JPH08165356A - Facing friction material and its production - Google Patents

Abstract

PURPOSE: To obtain a coating-based facing friction material excellent in abrasion resistance and friction characteristics, esp. coefficient of friction-sliding speed characteristics, by using a specific friction modifier and an org. binder. CONSTITUTION: The friction material is obtd. by forming a friction layer contg. a friction modifier, carbon fibers, and an org. binder on the surface of a metal core plate. The friction modifier used is a premix filler comprising amorphous porous particles obtd. by mixing a phenol resin with fine diatomaceous earth particles, solidifying the mixture under heating, and cooling and grinding the mixture. The org. binder used is a polyamideimide resin. The friction material is obtd. by mixing the phenol resin with the fine diatomaceous earth particles, solidifying the mixture under heating, cooling and grinding the mixture, mixing the resulting amorphous porous particles with carbon fibers and a polyamideimide resin to give a coating soln., and applying the soln. to a metal plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facing friction material and a method for manufacturing the same, and more particularly, to a friction member of a device having a friction mechanism such as a wear-resistant material for machines and home appliances, a friction facing material for automobiles and the like. The present invention relates to a useful facing friction material and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a friction material of this kind generally has a core plate made of a vapor-type friction material obtained by forming a composition containing a filler or a fiber exhibiting friction performance into a sheet or by roll forming or press forming. It is manufactured by adhering to a metal plate.

Further, there has also been proposed a facing material in which a coating liquid containing a filler or fibers is applied to a metal plate material serving as a core plate to form a friction layer.

[0004]

The friction material using the above-mentioned conventional paper-based friction material has the following drawbacks.

Conventional paper-based friction materials are inferior in wear resistance and heat resistance, and do not exhibit the characteristics adapted to recent high performance specification specifications. As for the friction material itself, the addition of fillers and fibers and the mixed state are not uniform, and it is difficult to obtain a friction material having stable properties. Friction materials that use iron-based metal plate as the core plate require many oil grooves to be formed in the core plate in order to ensure the rapid movement of oil, which is not easy to process and the processing cost is high. , There is a problem as an industrial material.

The friction characteristics are also not sufficient.

In the case of a facing type friction material, due to the relationship between the sliding speed (V) and the friction coefficient (μ), the friction coefficient increases as the sliding speed increases (hereinafter, this characteristic will be referred to as “μ-V characteristic”). Is a necessary condition. Conventional paper-based friction materials have a proportional relationship between the sliding speed and the friction coefficient, but have poor wear resistance and are difficult to put into practical use under severe operating conditions. The step of adhering the friction material and the core plate is complicated, and there is a problem of peeling of the friction material.

On the other hand, a facing material having a friction layer formed by coating has no problem of the friction material adhering step and peeling and has excellent wear resistance, but in terms of the relationship between the sliding speed and the friction coefficient, the sliding speed However, there is a problem that the coefficient of friction does not become as large as expected even if becomes larger, and sometimes shows a decreasing tendency.

The present invention solves the above-mentioned conventional problems and is a coating type facing friction material having excellent wear resistance and friction characteristics, and particularly a facing friction material having excellent μ-V characteristics and a method for producing the same. The purpose is to provide.

[0010]

The facing friction material according to claim 1 is a facing friction material comprising a metal core plate and a friction layer containing a friction modifier, carbon fibers and an organic binder formed on the surface of the metal core plate. The friction modifier is a premix filler composed of amorphous porous particles obtained by mixing a phenol resin and diatom fine particles, solidifying the mixture under heating conditions, and cooling and pulverizing the mixture, and the organic binder is a polyamide-imide type. It is a resin.

A method for producing a facing friction material according to a second aspect is a method for producing the facing friction material according to the first aspect, wherein the phenol resin and the diatom particles are mixed and the resulting mixture is heated. Amorphous porous particles are obtained by solidifying, cooling and pulverizing, and the porous particles are mixed with a polyamideimide resin together with carbon fibers to prepare a coating liquid, and the coating liquid is applied to a metal core plate. It is characterized by doing.

