1) Friction material is a component material that is applied to a power machine and relies on friction to perform braking and transmission functions. It mainly consists of a brake lining (brake pad) and a clutch face piece (clutch plate). Brake pads are used for braking and clutch plates are used for transmission.
Friction material is a functional accessory used in many sports machinery and equipment for transmission, braking, deceleration, steering, parking, etc. According to the function and installation parts, it is mainly divided into brake lining and clutch face piece. Friction materials are key safety parts in the automotive industry. The starting, braking and parking of automobiles are inseparable from friction materials. The quality and quality of friction materials are directly related to the safety of people's lives and property.
2) Material classification
A asbestos friction materials are divided into the following categories:
a Asbestos fiber friction material, also known as asbestos velvet friction material. Production: various brake pads, clutch plates, train synthetic brake shoes, asbestos velvet rubber belts, etc.
b Asbestos linear friction material. Production: winding clutch plates, chopped asbestos wire segment friction materials.
c Asbestos fabric friction material. Production: manufacture of brake bristles, brake belts, clutch covers, etc.
d Asbestos weave friction material. Production: Manufacture of oil immersion or resin dipped brake belts. Oil rig brakes and so on.
B Non-asbestos friction materials are divided into the following categories:
a Semi-metallic friction material for disc brake pads for passenger cars and heavy-duty vehicles. The material composition usually contains about 30% to 50% of ferrous metal materials (such as steel fiber, reduced iron powder, and foamed iron powder). Semi-metallic friction materials are therefore named.
b NAO friction material. In a broad sense, it refers to non-asbestos-non-steel fiber friction materials, but the discs also contain a small amount of steel fibers. The base material in the NAO friction material is in most cases a mixture of two or more fibers (inorganic fibers with a small amount of organic fibers).
c Powder metallurgy friction material. Also known as sintered friction material, the iron-based and copper-based powdery materials are mixed, pressed, and sintered at a high temperature. Suitable for braking and transmission conditions at higher temperatures. Such as: aircraft, trucks, brakes and transmissions of heavy construction machinery.
Advantages: long service life; disadvantages: high product price, large brake noise, heavy and brittle, and large wear and tear.
d Carbon fiber friction material.
Asbestos materials are widely used as friction brakes for automotive brake pads. Although its carrying capacity is not as good as that of powder metallurgy materials, the friction coefficient is high, and the dynamic and static friction coefficients are close, which makes the braking smooth, the noise is small, and the price is also low. Powder metallurgy friction materials are used in almost all areas except cars. It can work normally under high load and high temperature, especially for its stable friction coefficient and good wear resistance. It is used as a brake pad for aircraft landing, a large load ball screw friction plate and a motor-drive clutch plate. In transportation machinery such as automobiles, ships, trains, etc., in large and medium-sized construction machinery such as bulldozers, mine elevators, excavators and tractors, and agricultural machinery and light industrial machinery, various specifications and types of powder metallurgy friction plates and brake pads are excluded. Excellent completion of clutch and braking, but also reduce energy consumption and improve transmission accuracy. With the development of modern technology, the demand for high-performance friction materials is more urgent. The carbon-carbon composite material that appeared in the late 1970s is a promising friction material. It has stable high temperature friction performance, long life and light weight. It has been successfully used in the braking device of Concord and Boeing aircraft. It is only expensive and affects the wide range of applications. Graphite-based friction materials with good performance under moderate load, low temperature and wet friction are also promising new materials. It combines all the advantages of current asbestos and powder metallurgy materials and is inexpensive, making it an ideal friction material.