1. Performance and materials of bearings
Since the rings and rolling elements of rolling bearings are repeatedly subjected to high contact pressure and rolling contact, and the bearing retainers are subjected to tensile or compressive forces and sliding contact, there are certain requirements for the material properties of various parts of the bearings.
The performance requirements for bearing rings and rolling elements are high rolling fatigue strength, high hardness, and good friction resistance. The bearing retainer material requires high mechanical strength and good stability. In addition, the bearing material must also have good machinability. For bearings in special environments and uses, it is also required to have good high temperature resistance, impact resistance, and corrosion resistance.
The bearing ring and rolling element materials usually use high carbon chromium bearing steel. Most bearings use SUJ2 in the JIS steel grade, and large bearings use SUJ3.
In addition to the above steel grades, high-speed steel with excellent heat resistance and stainless steel with good corrosion resistance are also used according to different uses.
The material of the bearing stamping retainer is generally low-carbon steel. Brass plates and stainless steel plates can also be used according to different uses. The materials used to cut the cage are high-strength brass, carbon steel, and synthetic resin.
2. Bearing lubrication
The bearing lubrication methods are divided into grease lubrication and oil lubrication. In order to make the bearing function well, it is necessary to select a lubrication method that is suitable for the use conditions and purpose. From the perspective of lubrication performance, lubricating oil is more advantageous than grease. Grease can relatively simplify the structure around the bearing. Lubricating oil or grease should be selected according to the actual situation.
(1) Reduce friction and wear. Prevent metal contact in the contact parts of the rings, rolling elements and retainers that constitute the bearing, reduce friction and wear.
(2) Extend fatigue life. The rolling fatigue life of the bearing is extended if the rolling contact surface is well lubricated during rotation. On the contrary, if the oil viscosity is low and the lubricating oil film thickness is not good, it will be shortened.
(3) Discharge friction heat and cool. The circulating oiling method can use oil to discharge the heat generated by friction or the heat transmitted from the outside, and cool it. Prevent the bearing from overheating and prevent the lubricating oil from aging.
(4) Prevent foreign matter from entering the bearing, or prevent rust and corrosion.
