Bushing

A bushing is a cylindrical lining or insert that reduces friction, wear, or vibration between moving parts. It is the simplest form of bearing — a sleeve that surrounds a shaft or fits inside a hole, providing a sacrificial surface that can be swapped out when worn.

How it works

A bushing is pressed or inserted into a housing (the outer part), and a shaft rotates or slides inside it. The bushing material is softer than the shaft, so it wears instead of the more expensive component. When the bushing wears out, it can be swapped out cheaply — much cheaper than changing out the shaft or housing.

Common types

• Plain bushing (sleeve bearing): A simple cylindrical sleeve, often made from bronze, brass, nylon, or PTFE (Teflon). Used in motors, pumps, and general machinery.
• Oil-impregnated bushing: A porous bronze bushing soaked in oil. As the shaft rotates, heat draws oil to the surface, providing self-lubrication. Common in small motors and appliances.
• Flanged bushing: Has a flange on one end that locates the bushing in the housing and handles axial loads.
• Spherical bushing (rod end): Has a spherical inner surface that accommodates misalignment — used in automotive suspension linkages and control arms.
• Rubber bushing: A rubber sleeve used in automotive suspension to absorb vibration and allow slight movement between metal components.

Bushing vs. bearing vs. grommet

• A bushing is a plain bearing — a sleeve for a shaft.
• A bearing is a broader term that includes bushings, ball bearings, roller bearings, and other devices.
• A grommet lines a hole to protect wires or fabric — it does not support a moving shaft.