The present invention will be described in detail below.

In the present invention, the metal material constituting the core plate is not particularly limited, and the present invention can be applied to any metal material core plate, but preferably, the inexpensive iron generally used conventionally is used. Examples include alloys and lightweight aluminum alloys.

In the present invention, the friction layer forming surface of such a metal core plate is usually slit, and then the friction layer is formed by the method described later. By slitting the metal core plate, it is possible to appropriately supply or remove the oil in the oil during frictional sliding during actual use.

The size of the slit to be formed is not preferable if it is too large or too small, and the width of the slit is 0.5.
It is preferable that the depth is about 2 mm and the depth is about 0.1 mm to 0.5 mm. If the width of the slit is less than 0.5 mm, it takes too much time to remove oil, and if it exceeds 2 mm, the friction surface is relatively small, which is not preferable. Further, if the depth of the slit is less than 0.1 mm, there is a problem in supply and removal of oil, and if it exceeds 0.5 mm, there is a problem in the strength of the base material and the processing cost.

The amount of slits to be formed is not preferable if it is too large or too small. Generally, the total area of the slit portions is 20% or less of the total sliding area of the core plate, especially 3
It is preferably set to 10%.

In such a metal core plate, the surface on which the friction layer is formed is subjected to a blast treatment or the like as necessary to increase the surface roughness, thereby increasing the adhesive strength of the friction layer coated on this surface. be able to.

In the present invention, the carbon fibers dispersed in the coating liquid have an average diameter of 6 to 10.
Those having a micrometer and an average length of about 20 to 100 mm are preferably used. The carbon fiber is preferably blended so that the content ratio in the coating liquid is 1 to 10% by weight. If the proportion of the carbon fibers is less than 1% by weight, the durability of the friction layer formed is not sufficient, and if it exceeds 10% by weight, it becomes difficult to uniformly mix and disperse it in the coating solution, and a practical coating solution is prepared. I won't get it.

By blending carbon fibers, the strength of the friction layer and the friction coefficient can be improved.

As the premix filler added as a friction modifier, 0.3 to 0.5 parts by weight of diatom fine particles is added to 1 part by weight of the phenol resin, mixed and molded, and 200 to 300 parts thereof are added. What is baked and hardened at ℃, preferably about 250 ℃ is cooled and crushed, and the average particle size is 0.1 mm or less, preferably 30 to 70 μm.
It is produced by making amorphous crushed particles of about m.

In producing the premix filler,
0.5 parts of diatomaceous fine particles are added to 1 part by weight of phenol resin.
If it is less than 3 parts by weight, the friction layer cannot be sufficiently made porous by the diatom fine particles described in the section of the action described later.
On the contrary, if the amount of diatom particles exceeds 0.5 part by weight, premix molding with a phenol resin becomes difficult.

The diatom fine particles used are:
Those having an average particle size of about 10 to 150 μm are suitable.

The premix filler is preferably blended so that the content of the premix filler in the coating liquid is 1 to 10% by weight. If the content ratio of the premix filler is less than 1 part by weight, the friction layer cannot be made sufficiently porous, and if it exceeds 10 parts by weight, the strength of the friction layer tends to decrease.

By blending such a premix filler, it is possible to make the friction layer porous, impart elasticity, and further improve the μ-V characteristic by improving the strength.

In the present invention, as the friction modifier, it is preferable to use molybdenum disulfide particles, carbon particles, and other inorganic powders such as silica, alumina, and talc in addition to the premix filler. . These molybdenum disulfide particles have an average particle size of 5 to 20 μm, alumina particles have an average particle size of 0.1 to 10 μm, and carbon particles have an average particle size of 10 to 10. It is preferably 50 μm.

By using such friction adjusting particles in combination, the friction coefficient of the friction layer can be further stabilized.

The friction adjusting particles are preferably added so that the total content of the carbon fibers and the premix filler in the coating liquid is 5 to 20% by weight.

