JPH08177908A - Brake - Google Patents

Abstract

PURPOSE: To provide a brake high in durability and having a frictional characteristic in accordance with application, a use environment, and a control method by arranging carbon/carbon composite material, having different characteristics, as friction material in a disk and a pad. CONSTITUTION: A brake is used which is composed of a disk, having carbon/ carbon composite material (A), as friction material, and a pad, having carbon/ carbon composite material (B), as friction material; and in which characteristics of the carbon/carbon composite material (A) and the carbon/carbon composite material (B) are different. The different characteristics in this carbon/carbon composite material mean the difference of at least one or more items of the thermal physical property, mechanical physical property, an oxidation characteristic, or other material physical property of the carbon/carbon composite material. Thermal conductivity and thermal expansion coefficient, etc., are cited as the thermal physical property. For example, hardness, tensile strength, a compression elastic modulus, and inter-layer shear strength are noted as the mechanical physical property. For example, oxidation velocity and oxidation start temperature, etc., are noted as an oxidation characteristic. Density, etc., is noted as another physical property.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a disc pad type brake.

[0002]

Disc brakes are widely used as various friction brakes in various applications such as motorcycles, automobiles, railway vehicles, and aircraft. The disc brakes are classified into disc pad type brakes, multi-disc brakes, etc., depending on their types. Conventional disc brakes are made of organic materials, metal materials, carbon / carbon composite material materials, or the like.

The organic brake material is mainly used as a pad material of a disc pad type brake or a surface material (lining material) of the pad. A typical method for producing an organic brake material is to combine a thermosetting resin such as a phenolic resin with an organic fiber, a metal fiber, an inorganic fiber, etc. for reinforcement, and add various additives to adjust friction performance. It is used after being molded into the shape of, and subjected to heat treatment etc. depending on the application.

In the organic brake material, the organic components of its main constituents decompose at a temperature of about 300 ° C. or higher, so if it is used at a high speed or with a high pressing force, it is decomposed by frictional heat and deteriorates, which shortens its life significantly. However, there is a problem that sufficient braking force cannot be obtained due to a fade phenomenon or the like.

Typical examples of the metallic brake material include cast iron-based, forged steel-based, and alloy-based brakes. Metal-based brake materials are used as disk materials for disk-pad type brakes, and in recent years, application of aluminum alloy-based brake materials to disks has been considered for weight reduction. Further, alloy-based brake materials are also used as pad materials, and in particular, copper-based sintered alloys are widely used as pad materials. Metal-based brake materials are also widely used as disk materials for multi-disc brakes, and are mainly used mainly for aircraft brake materials.

When a metallic brake material is used at a high speed or with a high pressing force and frictional heat increases, a fade phenomenon occurs near the melting point of the metal which is the main constituent of the metallic brake material, and a sufficient frictional force cannot be obtained. was there. Further, when used at a temperature higher than the melting point, there was a problem that the disc and the lining were fused to each other after the suspension and could not be cut off, which necessitated extensive repair or replacement for restarting the operation.
Moreover, since the metal-based brake has a large specific gravity, the total weight of the entire vehicle on which it is mounted is large, which hinders reduction of fuel consumption and noise. Further, the metal-based brake material has a large coefficient of thermal expansion, which causes deterioration due to cracks and the like due to the impact of frictional heat.

The carbon / carbon composite material is a carbon material reinforced with carbon fiber. Since it has a smaller specific gravity than a metallic brake material, it can be significantly reduced in weight, and since it has no melting point, troubles such as fusion bonding can be avoided. It becomes possible. Further, the decomposition temperature is as high as about 3000 ° C. as compared with the organic brake material, and the deterioration due to frictional heat can be significantly reduced. Furthermore, the coefficient of thermal expansion is small, and the durability against thermal shock can be greatly improved.

[0008] Carbon / carbon composite material-based brake materials are used for applications requiring heat resistance and weight reduction, which are difficult to cope with with organic or metal-based brake materials. It is used for disc pad type brakes for auto-bye and competition cars, and multi-disc brakes for aircraft such as large passenger planes and fighters.

Among these, in the carbon / carbon composite material type disc pad type brake, carbon / carbon which is usually used for a disc is used.
The carbon composite material and the carbon / carbon composite material used for the pad have the same properties. Even if the characteristics of the carbon / carbon composite material are changed according to the application, usage environment and control method, the carbon / carbon composite material normally used for the disc and the carbon / carbon composite material used for the pad are the same new ones. It has been changed to a characteristic.

Further, even when the carbon / carbon composite material is improved in order to improve the durability and frictional characteristics, the carbon / carbon composite material used for the ordinary disc and the carbon / carbon composite material used for the pad are new. It has been changed to the same characteristics.

The carbon / carbon composite material used in conventional disc pad type brakes wears with use and requires regular replacement. In this case, usually new carbon /
It is replaced with a carbon composite material, but it may be replaced with a repair / recycled carbon / carbon composite material.

