JPH10130630A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a friction material which is excellent in stability of braking performance and hardly causes abnormal sound even when water is present on the surface by incorporating potassium titanate fibers thermally treated at 300 deg.C or higher as at least a part of a fiber component into a friction mate rial comprising a filler component and a binder component contg. the fiber component. SOLUTION: The thermal treatment is performed at 300 deg.C or higher, pref. 300-400 deg.C, for 1-8hr and may be carried out after molding the friction material. The treatment is considered to separate hydrophilic OH groups from potassium titanate to render the molecular terminals hydrophobic. Potassium hexatitante fibers or potassium octatitanate fibers are used as the potassium titanate fibers. The binder component comprises the fiber component and a thermosetting resin (e.g. a phenol resin, a urea resin, a melamine resin, or a modification of these resins). Graphite, barium sulfate, calcium carbonate, etc., are used as the filler component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pad, a brake lining, and a clutch mechanism for a vehicle such as an automobile.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material which is used as a shing or the like, and which is less likely to squeal and generate abnormal noise due to brake braking when wet with water and has excellent effect stability.

[0002]

2. Description of the Related Art Conventionally, friction materials used for brake pads, brake linings, clutch facings, and the like of vehicles such as automobiles have often used asbestos as a base material. As a result of pointing out that dust is harmful to the human body, its use is being regulated, and the demand for friction materials that do not use asbestos is increasing.

[0003] Therefore, many non-asbestos-based friction materials which do not use asbestos have been proposed, but fibers such as aramid fiber, potassium titanate fiber, and rock wool are often used as a reinforcing fiber instead of asbestos fiber. In particular, potassium titanate fiber is excellent in heat resistance, abrasion resistance, and fade resistance, and is often used for adjusting physical properties such as porosity.

[0004]

However, when the potassium titanate fiber is used to a certain extent or more, when the friction material surface becomes wet with water, the friction coefficient at the time of brake braking becomes unstable, and sometimes squeals and vibrations occur. It has recently been pointed out that abnormal noise occurs. In particular, the friction coefficient has recently increased after washing due to changes in the shape of wheels and the spread of high-performance car washing machines.
There are cases where abnormal sounds such as squeals and brake vibrations are generated.

[0005] Therefore, the problem to be solved by the present invention is:
In friction materials using potassium titanate fiber with excellent heat resistance and abrasion resistance, even if water adheres to the friction material surface due to car washing, etc., it provides a friction material with excellent braking effect and low noise generation. It is to be.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has the following constitutions: (1) a fiber component, a binder component such as a phenol resin, graphite, barium sulfate; A friction material containing a filler component such as (1), wherein at least a part of the fiber component contains potassium titanate fiber which has been subjected to a heat treatment at a temperature of 300 ° C. or more, (2) fiber Ingredients and pheno-
In a friction material containing a binder component such as a resin and a filler component such as graphite and barium sulfate, at least a part of the fiber component contains potassium titanate fiber,
(3) The friction material characterized by being manufactured by performing heat treatment at a temperature of 00 ° C. or more, (3) the potassium titanate fiber is a potassium hexatitanate fiber or a potassium octa titanate fiber (1) Or the friction material according to (2),
(4) The friction material according to (1) or (2), wherein the heat treatment time is 1 hour to 8 hours.

That is, the inventor of the present invention has found that a friction material using potassium titanate fiber having excellent heat resistance, abrasion resistance and fade resistance has an excellent stability in braking effect when wet with water. As a result of repeated studies aimed at providing a friction material that generates less noise, the friction material is manufactured using potassium titanate fibers that have been heat-treated at a temperature of 300 ° C. or higher in advance, or ordinary titanic acid is used. Performing molding using potassium fiber as one of the friction material raw materials, and then performing heat treatment at a temperature of 300 ° C. or more to produce the friction material, knowing that the above problem can be solved, and achieving the present invention. is there.

[0008]

Next, the present invention will be described in detail. Potassium titanate is an inorganic compound represented by the general formula K ₂ O · nTiO ₂ , but it is presumed that it absorbs moisture in the air and forms a hydrophilic OH group at the terminal of the molecule.
However, at a temperature of 200 ° C. or higher, it is assumed that the OH group is separated and the terminal of the molecule becomes hydrophobic. The present invention utilizes such characteristics of potassium titanate, and each embodiment is as follows.

First, a friction material using potassium titanate fiber which has been heat-treated at a temperature of 300 ° C. or more will be described. As for the type of potassium titanate fiber, potassium dititanate fiber, potassium tetratitanate fiber, potassium hexatitanate fiber, and potassium octa titanate fiber are well known, but in the present invention, in terms of heat resistance, etc. A potassium hexatitanate fiber or a potassium octa titanate fiber is preferred.

[0010] In this method, the potassium titanate fiber needs to be heat-treated before the mixing step of mixing with other friction materials. The heat treatment time is desirably 1 hour to 8 hours. If the heat treatment time is less than 1 hour, the stability of the braking effect and the effect of suppressing the generation of abnormal noise are small, and if it exceeds 8 hours, the strength may be reduced. The heat treatment temperature is preferably in a range of 300 ° C to 400 ° C.

With regard to the friction material raw material of the present invention, those used as a fiber component include various organic fibers, glass fibers, rock wool, in addition to heat-treated potassium titanate fibers.
Metal fibers such as copper, bronze, aluminum, and brass, and the binder component is a thermosetting resin such as phenol resin, urea resin, melamine resin, or a modified resin thereof. The filler component includes lubricating materials such as graphite, metal powder, and cash dust, and barium sulfate and calcium carbonate.

