Bushings

 Description

Bushings are used to reduce friction and wear inside a hole or to constrict and restrain motion of mechanical parts. They are also termed as plain bearings and are either sleeve-shaped linings or a long thin cylinder. They help to spread the friction from one particular spot to cover its surface; thus, friction is minimized. Bushing mechanism consists of a rotating shaft in a hole, which is lined with mechanical bushing. The shaft rotates inside the bushing with the bushing relieving its friction. Bushings fit into bore to provide wear resistance, strength, lubrication, and shape for the components, which are assembled by bolts or pins. Bushings are manufactured from Babbitt metal (white metal) as they effectively reduce friction and are also light weight. Other materials used are aluminum, plastic, rubber, bronze and carbon.

Types

The different types of bushings are:

• Lubricated mechanical bushings
• Non lubricated mechanical bushings
• Alloy bushings
• Carbon bushings
• Metric bushings
• Pipe bushings
• Plastic bushings
• Steel bushings
• Threaded bushings
• Clutch pedal shaft bushings
• Linear bushings
• Rotary bushings
• Aircraft bushings

Advantages

The basic advantages of bushings are:    

• Bushings can be replaced easily than other mechanical parts such as slides or frames
• Are less expensive than bearings
• Rubber bushings are less noisy since vibrations are transmitted through the rubber; they also do not need lubrication

Applications

Bushings are used to transfer loads from a fastening to a much larger surface in the underlying structure to reduce strain on individual fibers. Rubber bushings are made use of in a vehicle’s suspension for connecting various moving arms as well as pivot points to the vehicle’s chassis and other suspension parts. Plastic bushings are used with wheel assemblies for low speed vehicles like hand trucks and wheel barrows; they are also used in food processing machinery, packaging equipment, automotive equipment, pumps, and motors.