As a method for repairing and regenerating the worn carbon / carbon composite material, an example in which a worn carbon / carbon composite material is used as a core material and a surface material made of the carbon / carbon composite material is bonded to the core material (US Pat. No. 742, 948, Special Examination 4-
63026).

Further, although the carbon / carbon composite material disposed on the sliding surface has desired frictional characteristics, when the mechanical strength is insufficient under intended use conditions, a non-sliding internal part is provided for the purpose of reinforcing the mechanical strength. Alternatively, a report example in which a material of high strength different from the material of the sliding surface is bonded to the back surface (1992 2nd CP
C study group).

However, even in these prior arts, among the carbon / carbon composite materials usually used for disks and the carbon / carbon composite materials used for pads, those which are arranged on the sliding surface as a friction material have characteristics. Same carbon / carbon composite material was used.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly durable brake having friction characteristics tailored to the application, environment of use and control method.

[0016]

The present invention comprises a disk having a carbon / carbon composite material (A) as a friction material and a pad having a carbon / carbon composite material (B) as a friction material. The present invention relates to a disc pad type brake characterized in that the composite material (A) and the carbon / carbon composite material (B) have different characteristics.

First, the disc pad type brake according to the present invention will be described in detail. The discs and pads of the disc pad type brake according to the present invention have a friction material on the surface thereof. The friction material on the pad surface may be referred to as a lining. In the present invention, a carbon / carbon composite material is used as the friction material. In the present invention, the entire disc or the entire pad may be made of carbon / carbon composite material.

The material of the portion of the disc pad type brake according to the present invention excluding the friction material is not particularly limited, and conventionally known materials can be used. For example, various metal materials such as carbon steel, cast iron or aluminum can be used for the back plate for fixing the friction material, the cylinder for driving to press the pad, the main shaft for rotating the disk, and the like.

The disc pad type brake according to the present invention obtains a braking force by pressing the pad against the rotating disc. By being pressed, the sliding portions of the friction materials that rub against each other generate a frictional force, which is used as a braking force. The entire surface having a sliding portion is called a sliding surface, and the non-sliding portion is included in this sliding surface.

The sliding surface of the disk moves continuously between the sliding portion and the non-sliding portion during braking, but the sliding surface of the pad is
It is common to always slide during braking. Since the non-sliding part of the friction material surface of the disk is exposed to the atmosphere,
It is easily affected by oxidation due to frictional heat. On the other hand, the sliding surface of the pad constantly slides during braking, so that the sliding surface is not exposed to the atmosphere during braking, but the sliding time per unit surface area becomes longer and the amount of friction heat received becomes higher. Since it is necessary to dispose a driving device for pressing and separating on the back surface of the pad, it is necessary to consider heat insulation on the back surface. As described above, in the disc pad type brake, since the roles of the disc and the pad are different and the usage conditions are different, it is important to give the friction material unique characteristics.

Therefore, in the disc pad type brake comprising the disc having the carbon / carbon composite material (A) as the friction material and the pad having the carbon / carbon composite material (B) as the friction material, the carbon / carbon composite material is used. (A) and a carbon / carbon composite material (B) having different characteristics are used to obtain a novel disc pad type brake having high durability, which has friction characteristics according to the application, use environment and control method. I arrived.

Each of the carbon / carbon composite materials having different characteristics is processed as necessary, and a jig or the like is attached to the carbon / carbon composite material.
The friction material of the disc and the pad can be the whole or a part thereof.

When a plurality of pads are used, the carbon / carbon composite material used for one or more of them is
It is possible to have different properties than the carbon / carbon composite material used for the disc.

Further, two or more kinds of carbon / carbon composite materials having different characteristics are processed as needed, and a jig or the like is attached using an adhesive to make a part of a friction material included in each disk or pad. It can also be configured and arranged in other parts.

As described above, by disposing carbon / carbon composite materials having different characteristics according to the use, environment of use and control method at desired portions of the disks and pads as friction materials, the desired friction characteristics can be obtained. It is possible to obtain a highly durable disc pad type brake.

The different characteristics of the carbon / carbon composite material means that at least one item of thermophysical properties, mechanical properties, oxidation characteristics or other material properties of the carbon / carbon composite material is different.

Examples of the thermophysical properties include thermal conductivity and thermal expansion coefficient. Mechanical properties include hardness, tensile strength,
The compressive elastic modulus and the interlaminar shear strength are included. Examples of the oxidation characteristics include the oxidation rate and the oxidation start temperature. Examples of other physical properties of the material include density. This will be described in detail below, but any one or more of the following

Therefore, it is possible to obtain a disc pad type brake exhibiting new characteristics corresponding to each intended use, use condition or control method. The carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have a thermal conductivity of 0.1 to 1000.
The range of W / mK is desirable.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by having different thermal conductivities. In this case, the difference between one and the other of the carbon / carbon composite materials having different thermal conductivities is 0.1 to 700 W / m · K in the outer direction of the sliding surface, and more preferably 1 to 30.
It is 0 W / m · K, most preferably 5 to 100 W / m · K. 1 to 450 W / mK in the sliding surface direction,
It is more preferably 2-250 W / m · K, most preferably 10-150 W / m · K.