The heat-treated potassium titanate fiber may be uniformly mixed with other friction materials by a mixer such as a Lady Ge mixer, an Erich mixer, a Henschel mixer, and the like. The friction material of the present invention can be obtained through a heat treatment and a finishing step. There are no particular restrictions on the conditions such as preliminary molding, heat and pressure molding, and heat treatment after mixing the friction material, and they can be performed by a conventional method.

Next, a friction material manufactured by performing a heat treatment at a temperature of 300 ° C. or more after molding will be described. As for the type of potassium titanate fiber, potassium hexatitanate fiber and potassium octa titanate fiber are desirable as described above. The friction material of the present invention is the same as described above, except that ordinary potassium titanate fibers not subjected to heat treatment are used.
In addition, the mixing step and the molding step can be performed by a conventional method as described above. However, it is essential to perform the heat treatment at a temperature of 300 ° C. or higher. The heat treatment time is preferably 1 hour to 8 hours, and the heat treatment temperature is 3 hours.
00 ° C to 400 ° C is desirable.

[0014]

Next, an embodiment of the present invention will be described. Example A In addition to potassium octa titanate fiber, which was previously heat-treated at a temperature of 310 ° C. for 5 hours as a fiber component, aramid fiber and copper fiber, phenol resin was used as a binder component, graphite was used as a filler component, Using barium sulfate, calcium carbonate, and a friction modifier, mix them uniformly, and add
After pre-formed at 00kg / cm ^2, temperature of 0.99 ° C., and 10 minutes heated pressure molding at a pressure 400 kg / cm ^2, then the friction material of Example A of the heat-treated for 5 hours at a temperature 180 ° C. the composition shown in Table 3 I got In addition, the numerical value of Table 3 shows volume%.

Examples B to G In addition to potassium titanate fiber, aramid fiber and copper fiber as a fiber component, phenol resin as a binder component, graphite, barium sulfate, calcium carbonate as a filler component, friction control These materials were mixed uniformly using a material and preformed at room temperature and a pressure of 400 kg / cm ² ,
Heat and pressure molding was performed at 50 ° C. under a pressure of 400 kg / cm ² for 10 minutes, and then heat treatment was performed at a temperature of 310 ° C. to 350 ° C. to obtain friction materials of Examples BG having the compositions shown in Table 3. Table 1 shows the types of potassium titanate used and the conditions of the heat treatment. In the table, “octita” indicates potassium octitanate, “hexita” indicates potassium hexatitanate, and “tetratiter” indicates potassium tetratitanate.

Comparative Examples a to c Comparative Examples a to c having the compositions shown in Table 3 under the same conditions except that the heat treatment was performed at a temperature of 180 ° C. for 5 hours in the above Examples B to G.
Was obtained. Comparative Examples d to e Comparative Examples a to c having the compositions shown in Table 3 under the same conditions except that heat treatment was performed at a temperature of 250 ° C. for 3 hours in Examples B to G described above.
Was obtained. Table 2 shows the types of potassium titanate used and the conditions of the heat treatment.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

The friction materials of Examples and Comparative Examples produced as described above were mounted on an actual vehicle, and the vehicle was washed with a car washer.
Table 4 and Table 5 show the results of sensory evaluation of the degree of squealing and abnormal noise generated by repeating braking at m / h and a fluid pressure of 20 kg / cm ^2, and the results of measuring the change in friction coefficient before and after car washing by a dynamo test. Shown in Tables 4 and 5 also show the results of the shear strength test and the fade resistance test.

[0021]

[Table 4]

[0022]

[Table 5]

[0023]

As described above, the friction material of the present invention comprises a fiber component, a binder component such as phenol resin, and a filler component such as graphite and barium sulfate. A friction material is manufactured using potassium titanate fiber that has been subjected to heat treatment at a temperature of at least 300 ° C., or molding is performed using ordinary potassium titanate fiber as one of the raw materials of the friction material. As a result of producing a friction material by performing a heat treatment at a temperature, even if water adheres to the surface of the friction material, the braking effect is excellent and the noise is less generated. It is suitable as a friction material used for lining, clutch facing and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI F16D 69/02 F16D 69/02 E (72) Inventor Yuji Shishido 1-18-1 Nishiaraimachi, Adachi-ku, Tokyo Nisshin Boseki Co., Ltd. Inside the Tokyo plant (72) Inventor Yoshinori Ozaki 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Shigeru Ichikawa 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Mikio Gomi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Keiichi Nishiyama 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (4)

[Claims] 1. A friction material containing a fiber component, a binder component such as a phenol resin, and a filler component such as graphite and barium sulfate.
A friction material comprising potassium titanate fibers heat-treated at the above temperature. 2. A friction material containing a fiber component, a binder component such as a phenol resin, and a filler component such as graphite and barium sulfate, wherein at least a part of the fiber component contains potassium titanate fiber, and is molded. A friction material manufactured by performing a heat treatment at a temperature of 300 ° C. or more after completion. 3. The friction material according to claim 1, wherein the potassium titanate fiber is a potassium hexatitanate fiber or a potassium octa titanate fiber. 4. The friction material according to claim 1, wherein the heat treatment time is 1 hour to 8 hours.