Spherical Plain Bearings: Structure, Features & Applications

1. Structure of Spherical Plain Bearings

The structure of spherical plain bearings is simpler than that of rolling bearings. They mainly consist of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface.

Spherical plain bearings are generally used for low-speed oscillating motion (i.e., angular motion). Since their sliding surfaces are spherical, they can also perform tilting motion (i.e., self-aligning motion) within a certain angular range. Even when there is a large misalignment between the supporting shaft and the housing bore, the bearings can still operate normally.

2. Features of Spherical Plain Bearings

Spherical plain bearings can withstand large loads. Depending on their different types and structures, they can bear radial loads, axial loads, or combined loads where radial and axial loads exist simultaneously.

Composite materials are inlaid on the outer spherical surface of the inner ring, enabling the bearings to achieve self-lubrication during operation. They are typically used for low-speed oscillating motion and low-speed rotation, and can also perform tilting motion within a certain angular range. Even with significant misalignment between the supporting shaft and the housing bore, normal operation is maintained. Self-lubricating spherical plain bearings are applied in industries such as water conservancy and specialized machinery.

3. Applications of Spherical Plain Bearings

Spherical plain bearings are widely used in industries including engineering hydraulic cylinders, forging machines, construction machinery, automation equipment, automotive shock absorbers, and water conservancy machinery.

As spherical sliding bearings, the basic type of spherical plain bearings consists of inner and outer rings with spherical sliding contact surfaces. Based on their different structures and types, they can withstand radial loads, axial loads, or combined loads with both radial and axial actions.

Owing to their large spherical sliding contact area and wide tilt angle range, as well as the special processing techniques adopted for most spherical plain bearings (such as surface phosphating, galvanizing, chrome plating, or lining, padding, and spraying on the outer sliding surface), they possess high load capacity, impact resistance, corrosion resistance, and wear resistance. They also feature self-alignment, good lubrication, or self-lubrication without lubricant contamination—even with installation misalignment, they can operate normally. Therefore, spherical plain bearings are widely used for low-speed oscillating motion, tilting motion, and rotational motion.