The higher thermal conductivity is preferably 5 to 700 W / m · K in the sliding surface outside direction, more preferably 10 to 300 W / m · K, and in the sliding surface inside direction. 10 to 450 W / m · K is desirable, and more preferably 20 to 350 W / m · K.

On the other hand, the lower thermal conductivity is preferably 0.1 to 600 W / m · K in the outer direction of the sliding surface, and more preferably 0.1 to 200 W / m · K. In the inward direction, 1 to 350 W / mK is desirable,
More preferably, it is 1 to 150 W / m · K.

The carbon / carbon composite material of the pad has a lower thermal conductivity in the direction outside the sliding surface than the carbon / carbon composite material of the disk, or the carbon / carbon composite material of the disk. It is desirable that the carbon / carbon composite material of the pad has a higher thermal conductivity in the sliding surface direction.

The carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have a Shore hardness of 1 to 140, preferably 30 on the sliding surface.
The range of -140 is desirable.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by setting different Shore hardnesses. In this case, carbon with different Shore hardness /
The difference between one and the other of the carbon composite material is preferably 1 to 60,
It is more preferably 5 to 30.

The higher Shore hardness is 60-1.
It is preferably 40, more preferably 70 to 140, while the lower Shore hardness is preferably 30 to 100, more preferably 30 to 90. It is desirable that the carbon / carbon composite material of the pad has a lower Shore hardness than the carbon / carbon composite material of the disk.

The carbon / carbon composite material used for the disc and the carbon / carbon composite material used for the pad preferably have a tensile strength in the sliding surface in the range of 20 to 1000 MPa.

In the present invention, carbon / carbon composite materials having different properties can be obtained by setting different tensile strengths. In this case, the difference between one and the other of the carbon / carbon composite materials having different tensile strengths is preferably 1 to 200 MPa, more preferably 5 to 100 MPa, and most preferably 10 to 50 MPa.

The higher tensile strength is 50 to 10
00 MPa is desirable, more preferably 60 to 400
MPa, while the lower tensile strength is 20-40
0 MPa is desirable, and more preferably 30 to 300 M
Pa.

It is desirable that the carbon / carbon composite material of the disk has a higher tensile strength than the carbon / carbon composite material of the pad, and in particular, the one in which the inner circumferential portion of the disk has a high circumferential direction.

The carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have a compressive elastic modulus in the outer direction of the sliding surface of 0.1 to 300 GPa.
Those in the range of are desirable.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by setting different compressive elastic moduli. In this case, carbon with different compression modulus /
The difference between one side and the other side of the carbon composite material is 0.1 to 200 GPa
Is desirable, and more preferably 0.1 to 10 GPa.

The higher compression elastic modulus is 1 to 30.
0 GPa is desirable, more preferably 1 to 200 GP
a, while the lower compression modulus is 0.1-20
0 GPa is desirable, more preferably 0.5 to 100
It is GPa. It is desirable that the carbon / carbon composite material of the disk has a higher compressive elastic modulus than the carbon / carbon composite material of the pad.

The carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have an interlaminar shear strength of 0.1 to 30 MP in the direction of the sliding surface.
a, preferably in the range of 1 to 30 MPa.

In the present invention, carbon / carbon composite materials having different properties can be obtained by using different interlaminar shear strengths. In this case, the difference between one and the other of the carbon / carbon composite materials having different interlaminar shear strengths is 0.1-20MP.
a is desirable, and more preferably 1 to 15 MPa.

The higher interlaminar shear strength is 1 to 3.
0 MPa is desirable, and more preferably 3 to 20 MPa
On the other hand, the lower interlaminar shear strength is 0.1 to 20.
MPa is desirable, and more preferably 1 to 15 MPa. It is desirable that the carbon / carbon composite material of the pad has a higher interlaminar shear strength than the carbon / carbon composite material of the disk.

Further, it is desirable that the carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have a small oxidation rate in the air in the temperature range of 600 to 1200 ° C. Specifically, the oxidation rate is 10 ^{−10 to} 0.1 kg / k / min at 600 ° C.
g, at 800 ° C, 10 ^{-6 to} 0.2 kg / k / min
10 ^{-3 to} 0.3 kg / k / min at 1000 ° C
A smaller value is desirable within the range of g.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by setting different oxidation rates. In this case, the difference between the oxidation rates of one and the other of the carbon / carbon composite materials having different oxidation rates in the atmosphere is 6
At 00 ° C, 10 ^{-10 to} 0.2 kg / kg per minute is desirable, and more preferably 10 ^{-6 to} 0.01 kg / k per minute.
g.

[0048] Also, the smaller is desirably min 10 ^-10 ~0.01kg / kg oxidation rate in air at 600 ° C., more preferably min 10 ^-10 ~0.008k
g / kg, on the other hand, the one having a higher oxidation rate in the atmosphere at 600 ° C. is preferably 10 ^{−6 to} 0.1 kg / kg per minute, more preferably 10 ^{−4 to} 0.1 kg / kg per minute.
Is. Further, it is desirable that the carbon / carbon composite material of the disk has a lower oxidation rate in the atmosphere than the carbon / carbon composite material of the pad.

