JPH06159414A - Brake sliding section - Google Patents

Abstract

PURPOSE:To provide a brake sliding section comprising carbon fiber reinforced composite having stable braking effect. CONSTITUTION:In a brake sliding section comprising a disk and pad, both disk material and pad material are constituted by carbon fiber reinforced carbon composite wherein short carbon fibers comprising a plurality of bundles of monofilament frayed are used as reinforcements. A material for the disk is of a finely meshed matrix made of heat decomposition carbon and pitch, and a material for the pad is of a finely meshed matrix made of pitch and thermosetting resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake sliding portion made of a carbon fiber reinforced carbon composite material (hereinafter referred to as C / C composite material) having excellent friction and sliding characteristics.

[0002]

2. Description of the Related Art In recent years, in a vehicle disc brake, a C / C composite material has been used for a brake sliding portion of a disc or a pad from the viewpoint of weight reduction and performance improvement.

[0003]

However, the friction coefficient of the disk or pad using the C / C composite material is apt to change with temperature, and for example, the friction coefficient is low in a low temperature region such as the initial stage of braking, and then the friction progresses. The friction coefficient gradually or rapidly rises as the temperature rises, or
The phenomenon that the coefficient of friction remained low remained, and it was difficult to obtain a stable braking effect.

Therefore, the inventors of the present invention have conducted extensive studies on the brake sliding portion made of the C / C composite material, and as a result, have made the reinforcing material and the densified matrix of the disk material and the pad material specific. It is known that, due to the high friction coefficient level from low temperature to high temperature, the friction coefficient is stable in the low temperature range and the pad wear resistance is excellent, and stable braking effect is obtained. I got it.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a brake sliding portion composed of a disc and a pad, wherein the disc material and the pad material are both short fiber-shaped fibers each consisting of a bundle of a plurality of single fibers. Composed of carbon fiber reinforced carbon composite material, which is made by defibrating the carbon fiber of
The disk material is characterized by using pyrolytic carbon and pitch as a densified matrix, and the pad material is characterized by using pitch and thermosetting resin as a densified matrix.

The present invention will be described in detail below.

As the carbon fiber used in the present invention, any known carbon fiber such as pitch-based, PAN-based or rayon-based carbon fiber can be used, and if necessary, SiC, A
Inorganic fibers such as l ₂ O ₃ and carbon black, and inorganic substances may be added.

The form of these carbon fibers is a tow, a strand, a roving, a yarn or the like which is composed of a bundle of a plurality of single fibers, and a short fiber form obtained by cutting these is used. In the present invention, usually 0.3 to
Short fibers of about 100 mm, preferably about 5 to 50 mm are used. The diameter and elastic modulus of the carbon fiber itself are not particularly limited within the range generally used as a composite material.

When making a C / C composite material, for example, JP-A-62-62
-96364, JP-A-1-176273, and the like to defibrate and disperse to obtain a preform or sheet. These are impregnated with a matrix material, filled in a mold, and pressure-molded at a temperature of 100 to 500 ° C. to obtain a molded product having V _f (fiber content) of 5 to 65%, preferably 10 to 55%. . Then, in an inert gas atmosphere such as N ₂ gas at a temperature rising rate of 1 to 200 ° C./hr and 800 to 2500 ° C.
The temperature is raised up to the temperature and is fired to obtain a C / C composite material.

The C / C composite material obtained by the above-mentioned firing is subjected to a densification treatment and a final treatment, for example, by the following methods for disc material and pad material, respectively.
/ C composite material is obtained.

(A) Treatment of disk material The above C / C placed in the reaction tube by an induction heating coil or the like.
The composite material is heated, vapors of hydrocarbons or halogenated hydrocarbons are supplied into the reaction tube together with H ₂ gas, Ar gas or N ₂ gas, and voids are impregnated with the generated pyrolytic carbon to densify it. . Next, the C / C composite material is loaded into a tank heated to a predetermined temperature, the inside of the tank is evacuated, a molten pitch is supplied, and voids generated by firing are impregnated with a matrix material. After that, firing is performed at a temperature of 800 to 2500 ° C. The C / C composite material is densified by repeating the above steps. Further, if necessary, final heat treatment is performed at a temperature of 2500 ° C. or lower to obtain a C / C composite material for disk material.

(B) Treatment of pad material After the above-mentioned C / C composite material is loaded into a tank heated to a predetermined temperature and the inside of the tank is evacuated, a molten pitch and a thermosetting resin, preferably a phenol resin Are sequentially supplied, and the voids generated by firing are impregnated with the matrix material. Then, it is fired again at a temperature of 800 to 2500 ° C. The C / C composite material is densified by repeating the above steps. Further, if necessary, final heat treatment is performed at a temperature of 2500 ° C. or lower to obtain a C / C composite material for pad material.

