Commonly used sliding bearing materials include bearing alloys (also called Babbitt alloys or white alloys), wear-resistant cast iron, copper-based and aluminum-based alloys, powder metallurgy materials, plastics, rubber, hardwood and carbon-graphite, polytetrafluoroethylene (special Flon, PTFE), modified polyoxymethylene (POM), etc.
The sliding bearing absorbs and transmits the force between the relative moving parts, maintaining the position and positioning accuracy of the two parts. In addition, the directional motion must be converted into rotary motion (such as a reciprocating piston engine).
Sliding friction occurs when sliding bearings are working; the magnitude of sliding friction mainly depends on the manufacturing accuracy; and the magnitude of friction of sliding bearings mainly depends on the material of the sliding surface of the bearing. Sliding bearings generally have a self-lubricating function on the working surface; sliding bearings are divided into non-metallic sliding bearings and metal sliding bearings according to their materials.
Non-metallic sliding bearings are mainly made of plastic bearings. Plastic bearings are generally made of engineering plastics with better performance; more professional manufacturers generally have engineering plastic self-lubricating modification technology, through fiber, special lubricants, glass beads And so on, self-lubricating and enhancing modification of engineering plastics to achieve certain performance, and then using modified plastics to process into self-lubricating plastic bearings through injection molding.
The most commonly used metal sliding bearing in the early 21st century is the three-layer composite bearing. This kind of bearing is generally based on carbon steel plate. A layer of spherical copper powder is sintered on the steel plate through sintering technology, and then the copper powder layer is sintered. The upper layer is sintered with a layer of PTFE lubricant of about 0.03mm; the main function of the middle layer of spherical copper powder is to enhance the bonding strength between the steel plate and PTFE, and of course it also plays a role in bearing and lubricating during work.
1) Metal materials, such as bearing alloys, bronze, aluminum-based alloys, zinc-based alloys, etc.
Bearing alloys: bearing alloys are also called white alloys, mainly alloys of tin, lead, antimony or other metals. Because of their good wear resistance, high plasticity, good running-in performance, good thermal conductivity and good resistance to glue and oil It has good adsorption, so it is suitable for heavy load and high speed. The strength of the bearing alloy is relatively small and the price is more expensive. When used, it must be cast on bronze, steel belt or cast iron bushes to form a thinner coating.
2) Porous metal materials (powder metallurgy materials)
Porous metal material: Porous metal is a kind of powder material. It has a porous structure. If it is immersed in lubricating oil, the micropores are filled with lubricating oil, and it becomes an oil-containing bearing with self-lubricating properties. Porous metal materials have low toughness and are only suitable for steady non-impact load and medium and low speed conditions.
3) Non-metallic materials
Bearing plastics: Commonly used bearing plastics include phenolic plastic, nylon, polytetrafluoroethylene, etc. Plastic bearings have greater compressive strength and wear resistance. They can be lubricated with oil and water, and they also have self-lubricating properties, but they have poor thermal conductivity.