For the carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad, the oxidation start temperature was defined as a 1 mass% decrease when the temperature was raised at 10 ° C./minute in the atmosphere. When the oxidation start temperature is 300
Higher is desirable in the range of up to 1200 ° C.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by setting different oxidation start temperatures. In this case, the difference between the oxidation start temperatures of one and the other of the carbon / carbon composite materials having different oxidation start temperatures in the atmosphere is preferably 1 to 700 ° C., more preferably 1
It is 0 to 200 ° C.

Further, the one having a higher oxidation start temperature in the air is preferably 600 to 1200 ° C., more preferably 70 to 1200 ° C.
0 to 1200 ° C., on the other hand, one having a lower oxidation start temperature in the atmosphere is preferably 300 to 900 ° C., more preferably 300 to 750 ° C. It is desirable that the carbon / carbon composite material of the disk has a higher oxidation start temperature in the atmosphere than the carbon / carbon composite material of the pad.

The carbon / carbon composite material used for the disk and the carbon / carbon composite material used for the pad have a density in the range of 1.5 × 10 ^{3 to} 2.2 × 10 ³ kg / m ³ . Those are preferable.

In the present invention, carbon / carbon composite materials having different characteristics can be obtained by setting different densities. In this case, the difference between one and the other of the carbon / carbon composite materials having different densities is 0.01 × 10 ^{3 to} 0.7 × 10 ³ k.
g / m ³ , preferably 0.1 × 10 ^{3 to} 0.3 × 10 ³ k
g / m ³ .

The higher density is 1.5 × 10 ^3.
To 2.2 × 10 ³ kg / m ³ is desirable, and more preferably 1.7 × 10 ^{3 to} 2.1 × 10 ³ kg / m ³ , while the lower density is 1.4 × 10 ^3. ~ 2.0 x 10 ³ k
g / m ³ is desirable, and more preferably 1.6 × 10 ³ ~
It is 1.9 × 10 ³ kg / m ³ . It is desirable that the carbon / carbon composite material of the pad has a lower density than the carbon / carbon composite material of the disk.

In the present invention, in order to obtain a highly durable disc pad type brake having desired friction characteristics, carbon / carbon composite materials having different characteristics can be obtained by changing the physical properties of materials other than the above. You can

In the present invention, in order to obtain the desired frictional properties, carbon / carbon composite materials having different thermal conductivities or hardnesses are desired for the disk and the pad in accordance with the application, use environment and control method. It is desirable to place it at the site.

Next, the carbon / carbon composite material used in the present invention will be described in detail. In the present invention, the carbon / carbon composite material is a composite material containing carbon fibers and / or precursor fibers and a carbonaceous matrix as main components.

The carbon / carbon composite material used in the present invention has a fiber volume content of usually 10 to 80 vol%, preferably 20 to 70 vol%, more preferably 25 to 65 v.
ol%. If the fiber volume content is less than the above range, the effect of fiber reinforcement is not sufficient, and the material becomes brittle and has a low impact strength and fracture toughness, resulting in a brake material having sufficient performance and durability as a disc pad type brake. I can't exercise my abilities. On the other hand, when the fiber volume content exceeds the above range, the adhesive strength between the fibers is not sufficient, which is not preferable.

The matrix volume content of the carbon / carbon composite material used in the present invention is determined by the fiber volume content and the void volume, and is usually 19
It is about 89 vol%, preferably about 25-80 vol%.

The void volume ratio of the carbon / carbon composite material used in the present invention is usually 1 to 30 vol%, preferably 2 to 25 vol%, more preferably 2 to 10 vol%.
Is. Here, if the void volume ratio is less than the above range, the densification step becomes complicated, and improvement in performance commensurate with the increase in manufacturing time cannot be observed. On the other hand, when the void volume ratio exceeds the above range, the strength as a brake material becomes insufficient. Especially, it is not preferable to be applied to a rotating disk material.

Hereinafter, an example of the method for producing the carbon / carbon composite material used in the present invention will be described in detail. Examples of carbon fibers used in the carbon / carbon composite material include pitch-based, polyacrylonitrile (PAN) -based, and rayon-based carbon fibers. Incidentally, the carbon fiber is a carbon fiber pre-carbonized by firing the precursor fiber as a raw material in an inert gas,
Refers to graphitized fiber. The precursor fibers used in the carbon / carbon composite material include pitch fibers, infusible fibers, PAN fibers, flame-resistant fibers obtained by treating PAN fibers at 200 to 450 ° C. in an oxidizing atmosphere, rayon fibers, and rayon fibers with phosphoric acid. Various fibers such as fibers treated with salt or nitrate may be mentioned. At least one fiber selected from these carbon fibers and precursor fibers can be used for the carbon / carbon composite material, but pitch-based carbon fibers and their precursor fibers are particularly preferred because they can easily enhance the wear resistance.

