JP2864304B2 - Brake sliding part - Google Patents

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, C / C composite materials have been used for brake sliding portions of disks and pads in vehicle disk brakes from the viewpoint of weight reduction and performance improvement.

[0003]

However, the friction coefficient of a disk or pad using a C / C composite material tends to change depending on the temperature. For example, the friction coefficient in a low-temperature region, such as at the beginning of braking, is low. And the coefficient of friction increases gradually or rapidly as the temperature rises, or
The phenomenon that the coefficient of friction remained low occurred, and it was difficult to obtain a stable braking effect.

[0004] The inventors of the present invention have conducted intensive studies on the brake sliding portion made of the C / C composite material, and have determined that the reinforcing material and the densifying matrix of the disc material and the pad material are specified. In particular, the coefficient of friction is large from the low temperature range to the high temperature range, and it is excellent in stabilizing the coefficient of friction at low temperature and excellent in pad wear resistance.
We have learned that a stable braking effect can be obtained.

[0005]

According to the present invention, there is provided a brake sliding portion comprising a disk and a pad, wherein each of the disk material and the pad material is formed of a short fiber comprising a bundle of a plurality of single fibers. It is composed of a carbon fiber reinforced carbon composite material that uses defibrated carbon fiber as a reinforcing material,
The disk material is characterized by using a pitch as a densified matrix, and the pad material is characterized by using pyrolytic carbon and a thermosetting resin as a densified matrix.

Hereinafter, the present invention will be described in detail.

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

[0008] The form of these carbon fibers is tow, strand, roving, yarn, or the like made of a bundle of a plurality of single fibers, and is used as a short fiber obtained by cutting these. In the present invention, usually 0.3 ~
Short fibers of 100 mm, preferably about 5 to 50 mm are used. The diameter and elastic modulus of the carbon fiber itself are not particularly limited as long as they are generally used as a composite material.

When a C / C composite material is used, for example, Japanese Patent Application Laid-Open
-96364, JP-A-1-176273, etc. to be defibrated and dispersed into a preform or sheet. These are impregnated with a matrix material, filled into a mold, and molded under pressure at a temperature of 100 to 500 ° C. to obtain a molded body having a V _f (fiber content) of 5 to 65%, preferably 10 to 55%. . Then, at a temperature rising rate of 1 to 200 ° C./hr, 800 to 2500 ° C. in an inert gas atmosphere such as N ₂ gas.
Then, the temperature is raised to a value and fired to obtain a C / C composite material.

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

(A) Processing of disk material The above-mentioned C / C composite material is loaded in a tank heated to a predetermined temperature, the inside of the tank is evacuated, a molten pitch is supplied, and a matrix is formed in a void generated by firing. Impregnate the material. After this,
It is fired again at a temperature of 800 to 2500C. The C / C composite is densified by repeating the above steps.
Further, if necessary, a final heat treatment is performed at a temperature of 2500 ° C. or less to obtain a C / C composite material for a disk material.

(B) Treatment of pad material The above C / C placed in the reactor by an induction heating coil or the like
The composite material is heated, and the vapor of hydrocarbons or halogenated hydrocarbons is supplied into the reactor together with the H ₂ gas, Ar gas or N ₂ gas, and the voids are impregnated with the generated pyrolytic carbon and densified. I do. Next, the C / C composite material is placed in a tank heated to a predetermined temperature, and after the inside of the tank is evacuated, a thermosetting resin, preferably a phenol resin, is supplied to impregnate the gap with the matrix material. After this, 800 ~ 2500C
Firing at a temperature of The C / C composite is densified by repeating the resin impregnation step. Further, if necessary, a final heat treatment is performed at a temperature of 2500 ° C. or less to obtain a C / C composite material for a pad material.

[0013]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Production Example 1 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. The sheet was impregnated with a phenol resin and then dried to prepare a sheet in which 100 parts of carbon fibers were impregnated with 65 parts of a phenol resin. This sheet was laminated in a mold and pressed at 250 ° C. to obtain a molded body having a _{Vf of} about 50%. This molded body was fired in a heating furnace up to 2000 ° C.

