JPH0619198B2 - Friction plate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a friction plate, and more particularly to a friction plate for a brake of an aircraft, a railway, an automobile, an industrial machine or the like.

(Prior Art) A brake that uses a carbon fiber reinforced carbon material (hereinafter abbreviated as CFRC) for a friction disk is used in aircrafts and the like, and the brake is lighter than a conventional friction disk that uses a metal material. And improved performance.

The CFRC friction has the advantage that it shows a stable and high friction coefficient even at a very high sliding speed, and the variation of the friction coefficient with temperature is small. Further, since CFRC is excellent in heat resistance and heat conduction, it can be used under the condition that a large amount of frictional heat is generated.

This CFRC exhibits different physical properties depending on the form of the carbon fiber used. Specifically, the fiber form is filament,
There are woven fabrics, papers, chips fibers, non-woven fabrics, mats, etc., filaments and woven fabrics are made of long fibers, and the rest are made of short fibers. Here, the length division of the fiber is 100 mm or less as short fiber and more than 100 mm as long fiber. Although CFRC using short fibers is inexpensive, it has the drawback of being inferior to CFRC using long fibers in strength and toughness.

(Problems to be Solved by the Invention) CFRCs used as brake discs require strength, and because of their ease of handling, laminated CFRCs made of woven fabric are often used. However, when the CFRC having the laminated structure is rubbed, the woven cloth having a small amount of fibers and the woven cloth layer sometimes appear on the friction surface due to abrasion. This change in the state of the friction surface has a great influence on friction and is a major factor in making the friction coefficient unstable.

From the viewpoint of friction, it is desirable that carbon fibers are uniformly dispersed in an appropriate amount on the friction surface so that the state of the friction surface does not change due to abrasion. In order to easily and inexpensively produce CFRC having such a friction surface, short carbon fibers are uniformly dispersed in the carbon material. However, the shortcomings of using short carbon fibers are that, as described above, the strength and toughness are difficult to use when strength and toughness are required as in the case of a friction disc of a brake.

In view of the above, the present invention was developed to solve such problems.

(Means for Solving Problems) That is, the friction plate of the present invention is a friction plate made of a carbon fiber reinforced carbon material having at least one surface being a friction surface, and a carbon material using short carbon fibers. , A carbon material using long carbon fibers is used, and a laminated body of these materials is composed of carbon fibers reinforced carbon material, which is an integral molded body in which the layers are bonded together, and carbon using short carbon fibers is used. The material is a friction surface.

(Function) As described above, the combination of the carbon material using the short carbon fiber having excellent friction performance and the carbon material using the long carbon fiber having excellent strength characteristics is required for the CFRC brake plate. It is possible to obtain the one that simultaneously satisfies the two points of the friction performance and the strength characteristic.

The present invention will be described in detail below.

FIG. 1 is a specific example of the present invention and shows a friction disk, and a CFR mainly made of carbon fiber is used for the surface to be rubbed.
It is composed of both C materials (1) and (1 ') and CFRC material (2) using long carbon fibers for expressing high strength in the disc and the core.

The method of manufacturing the friction disc of the present invention will be described in order of steps for the friction disc shown as an example in FIG. A composite disk thermoformed from a woven fabric of long carbon fibers and a resin and a composite disk thermoformed from short carbon fibers and a resin are made. At this stage, it is desirable that the short fibers are uniformly dispersed in the composite material using the short fibers.

The resin used at this time is preferably a thermoplastic resin such as polyacrylonitrile, but a thermosetting resin such as phenol can also be used by controlling the softened state well. The above two kinds of composite materials are laminated. Lamination is performed by stacking the composite material using the woven cloth in the center and laminating the composite material using the short fibers on both sides of the composite material so that the triple structure shown in FIG. 1 is obtained. The resin in the composite of the laminate is inserted into a mold heated to an appropriate temperature for softening, and pressure is applied so that compression is applied between the layers of the laminate. At this time, it is desirable that the resin be softened so that the interface between layers disappears. Next, the laminate is inserted into a carbon mold, but the mold and carbon mold are pressed in the same direction, and the mold is placed in a high-temperature firing furnace capable of pressing to oxidize carbon. The laminated body in the mold is fired to a temperature of 1500 ° C. or higher while applying pressure in a non-oxidizing atmosphere in which the phenomenon does not occur.

It is important to select the heating rate during firing in consideration of carbonization of the resin. Specifically, in the temperature range of 800 to 1000 ° C or less, a large amount of gas is released due to the dispersion reaction of the resin, so it is desirable to have a slow temperature rise to avoid a rapid temperature rise, and a relatively rapid temperature rise is possible after that. is there.