As the carbonaceous pitch which is a raw material of the pitch-based carbon fiber, coal-based, petroleum-based or synthetic pitch having a softening point of usually 100 to 400 ° C., preferably 150 to 350 ° C. is used. To be As the carbonaceous pitch, either an optically isotropic pitch or an anisotropic pitch can be used, but an optically anisotropic pitch is preferable, and an optically anisotropic phase content of 60 to 60 is particularly preferable. 100 vol
An optically anisotropic pitch within the range of% is particularly preferably used. Melt spinning of the carbonaceous pitch by a known method gives pitch fibers having an average diameter of usually 5 to 100 μm, preferably 7 to 30 μm. Next, the pitch fiber is usually heated to 50 to 400 in an oxidizing gas atmosphere.
C., and preferably infusible within the temperature range of 100 to 350.degree. As the oxidizing gas,
Examples thereof include air, oxygen, nitrogen compounds, sulfur compounds, halogens, or a mixture thereof. The infusibilizing treatment time is usually 10 minutes to 20 hours. The obtained infusibilized fiber is further subjected to an inert gas atmosphere, usually 350 to 3000.
The carbon fiber can be obtained by treating at a temperature of ℃, preferably 400 to 2800 ℃ for 1 second to 5 hours.

The carbon fiber or precursor fiber is usually used as a fiber bundle of about 500 to 25,000 continuous carbon fibers. Further, at least one of these continuous fibers can be used as a unidirectional sheet or a laminate thereof, a two-dimensional woven fabric or a laminate thereof, a three-dimensional woven fabric, or a mat-like molded product.

It is also possible to use a continuous carbon fiber and / or precursor fiber cut to a desired length, or the carbon fiber and / or precursor fiber produced as a short fiber by a spinning process. I can. This fiber bundle can be opened and used as an aggregate of random short fiber filaments. Further, this short fiber can be used as a felt-like sheet, a laminate thereof, or a mat-like molded product.

Further, a molded product composed of the carbon fiber and / or the precursor fiber and at least one fiber selected from the fibers may be used as it is or in the form of a plate, a block or a cylinder. Therefore, these are collectively referred to as a carbon fiber molded body. As this molding method, a known method such as a laminating method, a needle punching method, a hot pressing method, a filament winding method can be used, or a plurality of these methods can be used.

In the present invention, the carbonaceous matrix means those obtained by the heat treatment of the organic precursor and those obtained by the thermal decomposition of the vapor phase precursor such as hydrocarbon. The organic precursors include thermoplastic ones and thermosetting ones.

A typical example of the thermoplastic organic precursor is carbonaceous pitch. As the carbonaceous pitch, coal-based, petroleum-based or synthetic pitch having a softening point of usually 60 to 400 ° C., preferably 60 to 350 ° C. is used.

As the binder pitch and the impregnating pitch, any one or more of the above-mentioned pitches can be used, but as the binder pitch, a pitch having a softening point in the temperature range of 200 to 400 ° C. is particularly preferably used and impregnated. A pitch having a softening point in the temperature range of 60 to 200 ° C. is particularly preferably used as the working pitch.

As the binder pitch and the impregnating pitch, either an optically isotropic pitch or an anisotropic pitch can be used. In particular, as the binder pitch, an optically anisotropic pitch having an optically anisotropic phase content of 60 to 100 vol% is preferably used.

A carbon / carbon composite material is manufactured by impregnating carbon fiber or a carbon fiber molded body with the above-mentioned thermoplastic organic precursor, followed by firing treatment. The firing treatment can be performed in a reduced pressure atmosphere or a normal pressure atmosphere, but is usually performed in a pressurized atmosphere or a uniaxial pressure press.

For the firing in a pressurized atmosphere, a pressure firing apparatus or a hot isostatic pressurizing apparatus is used, and the atmosphere is 0.1 to 1000 MPa, preferably 0.5 to 100 MPa in an inert gas or reducing gas atmosphere. Pressurized to a pressure within the range of about 100 MPa, usually 400 to 2000 ° C., preferably 500 to 15
It is performed within a temperature range of about 00 ° C.

The firing under the uniaxial pressure press is usually performed by a device such as a hot press under a uniaxial pressure within a range of usually 0.1 to 50 MPa, preferably 0.4 to 5 MPa and a maximum of 4
The temperature is in the range of about 00 to 2000 ° C, preferably about 500 to 1000 ° C. The atmosphere pressure in this case can be selected from vacuum, reduced pressure, normal pressure and increased pressure,
Further, the atmosphere gas can be selected from vacuum, an inert atmosphere, a reducing atmosphere and an atmospheric atmosphere.

