JP2001181606A - Frictional material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frictional material by which the reduction of effectiveness of a brake is extremely improved even in a state in which the frictional material does not fit a disk brake just after the mounting. SOLUTION: This frictional material is obtained by coating a thermoplastic resin containing one or more kinds of soft metal powders on the surface of a frictional member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to friction materials such as disc brake pads and brake linings used for braking automobiles, railway vehicles, various industrial machines and the like.

[0002]

2. Description of the Related Art Disc brakes are used as braking devices for automobiles, for example, and there are disc brake pads as braking members. At present, the mainstream of disc brake pads is disclosed in Japanese Patent Publication No. 59-4462,
As shown in JP-A-184525, steel fibers, brass fibers, metal fibers such as copper fibers, aramid fibers, organic fibers such as acrylic fibers and phenol fibers, alumina silica fibers, rock wool, potassium titanate are used as reinforcing fibers. A combination of fibers and inorganic fibers such as carbon fibers is used.

[0003] However, the conventional disk brake pads as described above, when in a state where they do not become familiar with the disk rotor immediately after being mounted, have reduced the effectiveness of the brake, and have often been a problem.

[0004]

SUMMARY OF THE INVENTION According to the first and second aspects of the present invention, there is provided a friction material in which a reduction in braking effect is significantly reduced even when the disk rotor is not familiar with the disk rotor immediately after mounting. Is what you do.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a friction material in which a surface of a friction member is coated with a thermoplastic resin containing at least one kind of soft metal powder. Further, the present invention relates to the friction material, wherein the soft metal powder is aluminum, zinc, or copper.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, examples of the thermoplastic resin coated on the surface of the friction member include acrylate resin, acrylic copolymer resin, vinyl acetate resin, modified ethylene vinyl acetate resin, and the like. As the soft metal powder contained in the thermoplastic resin, it is preferable to use one or more of aluminum, zinc, copper and the like, but there is no particular limitation as long as it is a soft metal powder.

The content of the soft metal powder is preferably 1 to 50% by weight based on 50 to 99% by weight of the solid content of the thermoplastic resin, and 70 to 97% by weight of the solid content of the thermoplastic resin.
More preferably, the content is 3 to 30% by weight.
The coating thickness of the thermoplastic resin containing the soft metal powder is 10
The range is preferably from 100 to 100 µm, more preferably from 20 to 80 µm, even more preferably from 30 to 60 µm.

In the present invention, as a material of the friction material, a generally known material is used, for example, steel fiber, brass fiber,
Fibrous substances such as aramid fiber, acrylic fiber, phenol fiber, ceramic fiber, rock wool, potassium titanate fiber, carbon fiber, phenol fiber, thermosetting resin such as epoxy resin, melamine resin, cashew resin and N
Binders including rubber compositions such as BR and SBR, organic friction modifiers such as friction dust, inorganic friction modifiers such as barium sulfate, graphite, antimony trisulfide and the like are used, and if necessary, brass, copper, etc. Of metal powder is added.

The content of the fibrous substance in the above composition is preferably 30 to 50% by weight, more preferably 35 to 45% by weight, in the whole composition of the friction member. The content of the binder is preferably from 8 to 18% by weight, more preferably from 10 to 15% by weight, in the whole composition of the friction member. The content of the organic friction modifier is preferably 3 to 18% by weight in the whole composition of the friction member,
More preferably, the content is 5 to 15% by weight. The content of the inorganic friction modifier is 25 to 4 in the total composition of the friction member.
The content is preferably 5% by weight, more preferably 30 to 40% by weight. These components are blended so that the total composition of the friction member is 100% by weight. The content of the metal powder added as necessary is preferably 1 to 20% by weight in the whole composition, and 3 to 15% by weight.
Is more preferable. These components are blended so that the total composition becomes 100% by weight.

[0010] The friction material according to the present invention is prepared by adding a material containing a fibrous substance, a binder and other friction modifiers, uniformly mixing the mixture, preforming the mixture, and then forming a back metal and a preform in a mold. After the body (which becomes a friction member after molding) is inserted, it is molded by a heat and pressure molding method, then heat-treated, cooled, and polished.
It is obtained by coating a thermoplastic resin containing more than one kind. The heating temperature at the time of molding is preferably from 130 to 170 ° C, more preferably from 140 to 160 ° C. Pressure is 30-6
0 MPa is preferable, and 40 to 50 MPa is more preferable. The heat treatment temperature is preferably 100 to 300 ° C, and 150 to 250 ° C.
C is more preferred.

[0011]

Embodiments of the present invention will be described below.

Example 1 The components shown in Tables 1 and 2 were blended, uniformly mixed by a mixer, preformed, and then a backing metal and a preformed body were inserted into a mold. 2.5 ° C, pressure 49MPa
Under heat and pressure for 5 minutes, baked at 200 ° C. for 5 hours, polished after cooling, and then 95% by weight of an aqueous acrylate resin solution having a concentration of 40% by weight and aluminum A mixed solution in which 5% by weight of the powder was uniformly mixed was applied and dried to obtain a disc brake pad having a thickness of 50 μm and covered with a thermoplastic resin containing a soft metal powder.

Comparative Example 1 A disc brake pad was obtained through the same steps as in Example 1 except that the surface of the friction member was not coated with a thermoplastic resin containing soft metal powder.

[0014]

[Table 1]

[0015]

[Table 2]

Next, a comparison test of the first efficacy was performed under the conditions shown in Table 3 for the disc brake pad of Example 1 and the disc brake pad of Comparative Example 1 according to the present invention.
Table 4 shows the results.

[0017]

[Table 3]

[0018]

[Table 4]

As shown in Table 4, Example 1 according to the present invention was used.
It is clear that the brake effect of the disc brake pad immediately after mounting is higher than that of the disc brake pad of Comparative Example 1.

[0020]

The friction material according to the first and second aspects can greatly reduce the reduction in the braking effect even when the friction material is not familiar with the disk rotor immediately after the friction material is mounted. It is a very suitable friction material.

Claims (2)

[Claims] 1. A friction material in which a surface of a friction member is coated with a thermoplastic resin containing at least one kind of soft metal powder. 2. The friction material according to claim 1, wherein the soft metal powder is aluminum, zinc, or copper.