JPH04258681A - Frictional material - Google Patents

Abstract

PURPOSE:To obtain a lightweight frictional material excellent in economy and showing excellent characteristics under high-speed high-load conditions by clamping a rotating disc made from carbon fibers having a specified fiber diameter with pads made from carbon fibers having a diameter larger than that of the former fiber. CONSTITUTION:This frictional material for a brake is provided with a rotor disc 1 and pads 2a, 2b for braking the rotor disc 1 by clamping it from both sides thereof. The rotor disc 1 is formed from a carbonaceous material prepared by using carbon fibers having a specified fiber diameter, for example, below 10mum; the pads 2a, 2b are formed from a carbonaceous material prepared by using carbon fibers having a diameter larger than that of the above fiber, for example, 10mum or larger. In this frictional material, the rotor disc of which sufficient strength is necessary is formed from high-strength carbon fibers for lightweightness and the pads, 2a, 2b are formed from carbon fibers excellent in abrasion resistance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a friction material, and more particularly to a friction material used as a brake friction material for high-speed, high-load applications.

0002

2. Description of the Related Art Conventionally, friction materials made of carbon fiber-reinforced carbon composite materials have been known as brake friction materials for high-speed, high-load use in aircraft, racing cars, and the like. A brake friction material using this carbon fiber-reinforced carbon composite material can be lighter in weight and have improved performance compared to a brake friction material using a metal material.

[0003] Furthermore, the friction between carbon fiber-reinforced carbon composite materials exhibits a stable and high coefficient of friction even at very high sliding speeds, and has the advantage that there is little variation in the coefficient of friction due to temperature. Furthermore, since the carbon fiber reinforced carbon composite material has excellent mechanical properties, the carbon fiber reinforced carbon composite material can be used alone without using a reinforcing plate made of a metal material or the like. As a result, the advantage of the carbon material itself, which is its light weight, can be effectively utilized.

Conventionally, when carbon fiber-reinforced carbon composite materials are used as brake friction materials, rotor disks and pads are usually made of the same material. Here, to briefly explain the braking operation, by sandwiching both sides of a rotating rotor disk between pads, the braking operation is performed by friction between the pad surface and the disk surface.

[0005]

[Problems to be Solved by the Invention] As mentioned above, when carbon fiber-reinforced carbon composite materials are used as conventional brake friction materials, both the rotor disk, which is a rotating body, and the pad that performs braking must be made of the same material. I was using it.

However, for example, when carbon fibers with a fiber diameter of less than 10 μm are used for both the rotor disk and the pad, there is a disadvantage that wear is greater than when carbon fibers with a fiber diameter of 10 μm or more are used. As a result, there was a problem in that the pads had to be replaced more frequently.

On the other hand, when carbon fibers with a fiber diameter of 10 μm or more are used for both the rotor disk and the pad, there is a problem in that the weight reduction that is the effect of using carbon fiber-reinforced carbon composite materials cannot be achieved as much. Ta. Comparing the specific gravity of the fiber itself, this means that the fiber diameter is 10μ.
This is because carbon fibers with a fiber diameter of m or more have a higher specific gravity than carbon fibers with a fiber diameter of less than 10 μm. If the weight reduction effect is reduced when carbon fibers having a fiber diameter of 10 μm or more are used in this way, this is particularly disadvantageous for the rotor disk, which is a rotating body.

Furthermore, since most carbon fibers with a fiber diameter of 10 μm or more are of low strength type, carbon fiber-reinforced carbon composite materials using them also have low strength. As a result,
There may be an inconvenience that the rotor disk breaks during use. For this reason, it is necessary to design the plate thickness thickly in advance. As a result, the rotor disk becomes heavier and there is a problem in that it is not possible to reduce the weight of the rotor disk.

[0009]Also, there are carbon fibers with a fiber diameter of 10 μm or more and high strength types, but these have the drawback of being very expensive and therefore not economically desirable.

