JPH1193996A - Manufacture of friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material of high quality simplifying control of temperature in a thermoforming process, also stabilizing always a physical characteristic and performance. SOLUTION: A back plate molded in prescribed shape to be formed by a degreasing process and primer process is left as heated almost at a thermoforming temperature, also in a preliminary forming unit formed by preliminary molding of a friction material, a bonding agent layer is formed, the back plate preheated by thermoforming and the preliminary forming unit are integrally secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing friction materials such as disk pads and brake shoes used for brakes of various vehicles and industrial machines.

[0002]

2. Description of the Related Art Conventionally, friction materials such as disk pads and brake shoes used for brakes of various vehicles and industrial machines are basically manufactured by joining two kinds of members to each other. That is, as shown in FIG.
The back metal (the above is line (A)) formed into a predetermined shape by a sheet metal press or the like, subjected to degreasing treatment and primer treatment, and coated with an adhesive, and, on the other hand, heat-resistant organic fibers, inorganic fibers, and metal. Fiber raw materials such as fiber, inorganic and
A preform formed by blending an organic filler, a friction modifier, and a powder raw material such as a thermosetting resin binder, and shaping (preforming) a sufficiently homogenized starting raw material at a predetermined pressure at room temperature. (The line (B)) is thermoformed at a predetermined temperature and pressure in a thermoforming step to fix the two members together, then perform after-curing, and finally finish to produce a friction material. (The line (C)).

[0003]

In the conventional method for producing a friction material, as described above, the preform and the back metal are produced and stored on separate production lines. The storage method is generally to leave the product in a factory or facility, so that the temperature of both members changes according to the ambient temperature (room temperature) of the storage location, and greatly fluctuates in the range of 10 to 35 ° C. throughout the year. . On the other hand, in the thermoforming step, the preformed body and the back metal are mounted on a heat mold, pressure is applied at a predetermined temperature, and the preform is held for a predetermined time.

In such a situation, the back metal and the preformed body are kept at a temperature of about 35 ° C., which is the storage temperature when they are mounted on a molding die in the summer, and 10 ° C. in the winter.
The temperature is around ℃, and the thermal energy required for thermoforming varies greatly depending on the season. Therefore, if the thermoforming conditions in summer are diverted to winter as they are, heating will be insufficient and peeling of the preform and the back metal will easily occur, and conversely, if the thermoforming conditions in winter are diverted to summer, excessive heating will result in preheating. Swelling, cracking, and the like are likely to occur in portions. still,
When the friction material is manufactured by changing the thermoforming conditions every season, complicated temperature control is required.

An object of the present invention is to provide a high-quality friction material which simplifies temperature control in a thermoforming process and has stable physical characteristics and performance at all times. It is in.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for heating a back metal formed into a predetermined shape, subjected to degreasing and priming, to substantially thermoforming temperature, A method for producing a friction material, wherein an adhesive layer is formed on a preform formed by preforming a preform, and the preheated back metal and the preform are integrally fixed by thermoforming. .

According to the above-mentioned method for producing a friction material of the present invention, the primer-treated back metal is preheated to substantially the thermoforming temperature before moving to the thermoforming step. Thermoforming can be performed under certain conditions, and temperature control for each season is not required, and a friction material of consistent quality can be obtained. Further, the time required for the thermoforming step can be reduced. On the other hand, since the adhesive layer is formed on the preform of the friction material, a friction material in which the back metal and the preform are firmly bonded is obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a friction material according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a flow sheet for explaining the friction material manufacturing method of the present invention,
It comprises a back metal processing line (A), a friction material preforming line (B), and a thermoforming line (C) for processing a product from the processed members obtained in the (A) and (B) lines. Hereinafter, each step will be described by exemplifying a brake disk pad as a friction material.

[0009] The back metal processing line (A) is a sheet metal press,
The main steps are degreasing, primer treatment and back metal preheating. In the sheet metal pressing step, a back metal material selected in advance is formed into a back metal 1 having, for example, a substantially rectangular shape shown in FIG. In the degreasing step, fats and the like adhering to the back metal 1 at the time of press working are removed using a cleaning agent. In the primer treatment step, as shown by a broken line in FIG. 2, a phenol resin primer is applied to the entire surface of the degreased back metal 1, dried, and dried.
The primer is cured by heating at 0 to 200 ° C. for about 1 hour to form the primer layer 3.

The present invention is characterized in that the back metal 1 having undergone the primer treatment step is preheated before moving to a thermoforming line (C) described later. In this back metal preheating step, the back metal 1 on which the primer layer 3 has been formed is heated to approximately the thermoforming temperature. Since the thermoforming temperature varies depending on the type of the preformed body of the friction material described later, the heating temperature in the back metal preheating step is appropriately selected according to the temperature. In addition, the temperature of the back metal 1 substantially matches the thermoforming temperature (150 to 200 ° C.) due to this preheating. Although the heating method is not particularly limited, for example, a method of putting the primer-treated back metal 1 into a high (low) frequency oven, a method of placing the back metal 1 on a hot plate, and the like can be adopted. The preheated back metal 1 is promptly transferred to a thermoforming step while maintaining a substantially thermoforming temperature.

