What is a cage?

Cage refers to a bearing part that partially wraps all or part of the rolling element and moves with it. It is used to isolate the rolling element and usually guide the rolling element and keep it in the bearing.

What is the role of the cage?

1. Maintain an appropriate distance between the rolling elements to prevent the rolling elements from contacting each other to reduce friction；

2. Make the rolling elements evenly distributed, so that the load is evenly distributed；

3. Guide the rolling elements in the no-load zone to improve the rolling conditions in the bearing and prevent destructive sliding.

The cage must withstand the stress caused by friction, strain and inertial forces, as well as the chemical corrosion effects of lubricants, additives in lubricants or substances produced by their aging, organic solvents or coolants.

Therefore, the design and material of the cage are extremely important for its performance and bearing reliability.

What are the types of cages?

Bearing cages are divided into stamping cages, solid cages and pillar cages.

1. The advantage of the stamping cage is that it is light in weight and has a large space inside, which can be easily accessed by lubricants.；

2. Solid cages usually allow higher speeds. When the bearing has other forms of movement other than rotation at the same time, especially at high speeds, machined metal cages should also be used.；

3. The pillar cage uses pins to penetrate the perforated roller, and the two ends of the pins are fixed to the washer.This cage is lighter in weight and can accommodate more rollers. It is only used for extra-large roller bearings.

What are the materials of the cage?

The cage materials are mainly stamped steel, machined steel, stamped brass, machined brass, polymeric materials, etc.

The stamped steel cage has high strength and can reduce friction and wear through surface treatment；

Machined steel cages are generally used for extra-large bearings or are not suitable for brass cages；

Stamped brass cage is used for some small and medium-sized bearings；

Machined brass cages are generally not affected by bearing lubricants and can be cleaned with ordinary lubricants. Brass cages should not be used at operating temperatures above 250℃.；

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