[0010] As another example of improvement, for example, in JP-A-63-130937, in order to maintain the strength as a structural material, a carbon fiber-reinforced carbon composite material using carbon fibers with a fiber diameter of less than 10 μm in the center was developed. A sandwich type rotor disk has been proposed in which carbon fibers with a fiber diameter of 10 μm or more are arranged on the friction surface. However, this proposed brake friction material has the disadvantage that peeling occurs at the boundary between the two materials when exposed to extremely high temperatures. This is a fiber diameter of 10μ
This is thought to be due to the difference in thermal expansion coefficient between carbon fibers with a fiber diameter of 10 μm or more and carbon fibers with a fiber diameter of less than 10 μm.

[0011] The present invention was made to solve the above-mentioned problems, and it provides a friction material that is lightweight, has excellent economic efficiency, and can obtain excellent characteristics under high-speed and high-load conditions. The purpose is to provide

0012

[Means for Solving the Problems] The friction material of the present invention includes a rotary plate made of a first carbon material using carbon fibers having a predetermined fiber diameter, and a diameter of the carbon fiber used for the first carbon material. It is made of a second carbon material using carbon fibers having a larger diameter, and includes brake pads for braking by sandwiching the rotating plate from both sides.

[0013]

[Function] In the friction material according to the present invention, the rotating plate is made of a first carbon material using carbon fibers having a predetermined fiber diameter, and the braking pad is made of a first carbon material using carbon fibers having a predetermined fiber diameter, and the braking pad is made of a carbon fiber having a diameter larger than the diameter of the carbon fiber used for the first carbon material. Since it is formed from the second carbon material using carbon fibers having a large diameter, the rotor disk (rotating plate), which requires strength, is formed from high-strength carbon fibers and is lightweight. Further, a pad (braking pad) that needs to have a low amount of wear is made of carbon fiber with excellent wear resistance. Furthermore, inexpensive carbon fibers can be used.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing the structure of a brake friction material according to an embodiment of the present invention.

Referring to FIG. 1, the brake friction material of this embodiment brakes the rotation of the rotor disk 1 by sandwiching the rotor disk 1, which is a rotating body, and the rotor disk 1, which rotates during braking, from both sides. pads 2a, 2
b. The rotor disk 1 has a fiber diameter of 10
It is constructed from a carbon material using carbon fibers of less than μm. Further, the pads 2a and 2b are made of a carbon material using carbon fibers having a fiber diameter of 10 μm or more. In this way, when a carbon fiber-reinforced carbon composite material using carbon fibers with a fiber diameter of less than 10 μm is used for the rotor disk 1, it is very advantageous for weight reduction. Furthermore, since carbon fibers with a fiber diameter of less than 10 μm have high strength, the wall thickness of portions where strength is required, such as the attachment portion of the rotor disk 1, can be made thinner. As a result, it becomes possible to further reduce the weight.

Note that the rotor disk 1 has a fiber diameter of 10 μm.
In the case of carbon fiber-reinforced carbon composite materials using carbon fibers with a diameter of less than m, the amount of wear appears to be a problem. However, since the friction area of the rotor disk is about five times that of the pad, the theoretical wear thickness is 1/5 of that of the pads 2a and 2b. Therefore, it is not necessary to consider the amount of wear as much as the pads 2a and 2b.

On the other hand, the amount of wear of the pads 2a and 2b is a problem, and they are required to have a low amount of wear. Note that there is not much requirement for strength. Therefore, the pads 2a, 2b are made of carbon fiber-reinforced carbon composite materials using carbon fibers with a fiber diameter of 10 μm or more, which have low strength but little wear.
If used for this purpose, the required characteristics can be obtained. Here, a problem can be considered that a carbon fiber-reinforced carbon composite material using carbon fibers having a fiber diameter of 10 μm or more is heavy. However, since there is little wear, the initial thickness can be made thinner, and this does not have a negative impact on weight reduction.