That is, if the total addition amount of these additives is less than 5% by weight, the effect of addition by each additive cannot be sufficiently obtained, and if it exceeds 20% by weight, uniform dispersion and mixing become difficult. Cause

In the present invention, a polyamide-imide resin is used as a binder resin for these additives. The polyamide-imide resin fixes the friction modifier such as carbon fiber or premix filler stably and firmly, and further, the core plate. It is suitable as a binder resin for the friction layer because it strongly adheres to and has excellent heat resistance.

In the present invention, the surface of the core plate is coated with a coating solution obtained by sufficiently uniformly dispersing and mixing the above components in a predetermined ratio by a spray coating method or a dipping method. In this coating, the coating solution is appropriately diluted with a suitable solvent so that the viscosity becomes suitable for the coating.

After coating, in order to enhance the adhesiveness between the binder resin and the core plate, the adhesiveness between the binder resin and various additives and the strength of the friction layer,
Baking is performed at 300 ° C. for about 10 to 60 minutes.

In the present invention, it is preferable to carry out the coating so that the thickness of the friction layer thus obtained is 50 to 300 μm. The friction layer thickness is 50
If it is less than μm, sufficient frictional characteristics cannot be obtained, and 300 μm
Even if it exceeds, there is no difference in the friction characteristics, and the thickness of the friction layer is undesirably increased.

[0033]

The inventors of the present invention have proposed a coating liquid additive and a manufacturing method for the coating type facing friction material in order to develop the μ-V characteristic, that is, the characteristic that the friction coefficient maintains an increasing tendency as the sliding speed increases. As a result of various studies, the surface condition and the layer structure of the friction layer of the facing friction material have a great influence on the μ-V characteristic, and the surface condition of the friction layer has unevenness and the friction The layer should be porous from this surface inwards.
It has been found that it becomes an important requirement for improving the −V characteristic.

That is, in order to obtain the frictional characteristics desired as a facing friction material, the lubricating oil content can be promptly removed from the surface of the friction layer, the friction layer itself is slightly elastically deformed, the surface is resistant to abrasion, and the friction High strength is an essential condition. Of these, conventional removal of lubricating oil includes conventional slitting and porosity imparting according to the present invention.

In the present invention, by making the friction layer porous, the lubricating oil content of the friction surface is rapidly moved to the inside of the friction layer at a high sliding speed, thereby lowering the friction coefficient of the friction surface. Good μ-V characteristics are ensured without performing

In forming the friction layer of the coating system, in order to secure the wear resistance and the friction coefficient of the obtained friction layer, carbon fiber, molybdenum disulfide which is an inorganic filler, and carbon powder, which have been conventionally used, are used. Sufficient characteristics can be obtained with alumina fine particles. In addition, the polyamide-imide resin is extremely effective as a resin having high heat resistance and abrasion resistance for firmly fixing these.

In the present invention, the coating type friction layer having excellent abrasion resistance, friction coefficient, heat resistance, etc. is further added with a phenol resin in order to make it porous to improve the μ-V characteristic. A premix filler is used in which diatom particles are mixed and solidified and then crushed.

The premix filler is amorphous porous particles in which the phenol resin and the diatomaceous fine particles are randomly bonded to each other, and the porous diatomaceous fine particles are dispersed and fixed in the phenol resin as the matrix. Phenolic resin nuclei of the particles of the premix filler have a good adhesion state with the polyamide-imide resin, which is the binder resin of the coating liquid, and are strongly bonded,
The polyamide-imide resin, which is a binder resin, cannot sufficiently penetrate into the fine gaps formed by the porous diatom fine particles formed therein, and as a result, the friction layer becomes a porous layer. Even if the friction layer becomes a porous layer in this way, the phenol resin core of the premix filler is firmly bonded to the polyamideimide resin of the binder resin,
The strength of the friction layer as a whole is not impaired, and good properties such as mechanical strength and wear resistance can be obtained as compared with the conventional coating type friction layer. Moreover, the friction layer is also provided with an appropriate elastic deformability.

