JP2003113879A - Brake pad manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a brake pad manufacturing step, to reduce the cost thereby, and to save on the thermal energy consumption. SOLUTION: In the brake pad manufacturing method in which a pressure plate and a preliminarily formed body of a raw friction material are integrally fixed to each other by the thermoforming, and the after-cure and painting is performed after the thermoforming, the painting is performed after the thermoforming, and the after-cure and the heating for the paint-baking are performed. The heating is preferably performed at the temperature of 180-300 deg. for 30-180 minutes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material such as a brake pad and a brake lining used for a brake of various vehicles and industrial machines, particularly a friction material which requires after-curing after thermoforming and requires painting. Regarding manufacturing method.

[0002]

2. Description of the Related Art Conventionally, friction materials mainly used for brakes of automobiles, railway vehicles, industrial machines, etc., generally include various fillers, various fibers for reinforcement, abrasives, graphite and metals. Various resins are blended with a friction adjusting material such as powder as a binding material for binding these materials. In the manufacturing process of a brake pad for a disc brake, which is an example of a conventionally known method for manufacturing a friction material, as shown in FIG. 2, a sheet metal press is formed into a predetermined shape, and a degreasing treatment and a primer treatment are performed. Pressure plate (above line (A)) coated with an adhesive, reinforcing fibers such as heat-resistant organic fibers, inorganic fibers, and metal fibers, inorganic / organic fillers, friction modifiers, binders, etc. Thermoforming a preform (above, line (B)) prepared by molding (preforming) a raw material that is sufficiently homogenized by mixing with the powder raw material In the process, it consists of a process (above line (C)) of thermoforming at a predetermined temperature and pressure to fix both members together, after-curing, and finally performing finishing processing such as polishing, painting and baking. To have. In the line (C), after-curing may be followed by painting, baking, and then polishing.

[0003]

However, in the conventional method for manufacturing a friction material, as described above, after-curing is performed after thermoforming, then painting and baking are performed, and heating is performed twice after thermoforming. ing. Therefore, there is a problem that a large amount of heat energy is consumed and the number of steps is also increased. In addition, since the friction material is heated by applying a load during after-curing, it is impossible to perform after-curing after coating.

In addition, the coating process in the conventional brake pad manufacturing process is performed as a process of decoratively finishing the brake pad after completion of each process such as thermoforming, heat treatment and polishing. Conventionally, this coating process has been performed by hand-painting or spray-painting a water-soluble paint on each surface of the brake pad excluding the sliding friction surface, that is, the exposed surface of the pressure plate and the side surface of the friction material with a spray gun. It was baked in an infrared furnace or a hot air circulation furnace. Therefore, the work efficiency of the painting process is poor,
Moreover, the variation in coating quality was also large.

The present invention has been made in view of such conventional problems, and an object thereof is to simplify the manufacturing process of the brake pad, reduce the cost therefor, and reduce the consumption of heat energy.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted diligent studies in order to solve the above-mentioned problems, and after thermoforming a conventional preform, perform post-curing and coating and baking through a polishing step. It has been found that all of the above problems can be solved by changing the order of the processes used to perform after-curing and baking after coating at the same time. Then, the present inventors have completed the present invention based on the above findings.

That is, the present invention has solved the above problems by the following constitution. (1) In a method of manufacturing a brake pad, in which a pressure plate and a preform of a friction material raw material are integrally fixed by thermoforming, and after-curing treatment and painting are performed after thermoforming, coating is performed after the thermoforming. After that, a method for manufacturing a brake pad is characterized in that after-cure treatment and heat treatment for baking of paint are performed. (2) The heat treatment is performed at a temperature of 180 to 300 ° C. for 30 minutes.
The method for producing a brake pad according to (1) above, wherein the heating is performed for 180 minutes.

That is, the essence of the present invention is to simultaneously perform after-curing and baking after painting of a vehicle friction material, particularly a vehicle brake pad for a disc brake. By doing so, one step can be omitted as shown in FIG. 1, that is, heating for two steps can be done by heating once, and it is possible to shorten the production time, reduce the processing cost and save energy. Become.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a friction material of the present invention will be described with reference to the drawings. FIG. 1 is a flow sheet for explaining the friction material manufacturing method of the present invention, which includes a pressure plate (P / P) processing line (A), a friction material preforming line (B), and (A), (B) A thermoforming line (C) for processing a product from the processing material obtained in each line. Hereinafter, each process will be described by exemplifying a brake pad for a disc brake as the friction material.

The P / P processing line (A) has sheet metal pressing, degreasing treatment, primer treatment and adhesive application as main steps. In the sheet metal pressing step, a P / P material selected in advance is formed into a P / P having, for example, a substantially rectangular shape and an opening portion at a predetermined position by pressing or the like. In the degreasing step, the oil and fat adhered to the P / P during the press working is removed using a cleaning agent. In the primer treatment step, a phenol resin-based primer is applied to the entire surface of the degreased P / P, dried, and heated at 180 to 200 ° C. for about 1 hour to cure the primer to form a primer layer.
Then, an adhesive is applied on the primer layer.

On the other hand, the friction material preforming line (B) is
Main processes are measuring, blending, stirring and preforming raw materials. Each of these steps can be performed in the same manner as a conventional friction material manufacturing step. That is, the starting raw material is put into a molding die and, for example, at room temperature, 9.8 to 49 MPa (100
Molding is performed under a pressure of about 500 kgf / cm ² ) to produce a preformed body.

