JP2533434B2 - Friction material and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material used as a disc pad, a brake lining, etc. of an automobile and a method for producing the same, and more specifically, a friction material which is not adversely affected by moisture and a friction material. The present invention relates to the improvement of the coating treatment process in the manufacturing method.

[0002]

Friction materials used for automobile disc pads, brake linings, etc. are generally composed of fiber components such as aramid fibers, glass fibers, ceramic fibers and metal fibers, and thermosetting resin components such as phenolic resins. ,graphite,
It is manufactured by first mixing a friction material including a filler component such as barium sulfate and other components that are added as necessary, and then molding the friction material into a desired shape, followed by heat treatment.

The friction material for disc pads, brake linings, etc. manufactured as described above should contain pores having a porosity of, for example, about 5 to 20% by volume in order to maintain good friction and wear performance. It is manufactured while adjusting,
In particular, recently, a friction material using a porous material has been developed for the purpose of preventing squeal during braking.

[Problems to be Solved by the Invention]

However, when moisture permeates from the outside into the voids such as the pores formed in the friction material or the pores of the porous material, the moisture is rapidly increased by the heat generated during braking. It may evaporate and cause a crack on the side surface of the friction material.

On the other hand, in the manufacturing process of the friction material, in order to obtain a good appearance, the side surface of the friction material and the surface of the back metal are coated with water-soluble paint by spray coating or electrodeposition coating after the heat treatment step. It is considered that this coating of the friction material can prevent moisture from permeating from the outside into voids such as the pores formed in the friction material and the pores of the porous material.

However, among the commonly used coating treatments, the effect of preventing the above penetration is small if the water-soluble paint is usually applied by spraying, and even in the case of electrodeposition coating, the above-mentioned water-soluble paint is not usually applied. It only shows slightly better penetration protection than spray coating. Furthermore, the use of paints using organic solvents has problems of working environment and recovery of organic solvents.

The present invention solves the above-mentioned problems in the prior art, and provides a friction material for a disk pad, a brake lining, etc., which does not allow water to permeate the voids from the outside, and a method for manufacturing the same. It was done as a purpose.

Further, the present invention solves the above-mentioned problems in the prior art, and a friction material which does not allow water to permeate the voids from the outside, and a friction material which deteriorates the working environment or which is an organic solvent. It was made for the purpose of providing a method which can be produced without causing the need for recovery of

[0009]

Means for Solving the Problems] The friction material to which the present invention is employed in order to achieve the above object construction, the fiber component, thermoset
Resin component, filler component and other added as needed
After mixing the appropriate components and molding into the desired shape, heat treatment
The resulting friction material has multiple water resistant layers.
In addition, the composition of the manufacturing method is such that the fiber component, the thermosetting resin component, the filler component and
And other appropriate components that are added as necessary, and
Friction consisting of heat treatment after molding to the desired shape
In the material manufacturing method, the coating process is the friction material molding process.
And at least once between the heat treatment process and the heat treatment
By applying at least once later, multiple water resistant layers
It is characterized in that it is formed.

That is, the inventor of the present invention has examined the infiltration route of water into the voids in the friction material, and found that the water is more absorbed from the side surface of the friction material and the boss hole than the friction surface with the mating material such as the rotor. Infiltration was much more, and therefore, the idea that the problems in the above-mentioned conventional technology could be solved if the side surface and the pores of the boss hole could be effectively closed by painting treatment was studied, and further research was conducted. As a result, the present invention has been achieved.

The present invention will be described in detail below.

The method of manufacturing the friction material of the present invention basically comprises the same steps as the manufacturing method of the prior art.
That is, fiber components such as aramid fiber, glass fiber, ceramic fiber and metal fiber, thermosetting resin components such as phenol resin, filler components such as graphite and barium sulfate, and other components added as necessary. The friction material is first mixed, then molded into a desired shape, and then heat-treated to produce a friction material for disc pads, brake linings, and the like.

The friction material of the present invention is characterized in that it has a water-resistant layer of a multi-dispersed layer on the surface.
The water resistant layer is formed, for example, by applying a coating treatment after molding the friction material, as in the production method of the present invention. Alternatively, electrodeposition coating or the like can be used, and these methods can be combined.