Even if diatom fine particles alone are added to the coating liquid, sufficient porosity cannot be obtained and a problem in terms of strength occurs.

Particularly, in the present invention, the diatom fine particles used for preparing the premix filler are porous inorganic fillers, are siliceous, have good thermal stability and are inexpensive.
Moreover, when the resin is added to and mixed with the phenol resin to be solidified, if the solidification is promoted by heating, the resin itself becomes porous, which is extremely advantageous for making the friction layer porous.

In the present invention, since the friction layer itself, which is made into a porous layer by the premix filler, can have a good function of removing the lubricating oil, the slitting of the core plate can be reduced.

[0042]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below.

Examples 1 and 2 An iron plate (thickness: 1.8 mm) was used, with an inner diameter of 50 mm and an outer diameter of 80 mm.
Was cut into a ring shape, and five oil grooves (radial slits) having a width of 2 mm and a depth of 0.4 mm were formed. A coating solution having the composition shown in Table 1 was applied to the surface of the core plate by a spray method, the temperature was raised to 250 ° C. in 30 minutes, and the temperature was kept at this temperature for 30 minutes for baking to obtain a thickness of 20.
A friction layer of 0 μm was formed.

The carbon fiber used had a fiber diameter of 6 to 10 μm and a fiber length of 50 to 100 μm. The molybdenum disulfide particles used as the friction modifier have an average particle size of 10 μm, and the carbon particles (graphite filler) have an average particle size of 40 μm.

As the premix filler, 0.3 part of diatom fine particles having an average particle size of 70 μm is added to 1 part by weight of a phenol resin.
A part having a particle size of 100 μm or less was used by adding and adding parts by weight, molding, baking at 250 ° C., and cooling and grinding.

Using the obtained facing friction material, the wear amount (500 minutes or 1 minute with the disc material of S45C steel as the mating material)
The amount of wear when a sliding test was performed at a speed of 5,000 minutes and 50 RPM) and the μ-V characteristics (relationship between the sliding speed and the friction coefficient measured by a SAE tester) were examined, and the results are shown in Table 1.

Comparative Example 1 With respect to a conventional paper-based facing friction material (paper-based friction material thickness 500 μm), the wear amount and μ-V characteristics were examined in the same manner as above, and the results are shown in Table 1.

Comparative Example 2 Facing friction was carried out in the same manner as in Example 1, except that the diatom fine particles were mixed with the phenol resin, molded and crushed to form a premix filler, but were simply crushed and blended in the coating liquid. Material was manufactured, and the wear amount and μ-V characteristics of the facing friction material were examined in the same manner, and the results are shown in Table 1.

[0049]

[Table 1]

From Table 1, it is clear that the facing friction material of the present invention has excellent wear resistance and good μ-V characteristics.

[0051]

As described above in detail, according to the facing friction material and the method for producing the same of the present invention, the adhesion between the base material core plate and the friction layer is good and there is no problem of peeling. It has excellent wear resistance. Excellent in μ-V characteristics. Excellent heat resistance and durability. The friction coefficient does not change over time and is stable over a long period of time. The material cost is low and it is provided at low cost. A facing friction material having excellent characteristics such as the above is provided.

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Claims (2)

[Claims] 1. A facing friction material in which a friction layer containing a friction modifier, carbon fibers and an organic binder is formed on the surface of a metal core plate, wherein the friction modifier is a mixture of phenol resin and diatom fine particles. The facing friction material is characterized in that it is a premix filler composed of amorphous porous particles obtained by cooling and pulverizing what is solidified under heating conditions, and the organic binder is a polyamide-imide resin. 2. A method for producing a facing friction material according to claim 1, wherein the phenol resin and the diatomaceous fine particles are mixed, the resulting mixture is heated and solidified, and then cooled and ground. Amorphous porous particles are obtained by mixing the porous particles with a carbon fiber and a polyamideimide resin to prepare a coating liquid, and the coating liquid is applied to a metal core plate. Production method.