wear performance. Also, regarding the method of absorbing water, it is effective to increase the porosity of the friction material, but there is a drawback that the strength and wear resistance of the friction material are reduced, and it is not effective enough to significantly reduce the morning effect. I can't expect.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention is a non-asbestos system capable of maintaining a good brake feeling without adversely affecting friction and wear performance even after being left in a high humidity atmosphere for a long time. It is to provide a friction material.

[0005]

The present invention has been made for the purpose of solving the problems other than the above, and its constitution is a fiber component such as aramid fiber, a thermosetting resin component such as phenol resin and graphite, A non-asbestos friction material containing a filler component such as barium sulfate, characterized in that at least a part of the filler component contains an aluminum granule having a porosity of 5 to 30% by volume. is there. That is,
The inventors of the present invention have conducted research for the purpose of obtaining a non-asbestos-based friction material that can always maintain a good brake feeling even in a high humidity atmosphere. The inventors have realized that the above-mentioned objects can be achieved by including them, and achieved the present invention.

The aluminum granules preferably have a porosity of 5 to 30% by volume, and when the porosity is 5% or less, the effect is small, and when the porosity is 30% or more, the strength of the aluminum granules decreases and the effect cannot be exhibited. The average particle size of the aluminum granulated product is preferably 0.1 to 1 mm. There is no particular limitation on the method for producing the aluminum granule, and for example, the granule can be produced using aluminum powder having an average particle diameter of about 5 to 500 μm.

Thus, as the fiber component used in the present invention, 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, examples of the binder include thermosetting resins such as phenol resin, urea resin, melamine resin, and modified resins thereof, and examples of the filler include the above aluminum. In addition to the granulated material, those having lubricity such as graphite, metal powder, cashew dust, barium sulfate, calcium carbonate and the like can be mentioned. There are no particular restrictions on the conditions for pre-molding, heat-press molding, and heat treatment of the friction material composition, and conventional methods can be used.

[0008]

The friction material of the present invention contains, as a filler component, an aluminum granule that easily absorbs water, so that a good brake feeling can be obtained even after being left for a long time in a high humidity condition. In addition, due to the structure of the granulated material, the strength of the friction material is not likely to decrease, and the friction and wear performance is not adversely affected.

[0009]

EXAMPLES Next, examples of the present invention will be described. Aramid fiber, glass fiber as the fiber component, phenol resin as the binder, aluminum granules as the filler, calcium carbonate, barium sulfate, cashew dust, graphite using a stirrer to uniformly mix them Friction material mixtures for the examples were obtained. The aluminum granule used had a porosity of 15% by volume. Then at room temperature a friction material mixture product, after pre-molded under a pressure 400 kg / cm ^2, temperature of 160 ° C., for 8 minutes heat pressure molding at a pressure 400 kg / cm ^2, then Table 1 was heat-treated for 5 hours at a temperature 180 ° C. Brake linings for medium-duty truck (4t) fronts having the compositions shown in Examples A and B were produced. In addition, the numerical value in a table shows volume%. Further, the brake linings of Comparative Examples a and b which did not use the aluminum granules were similarly obtained.

The brake linings of Examples A and B and Comparative Examples a and b produced by the above method were tested by a full size dynamo tester. Regarding the test conditions, the braking mechanism is a two-leading type, the inertia is 12 kgms ² , and the test code is as shown in Table 2. Table 3 shows the results of the morning aging test conducted after the rubbing and leaving them in a high humidity atmosphere for 12 hours. In the morning effect test, the braking torque is measured while the hydraulic pressure of the brake cylinder is kept constant, and the measured value is converted into deceleration. The numerical values in the table indicate deceleration (unit: G).
The larger the deceleration value, the steeper the brake. The baseline was measured for comparison with the deceleration during the morning effect test, and if the difference is small, the brake feeling is good.

[0011]

As described above, the friction material of the present invention is filled with organic fiber such as aramid fiber, inorganic fiber such as rock wool, metal fiber such as copper fiber, binder such as phenol resin and graphite, barium sulfate and the like. As a result of including aluminum granules in at least a part of the filler component, it is possible to obtain a good brake feeling even after standing for a long time in a high humidity state. It is suitable as a friction material used for brake pads, brake linings, clutch facings, etc. of industrial machines.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[Procedure amendment]

[Submission date] August 23, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

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 such as aramid fiber and a thermosetting resin component such as phenol resin, graphite and sulfuric acid. A non-asbestos-based friction material containing a filler component such as barium is characterized in that at least a part of the filler component contains an aluminum granule having a porosity of 5 to 30% by volume. . That is, the inventors of the present invention have conducted research for the purpose of obtaining a non-asbestos-based friction material that can always maintain a good brake feeling even in a high-humidity atmosphere, and as a result, a part of the filler component is made of aluminum. The inventors have realized that the above object can be achieved by incorporating the granules, and have accomplished the present invention.

Claims (2)

[Claims] 1. A non-asbestos-based friction material containing a fiber component, a thermosetting resin component such as a phenol resin, and a filler component such as graphite and barium sulfate, wherein at least a part of the filler has a porosity of 5 A non-asbestos-based friction material comprising aluminum granules of 30% by volume. 2. The non-asbestos-based friction material according to claim 1, wherein the content of the aluminum granules is 0.1 to 20% by volume based on the whole friction material.