Bush (mechanical)
A bush (bushing) is a simple mechanical lining or sleeve used to locate, support or reduce wear and vibration between moving parts; common in suspension, machinery, and rotating assemblies.
A bush, often called a bushing or plain bearing, is a cylindrical lining inserted into a housing to provide a wearing surface, locate a shaft, or form a strengthened mounting point between two parts. Bushes serve as a low-cost interface that guides motion, resists wear, damps vibration and transfers load. They are widely used where relative motion between components is required but a full rolling-element bearing is unnecessary or impractical.
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Types and characteristics
There are many shapes and designs of bushes. Common variants include sleeve (plain) bushes, flanged bushes for axial location, spherical bushes for small misalignment, and bonded rubber bushes that combine compliance with load transfer. Key characteristics are the bore diameter, wall thickness, length, material, and whether the bush is solid, split, or flanged.
- Plain sleeve: simple cylindrical liner for radial support.
- Flanged: includes a shoulder for axial location.
- Split or slotted: can be installed around an existing shaft.
- Elastomeric: rubber or polyurethane used where damping and flexibility are needed.
Materials and lubrication
Materials range from metals (bronze, steel, brass) to polymers (PTFE, nylon) and composite or sintered materials impregnated with lubricants. Some bushes are designed to be lubricated externally; others are self-lubricating, incorporating oil reservoirs or low-friction linings. Material choice is guided by load, speed, temperature, chemical exposure and maintenance regime.
Uses and examples
Bushes appear across many industries. In vehicles they link arms and pivot points to the chassis and reduce noise and vibration; see typical vehicle suspension applications where compliant bushes allow controlled movement. In rotating machinery, they support shafts and rotors, providing a replaceable wear surface that protects more expensive components. They are also common in hinges, presses, conveyor equipment and fixtures.
Installation, maintenance and selection
Proper installation often requires press-fitting or light interference fits to prevent movement of the outer shell. Maintenance considerations include periodic lubrication (if required), inspection for wear or cracking, and replacement when clearance or play reaches service limits. Selection factors include expected loads, shaft speed, environmental contaminants, available space and desired service life.
Distinctions and notable facts
Bushes differ from rolling-element bearings by providing sliding contact rather than rolling contact; they are generally simpler, quieter, and more tolerant of shock and misalignment but may have higher friction and wear under high-speed, high-precision conditions. In automotive applications the combination of metal sleeves and elastomeric elements is an important design choice to balance comfort, handling and durability relative to the vehicle chassis.
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AlegsaOnline.com Bush (mechanical) Leandro Alegsa
URL: https://en.alegsaonline.com/art/15587