JPH1017854A - Frictional member for brake and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frictional member for brakes which can be produced in a simplified manner by dispensing with a back plate. SOLUTION: This member has the first layer 12 formed by dispersing mainly a powdery material excellent in frictional characteristics on the sliding side facing a disk 20 and the second layer 14 formed by dispersing mainly a powdery material excellent in strength characteristics on the side other than the sliding side. The first layer 12 is brought into sliding contact with the disk 20 by directly pressing the second layer 14 against the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction member for a brake and a method of manufacturing the same, and more particularly to an improvement of a brake pad made of a copper-based friction material.

[0002]

2. Description of the Related Art Generally, an organic material is mainly used as a friction material for a brake, but a copper friction material is used as a friction material for a brake having a large braking load such as a bullet train. The use of copper-based friction materials is expected to increase further in the future as automobiles, railway vehicles and the like operate at higher speeds. By the way, among the friction materials for brakes, the production process will be described by taking a disk brake pad as an example. As shown in FIG. 3, the production of the pad is mainly made of copper powder, and various kinds of metal and nonmetal are added thereto. After the powder is added and uniformly mixed with a stirrer, the obtained powdery and frictional material base material is put into a preforming mold, and preforming is performed by compression molding at room temperature to approximate a predetermined size and shape. Next, a back metal is applied to the preformed product obtained by this preforming step.
In other words, the friction material naturally has a composition that emphasizes the friction characteristics. However, since the mechanical strength is generally low, a back metal (pressure plate) made of an iron-based material is used for reinforcing the strength of the copper-based friction material. Joined. For this reason, the back metal manufactured in a process different from the friction material is manufactured by, for example, punching a steel plate into a predetermined shape, removing oil lipids from the metal surface of the obtained processed product, degreased, and then performing a plating process. Is done. On the other hand, the preform is assembled after adding the back metal manufactured as described above, and then performing sintering,
In order to integrate the back metal into a final molded product, a sintering step of performing thermoforming treatment at a predetermined pressure and temperature is performed. After that, a finishing process such as a surface polishing process or a coating process is performed to manufacture a pad.

FIG. 4 shows an example of a brake disk pad obtained by the above-described manufacturing method. The pad 1 has a structure in which a back metal 5 is integrated with the friction material main body 3 on the side opposite to the sliding surface. . Such a pad was improved in strength and could be manufactured compactly.

[0004]

However, in such a disk pad, as described above, the back metal must be manufactured separately from the molding of the friction material, and in addition, the back metal is not subjected to, for example, copper plating. That sufficient joining strength between the friction material and the friction material cannot be secured, and that steps such as positioning of the friction material and the backing metal are required prior to the sintering and joining steps,
For this reason, there were many manufacturing processes, and there was a problem in productivity. or,
Even if it is manufactured by the above process, there is a possibility that the friction material and the back metal may have poor bonding, and there is a difference in thermal expansion between the copper material friction material and the iron material back metal. There was a concern that thermal deformation and thermal cracks would occur due to this. Furthermore, since the friction material of the copper-based material has good heat conduction, the friction heat is easily transmitted to the caliper side through the backing metal, and the temperature of the brake fluid and rubber parts rises to cause heat damage.
It was accompanied by such inconveniences. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a friction member for a brake and a method for manufacturing the same, which secure mechanical strength and simplify the manufacturing process thereof, and have an object to improve productivity. I do.

[0005]

According to the present invention, there is provided a brake friction member comprising a copper powder as a main component, which is formed by sintering and has excellent friction characteristics. A first layer formed by weight-dispersed blending of the material powder, and a second layer formed by weight-dispersed blending of material powder having excellent strength characteristics laminated on the first layer. Disposing the first layer on the side of the rotating body facing the rotating body, and arranging the second layer on the side opposite to the sliding part and directly pressing the first layer to make sliding contact with the surface of the rotating body; It is characterized by the following. Alternatively, it may be characterized in that a third layer having low thermal conductivity and having a hard material powder as a main component is formed on a surface layer of the second layer.

In order to achieve the above object, a method of manufacturing a brake friction member according to the present invention is directed to a method of manufacturing a brake friction member formed of copper powder as a main component and formed by sintering. The raw material obtained by mixing and stirring the material powder with excellent frictional properties into the powder, and the copper powder as the main material are mixed and stirred with the material powder that promotes sintering and contributes to the improvement in strength after sintering. The raw material obtained, and the raw material of a material powder having low thermal conductivity and having hard properties are sequentially charged into a single preforming mold, and after pressing, the preformed product is sintered and a predetermined shape is formed. It is characterized by obtaining a copper-based friction member.

In the friction member for a brake according to the present invention, a material layer having excellent structural material characteristics (mainly mechanical strength) is arranged on the side opposite to the sliding body with respect to the rotating body, so that the back metal of the conventional product is omitted. However, sufficient strength can be obtained, and the manufacturing process can be simplified. In addition, the omission of the back metal also avoids various problems. Further, if the third layer having low thermal conductivity is formed on the side opposite to the sliding portion of the friction member, heat damage due to frictional heat can be eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a friction member for a brake according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a friction member for a brake according to the present invention. In this embodiment, a case in which the friction member for brake is applied to a pad will be described. The brake friction member 10 includes a first layer 12 formed by mainly dispersing and blending a material powder having excellent friction characteristics, and a first layer 12 laminated on the first layer 12 to obtain structural material characteristics (mainly mechanical strength). The second layer 14 is formed by mainly dispersing and blending the material powder having excellent heat resistance, and the surface layer of the second layer 14 is formed mainly of a hard material powder having low thermal conductivity and low thermal conductivity. And a third layer 16 to be formed.