In the manufacturing method of the present invention, the above-mentioned coating treatment is performed at least twice or more, and a boss hole provided for improving the shear strength between the side surface of the friction material and the surface of the back metal, especially the back metal and the friction material. Department is targeted. It should be noted that the frictional surface with the mating material such as the rotor may be subjected to coating treatment, but this is meaningless because the frictional surface will be polished when the product is finished. Further, since a coating film is formed on the friction surface by coming into contact with the mating material during braking, it is considered that infiltration of water from the friction surface is small in practice.

There are basically two possible timings for the above-mentioned coating treatment, between the molding and heat treatment and after the heat treatment. The surface of the side surface of the friction material after molding is smooth with few irregularities. Good riding, on the other hand, the surface of the side surface of the friction material after heat treatment has a lot of irregularities, and the ride of the paint is bad. Therefore, from this viewpoint, it is preferable to perform between the molding and the heat treatment. In addition, coating before heat treatment prevents oxidative deterioration of the friction material during heat treatment,
It also has a positive effect on strength.

[0016] The above-mentioned coating treatment is, for example, at least 1.
It may be performed in a plurality of steps, such as performing one time between the molding and the heat treatment and at least one time after the heat treatment.

Further, in the manufacturing method of the present invention, Teflon resin powder or silicon resin powder may be added to the coating material for coating, and these particles may close the pores on the side surface of the friction material. When these particles are added, most of the pore diameter of the friction material is about 0.01 to 10 μm, and therefore resin powders having different particle diameters may be appropriately selected and used depending on the friction material. Also, Teflon resin powder is more water repellent, and is therefore preferable to silicon resin powder from this viewpoint.

[0018]

EXAMPLES Next, examples of the present invention will be described.

Manufacture of Intermediate Product Using a non-asbestos-based friction material which has been conventionally used,
Mix these uniformly with a stirrer, then preform,
Heat-press molding was carried out to obtain a disc pad intermediate product.

Example 1 The side surface of the friction material and the surface of the back metal of the above intermediate product were spray-coated with a water-soluble melamine alkyd coating, and then heat-treated. Then, the second application of the melamine alkyd-based water-soluble paint was applied to the side surface of the friction material and the back metal to obtain the disk pad of Example 1.

Example 2 Tetrafluoroethylene resin (Teflon [trade name]) powder was added to the melamine alkyd water-soluble paint in Example 1, and a disk pad of Example 2 was obtained in the same manner.

Comparative Example 1 After heat-treating the above intermediate product in the conventional manner, spray coating of a melamine alkyd water-soluble paint was applied to the side surface of the friction material and the back metal to obtain a disk pad of Comparative Example 1.

Comparative Example 2 A disk pad of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that tetrafluoroethylene resin powder was added to the melamine alkyd water-soluble paint.

A water absorption test and a crack test were conducted on the disk pads of Examples and Comparative Examples obtained by the above method. The results are shown in Table 1 and FIG.

[Table 1]

In the water absorption test, the disk pad was completely immersed in water, and the ratio of the weight of water absorption to the total weight of the friction material after a certain period of time was measured. In the crack test, the braking start temperature was 300 ° C. and the initial speed was 120 km. / H brake braking 10
This operation is repeated 0 times, and then the disc pad is soaked in water for 1 hour. This operation is repeated for several cycles, and the state of cracks is measured for each cycle.

[Brief description of drawings]

FIG. 1 is a graph showing the results of a water absorption test conducted on disk pads of Examples and Comparative Examples.

Claims (7)

(57) [Claims] 1. A fiber component, a thermosetting resin component, and a filler composition.
Minute and other appropriate components added as needed
And then heat-treat it after molding it into the desired shape.
In addition, the feature is that a plurality of water resistant layers are formed.
Friction material 2. The water resistant layer is formed by a coating process.
The friction material according to claim 1, wherein 3. The water resistant layer comprises at least a side surface of the friction material and
The friction material according to claim 1, wherein the friction material is formed in the boss hole. 4. The water resistant layer is made of Teflon resin powder or silicone.
The resin composition according to claim 1, which contains a resin powder.
Friction material. 5. A fiber component, a thermosetting resin component, and a filling material composition.
Minute and other appropriate components added as needed
And then heat-treating after molding into the desired shape.
In the method of manufacturing the friction material,
At least once between the mold step and the heat treatment step,
By applying at least once after heat treatment,
Made of friction material characterized by forming a water layer
Build method. 6. The coating process uses at least a molded friction material.
The friction material according to claim 5, which is also applied to the side surface and the boss hole.
Build method. 7. Teflon resin powder as a paint for coating treatment
Alternatively, it is performed by adding a silicon resin powder.
Manufacturing method of the friction material.