JPH09112607A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent crack initiation at the interface between an intermediate layer incl. pad layer and a heat insulation layer and facilitate manufacture by enclosing the intermediate layer with pad layer so that the surface of the intermediate layer including heat insulating material layer joined with one surface of a metal plate is not exposed. SOLUTION: A pad layer 18 and heat insulating material layer 20 constitute a lining 16, and a heat insulating material layer 20 joined with one surface of a metal plate 14 is enclosed with the pad layer 18. Therefore, the interface between two layers can be covered with the pad layer 18. Therefore, the part around the surface of the pad layer 18 is rapidly cooled when the lining 16 consisting of the heat insulating material layer 20 and pad layer 18 is heated followed by heat radiation, but the part around the interface between the layer 20 and pad layer 18 is cooled more slowly than the part around the surface of the pad layer 18. Accordingly it is possible to cool the lining 16 with no risk of steep widening of the difference in the contraction ratio (linear coefficient of thermal expansion) between the two layers, and crack initiation in the interface can be precluded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material, and more particularly to a friction material in which a pad layer is joined to one surface side of a metal plate via a heat insulating material layer.

[0002]

2. Description of the Related Art As a friction material used for a disc brake of a vehicle such as an automobile, for example, a friction material 10 shown in FIG.
Is used. The friction material 10 shown in FIG.
A lining material 16 is integrated with one surface of the metal plate 14 having the holes 12 formed therein. Such friction material 10
As shown in FIG. 3, which is a vertical cross-sectional view taken along the line XX of FIG. 2, part of the lining material 16 enters the binding holes 12 and 12 to bond the metal plate 14 and the lining material 16. I am trying to wear it. Further, the lining material 16 is composed of a pad layer 180 that comes into contact with the rotating disk rotor and a heat insulating material layer 200 as an intermediate layer. This heat insulation layer 200
Has a role of joining the metal plate 14 and the pad layer 180, and excessive heat transfer to the metal plate 14 of frictional heat generated by the contact between the disk rotor and the pad layer 180 at the time of brake operation. It also has a role as a heat insulating layer for preventing the above. This is because when the metal plate 14 is heated, vapor lock may occur due to evaporation of brake oil in the brake cylinder that presses the other surface of the metal plate 14.

As described above, since the pad layer 180 forming the lining material 16 and the heat insulating material layer 200 have different roles, the characteristics of the resin as the binder forming each layer are also different. That is, the resin for the pad layer used for the pad layer 180 has excellent abrasion resistance, and the resin for the heat insulating material layer used for the heat insulating material layer 200 is the same as the metal plate 14. A material having good binding property is used. Therefore, the friction material shown in FIG.
Since the coefficient of linear expansion of 0 is different from that of the heat insulating material layer 200, there is a drawback that cracks easily occur at the boundary surface between the two layers due to thermal strain caused by heat such as friction heat. In order to solve such a drawback, Japanese Patent Application Laid-Open No. 56-80532 proposes a friction material in which the heat insulating material layer 200 has multiple layers and the linear expansion coefficient of each layer is inclined.

[0004]

According to the friction material proposed in the above publication, cracks generated at the interface between the pad layer 180 and the heat insulating material layer 200 due to thermal strain due to heat such as friction heat are generated. Can be reduced. However, even in such a friction material, it was found that cracks still tend to occur at the boundary surface between both layers by repeating heating and cooling of the lining material 16. On the other hand, a part of heat such as frictional heat is radiated even through the metal plate 14, so that the heat insulating performance of the heat insulating material layer 200 is such that vapor lock due to evaporation of brake oil in the brake cylinder does not occur. Insulation is sufficient. In this respect, the heat insulating material layer 20
When 0 is a multi-layer, when the heat insulating material layer 200 is thicker than a predetermined thickness and exhibits more heat insulation performance than necessary, heat such as frictional heat is accumulated in the pad layer 180 and the braking performance is increased. May decrease. Further, the heat insulating material layer 20
The multi-layering of 0 complicates the manufacturing process of the friction material. Also,
Between the heat insulating material layer 200 and the pad layer 180, there may be provided a functional layer, for example, an alarm layer that comes into contact with the disc rotor to generate an abnormal noise when the pad layer 200 is worn down. When the heat insulating material layer 200 is provided, the intermediate layer including the heat insulating material layer 200 is maintained at a predetermined thickness.
Is required to be as thin as possible. Therefore, an object of the present invention is to provide a friction material in which cracks are unlikely to occur at the interface between the intermediate layer including the pad layer and the heat insulating material layer even when heating and cooling are repeatedly applied, and which is easy to manufacture. It is in.

