JPH08177914A - Radiation heat type surface heat-treating method for friction material - Google Patents

Abstract

PURPOSE: To prevent the generation of the crack or swelling of a friction mate rial to improve a yield by heat-treating the friction material surface by radiation heat due to a red-heated sheet-like heater. CONSTITUTION: A first sheet-like burner 3 and a second sheet-like burner 4 of a rectangular shape matched with the shape of a friction material are juxtaposed at an interval of given distance at a given height from the friction material surface at the given position of a conveyer belt 2 for carrying the friction material 1 to be heat-treated by an intermittent feeding action. In these sheet- like burners 3 and 4, since a combustion gas is burnt through many small holes, a lower end combustion surface is red-heated to become a radiation heat source. The friction material 1 is carried by the conveyer belt 2 under the red-heated sheet-like burners 3 and 4, at first, is stopped for a fixed time under the first sheet-like burner 3 to be pre-heated, and then is moved to under the second sheet-like burner 4 to be full-burnt. The generation of the defectiveness such as a crack or swelling due to a sudden thermal shock can be eliminated, and all the surface can be uniformly burnt by thus heat-treating the surface of the friction material 1 by using radiation heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface heat treatment method in the production of friction materials, and more particularly to an improved product yield.

[0002]

BACKGROUND OF THE INVENTION Friction materials used for vehicle brakes and the like have hitherto been used in a manufacturing process thereof in which a flame is directly applied to the surface of the friction material in order to improve the initial fade as a brake characteristic and the effectiveness. The surface heat treatment was applied to burn off the organic components in the friction material. However, this treatment method has a drawback that the product defect rate due to cracks and blisters is high, and further, uniform heat treatment cannot be performed, so that it is difficult to obtain stable quality characteristics, and that it can be applied only to a planar friction material.

[0003]

As a result of various studies in view of the above, the present invention is effective for the initial fading and effectiveness countermeasures of the friction material by uniformly and surely performing the oxidative combustion of the organic component of the friction material. A radiant heat type surface heat treatment method for friction materials has been developed that achieves a high degree of burntness and enables reduction of product defect rate.

That is, the method of the present invention is applied to the production of friction materials.
It is characterized in that the friction material surface is heat-treated by radiant heat from the red-heated sheet heating element. At this time, a sheet burner in which combustion gas is burned through many small holes on the surface is used as the sheet heating element. It is more effective to use two or more friction materials and heat-treat them sequentially with these surface burners.

[0005]

[Function] As a method of improving the fade and effect of the friction material, there are a material designing method and a manufacturing designing method such as oxidative combustion of organic components on the surface of the friction material. The method of the present invention relates to the improvement of the latter technique, and in the conventional method of directly applying a flame to the surface of the friction material, since the flame hits the surface of a wide friction material unevenly, it is possible to bake to a uniform quality. This was done to solve the problem of being unable to do so.

Therefore, in the present invention, since the entire surface of the friction material is uniformly heated by the sheet heating element which generates radiant heat to gasify and remove the organic component, and further only the gasified organic component is burned, the friction material is used. There is no direct thermal shock to the. Therefore, the incidence of defective products such as cracks and blisters decreases.

The planar heating element referred to in the present invention is a surface heating element having electric resistance heating elements arranged in a planar shape, or a planar burner in which combustion gas is burned through a large number of small holes on the surface. Anything that can be generated in. Here, the planar heating element can be formed into an appropriate surface shape in accordance with the surface shape of the friction material to be heated, which is effective for further uniform heating. Further, the planar heating element is convenient because it can be molded to a curved friction material whose surface is not a flat surface in accordance with such a shape. In particular, with the planar burner, the atmosphere temperature can be controlled easily and inexpensively by controlling the distance to the object to be heated, the amount of gas, and the heating time, and the organic components in the friction material can be burned and removed uniformly and stably. . Furthermore, it is more effective to use two or more sheet burners, preheat the friction material in the first sheet burner, and perform main heating in the second sheet burner and thereafter.

[0008]

The present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, at a predetermined position of a conveyor belt (2) that conveys a friction material (1) to be heat-treated by intermittent feeding operation, at a predetermined height from the friction material surface, and in a friction material shape. The combined rectangular first planar burner (3) and rectangular second planar burner (4) were placed side by side at a predetermined distance. Note that (6) is a burner mounting member. These planar burners (3) and (4) have a gas introduction pipe (5) for sending combustion gas into the burner body box, and a large number of the gases are formed by sintering fine metal fibers in layers. It is composed of a mat-shaped lower end combustion surface having small holes. Since the combustion gas is burned through the large number of small holes, the lower end combustion surface is red-heated and becomes a radiant heat source. Note that durability can be increased by further fixing a ceramic fiber cloth to the lower end combustion surface.

The friction material (3) is conveyed by the conveyor belt (2) below the planar burners (3) and (4) which are thus heated red. That is, first, it is stopped below the first planar burner (3) for a certain period of time and baked (preheating), and then moved below the second planar burner (4) for main baking. By subjecting the friction material to surface heat treatment using radiant heat in this manner, it is possible to uniformly burn the entire surface without causing defects such as cracks and blisters due to a rapid thermal shock caused by a direct flame as in the conventional case. Therefore, quality is stable and productivity is improved.

The surface unevenness of the friction material and the product yield of the friction material when the surface of the ordinary friction material is heat-treated by the apparatus shown in FIG. 1 are compared with those of the conventional surface treatment by direct flame. And shown in FIG. 2 and FIG. The surface temperature of the friction material during the surface heat treatment is shown in FIG. 4 in comparison with the conventional one.

As is apparent from FIGS. 2 and 3, in the present invention, there is no burning unevenness in the friction material, and the product yield is greatly improved. Further, in the present invention, the temperature of the treated surface of the friction material is high and it is difficult for uneven burning to occur.

[0012]

As described above, according to the present invention, in the surface heat treatment of the friction material, the temperature control is easy and the occurrence of cracks and blisters is small, so that the quality stability is excellent and the productivity is improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the method of the present invention.

FIG. 2 is a diagram showing the results of investigating burn unevenness of a friction material by the method of the present invention and the conventional method.

FIG. 3 is a diagram showing the results of investigation of product yields according to the method of the present invention and the conventional method.

FIG. 4 is a diagram showing measurement results of surface temperature distribution during surface heat treatment according to the method of the present invention and the conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Friction material 2 Conveyor belt 3 1st planar burner 4 2nd planar burner 5 Gas introduction pipe 6 Burner mounting member

Claims (2)

[Claims] 1. A radiant heat type surface heat treatment method for a friction material, characterized in that the surface of the friction material is heat-treated by radiant heat generated by a planar heating element that is heated red when producing the friction material. 2. The planar heating element according to claim 1, wherein two or more planar burners in which combustion gas is burned through a large number of small holes on the surface are used as the planar heating element, and the friction material is sequentially heat-treated by these planar burners. Radiant heat type surface heat treatment method for friction materials.