JP2000344901A - Non-asbestos friction material for automabile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject friction material preventing meltdown through the prevention of local contact even in a high temperature state, not causing abnormal abrasion and making the lowering of braking action be reduced by including a specific amount of organic ingredients and by scorching the surface of a friction material. SOLUTION: This non-asbestos friction material for automobiles comprises (A) a back metal, (B) fibrous substrate material (e.g. steel fiber, etc.), (C) a friction regulator (e.g. rubber dust, barium sulfate, etc.), and (D) a binder (e.g. an acrylic rubber-modified phenolic resin, etc.), in such a way that the amount of organic ingredients contained in components A to D is 50-80 vol.% based on the total volume of all the friction materials. The friction material is obtained by preforming a mixture of components B, C and D, by feeding the preform together with the component A into a metal mold to form them, by heat treatment and by scorching the surface of the molded product. The contact of the component B preferably is 10-35 vol.% based on the total volume of all the friction materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material such as a disc brake pad and a brake lining which are used in contact with an automobile braking device having a disc rotor or a drum made of an aluminum alloy reinforced by dispersing a hard material.

[0002]

2. Description of the Related Art Conventionally, a disc rotor or a drum made of cast iron (mainly FC25) has been used for a braking device of an automobile. The use of an aluminum alloy disk rotor or drum using a hard material such as SiC as a reinforcing material has begun to be studied.

Further, friction materials used in contact with a disk rotor or a drum include metal fibers and inorganic fibers as disclosed in JP-A-49-21544 and Lubrication Vol. 19, No. 9 (1974). , Non-asbestos fiber base materials such as organic fibers, binders containing thermosetting resins such as phenolic resins as binders, lubricants such as graphite and antimony trisulfide as friction modifiers, metals such as iron, copper and brass Filler such as powder, barium sulfate, calcium carbonate, cashew dust, N
A friction material called NAO (Non Asbestos Organic) material obtained by heating and pressing a mixture containing an organic friction modifier such as BR and SBR is generally used. Also, the same friction material as described above has been used.

However, when a conventional friction material is used for a disk rotor or a drum made of an aluminum alloy, the surface of the disk rotor or the drum may be damaged at high temperatures, causing abnormal wear. This is because the surface of the aluminum alloy disk rotor or drum melts due to the local contact of the friction material, and the surface of the disk rotor or drum melts, and the molten aluminum alloy adheres to the friction material side, further promoting wear. And abnormal wear may occur.
No. 72 publication.

[0005]

According to the first and second aspects of the present invention, even in a high temperature state, local contact of the friction material is prevented to prevent melting of the aluminum alloy disk rotor or drum, and abnormal wear is prevented. An object of the present invention is to provide a non-asbestos friction material for automobiles, which has no effect and is less reduced in effectiveness. A third aspect of the present invention is to provide a non-asbestos friction material for automobiles, which is particularly effective, among the first and second aspects of the invention. The invention according to claim 4 is the invention according to claims 1 and 2
In particular, it is an object of the present invention to provide a non-asbestos friction material for automobiles which is excellent in preventing a disk rotor or a drum made of an aluminum alloy from melting.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a friction member comprising a back metal, a fibrous base material, a friction modifier and an organic component contained in a binder in an amount of 50 to 80% by volume in all the friction members. The present invention relates to a non-asbestos friction material for automobiles, wherein the friction member has a scorch-treated surface. Also, the present invention
The present invention relates to a non-asbestos friction material for automobiles in which a fiber base material is contained in an amount of 10 to 35% by volume in all friction members.