[0005]

In order to solve the above-mentioned problems, the inventors of the present invention firstly set a friction material in which the intermediate layer is a single heat-insulating material layer on the boundary surface between the pad layer and the heat-insulating material layer. As a result of studying the cause of easy occurrence of cracks, as shown in FIG. 4 which is an enlarged view of P portion of FIG. 3, a pad layer 180 and a heat insulating material layer 20 forming a conventional lining material 16 of a friction material are formed.
Since the boundary with 0 is exposed on the side end surface of the lining material 16, it has been found that cracks are likely to occur on the boundary surface between both layers. That is, the lining material 16 is heated by heat such as friction heat.
When the lining material 16 is heated and then allowed to cool, the vicinity of the surface of the lining material 16 is rapidly cooled. Therefore, the temperature lowering rate of the temperature near the surface of the lining material 16 is faster than the temperature rising rate when the lining material 16 is heated. . Therefore, the lining material 16
The difference in shrinkage ratio (difference in linear expansion coefficient) between the pad layer 180 and the heat insulating material layer 200, which constitutes the above, is closer to the side end surface of the lining material 16 where the boundary between the two layers is exposed than when the lining material 16 is heated. This is because it is easy to become apparent when it is allowed to cool. Based on such findings, the present inventors have made further studies,
By covering the vicinity of the side end surface of the lining material 16 where the boundary between the pad layer 180 and the heat insulating material layer 200 is exposed with the pad layer 180, cracks in the boundary surface between the two layers that are likely to occur when the lining material 16 is allowed to cool. The inventors have found that the above can be prevented and have reached the present invention.

That is, according to the present invention, in a friction material in which a pad layer is bonded to one surface side of a metal plate via an intermediate layer including a heat insulating material layer, a heat insulation material bonded to one surface side of the metal plate. In the friction material, the intermediate layer is covered with a pad layer so that the surface of the intermediate layer including the layer is not exposed. In the present invention having such a configuration, by forming the intermediate layer joined to the one surface side of the metal plate as a single heat insulating material layer, it is possible to easily manufacture a friction material having good heat dissipation. Further, by forming the intermediate layer joined to the one surface side of the metal plate as a multilayer, a functional layer capable of exhibiting a function such as an alarm function can be formed on the heat insulating material layer.

According to the present invention having such a configuration, since the intermediate layer including the heat insulating material layer bonded to one surface side of the metal plate is covered with the pad layer, the boundary between both layers is also covered with the pad layer. ing. Therefore, when the lining material composed of the intermediate layer and the pad layer is cooled after being heated, the surface of the pad layer is rapidly cooled, but the vicinity of the interface between the intermediate layer and the pad layer is Since it is cooled more slowly than near the surface, the difference in shrinkage between the two layers (difference in linear expansion)
As a result of being cooled without being rapidly expanded, it is possible to prevent cracks occurring at the boundary surface between the two layers.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The appearance of the friction material according to the present invention is the same as that of the friction material 10 shown in FIG. 2 described above, and one surface of the metal plate 14 having the binding holes 12, 12 is formed. The lining material 16 is integrated on the side. A part of the lining material 16 enters the inside of the attachment holes 12 and 12 to bond the lining material 16 and the metal plate 14 together. In the present invention, the pad layer 18 and the heat insulating material layer 20 constituting the lining material 16 shown in FIG. 2 have the heat insulating material layer 20 bonded to one surface side of the metal plate 14 as shown in FIG. Covered by layer 18.
Therefore, the boundary between both layers can be covered with the pad layer 18. In this way, when the boundary between the pad layer 18 and the heat insulating material layer 20 is covered with the pad layer 18, when the lining material 16 composed of the heat insulating material layer 20 and the pad layer 18 is heated and then allowed to cool, Although the vicinity of the surface of the pad layer 18 is rapidly cooled, the vicinity of the interface between the heat insulating material layer 20 and the pad layer 18 is gradually cooled as compared with the vicinity of the surface of the pad layer 18.