Although this is the step of adhering the laminate in the mold, it is possible to omit this step and perform the same adhering step in the carbon mold.

Since the carbonization of the resin is completed, the composite material fired at a high temperature of 1500 ° C. or higher is obtained as CFRC. Also, the obtained CFRC has a triple structure of CFRC depending on the length of the carbon fiber as shown in FIG. 1, and the interlayer interfaces of each of them are almost lost, and the obtained CFRC is an integrated CFRC.
It is said.

The above steps have been described with reference to FIG. 1 and the stacking of the disks has been described, but the shape of the stack is not limited.

(Examples) Examples of the present invention will be described below.

Example 1. A PAN-based high-strength carbon fiber (using Toray T-300) woven cloth and a thermoformed composite disk of a polyacrylonitrile resin were prepared. Similarly, a disk made of a composite material was made from a short fiber cut into a length of 10 to 50 mm and a resin. Three composite discs were formed by placing the composite disc of the former in the center and the composite disc of the latter above and below the disc. As molding conditions, a mold temperature of 180 ° C., a pressing force of 50 kg / cm ² , and a pressing time of 30 minutes were used. The composite laminated plate molded as described above is put into a carbon mold, and the laminated plate is baked in a non-oxidizing atmosphere while being pressurized to 2000 ° C. CF
I got RC. Pressurization during firing started from 400 ℃, 2000
Continued to ℃. On the way, the region of 700 to 1000 ° C was fired without applying pressure. The applied pressure was 200 kg / cm ² .

The CFRC obtained in the above step was processed into a friction test sample, and the CFRCs using short fibers were rubbed to measure the friction coefficient.

In the measurement, inertia braking was repeated 200 times, and the friction coefficient during inertia braking was measured. The test is an inertial load of 3.5 kg ・ m ・ sec ² ,
Braking was performed with a disc rotation speed of 650 rpm and a deceleration control of 0.3 g. The friction coefficient at 200 cycles is shown in FIG.

As shown in the figure, the friction disk manufactured according to the present invention showed a very stable friction coefficient. The shear strength of the carbon material obtained in the above process was measured by ASTM D2344. The shear strength including the layers of the two types of CFRC is 1.1 kg / mm ² , and the shear strength of CFRC using long fibers is 1.2 kg.
It was found that there was no significant difference between the ^two at a value of / mm ² , and the layers of CFRC to which the fiber length according to the present invention was added were strongly bonded.

Comparative Example 1. A composite material disk thermoformed from the same carbon fiber woven fabric and polyacrylonitrile resin as in Example 1 was fired to 2000 ° C. by the same pressure firing method as in Example 1 to obtain only long fibers. Then, the same friction test as in Example 1 was performed. The friction coefficient during the test is shown in FIG. 4, and it can be seen that the friction coefficient is extremely unstable as compared with FIG.

(Effect of the Invention) The friction plate of the present invention is superior in friction performance to the conventional CFRC friction plate and is inexpensive in terms of price. Also, in terms of weight, it is lighter than a conventional metal friction plate.

Therefore, the CFRC friction plate of the present invention can be used for wider applications than conventional products. Specifically, it can be used as a brake for airplanes, railways, automobiles and the like.

[Brief description of drawings]

FIG. 1 is a perspective external view of a friction disc according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA ′ of FIG. FIG. 3 is a diagram for explaining the relationship between the braking frequency and the friction coefficient of the friction disc of the embodiment of the present invention, and FIG. 4 is a diagram for explaining the braking frequency and the friction coefficient of the friction disc of the comparative example. It is illustrated. (1), (1 ') …… CFRC material using short fibers, (2) …… CFRC material using long fibers

Claims (3)

[Claims] 1. A friction plate made of a carbon fiber reinforced carbon material, at least one surface of which is a friction surface, wherein a carbon material using short carbon fibers and a carbon material using long carbon fibers are used. A layered body of carbon material is bonded between layers, and the layered body is composed of a carbon fiber reinforced carbon material which is an integrally formed body, and a carbon material using short carbon fibers is a friction surface. Board. 2. A laminated body in which a carbon fiber reinforced carbon material, which is an integrally formed laminated body, is formed by laminating two or more kinds of composite materials of carbon fibers and a resin and applying pressure at a softening temperature of the resin. The friction plate according to claim (1), wherein the friction plate is obtained by forming a laminate and firing the laminate in a non-oxidizing atmosphere at 1500 ° C. or higher. 3. A carbon fiber reinforced carbon material using short carbon fibers in the form of at least one of a chopped fiber, felt, paper, or non-woven fabric, and a wound or woven fabric of filament. The friction plate according to claim (1), which is composed of a carbon fiber reinforced carbon material using long carbon fibers of one type.