[0013]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Production Example 1 Pitch-based carbon fiber having 4000 filaments cut into 30 mm length was defibrated to obtain a sheet oriented two-dimensionally at random. This sheet was impregnated with phenol resin and then dried to prepare a sheet in which 65 parts of phenol resin was impregnated with respect to 100 parts of carbon fiber. This sheet was laminated in a mold and pressure-molded at 250 ° C. to obtain a molded body having V _{f of} about 50%. After densifying this molded body in a heating furnace to 2000 ° C., it is heated by a high frequency induction heating device, and hydrocarbon vapor is introduced into the reactor as a carrier gas of nitrogen gas, and densification is performed by filling pores with pyrolytic carbon. Processed.

Next, after impregnating the pitch, 1 in a heating furnace
It was baked at 000 ° C. Further, the same impregnation-firing operation was repeated again, and then heat treatment at 2000 ° C. was performed to obtain a C / C composite material for a disk material having a porosity of 11%.

Production Example 2 A pitch-based carbon fiber having 4000 filaments cut into a length of 30 mm was defibrated to obtain a two-dimensionally randomly oriented sheet. This sheet was impregnated with phenol resin and then dried to prepare a sheet in which 65 parts of phenol resin was impregnated with respect to 100 parts of carbon fiber. This sheet was laminated in a mold and pressure-molded at 250 ° C. to obtain a molded body having V _{f of} about 50%. The compact was fired in a heating furnace to 2000 ° C., impregnated with pitch, and then fired in a heating furnace at 1000 ° C. After that, it was impregnated with a phenol resin and then fired to 1000 ° C. in a heating furnace.

Further, the impregnation of the phenol resin and the firing were repeated again, and then a heat treatment at 2000 ° C. was performed to obtain a C / C composite material for a pad material having a porosity of 14%.

A bench test in accordance with JIS D4411 using the thus obtained disc material and pad was conducted at a low temperature range of 100 ° C. or lower to 100 to 450 ° C.
Friction coefficient up to the high temperature range of μ = 0.4
.About.0.5 and .mu. = 0.4 to 0.45, the variation of the friction coefficient in the low temperature region is .mu. = 0.05 to 0.1, and the variation of the friction coefficient in the high temperature region is .mu. =
It was 0.2 or less. Furthermore, the amount of pad wear is 0.1
It was 0.2 mm.

Comparative Example 1 C / of a conventional product using CVD carbon as a matrix
As a result of performing the same test as above using the C composite material as the disk material and the pad material, the friction coefficient in the low temperature range of 100 ° C. or lower is μ = 0.33 to 0.35, 100 to 450 ° C.
The friction coefficient in the high temperature range of was 0.30 to 0.4. Further, the variation of the friction coefficient in the low temperature range is μ =
The coefficient of friction was 0.10 to 0.15, and the variation in the friction coefficient in the high temperature range was μ = 0.05 to 0.1. Further, the amount of wear was 0.2 to 0.3 mm.

[0020]

As described above, according to the present invention, in the brake sliding portion of the C / C composite material, the disk material uses the C / C composite material in which the pyrolysis carbon and the pitch are the densified matrix, and the pad material is used. By using a C / C composite material in which a pitch and a thermosetting resin are used as a densified matrix, the friction coefficient level from the low temperature range to the high temperature range is high, the friction coefficient in the low temperature range is stable, and the wear is reduced. It is possible to obtain a brake sliding portion having a small amount and a stable braking effect.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Yanagisawa Inventor Masahiro Ueda City, Nagano Prefecture 840 Kokubu, Nissin Industry Co., Ltd. (72) Inventor Kohei Okuyama 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd. Inside the Research Institute (72) Inventor Kazuo Niwa, No. 1 state town in Sakaide City, Kagawa Prefecture, Sakaide Factory, Mitsubishi Chemical Co., Ltd. (72) Toshihiro Fukagawa, No. 1 state town, Sakaide City, Kagawa Prefecture, Sakaide Factory, Mitsubishi Chemical Corporation

Claims (1)

[Claims] 1. In a brake sliding portion composed of a disc and a pad, the disc material and the pad material are both made of a carbon fiber obtained by defibrating short fiber carbon fibers each consisting of a bundle of a plurality of single fibers as a reinforcing material. It is composed of a fiber-reinforced carbon composite material, and the disk material has pyrolytic carbon and pitch as a densified matrix, and the pad material has pitch and thermosetting resin as a densified matrix. Brake sliding part.