Effects of balancing and link flexibility on dynamics of a planar mechanism having joint clearance

An experimental study is proposed to investigate the effects of balancing and link flexibility on the dynamics of a mechanism with imperfect revolute joints, that is, joints having radial clearance. A planar slider-crank mechanism, widely used in vehicle engines, is used in the experimental investigation. Bearing vibrations are considered to evaluate the reflection of balancing and link flexibility effects on a mechanism having two revolute joints with clearance. On the other hand, these vibrations are measured to clarify how the balancing and link flexibility feature can decrease the undesired effects of joint clearances. For this purpose, three accelerometers, an analyzer and a PC are used for measuring the related vibrations on the main frame. The experimental results show that joint clearance leads to sudden changes in motion characteristics of the mechanism. During small time intervals, these sudden changes cause forces to impact in the joints of the mechanism with clearance. This also leads to some vibration peaks, and increases the vibration amplitudes. Furthermore, the flexibility feature of the mechanism link has a crucial role in decreasing additional vibration arising from joint clearance. Also, the undesired effects of clearance are reduced to some degree by using the balancing.