The thermosetting organic precursor is usually a carbonizing resin, specifically, for example, phenol resin, furan resin,
Examples thereof include carbonizable thermosetting resins such as carbodiimide resins. The curing temperature of these thermosetting resins is usually 80.
To 200 ° C, preferably 110 to 150 ° C. Carbon fiber or a carbon fiber molded product was impregnated with the thermosetting organic precursor, molded, cured within the above curing temperature range, and optionally post-cured within a temperature range of 140 to 300 ° C. Then, a carbon / carbon composite material can be manufactured by performing a firing treatment.

The molding treatment is a lamination method, a hot pressing method,
Known methods such as a filament winding method and a roll forming method can be used, and a plurality of these methods can also be used.

The curing treatment and the post-curing treatment can be carried out during the molding treatment, after the molding treatment, or at both stages. The firing treatment is usually 200 to
It can be carried out in a temperature range of 3000 ° C., preferably 500 to 2500 ° C. under vacuum, reduced pressure, in an inert atmosphere or a reducing atmosphere.

Specific examples of the inert gas include those commonly used as inert gases such as nitrogen, argon and helium, and examples of the reducing gas include hydrogen and carbon monoxide. Can be mentioned. The term "under vacuum or under reduced pressure" refers to a state in which the inert gas, reducing gas or atmosphere exists below atmospheric pressure, and at least 10 ^-5 Pa
It refers to a state that exists.

As the gas phase precursor, all compounds containing carbon atoms capable of being gasified can be used. A carbon / carbon composite material can be obtained by depositing pyrolytic carbon obtained by pyrolyzing a vapor-phase precursor on carbon fiber or a carbon fiber molded body.

The treatment for depositing pyrolytic carbon is a method of vapor-decomposing hydrocarbons and the like to form carbon, which is generally called chemical vapor deposition (CVD). Is. Specifically, for example, hydrocarbons such as methane, ethane, acetylene, propane, benzene, natural gas, etc., or at least one of these hydrocarbons diluted with an inert gas or hydrogen is used as a raw material, and pyrolytic carbon is formed into carbon fiber molded bodies. Deposit.

At this time, the thermal decomposition temperature is usually 700 to 300.
It is in the range of 0 ° C, preferably 800 to 2500 ° C.
Moreover, although the pressure at the time of thermal decomposition can be performed at normal pressure,
The pressure is preferably reduced, specifically 50 to 1000
It is within the range of 0 Pa, preferably about 50 to 5000 Pa.

The carbon / carbon composite material thus obtained is
When the target carbon / carbon composite material has physical properties such as density, matrix volume content or void volume ratio, the carbon / carbon composite material is used as it is or after polishing or the like is processed to produce a friction for a brake. It can be a material.

The obtained carbon / carbon composite material does not have the desired physical properties of the carbon / carbon composite material, such as density, matrix volume content, void volume ratio, hardness and thermal conductivity. In this case, the carbon / carbon composite material is further impregnated with the above-mentioned organic precursor and subjected to a firing treatment, or a treatment of depositing pyrolytic carbon is performed once or more to obtain the desired physical properties. It is also possible to obtain a carbon / carbon composite material having This process step is called a densification process.

Further, the obtained carbon / carbon composite material is
When the target carbon / carbon composite material does not have the physical properties such as density, matrix volume content, void volume ratio, hardness, thermal conductivity, etc., the carbon / carbon composite material is densified as described above. After the treatment, a firing treatment can be performed.

The firing treatment is performed on the carbon / carbon composite material by
This is a process of baking in an inert atmosphere under reduced pressure, normal pressure or pressure, and the pressure of this inert atmosphere is 10 ^-8 to 2
It is within the range of 00 MPa, preferably 0.1 to 100 MPa. The processing temperature is usually 1500 to 3000 ° C., though it varies depending on the desired physical properties.

Further, the firing treatment can be carried out every time after the densification treatment or discontinuously after an arbitrary number of times according to the physical properties of the intended carbon / carbon composite material, and the temperature thereof can also be changed. It can be selected for each firing process.

Among the above-mentioned carbon / carbon composite material production methods, carbon fiber species, precursor fiber species, carbon fiber and precursor fiber production methods, carbon fiber volume content, two or more carbon fibers and precursors When body fiber is used, its compounding ratio,
The type of carbon fiber molded product, the type of matrix raw material, the volume content of the matrix, the product with two or more types of matrix, the composite ratio, the volume content of voids, the densification treatment method or its conditions, the firing treatment conditions, etc. By appropriately setting one or more of these conditions, it is possible to obtain a carbon / carbon composite material having at least one or more different properties.

[0086]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 A petroleum pitch-based carbon fiber felt mat was used as the reinforcing fiber.
Felt mat reinforced carbon / carbon composite material B using a carbonaceous matrix made from petroleum pitch as a matrix
Was used as the brake disc material.

Further, as the reinforcing fiber, a petroleum pitch-based carbon fiber 2
The two-dimensional woven fabric was a two-dimensional reinforced carbon / carbon composite material A using a carbonaceous matrix made of petroleum pitch as a brake pad material. Table 1 shows various physical properties of A and B.

