Plain bearings and general manufacturing materials

A bearing that uses the sliding motion of the shaft and the bearing to bear the load is called a sliding bearing. According to the difference in the formation principle of the oil film on the two relative moving surfaces of the sliding bearing. It can be divided into hydrodynamic lubricating bearings (also known as dynamic bearings) and hydrostatic bearings (also known as hydrostatic bearings). Generally discussed is the hydrodynamic lubricated bearing, which brings oil between the two surfaces through the relative motion of the shaft and the bearing, forming a sufficient pressure film to separate the two surfaces to bear the load.

The commonly used bearing materials are divided into two categories: metallic materials and non-metallic materials.

(1) Cast iron. Ordinary gray cast iron or wear-resistant gray cast iron with alloys of nickel, chromium, and titanium, or ductile iron, can be used as materials for light-load low-speed bearing bushes. In these materials, the flake or spherical graphite component can form a layer of graphite with lubricating effect after covering the surface of the material. After the surface of wear-resistant cast iron is treated with phosphating, a porous thin layer can be formed, which helps to improve its wear resistance.

(2) Bearing alloy. (usually babbitt or white alloy) bearing alloys are divided into two categories: one is made of tin as the basic component, with an appropriate amount of antimony and copper added, called tin-based bearing alloys, such as ZChSnSb11-6; the other is based on tin-based bearing alloys. Lead is the basic component, and an appropriate amount of tin and antimony is added, which is called lead-based bearing alloy, such as ZCnPbSn16-16.

(3) Copper alloy. Copper alloys can be divided into: cast lead bronze; cast tin zinc lead bronze; cast tin phosphor bronze; cast aluminum bronze; cast brass.

(4) Aluminum alloy. It is divided into two categories: low-tin aluminum alloys, containing about 6.5% tin; high-tin aluminum alloys, containing up to 20% tin.

(5) Ceramic metal. This is a bearing material made of different metal powders by pressing and sintering. This material has a porous structure, and the pores account for about 10% to 35% of the volume. It is soaked in hot oil before use to fill the pores with lubricating oil. It has self-lubricating properties, also known as oil-bearing bearings.

(6) Graphite. Graphite bearing bushes can be pure graphite, which has low strength; plastics, resins, silver, copper or babbitt alloys can also be added to increase strength and improve adaptability.

(7) Other non-metallic materials.

1) Rubber. Mainly used in places where water is used as a lubricant and is relatively dirty.

2) Phenolic tape. It is a layered material of cotton cloth, asbestos cloth or other man-made fiber cloth bonded with phenolic resin.

3) Nylon. For low load bearings.