chapter  12
16 Pages

Balancing and vibrations

ByAllan Bonnick

Many vehicle systems can be adversely affected by vibrations that arise from rotation and reciprocation of moving parts. Two prominent examples are wheels and tyres and the moving parts of engines. A road wheel and tyre assembly may be out of balance owing to slight imperfections in the tyre or wheel. Any imbalance in the wheel and tyre assembly will give rise to disturbing forces as the wheel rotates. In the vertical plane an out-of-balance force will attempt to move the wheel up and down and the effect may be to cause vibrations in the suspension system. To achieve engine balance the following two types of balancing have to be considered: reciprocating parts, mainly pistons and part of the connecting rods; and rotating parts, mainly flywheels, crankshafts and part of the connecting rods, and other components such as camshafts.