Next, an experiment conducted to confirm the effects of the present invention will be explained. First, in this experiment, three types of experiments were conducted: Example 1, Comparative Example 1, and Comparative Example 2. The test conditions were the same for each case, 300 km/
This is a dynamo test that simulates a case where a racing car running at 1.0 km/h decelerates to 70 km/h at a deceleration of 1.0 G. The racing car rotor, pad, and test results used in Example 1, Comparative Example 1, and Comparative Example 2 will be described below. (Example 1) In this Example 1, a racing car rotor (ventilated type with 24 through holes of Φ9 mm) of Φ280 x 22 mm was made of PAN-based carbon fiber (fiber diameter: 7 μm, tensile strength: 3.5GPa)
It is made of carbon fiber-reinforced carbon composite material. The pad is made of pitch-based carbon fiber (fiber diameter: 15 μm)
It is made of carbon fiber-reinforced carbon composite material. A dynamo test was conducted on a brake friction material composed of such a racing car rotor and pad. (Comparative Example 1) In this comparative example, both the Φ280 x 22 mm racing car rotor (ventilated type with 24 Φ9 mm through holes) and the pad were made of PAN-based carbon fiber (fiber diameter: 7 μm, It is constructed from a carbon fiber reinforced carbon composite material with a tensile strength of 3.5 GPa. A dynamo test was conducted on a brake friction material composed of such a racing car rotor and pad. (Comparative Example 2) In Comparative Example 2, both the Φ280 x 22 mm racing car rotor (ventilated type with 24 Φ9 mm through holes) and the pad were made of pitch-based carbon fiber (fiber diameter: 7 μm). ) is made of carbon fiber-reinforced carbon composite material. A dynamo test was conducted on a brake friction material composed of such a racing car rotor and pad.

The following experimental results were obtained for Example 1, Comparative Example 1, and Comparative Example 2.

In the brake friction material of Example 1, Comparative Example 1
The life of this brake friction material was 1.5 times longer than that of other brake friction materials.

The brake friction material of Comparative Example 2 broke after the 20th braking. In this way, as in Example 1, fiber diameter 7 was applied to a racing car rotor (rotor disk).
A carbon fiber-reinforced carbon composite material made of carbon fiber with a tensile strength of 3.5 GPa is used for the pad, and the fiber diameter is 15 μm.
By using a carbon fiber-reinforced carbon composite material made of carbon fibers, we were able to provide a brake friction material with excellent properties as a brake friction material for high-speed, high-load applications.

[0023]

According to the friction material according to the present invention, the rotating plate is formed of the first carbon material using carbon fibers having a predetermined fiber diameter, and the braking pad is formed of the carbon material used for the first carbon material. By forming the second carbon material using carbon fibers having a diameter larger than the diameter of the fibers, the rotor disk (rotating plate), which requires strength, is formed from high-strength carbon fibers and is lightweight. . Further, a pad (braking pad) that needs to have a low amount of wear is made of carbon fiber with excellent wear resistance. Further, since conventional carbon fibers can be used, the cost is not high. As a result, it is lightweight, economical, and
Moreover, it was possible to provide a friction material that can obtain excellent properties under high-speed, high-load conditions.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure of a brake friction material according to an embodiment of the present invention.

[Explanation of symbols]

1 Rotor disk 2a, 2b pad

Claims (3)

[Claims] Claim 1: A rotary plate made of a first carbon material using carbon fibers having a predetermined fiber diameter; and a rotating plate made of a first carbon material using carbon fibers having a diameter larger than the diameter of the carbon fibers used for the first carbon material. A friction material made of a second carbon material and comprising a brake pad for braking by sandwiching the rotary plate from both sides. 2. The carbon fiber used in the first friction material has a diameter of less than 10 μm, and the carbon fiber used in the second carbon material has a diameter of 10 μm or more. The friction material according to claim 1. 3. A friction material, wherein the carbon fiber used for the first carbon material has a tensile strength of 2 GPa or more.