JPH10219002A - Method for producing carbon-based wet friction material - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a method of manufacturing a carbon-based wet friction material capable of imparting excellent friction coefficient and wear resistance in a balanced manner. SOLUTION: 1) A carbon fiber composite woven resin (C) in which a carbon fiber plain woven cloth is impregnated with a thermosetting resin solution and heat-cured.
FRP) Process the sheet into segments and have a porosity of 10%
The segmented CFRP sheet substrate having a porosity of less than 10
A 20% segmented CFRP sheet substrate is alternately joined to a metal support plate. 2) Segmented CFRP of 1)
The sheet is fired and carbonized at 800 ° C. or higher in a non-oxidizing atmosphere to form a carbon fiber composite carbon (C / C) sheet, and has a porosity of 1
C / C sheet substrate of less than 0% and C having a porosity of 10 to 20%
/ C sheet substrate is alternately joined to the metal support plate. 3)
A CFRP sheet substrate and a C / C sheet substrate are alternately joined to a metal support plate, and the porosity of one substrate is set to less than 10%, and the porosity of the other is set to 10 to 20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a carbon-based wet friction material used in a wet state in which an oil liquid such as a lubricating oil is interposed between opposing friction surfaces, and particularly to a brake lining and clutch facing. The present invention relates to a method for producing a carbon-based wet friction material containing carbon fiber as a main component, which is provided with a well-balanced friction performance suitable for a disk pad, a differential limiting device (LSD), and the like.

[0002]

2. Description of the Related Art Conventionally, as a friction material mainly composed of carbon fiber, a material of a composite structure in which a carbon fiber base material is bonded with a resin binder or a carbon binder has been developed. For example, Japanese Unexamined Patent Publication No. 50-72050 discloses an in-oil operation for transmitting force between movable parts, comprising one support material and one friction layer containing a carbon fiber web impregnated with an organic resin binder. Japanese Patent Application Laid-Open No. 62-21528 discloses a friction element in which a composition containing a fibrous substance such as carbon fiber and a binder is heated under pressure at 350 to 1000 ° C. in a non-oxidizing atmosphere. The manufacturing method of the material is again
No. 54270 discloses that a carbon material obtained by firing a molded product obtained by solidifying a carbon fiber woven fabric with a furan resin or the like is impregnated with coal tar or coal tar and / or pitch and a furan resin, and then fired, impregnated, The dynamic friction coefficient obtained by repeating firing and firing at least once at 2300 ° C. or higher is 0.1 to 0.40, and the amount of wear is 100 × 1.
Carbon fiber reinforced carbon friction materials of ^0-4 mm / plane / stop or less have been proposed.

[0003] In addition, Japanese Patent Publication No. 2-37492 discloses an energy having a continuous porosity in the range of 15 to 85% by forming a coating of pyrolytic carbon on a carbon fiber support having continuous porosity. Friction assembly for absorption
Japanese Patent No. 40890 discloses a mesh woven fabric formed by weaving carbon fibers, a carbon coating only on the surface of the carbon fibers by a chemical vapor deposition (CVD) process, and a mesh woven fabric after the carbon coating is formed. Disclose a wet friction material that retains porosity. Japanese Patent Application Laid-Open No. 7-12158 discloses that a continuous yarn containing an admixture containing a friction modifier and a binder as main components and a continuous yarn mainly containing a binder are twisted by a predetermined number of twisted yarns. In other words, friction materials in which a continuous yarn mainly containing a binder has a large number of fine voids have been proposed, but since they are not wet friction materials, the storage and retention of oily components has not been studied.

A wet friction material requires that an oily component such as a lubricating oil always be present between friction surfaces during use. Therefore, the ability of the friction material itself to retain the oil liquid is such that the friction material itself has seizure resistance and abrasion resistance. Have a great effect on For this reason, it is necessary to have appropriate pores and voids for storing and holding the oil liquid inside the tissue of the friction material. However, a carbon fiber composite carbon material (C / C material) obtained by a method in which a carbonizing resin or a binder such as pitch is applied to a carbon fiber base material and then fired and carbonized in a non-oxidizing atmosphere is used. The pores after the binder component has volatilized become too large and the ability to absorb and retain the oil liquid decreases, and at the same time, the elastic modulus of the carbon fiber increases, weakening the tissue and impairing the handling properties and reducing the frictional properties. Because of the fluctuation, there is room for improvement as a wet friction material.