The present invention also relates to a non-asbestos friction material for automobiles, wherein the friction modifier contains cashew dust having a maximum particle size of 400 μm or less, and the cashew dust is contained in the entire friction member in an amount of 15 to 30% by volume. . Further, the present invention provides
The present invention relates to a non-asbestos friction material for automobiles, wherein a binder is contained in the entire friction member in an amount of 15 to 35% by volume.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Examples of the fibrous substance in the present invention include steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber, phenol fiber, glass fiber, and the like.
Ceramic fibers, rock wool, olastonite, potassium titanate fibers, carbon fibers and the like can be mentioned. As the binder in the present invention, conventionally known binders are used and are not particularly limited. However, a part or all of the binder reacts with acrylic rubber or reacts with phenol resin, silicone rubber or silicone oil finely dispersed in the rubber. Alternatively, it is preferable to use a phenol resin or the like finely dispersed in the rubber or oil because squealing hardly occurs. If necessary, isoprene rubber, NBR, SBR, or the like can be used as the rubber other than the above.

Examples of the friction modifier in the present invention include organic friction modifiers such as rubber dust and cashew dust, barium sulfate, graphite, antimony trisulfide, molybdenum disulfide, mica, zirconia, silica, alumina, mullite, and the like. Examples include inorganic friction modifiers such as talc, clay, calcium carbonate, calcium oxide, and magnesium carbonate. In the present invention, metal powders such as iron, brass, copper, tin, and zinc are added as necessary in addition to the above components.

[0010] The content of the fibrous substance in the above is preferably from 10 to 35% by volume, more preferably from 15 to 25% by volume in the total friction member in terms of mechanical strength. The content of the binder is preferably 15 to 35% by volume in all the friction members from the viewpoint of preventing the disk rotor or the drum from melting in a high temperature state and effective at a high temperature.
More preferably, it is 0% by volume. The content of cashew dust is preferably from 15 to 30% by volume, more preferably from 20 to 25% by volume, from the viewpoint of preventing the disk rotor or the drum from melting in a high-temperature state and effective at a high temperature.

The content of the friction modifier excluding cashew dust is preferably from 10 to 50% by volume, more preferably from 20 to 40% by volume in all the friction members in view of the coefficient of friction and the like. The content of the metal powder added as necessary is preferably 3 to 15% by volume, and more preferably 5 to 12% by volume in all the friction members. These components are blended so that the total friction member is 100% by volume. In the present invention, the volume% of each component is a value calculated by dividing the used weight of the component by the density of the component.

In the present invention, the amount of the organic component contained in the above-mentioned fiber base material, friction modifier and binder is 50 to 80% by volume, preferably 52 to 75% by volume, more preferably, in all the friction members. Is 55 to 70% by volume, and if it is less than 50% by volume, local contact of the friction material easily occurs in a high temperature state, and it becomes difficult to prevent melting of the disk rotor or the drum. Significant decrease in effectiveness at high temperatures.

The friction material according to the present invention is prepared by adding a material containing a fiber base material, a binder and a friction modifier to the mixture, uniformly mixing the mixture, preforming the mixture, and then placing a backing metal and a preform in a mold. After being inserted, it is molded by a heat and pressure molding method, then heat-treated, and further subjected to scorch treatment. The heating temperature during molding is preferably 130 to 170 ° C,
140-160 degreeC is more preferable. Pressure is 20-60MP
a is preferable, and 30 to 50 MPa is more preferable. The heat treatment temperature is preferably from 100 to 300C, more preferably from 150 to 250C.

The scorch treatment includes a method of pressing a hot plate against a friction member, a method of heating with a direct flame such as a gas flame, and a method of heating with radiant heat such as far-infrared rays, and is not particularly limited. The scorch treatment temperature is preferably 400 ° C. or higher,
400-500 degreeC is preferable and 430-470 degreeC is more preferable. When the scorch treatment is not performed, not only the effect at a high temperature is greatly reduced, but also the coefficient of friction may increase rapidly at the beginning of the grinding.

[0015]

The present invention will be described below with reference to examples. Example 1, Comparative Examples 1 to 5 The components shown in Table 1 were blended, uniformly mixed in a mixer, preliminarily molded, and then a backing metal and a preformed body were inserted into a mold. , 10 at pressure of 40MPa
It was heat-pressed for minutes, and then heat-treated at 200 ° C. for 6 hours. Further, the surface was scorched at a temperature of 450 ° C. to obtain a disc brake pad.

