The function of the cage is to evenly distribute the rolling elements inside the bearing to prevent the rolling elements from colliding with each other and the friction between the rolling elements and the rolling elements.

If there is no cage, the rolling elements will not be evenly distributed inside the bearing, and the bearing cannot operate normally.

Individual types of bearings can be free of cages, but the rolling elements must be filled with the inside of the bearing. This can improve the bearing capacity, but will greatly reduce the bearing speed.

The types of cage materials are: mild steel/stainless steel cage, bakelite/plastic (nylon) cage, brass/bronze/aluminum alloy cage, etc.

When the rolling bearing is working, the bearing heats and wears due to sliding friction. Especially under high temperature operation conditions, the action of inertial centrifugal force aggravates the friction, wear and heat. Therefore, in addition to a certain strength, the material of the cage is required to have good thermal conductivity, small friction factor, good wear resistance, strong impact toughness, low density and linear expansion coefficient close to the rolling body. In addition, the stamping cage needs to withstand more complex stamping deformation, and also requires the material to have good processing properties. Some of the cages with extremely high requirements will also have a layer of silver.