Whirl suppression in hand-held power tool rotors using guided rolling balancers

Residual unbalance in hand-held power tool rotors transmits undesirable vibrations to the hand of its operator. These vibrations can be effectively suppressed using an automatic balancing element constrained to move in a circular path. In an earlier analysis, the effectiveness of the balancing element on the unbalance rotor vibration suppression was investigated by assuming smooth contact between the balancing element and its guide. The influence of the rolling motion of the balancing element due to friction at the contact is examined in the present study using a three-degree-of-freedom system model in a rotating reference frame. Investigation shows that the rolling motion in a carefully designed balancer improves its stability and its effectiveness in vibration reduction. (C) 1998 Academic Press.