[0005] Further, in the friction material of the C / C composite system, condensed water and decomposed gas generated from the binder component are absorbed in the matrix structure during the heat curing and calcination stages of the manufacturing process, and a foaming phenomenon occurs. In the carbonization process, cracks and breakage occur in the material structure, and the strength of the obtained friction material is extremely reduced, which makes it difficult to provide normal friction characteristics. This problem was addressed in Tokuhei 2-37492.
This does not occur if a method of directly forming a carbon coating on the carbon fiber surface by CVD as described in Japanese Patent Application Laid-Open Publication No. Hei. Since it is necessary to set conditions, it is not very advantageous as an industrial friction material manufacturing means.

Accordingly, the present applicant has proposed a method for producing a wet carbon-based friction material having excellent storage and retention properties of oily components using carbon fiber as a base material, using a carbon fiber plain woven cloth having a cross pitch width of 0.7 to 3.0 mm. A kneaded mixture of a carbonizable thermosetting resin liquid and carbon black is applied and heat-cured, and the resulting CFRP cured sheet is cut into a predetermined shape and then joined to a metal support plate. A carbon-based wet friction material, and a calcination treatment at a temperature of 800 ° C. or more in a non-oxidizing atmosphere, and a carbonizable thermosetting resin liquid and carbon black are again applied to the obtained C / C plate. A method for producing a carbon-based wet friction material characterized in that the compounded kneaded material is adhered, thermally cured, and joined to a metal support plate, has been developed and proposed as Japanese Patent Application No. 7-251768.

Further, as a result of research on carbon-based wet friction materials, the present applicant has found that a cross-pitch width of 0.7 as a method for producing a carbon-based wet friction material having a high friction coefficient and abrasion resistance in a well-balanced manner. A carbon fiber plain woven cloth of about 3.0 mm is impregnated with a thermosetting resin solution, a resin content of 35 to 50% is applied, and a pore diameter of 0.1 obtained by heat curing.
A method for producing a wet friction material, comprising cutting a cured sheet having a porosity of 0.5 to 35% at a thickness of from 300 to 300 .mu.m into a predetermined shape and joining the cut sheet to a metal support plate (Japanese Patent Application No. 8-165398). No.)

[0008]

As a result of continuing research on the relationship between porosity and friction performance, the present inventor has found that
It has been found that the friction coefficient and the wear resistance can be imparted in a well-balanced manner by combining segmented substrates having different porosity.

The present invention has been developed based on the above findings, and has as its object the purpose of brake lining, clutch facing, disk pad and differential limiting device (LSD).
It is an object of the present invention to provide an industrial production method of a carbon-based wet friction material having a high balance of friction coefficient and abrasion resistance, which can be suitably used for, etc.

[0010]

According to a first aspect of the present invention, there is provided a method for producing a carbon-based wet friction material for achieving the above object, by impregnating a carbon fiber plain-woven cloth with a thermosetting resin solution. Heat cured carbon fiber composite cured resin sheet (hereinafter referred to as
It is called “CFRP sheet”. ) Is used as a base material, and the base material is processed into a segment, and the porosity is less than 10%, and the porosity is 10 to 20%.
And the segmented CFRP sheet base material is alternately joined to a metal support plate.

According to a second aspect of the present invention, there is provided a method of manufacturing a carbon-based wet friction material, comprising a step of impregnating a carbon fiber plain-woven cloth with a thermosetting resin solution and heating and curing the same.
P sheet) is processed into a segment shape, and then calcined and carbonized at a temperature of 800 ° C. or more in a non-oxidizing atmosphere. Segmented C / having a ratio of less than 10%
The configuration is characterized in that the C sheet substrate and the segmented C / C sheet substrate having a porosity of 10 to 20% are alternately joined to a metal support plate.

