There are three kinds of materials commonly used in journal bearings: metallic materials, porous metal materials and non-metallic materials. Different materials vary greatly in performance, application scenarios and cost. The specific analysis is as follows:
1. Metal materials
Bearing alloy (Babbit Alloys)
Ingredients: Based on tin (Sn) or lead (Pb), add hard particles such as antimony (Sb) and copper (Cu).
Performance: Soft substrate has excellent abrasion, compliance and embedding properties, while hard grains enhance abrasion resistance. It has excellent thermal conductivity and oil adsorption performance, but the mechanical strength is relatively low, expensive.
Uses: Used in high speed and heavy load situations (such as spindle of steam turbines and generator), need to be cast on steel or cast iron bearing shells to form bearing linings. Tin bearing alloys, for example, have a low thermal expansion coefficient and are suitable for precision machinery.
Copper alloy
Type: tin bronze (medium, medium or heavy load), lead bronze (high speed and heavy load), aluminum bronze (low speed and heavy load).
Performance: High strength, good abrasion resistance, but poor abrasion performance. Tin bronze and lead bronze have excellent abrasion resistance, while aluminium bronze has weak anti-gluing ability but high hardness.
Uses: Widely used in general machinery (such as gearbox, machine tool spindle, etc.), accounting for more than 50% of the sliding bearing market.
Cast iron
Type: gray cast iron, wearable cast iron.
Performance: Poor plasticity, low abrasion performance, but low cost.
Uses: Suitable for low speed, light load or unimportant situations (e.g. manual mechanism, construction machinery hinge point).
2 Porous Metallic Materials
Oil-soaked bearings
Ingredients: Made from pressed and sintered metal powders (e.g. iron and copper), a porosity 10% to 35%.
Performance: Self-lubricating. During operation, the lubricant enters the friction surface due to the suction effect the rotating shaft neck. When the machine stops, it is sucked back by capillaries. It has low toughness and is only suitable for smooth operation without impact loads and low to mediumspeed.
Usage: It is commonly used in household appliances (such as fan motors), office equipment (such as printer), etc.
3. Non-metallic materials
Plastics
Type: nylon, polyteflon, polycarbonate, etc.
Performance: Low friction coefficient, wear resistance, corrosion resistance, self-lubrication, but low bearing capacity, large thermal deformation.
Uses: Suitable for low load, low speed, low working temperature (such as food machinery, toys, etc.).
Graphite
Performance: Good self-lubrication, low friction coefficient, good abrasion resistance, low thermal expansion coefficient, good chemical stability.
Uses: Used in turbine flowmeters and other instruments that need direct contact with media.
Jewels
Type: Natural agate, corundum or artificial ruby.
Performance: Low friction coefficient, high hardness, corrosion resistance, low thermal expansion coefficient, high compressive strength.
Uses: Mainly used for precision, small instrument (such as gyroscope, Angle sensor, etc.).