On the other hand, the preforming line (B) for the friction material is:
The main processes are the measurement, blending, stirring, preforming and application of the adhesive. In this preliminary forming line (B), first, fiber raw materials such as heat-resistant organic fibers, inorganic fibers, and metal fibers are mixed with powders such as inorganic / organic fillers, friction modifiers, solid lubricants, and thermosetting resin binders. The raw materials are blended in a predetermined ratio and sufficiently homogenized by stirring to prepare a starting raw material. In the above, for example, synthetic rubber or cashew resin or the like as an organic filler, metal particles such as copper or aluminum or zinc as an inorganic filler, scaly inorganic substances such as balm curite or mica, particles such as barium sulfate or calcium carbonate Can be mentioned. Examples of the organic fibers include aromatic polyamide fibers and oxidized acrylic fibers. Examples of the inorganic fibers include ceramic fibers such as potassium titanate fiber and alumina fiber, glass fibers, carbon fibers, and rock wool. Examples thereof include copper fiber and steel fiber. Examples of the thermosetting resin binder include a phenol resin (including various phenol resins modified with a straight phenol resin and rubber), a melamine resin, an epoxy resin, a cyanate ester resin, and the like. Further, as a friction modifier, for example, alumina or silica,
Examples of the solid lubricant include metal oxides such as zirconia and the like, and examples of the solid lubricant include graphite and molybdenum disulfide.

Next, this starting material is put into a molding die and molded at normal temperature under a pressure of about 100 to 500 kgf / cm ² to produce a preformed body 4 as shown in FIG. 3, for example. In FIG. 3, reference numeral 5 denotes a projection that fits into the opening 2 of the back metal 1 shown in FIG.

An adhesive layer 6 is formed on the surface of the obtained preform 4 on which the projections 5 are provided. As shown in FIG. 6, in the conventional manufacturing method, an adhesive is applied to the back metal 1. In the present invention, however, the adhesive is applied instead of the back metal 1 because the back metal 1 is preheated as described above. The agent layer 6 is formed on the preform 4 side. As the adhesive layer 6, a powder or sheet-like adhesive which has been conventionally used can also be used.

The back metal 1 and the preform 4 of the friction material treated as described above are then transferred to a thermoforming line (C). This thermoforming line mainly includes a thermoforming step, a heating step and a finishing step. In the thermoforming step, first, the preheated back metal 1 is set in a hot press machine while maintaining substantially the thermoforming temperature, and the preform 4 is placed thereon. Subsequently, the preform 4 is held at a thermoforming temperature (150 to 200 ° C.) under a predetermined pressure for a predetermined period of time for thermosetting, and the back metal 1 and the preform 4 are integrally fixed. According to the present invention, since the back metal 1 is preheated to substantially the thermoforming temperature at the time of thermoforming, the temperature can be raised to the thermoforming temperature in a very short time, and the time required for the entire thermoforming can be significantly reduced.

Thereafter, according to a conventional method, after-curing is performed in a heating step and finishing is performed in a finishing step.
Is completed. As shown in the sectional view of FIG. 5, the disk pad 7 has the back metal 1 and the preform 4 joined by an adhesive layer 6 formed on the preform 4.

The amount of heat required to produce one disk pad (back metal / non-asbestos friction material) for a passenger car in summer and winter is calculated based on the friction material manufacturing method according to the present invention and the case where the back metal is not preheated. The results of trial calculations are shown for the case of the conventional friction material manufacturing method. In the calculation, the room temperature in summer was 35 ° C., the room temperature in winter was 10 ° C., the weight of the backing metal was 240 g, the specific heat was 0.45 J / kg, the weight of the friction material was 120 g, and the specific heat was 0.7 J / kg. Table 1 shows the calculation results.

[0017]

[Table 1]

From Table 1, the required heat difference between summer and winter is:
In the case of the present invention in which the back metal is preheat-treated, the value is 2 J, whereas in the case of no pre-heat treatment, the value greatly changes to 5 J. From this, it became clear that temperature control is unnecessary in the case of the present invention, and more stable production can be performed throughout the year. The time required for the thermoforming step was 10 minutes when the back metal was not pre-heated, whereas the time required for the thermoforming step was about 7 minutes in the case of the present invention in which the back metal was pre-heated. confirmed.

[0019]

As described above, according to the present invention,
A friction material of a constant quality can be stably produced throughout the year without performing seasonal temperature control in the thermoforming process, and the time required for the thermoforming process can be shortened. Further, an adhesive is applied to the preform, and a friction material in which the back metal and the preform are firmly bonded is obtained.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a process for carrying out a method of manufacturing a friction material according to the present invention.

FIG. 2 is a plan view showing an example of a back metal.

FIG. 3 is a perspective view showing an example of a preform of a friction material.

FIG. 4 is a plan view showing a state in which a back metal and a preform of a friction material are integrated.

FIG. 5 is a sectional view taken along the line AA in FIG. 4;

FIG. 6 is a flow sheet showing a process for performing a conventional friction material manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backing metal 2 Opening 3 Primer layer 4 Preform of friction material 5 Projection 6 Adhesive layer 7 Friction material (disk pad)

Claims (1)

[Claims] 1. A back metal formed into a predetermined shape, subjected to a degreasing treatment and a primer treatment, is heated to substantially a thermoforming temperature, and an adhesive layer is formed on a preformed body obtained by preforming a friction material material. A method of manufacturing a friction material, comprising: forming and pre-fixing the preheated back metal and the preform by thermoforming.