In a third aspect of the present invention, there is provided a method for producing a carbon-based wet friction material, wherein a segmented CFRP sheet substrate according to claim 1 and a segmented C / C sheet substrate according to claim 2 are alternately arranged. The porosity of one substrate is less than 10% and the porosity of the other substrate is 10 to 10%.
20% is a structural feature.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a carbon fiber constituting a carbon-based wet friction material of the present invention, a plain woven cloth manufactured from various raw materials such as polyacrylonitrile, rayon, and pitch is used. The carbon fiber plain weave cloth used is
Surface treatment for improving wettability may be performed.

As the thermosetting resin solution to be impregnated into the carbon fiber plain woven cloth, for example, a carbonizing thermosetting resin solution such as a phenol resin, a furan resin, an epoxy resin, or a mixed resin thereof may be used with methanol, ethanol, A solution dissolved in an appropriate organic solvent such as ether or acetone is used. The concentration of the thermosetting resin solution is adjusted depending on the amount of resin to be applied to the carbon fiber plain woven cloth, but preferably has a low viscosity for uniform impregnation.

As a method for impregnating the carbon fiber plain woven cloth with the thermosetting resin solution, conventional means such as coating and dipping is applied, and the amount of resin impregnated in the carbon fiber plain woven cloth depends on the target porosity. Adjust with. The carbon fiber plain woven cloth impregnated with a predetermined amount of resin is air-dried at a temperature of 100 to 140 ° C., and the organic solvent is volatilized and removed to obtain a prepreg sheet, which is then cured by heating. Heat-curing is performed by sandwiching the prepreg sheet between heat-resistant metal plates and flat plates such as ceramics.
While maintaining under pressure of 0 gf / cm ² , place in heating furnace
It is carried out by heating to a temperature of 200 to 300 ° C. at a temperature rising rate of 0 ° C./hr or less and appropriately holding the temperature. 5gf / cm ²
When the pressing force is less than the above, the deformation of the cloth becomes large and it is difficult to obtain a flat plate, and when the pressing force exceeds 40 gf / cm ² , the irregularities of the carbon fiber texture are lost.

The thus obtained C having different porosity is obtained.
The FRP sheet is punched and cut into segments having a predetermined shape. The cut CFRP sheet has a porosity of 1
CFRP sheet base material of less than 0% and porosity of 10 to 20
% Of the CFRP sheet base material is alternately and integrally joined to a metal support plate such as an iron plate. Bonding is performed by hot pressing through a resinous adhesive.However, the surface of the metal support plate is shot blasted and roughened before coating with the same thermosetting resin solution as the matrix binder. ,
It is preferable to adopt a method of hot-press bonding the cured sheet to this. After joining, the wet friction material is manufactured by drying.

According to a second aspect of the present invention, there is provided a method for producing a segmented CFRP sheet having a different porosity according to the first aspect of the present invention, by calcining the CFRP sheet at a temperature of 800 ° C. or more in a non-oxidizing atmosphere. Processing to obtain C / C sheets having different porosity, a C / C sheet substrate having a porosity of less than 10%,
A porosity of 10 to 20% C / C sheet substrate alternately,
For example, it consists of a process of integrally joining to a metal support plate such as an iron plate.

The firing carbonization of the CFRP sheet is performed in a carbonization furnace maintained in a non-oxidizing atmosphere. As the carbonization furnace, a lead hammer furnace which is covered with a carbonaceous packing material such as coke powder and fired and carbonized, and an electric furnace in which the system is kept in an atmosphere of an inert gas such as nitrogen or argon are used.
It is necessary to set the carbonization temperature to a temperature of 800 ° C. or higher. If the temperature is lower than 800 ° C., the carbonization of the thermosetting resin becomes incomplete, and the strength decreases.

