Transient rolling behaviour of a slider supported by two rollers

A rolling element has a spring characteristic in the transient displacement region from the stationary state to a continuous rolling motion. For this reason, a bearing having a rolling element is useful for constructing an ultra-precision positioning device. In this paper, a mechanism for the damping capacity generation of a rolling element is investigated, to improve the dynamic characteristic of this positioning device. A stage supported by two rollers is constructed, and its tangential displacement is measured accurately when the driving force is acting. As a result, it is confirmed that the rolling element has a nonlinear spring characteristic. Energy loss is generated by the reciprocating motion of the stage in the transient displacement region. This is the main cause of the damping capacity. Furthermore, this energy loss or damping capacity of the stage can be improved by using two rollers with different diameters.