The brake friction member 10 is incorporated in a caliper (not shown), and a first layer 12 is arranged to face a surface of a disk 20 as a rotating body to form a sliding surface, and a second layer 14 is formed. And the third layer 16 is arranged on the side opposite to the sliding surface, and the second layer 14 is directly pressed by the caliper piston via the third layer 16 so that the first layer 12 is Is to be brought into sliding contact.

Next, a method for manufacturing a friction member for a brake according to the present invention will be described based on the manufacturing steps shown in FIG.
First, in the stirring step, a material powder necessary for frictional characteristics such as graphite, ceramics, mica, etc. is mixed and stirred in advance with the copper powder of the main material, and the material to be the first layer 12 and the copper powder of the main material are mixed. Mixing and stirring phosphor copper powder, which promotes sintering as a post-process and contributes to improvement in strength after sintering, between the material to be the second layer 14 and the zirconia powder as the main material, and between the zirconia particles. By mixing and stirring phosphor copper powder acting as a binder in the sintering step, materials for the third layer 16 are separately obtained. Next, in a pre-forming mold having a desired outer shape of the friction material, the above-mentioned materials weighed in an appropriate amount are weighed from the sliding portion side, that is, from the first layer 12 in the order of the first layer 12 and the second layer 12.
After the layers 14 and the third layer 16 are successively charged.
Press molding at room temperature to obtain a preformed product. Thereafter, the preformed product is heated and sintered in a sintering furnace in a reducing atmosphere under a predetermined pressure, temperature and time to obtain a sintered body of a friction material. Finally, the sintered body is subjected to a finishing step such as a surface polishing treatment or a coating treatment in the same manner as in the conventional process to obtain a friction member for a brake, which is a final product. That is, the friction member 10 for a brake according to the present invention does not include the back metal of the conventional product. Therefore, in order to secure mechanical strength in place of the back metal, a layer having excellent structural material characteristics is formed on the side opposite to the sliding portion corresponding to the disk.

As described above, the friction member for a brake according to the present invention does not require the back metal of the conventional structure.
The manufacturing process can be greatly simplified. Further, omitting the back metal does not cause a problem such as a crack caused by a difference in thermal expansion in the conventional structure and a problem such as a poor bonding between the pad and the back metal. Further, by omitting the back metal, the weight of the friction member can be reduced. Further, the friction member for a brake according to the present invention can have a structure in which the friction characteristics do not differ at all by forming the same sliding material side as that of the conventional product on the sliding portion facing the disk. On the other hand, by using a material composition that emphasizes strength on the side opposite to the sliding portion, desired structural material characteristics can be obtained, and there is no problem in strength due to the omission of the back metal. Furthermore, if the surface layer on the side opposite to the sliding portion has a low thermal conductivity, and a layer of hard zirconia powder is provided,
Not only did heat damage due to frictional heat during braking not occur on the brake fluid and rubber parts through the caliper, but also good results were obtained with respect to wear resistance. In the above embodiment, the case where the friction member for a brake of the present invention is applied to a pad has been described. However, it is preferable that the friction member is applied to a brake lining.

[0012]

According to the brake friction member of the present invention,
A series of back metal manufacturing processes such as punching of back metal, rust prevention / plating, positioning with friction material in the sintering / joining process, etc. can be eliminated due to omission of the back metal, and the friction material manufacturing process can be simplified. . In addition, the omission of the back metal eliminates poor bonding between the friction material and the back metal, and can further prevent the occurrence of thermal deformation and thermal cracks due to a difference in thermal expansion. Also, by forming a layer mixed with a hard powder material having low thermal conductivity on the surface layer on the side opposite to the sliding part, functions such as reduction of heat damage due to frictional heat and improvement of wear resistance are added. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a friction member for a brake according to the present invention.

FIG. 2 is a process chart illustrating a method for manufacturing the friction member for a brake of FIG. 1;

FIG. 3 is a process diagram illustrating a conventional method for manufacturing a friction member for a brake.

FIG. 4 is an external perspective view illustrating a conventional pad.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Brake friction member 12 1st layer 14 2nd layer 16 3rd layer 20 Disc

Claims (3)

[Claims] 1. A brake friction member formed mainly of copper powder and formed by sintering, wherein a first layer formed by weight-dispersing and blending a material powder having excellent friction characteristics; A second layer formed by laminating and mixing material powders having excellent strength characteristics in a weight-dispersed manner, wherein the first layer is disposed on the sliding portion side facing the rotating body,
A friction member for a brake, wherein the second layer is arranged on the side opposite to the sliding portion and is pressed directly to bring the first layer into sliding contact with the surface of the rotating body. 2. The friction for a brake according to claim 1, wherein a third layer having a low thermal conductivity and comprising a hard material powder as a main component is formed on a surface layer of said second layer. Element. 3. A method of manufacturing a friction member for a brake, comprising copper powder as a main component and formed by sintering, wherein a raw material obtained by mixing and stirring a material powder having excellent friction characteristics with a copper powder as a main material. A material powder that promotes sintering and contributes to improvement in strength after sintering is mixed with the copper powder of the material.
The raw materials obtained by stirring, and the raw materials of the material powder having low thermal conductivity and having hard properties are sequentially put into a single preforming mold, and after pressing, the preformed product is sintered. A method for producing a friction member for a brake, wherein a predetermined copper-based friction member is obtained.