Next, after impregnating the pitch, 1 hour in a heating furnace.
It was baked at 000 ° C. Further, the same operation of impregnation and firing was repeated again, and thereafter, heat treatment was performed at 2000 ° C. to obtain a C / C composite material for a disk material having a porosity of 8%.

Production Example 2 A pitch-based carbon fiber having a length of 10 mm and a filament count of 4000 was wet-fibrillated, and then an outer cylinder 300 mm and an inner cylinder 120 were prepared.
mm into a dough-shaped bottom with a mesh screen of 150 mesh and water into a mold having a bottom plate on the outside, together with water.After stirring uniformly, the whole solution was removed at once from the bottom by pulling out the bottom plate. A donut-shaped preform in which the fibers were uniformly dispersed was obtained.

After the preform is dried, it is impregnated with a phenolic resin, dried to form a prepreg, placed in a mold having the same inner and outer diameters as above, and molded and cured at a temperature of 250 ° C., and a V _{f of} 50% Was obtained. This compact is fired in a heating furnace up to 2000 ° C., heated by a high-frequency induction heating device, and introduced into the reactor with hydrocarbon vapor as a carrier gas using nitrogen gas as a carrier gas. Processing was performed.

Next, after impregnating with a phenol resin, it was baked at 1000 ° C. in a heating furnace. Further, the same operation of impregnation and firing was repeated again, and thereafter, heat treatment was performed at 2000 ° C. to obtain a C / C composite material for a pad material having a porosity of 16%.

Using the disk material and pad material obtained in this manner, the results of a bench test in accordance with JIS D4411 show that the temperature range is from 100 ° C. or lower to 100 ° C. to 450 ° C.
Coefficient of friction up to the high temperature range of μ = 0.5
.Mu. = 0.55 and .mu. = 0.45 to 0.5, and the variation of the friction coefficient in the low temperature range is .mu. = 0.05 to 0.1, and the variation of the friction coefficient in the high temperature range is also .mu.
It was 0.1 or less. Furthermore, the pad wear amount is 0.1m
m or less.

Comparative Example 1 A conventional C / C
Using the C composite material for the disk material and the pad material, the same test as above was carried out. The results show that the friction coefficient in a low temperature range of 100 ° C. or less is μ = 0.33 to 0.35, 100 to 450 ° C.
Has a coefficient of friction in a high temperature range of μ = 0.35 to 0.4. The variation of the friction coefficient in the low temperature range is μ =
0.10 to 0.15, and the variation of the friction coefficient in the high temperature range was μ = 0.05 to 0.1. Further, the wear amount was 0.2 to 0.3 mm.

[0021]

As described above, the present invention uses a C / C composite material having a dense matrix as a disc material in a brake sliding portion of a C / C composite material, and uses pyrolytic carbon and a pad material as pad materials. By using a C / C composite material using a thermosetting resin as a densified matrix, the friction coefficient level from low to high temperatures is high, the friction coefficient is stabilized at low temperatures, and wear is enhanced. It is possible to obtain a brake sliding portion having a small amount and a stable braking effect.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Yanagisawa 840 Kokubu, Ueda-shi, Nagano Nissin Kogyo Co., Ltd. Within the Research Institute (72) Inventor Kazuo Niwa 1 Bancho-cho, Sakaide-shi, Kagawa Prefecture Mitsubishi Sakaide Co., Ltd. References JP-A-60-8536 (JP, A) JP-A-62-96364 (JP, A) JP-A-1-176273 (JP, A) JP-A-63-274664 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) F16D 69/02 F16D 65/12 F16D 69/00

Claims (1)

(57) [Claims] 1. A brake sliding portion comprising a disk and a pad, wherein each of the disk material and the pad material is made of a carbon fiber having a reinforcing fiber made of a short fibrous carbon fiber made of a bundle of a plurality of single fibers. A brake material comprising a fiber-reinforced carbon composite material, wherein the disc material has a pitch of a densified matrix, and the pad material has a densified matrix of pyrolytic carbon and a thermosetting resin. Moving part.