In the above raw materials, examples of the reinforcing fiber include organic fiber such as aromatic polyamide fiber, flame-resistant acrylic fiber or the like, copper fiber, metal fiber such as steel fiber, potassium titanate fiber or Al ₂ O ₃ —SiO ₂ system. Inorganic fibers such as ceramics fibers may be mentioned. Examples of the inorganic filler include inorganic particles such as barium sulfate and calcium carbonate, and scale-like inorganic substances such as vermiculite and mica.
Examples of the binder include thermosetting resins such as phenol resins (including straight phenol resins and various modified phenol resins such as rubber), melamine resins, epoxy resins, and polyimide resins. Examples of the friction modifier include inorganic friction modifiers such as alumina, silica, magnesia, zirconia, and chromium oxide; organic friction modifiers such as synthetic rubber and cashew dust; and solid lubricants such as graphite and disulfide. Examples thereof include molybdenum.

Various composition ratios can be adopted as the composition of the friction material. That is, these may be mixed alone or in combination of two or more, depending on the frictional characteristics required for the product, such as friction coefficient, wear resistance, vibration characteristics, and squealing characteristics.

The P / P and friction material preforms treated as described above are then transferred to a thermoforming line (C). The thermoforming line mainly includes a thermoforming process, a painting process, a heating process and a polishing process. In the thermoforming step, first, the P / P is set in the hot press machine, and the preform is placed on it. This thermoforming temperature (usually 140-200
(° C) under a predetermined pressure for a predetermined time to heat-cure the preform, and at the same time, fix the P / P and the preform together with an adhesive.

After that, as described in the above-mentioned prior art, the paint is applied to the exposed surface of the P / P and the side surface of the friction material, and then heated at 180 to 300 ° C. for 30 to 180 minutes, after-curing and painting. And baking at the same time,
After that, a polishing process is performed in a finishing process, and one step is omitted as compared with the process of the conventional technique shown in FIG. In this heating process, after-curing is also performed, and the heating temperature is set to a relatively high temperature as described above. Therefore, if the temperature is suddenly heated to a temperature of 180 to 300 ° C., the baking of the paint does not work well. Since the coating film may crack, for example, at the beginning of heating, heating to a temperature of about 170 ° C. to dry it, and after performing initial baking, it is necessary to raise it to the above temperature to perform baking and after-curing. Good. Due to such heating temperature, it becomes higher than the baking temperature of the conventional paint, so when the paint used cannot withstand the above temperature even with the conventional water-soluble paint, it can withstand the heating temperature. It is good to select the paint that makes the coating film.

[0016]

The present invention will be described in detail with reference to the following examples. However, the present invention is not limited to these examples.

Example 1 A linear ultra-high molecular weight straight novolac type phenol resin prepared by previously blending a linear novolac phenol resin having a weight average molecular weight of 33.000 or more with about 10% by weight of a curing agent (hexamethylenetetramine). An adhesive was prepared by dispersing in an organic solvent. (The molecular weight is a value converted into polystyrene by GPC). The adhesive was uniformly applied by spraying to P / P that had been degreased, washed, and primed in exactly the same manner as in the past. The P / P coated with the adhesive was put in a heating furnace at 70 ° C. and dried.

After that, the preform obtained in the above-mentioned preform line (B) in FIG. 1 is placed on the P / P to form the preform in the thermoforming line (C) in FIG. Through the process, a brake pad having the current composition was produced. At that time, in order to maximize the friction material strength out of the physical properties after thermoforming, the optimum molding conditions were determined from the results of preliminary experiments as a molding surface pressure of 52.9 MPa, a molding temperature of 152 ° C., and a molding time of 300.
In seconds, the P / P and the preform were integrally fixed together with the thermosetting of the preform.

Further, the raw material composition is changed so that the physical property value after after-curing becomes equivalent to that of the conventional process product (the friction material part is heated by applying a load), and mainly the binder amount is reduced. The heating (after-cure) conditions and the paint-baking conditions were examined, and from the results of preliminary experiments, heating was performed for both baking and after-curing of the paint under the temperature and time conditions shown in Table 1.

[0020]

[Table 1]

Under these conditions, both coating baking and after-curing were satisfied, and the adhesion, hardness, rustproofing power, etc. of the coating film of the obtained brake pad became equivalent to those of the conventional process product shown in FIG. In addition, regarding the characteristics of the friction material obtained in the manufacturing process of the present invention (FIG. 1), the effects, noise, and wear were the same as those of the conventional process product of FIG. 2.

[0022]

EFFECTS OF THE INVENTION According to the present invention, baking of coating and after-curing are simultaneously performed so that heating for two steps is not carried out by one heating, production lead time is shortened, processing cost is reduced, and saving is achieved. Energy became possible.

[Brief description of drawings]

FIG. 1 is a flow sheet showing steps for carrying out a brake pad manufacturing method of the present invention.

FIG. 2 is a flow sheet showing a manufacturing process of a conventional brake pad.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 31:16 B29L 31:16 F term (reference) 3J058 BA61 DD11 EA33 EA37 FA01 FA11 FA21 FA31 GA03 GA06 GA12 GA20 GA26 GA28 GA33 GA34 GA35 GA37 GA38 GA39 GA40 GA43 GA45 GA55 GA57 GA58 GA64 GA65 GA73 GA81 GA92 4F204 AD03 AE08 AG03 AH17 FB01 FB11 FF05 FW06 FW37

Claims (2)

[Claims] 1. A method of manufacturing a brake pad, wherein a pressure plate and a preform of a friction material raw material are integrally fixed by thermoforming, and after-curing and painting are performed after thermoforming. A method for manufacturing a brake pad, which comprises performing after-cure treatment and heat treatment for baking the coating. 2. The method of manufacturing a brake pad according to claim 1, wherein the heat treatment comprises heating at a temperature of 180 to 300 ° C. for 30 to 180 minutes.