[0016]

[Table 1]

Next, a disc brake pad according to the present invention (Example 1) and a disc brake pad not included in the present invention (Comparative Examples 1 to 5) are combined with a disc rotor made of an aluminum alloy to comply with JISO C406. Then, the appearance of the disk rotor after fading, in which the lowest coefficient of friction during fading and the highest temperature, were observed. The maximum temperature during fading was 430 ° C.

As a result of the test, the disk rotor of the present invention using the disk brake pad of Example 1 and the disk brake pads of Comparative Examples 1, 4 and 5 showed no disc rotor surface, and showed a good surface. Comparative Example 2
In the case of using the disc brake pads of Nos. 3 and 3, the surface of the disc rotor had streaking. The minimum friction coefficient at the time of fade was 0.32 for the disc brake pad of Example 1, and 0.20, 0.33 for the disc brake pads of Comparative Examples 1, 2, 3, 4 and 5, respectively.
0.32, 0.17 and 0.19.
And the disc brake pads of Nos. 5 and 5 showed a decrease in the coefficient of friction.

Further, the coefficient of friction of the disc brake pad of Comparative Example 2 increased to 0.50 at the beginning of the grinding,
Thereafter, the coefficient of friction stabilized at 0.35, whereas the coefficient of friction of the disc brake pads of Example 1, Comparative Examples 1 and 3 was stable at about 0.35 without increasing at the beginning of the balancing. Also, in the disc brake pads of Comparative Examples 4 and 5, the friction coefficient was stable at 0.30 without increasing at the beginning of the fitting.

[0020]

According to the first and second aspects of the present invention, the non-asbestos friction material for automobiles prevents local contact of the friction material even at a high temperature, prevents the aluminum alloy disk rotor or drum from melting, and causes abnormal wear. It is a non-asbestos friction material for automobiles without any effect and with little reduction in effectiveness, and is industrially very suitable. The non-asbestos friction material for automobiles according to claim 3 is a non-asbestos friction material for automobiles which is particularly effective among the non-asbestos friction materials for automobiles according to claims 1 and 2. The non-asbestos friction material for an automobile according to the fourth aspect is the non-asbestos friction material for an automobile which is excellent in preventing melting of a disc rotor or a drum made of an aluminum alloy, among the non-asbestos friction materials for an automobile according to the first and second aspects.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16D 69/02 F16D 69/02 A F-term (Reference) 3J058 AA01 AA41 BA34 BA42 BA76 CA02 CA42 CB01 CB11 EA08 FA01 GA03 GA04 GA07 GA20 GA22 GA23 GA24 GA27 GA28 GA33 GA34 GA35 GA37 GA38 GA39 GA43 GA45 GA48 GA50 GA55 GA59 GA73 4F071 AA01 AA10 AA41 AA56 AA73 AB07 AB18 AB23 AB26 AD01 AD06 AE12 AH07 DA04 DA05 DA09 DA09

Claims (4)

[Claims] 1. A friction member comprising a backing metal, a fibrous base material, a friction modifier and an organic component contained in a binder in an amount of 50 to 80% by volume in all the friction members. A non-asbestos friction material for automobiles whose surface is scorched. 2. The fiber base material according to claim 1, wherein the friction material has 10 to 35
The non-asbestos friction material for automobiles according to claim 1, which is contained by volume%. 3. The non-asbestos for automobiles according to claim 1, wherein the friction modifier contains cashew dust having a maximum particle size of 400 μm or less, and the cashew dust is contained in the entire friction member in an amount of 15 to 30% by volume. Friction material. 4. The non-asbestos friction material for an automobile according to claim 1, wherein the binder is contained in an amount of 15 to 35% by volume in all the friction members.