Further, the manufacturing method according to the third invention of the present invention is characterized in that the CFRP sheet substrate obtained in the first invention and the C / C sheet substrate obtained in the second invention are alternated. To
For example, it consists of a process of integrally joining to a metal support plate such as an iron plate. In this case, it is necessary to set the porosity of one base material to less than 10% and the porosity of the other base material to 10 to 20%. That is, when the porosity of the CFRP sheet substrate is set to less than 10%, the porosity of the C / C sheet substrate alternately joined to the CFRP sheet substrate is 10 to 2%.
0%, and conversely, the porosity of the C / C sheet substrate is 10%
When the porosity is set to less than 10%, the porosity of the CFRP sheet substrate alternately joined to the C / C sheet substrate is set to 10 to 20%.

The pores of the substrate structure of the wet friction material hold an oily substance for cooling and are supplied to the friction surface. Therefore, in order to impart excellent friction performance and stabilize the friction performance, It is important to keep the oily substance stable and to supply it smoothly to the friction surface. However, as the porosity increases, the coefficient of friction increases, but the amount of wear increases. On the other hand, when the porosity is small, the amount of wear decreases, but the coefficient of friction tends to decrease. In particular, when the porosity is less than 10%, the abrasion resistance is improved, but the friction coefficient is reduced, and a seizure phenomenon due to a decrease in the amount of retained oil tends to occur. On the other hand, the porosity is 10
At 20%, the abrasion resistance is reduced, but the friction coefficient is improved, and the seizure phenomenon can be prevented by improving the oil holding amount. If the porosity exceeds 20%, it will be extremely worn and cannot be used as a friction material.

According to the present invention, a CFRP sheet substrate or a C / C sheet substrate is used as a segmented sheet substrate for forming a friction surface of a wet friction material, and the porosity is less than 10%. By forming a friction surface by alternately arranging up to 20% of the sheet base material, the oil material can be stably maintained and smoothly supplied, and the friction performance is improved. Therefore, it is possible to impart a good balance of friction performance such as a friction coefficient and abrasion resistance of the friction surface. In addition, wet friction materials used in a high-temperature atmosphere include C
It is also possible to improve heat resistance by using a / C sheet base material.

[0022]

EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples. However, the invention is not limited to the scope of these examples.

Examples 1 to 5 As the carbon fiber plain woven cloth, a plain woven cloth woven from a polyacrylonitrile-based high-strength high-modulus carbon fiber was used. As a thermosetting resin solution, a solution prepared by dissolving a phenol resin precondensate in ethanol was applied while changing the resin concentration, sufficiently impregnated into carbon fibers, and then air-dried for 24 hours to be pre-cured. The thus obtained prepreg sheets having different amounts of adhered resin are sandwiched between graphite flat plates and 10 gf
/ cm ² while applying pressure to the electric furnace, 5 ℃ / hr
The sample was heated to 250 ° C. at a temperature rising rate and held for 2 hours to produce CFRP sheets having different porosity. This CFRP sheet was punched and cut into a segment shape (30 mm × 10 mm). The obtained segmented CFRP sheet base materials having different porosity are alternately combined, and shot-blasted iron metal support plate (outer diameter 80 mm, inner diameter 50 mm, thickness 1.0 mm)
60kg using phenol resin precondensate as binder
It was heated to a temperature of 220 ° C. under a pressure of f / cm ² , held for 2.5 minutes, and subjected to hot-pressure bonding to produce a carbon-based wet friction material for testing.

Further, the prepared segmented CFRP sheets having different porosity are placed in an electric furnace maintained in a nitrogen atmosphere, heated to 1000 ° C. at a temperature rising rate of 5 ° C./hr, and held for 5 hours for a calcination carbonization treatment. did. The segmented C / C sheet base materials having different porosity obtained in this manner are alternately combined, and a blasted iron metal support plate (outer diameter: 80 mm, inner diameter: 50 mm, thickness: 1.0 mm) is initially phenolic resin-coated. The condensate was used as a binder, heated to a temperature of 220 ° C. under a pressure of 60 kgf / cm ² , held for 2.5 minutes and subjected to hot-pressure bonding to produce a carbon-based wet friction material for testing. Also, a segmented CFRP sheet base material having a different porosity and a segmented C / C base material are alternately combined, and similarly hot-press bonded to an iron metal support plate to form a carbon-based wet friction material for testing. Manufactured.

