JPH0693110A - Asbestos-free friction material - Google Patents

Abstract

PURPOSE:To provide a material which does not contain asbestos as a fibrous ingredient, has a stable coefficient of friction, and is less apt to wear. CONSTITUTION:The material, to be used as an automotive brake pad, brake lining, clutch facing, etc., comprises a non-asbestine fibrous ingredient, a thermoset resin, e.g. a phenolic resin, and a filler, e.g. graphite or barium sulfate, and further contains powdery iron sulfide.

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 an automobile disc brake, a drum brake, a clutch facing, etc., which does not contain asbestos as a fiber component and has a stable friction coefficient and less wear. It relates to a friction material.

[0002]

2. Description of the Related Art Conventionally, asbestos has been often used as a base material for friction materials used for automobile disc brakes, drum brakes, clutch facings, etc. However, asbestos is harmful to humans due to its dust. As a result of being pointed out, its use is being regulated, and there is a strong 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 thermosetting resin is used as a filler, and an abrasive such as alumina or zirconium silicate or a lubricant such as graphite or molybdenum disulfide is used.

[0004]

In recent years, various braking methods are applied to automobiles for complicated traffic conditions such as speeding up and traffic congestion. Therefore, friction materials used for disc brakes, drum brakes, clutch facings, etc. are required to have, for example, a coefficient of friction from low speed to high speed and stability of the coefficient of friction from low temperature to high temperature of the friction material. Needless to say, it is better that wear of the friction material is smaller in any braking method.

However, in a friction material using a thermosetting resin such as the above-mentioned phenol resin as a binder, the resin melts or decomposes at a high temperature to generate gas, which causes a fade phenomenon to cause an unstable friction coefficient. There is a problem that becomes. In order to solve this problem, it is the current situation that the resin component is suppressed to a small amount of 15 to 25% by volume of the total amount of the friction material. However, if the organic binder is reduced, the strength of the friction material decreases and the wear amount. Has the drawback of becoming large.

Therefore, the problem to be solved by the present invention is to provide a non-asbestos-based friction material having a stable friction coefficient in the above-mentioned non-asbestos-based friction material and less abrasion of the friction material.

[0007]

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 and barium sulfate. In a friction material containing a filler component such as the above, iron sulfide powder is included in at least a part of the filler component.

Commonly well-known iron sulfides usable in the present invention are FeS, Fe ₃ S ₄ , Fe ₂ S ₃ and Fe.
There are four types of S ₂ , but FeS is most suitable. That is, the inventor of the present invention has conducted research for the purpose of obtaining a non-asbestos-based friction material having a stable friction coefficient and less wear of the friction material, and as a result, iron sulfide powder is included as a part of the filler component. Thus, the inventors have realized that the above-mentioned object can be achieved and accomplished the present invention.

It is generally known that sulfides such as molybdenum disulfide and antimony trisulfide are added to improve wear of friction materials, but these sulfides have a cleavage property and have a Mohs hardness of 3 or less. It is believed to show good wear properties.

However, molybdenum disulfide and antimony trisulfide are not good fillers in terms of stability of friction coefficient, and it is considered that the reason is that they are scientifically unstable. On the other hand, iron sulfide has no cleavage property and has a relatively high Mohs hardness of 4, so it is unlikely that it has a lubricating effect and is effective for wear resistance. Wear of the friction material is believed to be reduced due to the formation of the coating.

That is, when a part of the friction material component scraped off during braking is adhered to the facing surface to form a stable coating, the friction material tends to be worn well. Iron sulfide
Since the chemically safe FeS coating is formed on the friction surface as described above, the friction coefficient is easily stabilized.

In the present invention, other than iron sulfide powder, those used as a filler component include graphite, metal powder, molybdenum disulfide, cashew dust, etc. having a lubricating action, barium sulfate, calcium carbonate, etc. Is mentioned.

The fibers used include organic fibers such as aramid fibers, glass fibers, rock wool, ceramic fibers, inorganic fibers such as potassium titanate fibers, iron, copper, bronze, aluminum, brass and the like. Examples of the binder include thermosetting resins such as phenol resin, urea resin, melamine resin or modified resins thereof, and heat resistant resins such as polyacetal, aromatic polyimide resin, and fluororesin.

[0014]

The friction material of the present invention is a non-asbestos friction material, and by incorporating iron sulfide powder in at least a part of the filler component, the friction coefficient is stabilized and the wear resistance is also improved.

[0015]

The present invention will be described below. Using aramid fiber, rock wool, iron fiber as the fiber base material, phenol resin as the binder, iron sulfide powder as the filler, graphite, barium sulfate, and zirconium silicate powder, and mixing them uniformly. , Room temperature, pressure 400k
Heat press molding at g / cm ² for 10 minutes, then 180 ℃
After heat treatment for 5 hours, friction materials of Examples A to C having the compositions shown in Table 1 were obtained. The iron sulfide powder used had a composition of FeS.

Further, friction materials of Comparative Examples a to e containing no iron sulfide powder shown in Table 2 were similarly obtained. The numerical values in Table 1 and Table 2 show% by volume.

A friction and wear test (JAS) was performed on the friction materials of Examples A to C and Comparative Examples a to e produced by the above method.
The results of the test conducted by O C427) are shown in Table 3, respectively.
It shows in Table 4. From Tables 3 and 4, the examples containing iron sulfide powder have less variation in the friction coefficient depending on the friction material temperature than Comparative Example a containing no lubricant and Comparative Examples b to e containing a lubricant used conventionally. I understand.

Further, Example A, Comparative Examples b and d, and Example C
Comparing the pad wear amounts of Comparative Examples c and e, the wear resistance effect of iron sulfide is clear.

[0019]

As described above, the non-asbestos-based friction material of the present invention which does not contain asbestos as a fiber base material has organic fibers such as aramid fibers and inorganic fibers such as rock wool as shown in Examples.
Metallic fiber such as iron fiber, binder such as phenol resin, and filler components such as graphite and barium sulfate. As a result of including iron sulfide powder in a part of the filler, the friction coefficient becomes stable as described above. Since the amount of wear of the friction material is small, it is suitable as a friction material used for brake pads, brake linings, clutch facings, etc. of automobiles.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

Claims (3)

[Claims] 1. A non-asbestos-based friction material containing a fiber component other than asbestos, a thermosetting resin component such as a phenol resin, and a filler component such as graphite and barium sulfate in at least a part of the filler component. A non-asbestos friction material comprising iron sulfide powder. 2. The non-asbestos-based friction material according to claim 1, wherein the content of the iron sulfide powder is 0.1 to 20% by volume based on the total amount of the friction material. 3. Fiber components other than asbestos include organic fibers such as aramid fibers, glass fibers, rock wool, ceramics fibers, inorganic fibers such as potassium titanate fibers, and metals such as iron, copper, bronze, aluminum and brass. The non-asbestos-based friction material according to claim 1, which is a fiber.