JPH10205556A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the life of a friction member by making use of brake squeal, by using a friction material component in which fiber materials, friction adjusting agent and binding agent are contained in the friction member to be brought in contact with a back metal and the hard particles having the specified Mohs' hardness or more and the specified wt.% are contained as friction adjusting agent in all components. SOLUTION: As fiber materials to be used for a friction member to be brought in contact with a back metal, the fiber material in which one or two kinds or more fibers out of Aramid fiber, acrylic fiber, metallic fiber such as bronze fiber are mixed with each other is used. As binding agent, the similar material described above can be used. As friction adjusting agent, hard particle having the Mohs' hardness of 5 or more is used. As the hard particles having the Mohs' hardiness of 5 or more, wollatonite, alumina, etc., can be mentioned. The content of the hard particles having the Mohs' hardness of 5 or more is set in the range of 1 to 50wt.% in relation to a friction material component, preferably, in the range of 5 to 40wt.%.

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 for braking a passenger car, a truck, an industrial machine and the like.

[0002]

2. Description of the Related Art Conventionally, as a friction material composition for a brake of an automobile, JP-A-6-128561 and JP-A-5-128561 have been known.
No. 152082, JP-A-2-262149,
As shown in JP-A-64-55441, metal fibers, inorganic fibers, organic fibers as a base material, a phenol resin or a modified phenol resin as a binder, graphite, cashew dust, inorganic grinding as a friction modifier, etc. A combination of an agent, barium sulfate and the like has been used. The friction material has been manufactured by stirring and mixing so that these components become uniform, and then heating and pressing.

In a friction material manufactured using the above-described friction material composition, as a means for detecting the life of the friction member, as disclosed in Japanese Patent Publication No. 3-16535, for example, Is about 1 to 2 mm, the metal wear alarm attached to the back metal comes into contact with the rotor and is detected by the wear alarm generated at that time.

[0004] However, the above-mentioned method has a problem in that a process for producing a wear alarm piece and a step for mounting the wear alarm piece on a back metal are added, and the work efficiency is reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a friction material in which the working efficiency is not reduced and the life of the friction member is detected by using brake squeal.

[0006]

According to the present invention, a friction member on the side in contact with a back metal contains a fibrous substance, a friction modifier and a binder, and comprises a hard composition having a Mohs hardness of 5 or more as a friction modifier. The present invention relates to a friction material using a friction material composition containing 1 to 50% by weight therein.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the thickness of a friction member provided on a side in contact with a back metal is preferably 3 mm or less,
2.5 mm or less is more preferable, and 2 mm or less is further preferable. In order to prevent the friction member from being partially worn and the backing metal from contacting the rotor, at least the lower limit is required to be 1 mm.

A friction member normally used for braking is disposed above the above-mentioned friction member. The friction material composition used for this friction member is not particularly limited. -128561, JP-A-5-1
JP-A-52082, JP-A-2-262149, JP-A-64-55441, etc., organic fibers such as aramid fibers, acrylic fibers, phenol fibers, and cellulose fibers, glass fibers, ceramic fibers, and rock wool. An inorganic fiber such as carbon fiber, steel fiber, copper fiber, brass fiber, a fibrous material obtained by mixing one or two or more fibers of metal fibers such as bronze fiber, phenol resin, urea resin, melamine resin or One or more of these modified resins, aromatic polyimide resins, polyacetals, NBR powders, one or more binders, metal powder, graphite, barium sulfate, calcium carbonate, magnesium carbonate, friction dust, etc. A friction material composition containing a friction modifier and the like is used.

The content of the fibrous substance is preferably in the range of 20 to 50% by weight, more preferably 30 to 40% by weight, based on the friction material composition. The content of the binder is preferably in the range of 9 to 18% by weight, more preferably 12 to 15% by weight, based on the friction material composition. The content of the friction modifier is 4 to the friction material composition.
The range is preferably from 0 to 65% by weight, and more preferably from 45 to 60% by weight.

On the other hand, as the fibrous substance used for the friction member in contact with the back metal according to the present invention, the same substances as those described above are used. The content of the fibrous substance is preferably in the range of 20 to 50% by weight based on the friction material composition.
More preferably, it is in the range of 0 to 40% by weight.

As the binder, those similar to the above can be used. The content of the binder is preferably in the range of 9 to 18% by weight, more preferably 12 to 15% by weight, based on the friction material composition.

Further, as a friction modifier, metal powder (iron,
Copper, brass, tin, etc.), graphite, barium sulfate, calcium carbonate, magnesium carbonate, friction dust, and the like. One or more of these are used, and the Mohs hardness of the present invention is 5 or more. Hard particles are used. The content of the friction modifier containing the hard particles having a Mohs hardness of 5 or more is preferably in the range of 40 to 65% by weight, more preferably in the range of 45 to 60% by weight, based on the friction material composition. Hard particles having a Mohs hardness of 5 or more are preferably contained in the friction modifier in an amount of 2 to 80% by weight.
More preferably, the content is 0 to 65% by weight.