Therefore, the lining material 16 can be cooled without abruptly expanding the difference in shrinkage rate (difference in linear expansion coefficient) between the two layers, and cracks occurring at the boundary surface between the two layers can be prevented. Here, the thickness t of the pad layer 18 that covers the side surface of the heat insulating material layer 20 is sufficient to be about 1 to 1.5 mm. In the friction material shown in FIG. 1, short fibers 22, 22 ... Made of aramid or metal are mixed in the heat insulating material layer 20. .. existing in the vicinity of the surface of the heat insulating material layer 20 of the short fibers 22, 22 .. 18
And are integrated. The heat insulating material layer 20 and the pad layer 1
As a material for forming 8, a material conventionally used for manufacturing a friction material can be used.

The manufacture of the friction material having the structure shown in FIG.
The metal plate 14 having the binding holes 12, 12 is subjected to various surface treatments and then dried. Such surface treatment includes a degreasing step of degreasing the metal plate 14, and a shot processing step of spraying particulate matter toward the surface of the metal plate 14 to increase the binding strength between the lining material 16 and the metal plate 14. Etc. are included. On the other hand, the pad raw material forming the pad layer 18 forming the liner 16 and the heat insulating raw material forming the heat insulating material layer 20 are separately adjusted and weighed. As the pad raw material and the heat insulating material raw material, the raw materials conventionally used for friction materials can be used. Next, a predetermined amount of pad raw material is placed on the heat insulating material of the metal plate 14 so as to completely cover the surface of the predetermined amount of heat insulating material placed on the one surface side of the surface-treated metal plate 14. To place. After that, the heat insulating raw material and the pad raw material placed on the metal plate 14 are heated and pressure-molded, and further baked at a predetermined temperature. The obtained friction material can be subjected to post-processing such as polishing the surface thereof, if necessary.

In the friction material thus obtained, as shown in FIG. 1, the surface of a single heat insulating material layer 20 joined to one surface of the metal plate 14 is covered with a pad layer 18. It is a thing. Even when the heat insulating material layer 20 of the friction material is a single layer, cracks generated at the boundary surface between the two layers due to the difference in shrinkage rate between the layers (difference in linear expansion coefficient) during heat dissipation of the lining material 16. Can be prevented. Therefore, as the heat insulating material layer 20 is a single layer, the thickness of the heat insulating material layer 20 can be easily adjusted. As a result, the heat insulating performance of the heat insulating material layer 20 can be easily optimized and the friction material can be easily manufactured. Can be However, if the heat insulating material layer 20 can be formed to have a predetermined thickness even if it has multiple layers, the heat insulating material layer 20 can have multiple layers and the shrinkage rate of the heat insulating material layer 20 can be provided with an inclination. As described above, if the shrinkage rate of the heat insulating material layer 20 can be provided with an inclination, it is possible to further reduce the occurrence of cracks at the boundary surface between the pad layer 18 and the heat insulating material layer 20. Further, a layer provided with a functional layer such as the above-mentioned alarm layer on the heat insulating material layer 20 may be used as the intermediate layer. Even with such an intermediate layer, by covering the surface thereof with the pad layer 18, it is possible to prevent cracks occurring at the boundary surface between the intermediate layer and the pad layer 18.

[0012]

According to the present invention, it is possible to prevent cracks occurring at the boundary surface between the pad layer and the heat insulating material layer constituting the lining material due to the cooling of the heated lining material. You can improve the property.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view for explaining an example of a friction material according to the present invention.

FIG. 2 is a front view for giving a general description of a friction material.

FIG. 3 shows a case where the friction material shown in FIG. 2 is a conventional friction material,
It is a longitudinal cross-sectional view in the XX plane.

FIG. 4 is an enlarged partial cross-sectional view of the vertical cross-sectional view shown in FIG.

[Explanation of symbols]

 10 Friction Material 12 Bonding Hole 14 Metal Plate 16 Lining Material 18 Pad Layer 20 Thermal Insulation Material Layer

Claims (3)

[Claims] 1. A friction material in which a pad layer is bonded to one surface side of a metal plate via an intermediate layer including a heat insulating material layer, wherein the intermediate material includes a heat insulating material layer bonded to one surface side of the metal plate. A friction material, wherein the intermediate layer is covered with a pad layer so that the surface of the layer is not exposed. 2. The friction material according to claim 1, wherein the intermediate layer joined to one surface side of the metal plate is a single heat insulating material layer. 3. The friction material according to claim 1, wherein the intermediate layer bonded to one side of the metal plate is a multilayer.