Comparative Examples 1 to 3 In addition, for comparison, a carbon-based wet friction test was conducted in the same manner as in the example except that a segmented CFRP sheet having a single porosity or a C / C sheet was used for comparison. Lumber was manufactured.

Each friction material was subjected to a wet friction test with a constant speed tester under the following conditions, and the obtained friction coefficient and wear amount were compared with the porosity of the sheet base material using the results, and are shown in Table 1. . Wet friction test conditions: Opposite surface of friction material; steel SK5 (diameter 80 mm) Rotation speed: 20 rpm Pressing pressure: 20 kgf / cm ² Lubricating oil; hypoid gear oil (75W-90) As the average value of the values every 30 minutes, the wear amount was measured with a micrometer for the thickness of the friction plate (4 points at every 90 °), and the average value of the 4 points was indicated by the difference between the thickness before and after the test. The porosity was calculated by measuring the amount of pores having a pore diameter in the range of 0.5 to 300 μm using a mercury porosimeter.

[0027]

[Table 1]

From the results in Table 1, it is found that C having a porosity of less than 10%
FRP sheet or C / C sheet and porosity is 10-2
The wet friction material produced by the production method of the embodiment in which 0% CFRP sheets or C / C sheets are alternately combined has a good friction coefficient level and a low wear amount, and provides a good balance of friction performance. You can see that However, it is recognized that the wet friction material according to the production method of the comparative example using only the CFRP sheet or the C / C sheet having a single porosity has a large amount of wear and does not have a sufficient balance with the friction coefficient. In particular, it can be seen that in Comparative Examples 1 and 2 using a CFRP sheet or C / C sheet having a high porosity, the amount of wear significantly increased, and in Comparative Example 3 using a CFRP sheet having a low porosity, the friction coefficient was decreased. .

[0029]

As described above, according to the method for producing a carbon-based wet friction material of the present invention, the porosity is less than 10%.
Since it is combined with a segmented CFRP sheet base material of up to 20% or a C / C sheet base material and alternately joined to a metal support plate, it is possible to impart a good friction coefficient and wear resistance in a well-balanced manner. is there. Therefore, the material design is facilitated in accordance with the friction performance, and it is extremely useful as a method for manufacturing brake linings, clutch facings, disk pads, differential limiting devices (LSD), etc., which require high friction performance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16D 69/00 C04B 35/52 E

Claims (3)

[Claims] 1. A carbon fiber composite woven resin sheet (hereinafter, referred to as a “CFRP sheet”) obtained by impregnating a thermosetting resin solution into a carbon fiber plain woven cloth and heat-curing the base material. After processing, a segmented CFRP sheet base material having a porosity of less than 10% and a porosity of 10
A method for producing a carbon-based wet friction material, wherein 〜20% of a segmented CFRP sheet substrate is alternately joined to a metal support plate. 2. A carbon fiber composite woven resin sheet (CFRP sheet), which is obtained by impregnating a carbon fiber plain woven cloth with a thermosetting resin solution and curing by heating, is processed into segments and then heated to a temperature of 800 ° C. or more in a non-oxidizing atmosphere. A carbon fiber composite carbon sheet (hereinafter, referred to as a “C / C sheet”) which has been subjected to a calcination treatment with a segmented C / C sheet having a porosity of less than 10% and a porosity of 10 to 10%. A method for producing a carbon-based wet friction material, wherein 20% of segmented C / C sheet substrates are alternately joined to a metal support plate. 3. The segmented CFRP sheet base material according to claim 1 and the segmented C / C sheet base material according to claim 2 are alternately joined to a metal support plate, and the porosity of one of the base materials. Is less than 10%, and the porosity of the other substrate is 10 to 10.
A method for producing a carbon-based wet friction material, characterized in that the content is 20%.