Hard particles having a Mohs hardness of 5 or more include:
Olastonite, alumina, zirconia, silicon carbide and the like can be mentioned, and one or more of these can be used. The content of hard particles having Mohs hardness of 5 or more is
1 to 50% by weight, preferably 5 to 50% by weight based on the friction material composition
If it is less than 1% by weight, the added effect, that is, the life of the friction member cannot be detected. On the other hand, if it exceeds 50% by weight, the rotor is damaged and the life of the rotor is shortened.

In order to obtain a friction material using the friction material composition according to the present invention, a friction material containing 1 to 50% by weight of a hard particle having a Mohs hardness of 5 or more in a part of the friction modifier is contained in the whole composition. Preforming two types of friction material compositions, a material composition and a commonly used friction material composition, to obtain a preformed body having a two-layer structure,
Then, the back metal and the layer containing the hard particles having a Mohs hardness of 5 or more of the preform are inserted into the mold with the lower side facing down, and then molded by the heat and pressure molding method.

[0015]

Embodiments of the present invention will be described below. The components shown in Table 1 were blended and uniformly mixed with a mixer to obtain mixed powders A to F.

[0016]

[Table 1]

Example 1 A mixed powder A was filled in a mold, and a mixed powder F was
And preformed under a pressure of 30 MPa to obtain a preformed body having a two-layer structure. Thereafter, a preform layer of the mixed powder A containing zirconia, which is a hard particle having a Mohs hardness of 5 or more, of the back metal and the preform obtained above is inserted into another mold with the lower side facing downward. The zirconia is a hard particle having a thickness of 3 mm and a Mohs hardness of 5 or more on the side in contact with the backing metal, which is formed by heating and pressing at 150 ° C. and a pressure of 50 MPa for 5 minutes and further heat-treating at 200 ° C. for 5 hours. Was provided, and a disk pad having a friction member made of mixed powder F having a thickness of 7 mm was further provided thereon.

Example 2 A mixed powder B was filled in a mold, and a mixed powder F was
And preformed under a pressure of 30 MPa to obtain a preformed body having a two-layer structure. Thereafter, a disk pad was obtained through the same steps as in Example 1.

Example 3 A mixed powder C was filled in a mold, and then a mixed powder F was
And preformed under a pressure of 30 MPa to obtain a preformed body having a two-layer structure. Thereafter, a disk pad was obtained through the same steps as in Example 1.

Example 4 A mixed powder D is filled in a mold, and then a mixed powder F is
And preformed under a pressure of 30 MPa to obtain a preformed body having a two-layer structure. Thereafter, a disk pad was obtained through the same steps as in Example 1.

Comparative Example 1 A mixed powder E was filled in a mold, and a mixed powder F was
And preformed under a pressure of 30 MPa to obtain a preformed body having a two-layer structure. Thereafter, a disk pad was obtained through the same steps as in Example 1.

Comparative Example 2 A mold was filled only with the mixed powder F, and preformed under a pressure of 30 MPa to obtain a preformed body having a one-layer structure. Thereafter, the back metal and the preformed body obtained above were inserted into another mold, heated and pressed at a temperature of 150 ° C. and a pressure of 50 MPa for 5 minutes, and further heat-treated at 200 ° C. for 5 hours. A disk pad provided with a friction member having a thickness of 10 mm was obtained.

Next, in order to conduct a comparative test, the disk pad obtained above was polished until the upper surface of the back metal became 3 mm.
The disk pad according to the present invention and the disk pad of the comparative example were subjected to a brake squeal comparison test under the conditions shown in Table 2. In the test, the deceleration and the temperature were changed as shown in Table 3 and the disc brake was braked under the conditions of (1) to (35), and this was performed for 50 cycles [1 cycle from (1) to (35)]. The squeal occurrence rate was determined by the equation shown in Equation 1. Table 4 shows the results.

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

(Equation 1)

[0027]

[Table 4]

As shown in Table 4, the disk pad according to the present invention generates a brake squeal, which makes it possible to detect the life of the friction member. On the other hand, a disk pad not included in the present invention has a disadvantage that brake squeal is generated but the rotor is seriously damaged, or a brake squeeze is not generated at all and the life of the friction member cannot be detected. Was.

[0029]

The friction material according to the present invention is a friction material in which the working efficiency is not reduced and the life of the friction member is detected by using brake squeal.

Claims (1)

[Claims] 1. A friction member on the side in contact with the back metal contains a fibrous substance, a friction modifier and a binder, and hard particles having a Mohs hardness of 5 or more are included in a part of the friction modifier in the total composition.
A friction material using a friction material composition containing by weight.