At this time, the out-of-plane thermal conductivity of the pad material A is lower than that of the disk material B. The in-plane thermal conductivity of the pad material A is higher than that of the disk material B. Further, the Shore hardness of the sliding surface is lower in the pad material A than in the disk material B.

A disc pad type brake having the carbon / carbon composite materials B and A on discs and pads was evaluated using a brake tester, and the friction coefficient and the wear amount were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.3 and the wear amount of the disk is 0.4 μm.
/ Cycle, the wear amount of the pad was 0.6 μm / cycle, and a highly durable brake was obtained (Table 3).

Example 2 A petroleum pitch-based carbon fiber felt mat was used as the reinforcing fiber.
Felt mat reinforced carbon / carbon composite material B using a carbonaceous matrix made from petroleum pitch as a matrix
Was used as the brake disc material.

A felt pad reinforced carbon / carbon composite material C having the same hardness and thermal conductivity as the brake pad material was prepared by using the same reinforcing fiber and matrix and changing the firing conditions. Table 1 shows the physical properties of B and C. At this time, the out-of-plane thermal conductivity of the pad material C is lower than that of the disk material B.

A disc pad type brake having the carbon / carbon composite materials B and C on discs and pads was evaluated using a brake tester, and the friction coefficient and the amount of wear were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.5 and the wear amount of the disk is 0.8 μm.
/ Time, the amount of wear of the pad was 0.5 μm / time, and a brake having a large braking force was obtained (Table 3).

Example 3 A brake test was conducted in the same manner as in Example 2 except that the carbon / carbon composite material C was used as the disk material and the carbon / carbon composite material B was used as the pad material. At this time, the in-plane thermal conductivity of the pad material B is higher than that of the disk material C. The Shore hardness of the sliding surface of the pad material B is lower than that of the disk material C.

A disc pad type brake having the carbon / carbon composite materials C and B on discs and pads was evaluated using a brake tester, and the friction coefficient and the amount of wear were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.5, and the wear amount of the disk is 0.9 μm.
/ Time, the wear amount of the pad was 0.6 μm / time, and a brake having a large braking force was obtained (Table 3).

Example 4 A petroleum pitch-based carbon fiber felt mat was used as the reinforcing fiber.
Felt mat reinforced carbon / carbon composite material B using a carbonaceous matrix made from petroleum pitch as a matrix
Was used as the brake disc material.

Felt mat reinforced carbon / carbon composite material C in which the same reinforcing fiber and matrix were used, and the firing conditions were changed to change the hardness and the thermal conductivity was used as one of the brake pad materials.

Further, as the reinforcing fiber, 2 of petroleum pitch-based carbon fiber is used.
The two-dimensional reinforced carbon / carbon composite material A using a carbonaceous matrix made of petroleum pitch as a raw material was used as one of the brake pad materials. A and B and C
Various physical properties of are shown in Table 1.

At this time, the out-of-plane thermal conductivity of the pad materials A and C is lower than that of the disk material B. The in-plane thermal conductivity of the pad material A is higher than that of the disk material B. Further, the Shore hardness of the sliding surface is lower in the pad material A than in the disk material B.

A disc pad type brake having the carbon / carbon composite materials B and A and C on discs and pads was evaluated using a brake tester, and the friction coefficient and the wear amount were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.4 and the wear amount of the disk is 0.6.
The wear amount of the pad was 0.6 μm / time, and a brake having a high durability and a large braking force was obtained (Table 3).

Comparative Example 1 A brake test was conducted in the same manner as in Example 1 except that the above-mentioned carbon / carbon composite material A was used for both the disc material and the pad material.

As a result, the coefficient of friction was 0.4, the wear amount of the disk was 1.2 μm / cycle, and the wear amount of the pad was 3.6 μm.
/ Time, and the amount of wear increased as compared with Example 1 (Table 3).

Comparative Example 2 A brake test was conducted in the same manner as in Example 1 except that the above-mentioned carbon / carbon composite material B was used for both the disc material and the pad material. As a result, the coefficient of friction is 0.2-0.5,
It was not stable compared to Example 1 (Table 3).

Comparative Example 3 A brake test was conducted in the same manner as in Example 1 except that the carbon / carbon composite material C described above was used for both the disk material and the pad material.

As a result, the coefficient of friction was 0.6, the wear amount of the disk was 1.8 μm / cycle, and the wear amount of the pad was 4.0 μm.
/ Time, and the amount of wear increased as compared with Example 2 (Table 3).

Comparative Example 4 A brake test was conducted in the same manner as in Example 1 except that the above-mentioned carbon / carbon composite material B was used as the disk material and the copper-based sintered alloy was used as the pad material. As a result, the disc was significantly worn, and the test was interrupted midway (Table 3).

Comparative Example 5 A brake test was conducted in the same manner as in Example 1 except that gray cast iron FCV-50 was used as the disk material and carbon / carbon composite material A was used as the pad material. As a result, almost no wear occurred on both the disc and the pad, but the friction coefficient was 0.1.
It was so low that sufficient braking force could not be obtained (Table 3).

