What is the "bearing cage" on deep groove ball bearings

1 Definition

Cage, also known as bearing cage, refers to a bearing component that partially wraps all or part of the rolling element and moves with it, used to isolate the rolling element. It usually guides the rolling element and keeps it inside the bearing.

2 Major role

1. Maintain an appropriate distance between rolling elements to prevent contact between them and reduce friction;

2. Make the rolling elements evenly distributed, so as to evenly distribute the load;

3. Guide the rolling element in the unloaded area to improve the rolling conditions in the bearing and prevent damaging sliding.

The retainer must withstand stress caused by friction, strain, and inertial forces, as well as chemical corrosion from lubricants, additives in lubricants, or substances produced due to their aging, organic solvents, or coolants.

Therefore, the design and materials of the cage are extremely important for its performance and the reliability of the bearings.

3 Type of cage

The bearing cage is divided into stamped cages (Figure 1)

Solid retainer (Figure 2) and pillar retainer

1.The advantages of stamping cages are light weight, large internal space, and easy entry of lubricants;

2. Solid cages usually allow for higher rotational speeds. When bearings have other forms of motion besides rotation, especially at high speeds, machined metal cages should also be used;

3. The pillar holder is connected to a perforated roller with a pin, and the two ends of the pin are fixed to the washer. This type of cage is lightweight and can accommodate more rollers, and is only used for oversized roller bearings.

4 Retainer material

The main materials for retaining frames include stamped steel, machined steel, stamped brass, machined brass, polymer materials, etc.

Stamped steel cages have high strength and can reduce friction and wear through surface treatment;

Machined steel cages are generally used for oversized bearings or situations where brass cages are not suitable;

Stamped brass cages are used for some small and medium-sized bearings;

Machined brass cages are generally not affected by the lubricant of bearings and can be cleaned with ordinary lubricants. Brass cages should not be used for working temperatures above 250 ℃;

Compared to metal cages, polymer materials (such as nylon 66 and nylon 46) have many advantages such as good toughness, resistance to friction and wear, impact resistance, acid and corrosion resistance.