Example 5 A petroleum pitch-based carbon fiber felt mat was used as the reinforcing fiber,
Felt mat reinforced carbon / carbon composite material B using a carbonaceous matrix made from petroleum pitch as a matrix
Was used as the brake disc material.

A felt mat of petroleum pitch-based carbon fiber is used as the reinforcing fiber, a carbonaceous matrix made of petroleum pitch as a raw material for the matrix, and a felt mat reinforced carbon / carbon composite material D using pyrolysis carbon of vapor phase are used as a brake pad material. And Various physical properties of B and D are shown in Tables 1 and 4. At this time, the out-of-plane thermal conductivity of the pad material D is lower than that of the disk material B.

A disc pad type brake having the carbon / carbon composite materials B and D on discs and pads was evaluated using a brake tester, and the friction coefficient and the wear amount were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.4 and the wear amount of the disk is 0.5 μm.
/ Cycle, the wear amount of the pad was 0.4 μm / cycle, and a highly durable brake was obtained (Table 5).

Example 6 A petroleum pitch-based carbon fiber felt mat was used as the reinforcing fiber.
Felt mat reinforced carbon / carbon composite material B using a carbonaceous matrix made from petroleum pitch as a matrix
Was used as the brake disc material.

A mat-shaped molded product of continuous fibers of petroleum pitch-based carbon fiber was used as a reinforcing fiber, and a mat-reinforced carbon / carbon composite material F using a carbonaceous matrix made of petroleum pitch as a matrix was used as a brake pad material. Physical properties of B and F are shown in Tables 1 and 4. At this time, the out-of-plane thermal conductivity of the pad material F is lower than that of the disk material B. In addition, the Shore hardness of the sliding surface is greater than the pad material F than the disk material B.
Is lower.

A disc pad type brake having the carbon / carbon composite materials B and F on discs and pads was evaluated using a brake tester, and the friction coefficient and the amount of wear were measured. Table 2 shows the test conditions at this time. As a result, the coefficient of friction is 0.3 and the wear amount of the disk is 0.4 μm.
/ Cycle, the wear amount of the pad was 0.8 μm / cycle, and a highly durable brake was obtained (Table 5).

Example 7 Felt mat of petroleum pitch-based carbon fiber was used as the reinforcing fiber,
A brake mat material was made of felt mat reinforced carbon / carbon composite material D using a carbonaceous matrix made from petroleum pitch as a matrix and vapor phase pyrolysis carbon.

[0115] A mat-shaped molded product made of a continuous fiber of petroleum pitch-based carbon fiber as the reinforcing fiber, a carbonaceous matrix made of petroleum pitch as the raw material and a matte-reinforced carbon / carbon composite material E using vapor phase pyrolysis carbon as the matrix E. Was used as the brake pad material. Table 4 shows various physical properties of D and E. At this time, the out-of-plane thermal conductivity of the pad material E is lower than that of the disk material D. The Shore hardness of the sliding surface is lower in the pad material E than in the disk material D.

A disc pad type brake having the carbon / carbon composite materials D and E on discs and pads was evaluated using a brake tester, and the friction coefficient and the amount of wear were measured. Table 2 shows the test conditions at this time. As a result, the friction coefficient is 0.4 and the wear amount of the disk is 0.2 μm.
/ Time, the amount of pad wear was 0.5 μm / time, and a highly durable brake was obtained (Table 5).

Example 8 A mat-shaped molded product made of continuous fibers of petroleum pitch-based carbon fibers as reinforcing fibers, and a mat-reinforced carbon / carbon composite material F using a carbonaceous matrix made of petroleum pitch as a brake disc material. And

[0118] A mat-shaped molded product of a continuous fiber of petroleum pitch-based carbon fiber as a reinforcing fiber, a carbonaceous matrix made of petroleum pitch as a matrix, and a mat-reinforced carbon / carbon composite material E using vapor-phase pyrolysis carbon Was used as the brake pad material. Table 4 shows the physical properties of F and E. At this time, the out-of-plane thermal conductivity of the pad material E is lower than that of the disk material F.

A disc pad type brake having the carbon / carbon composite materials F and E on discs and pads was evaluated using a brake tester, and the friction coefficient and the amount of wear were measured. Table 2 shows the test conditions at this time. As a result, the friction coefficient is 0.6 and the wear amount of the disc is 0.7 μm.
/ Time, the amount of wear of the pad was 0.5 μm / time, and a brake having a large braking force was obtained (Table 5).

[0120]

[Table 1]

[0121]

[Table 2]

[0122]

[Table 3]

[0123]

[Table 4]

[0124]

[Table 5]

[0125]

According to the present invention, it is possible to obtain a highly durable disc pad type brake having friction characteristics according to the use, the use environment and the control method.

Claims (1)

[Claims] 1. A disc comprising a carbon / carbon composite material (A) as a friction material and a pad having a carbon / carbon composite material (B) as a friction material, the carbon / carbon composite material (A) and the carbon / carbon composite material (A). A disc pad type brake characterized in that the carbon composite material (B) has different characteristics.