Dynamical behavior of noncontact driving cam mechanism using permanent magnets

In general cam mechanisms, mechanical contact between a cam driver and a cam follower causes problems such as frictional wear, needs for lubrication and noise. Accordingly, we proposed a new cam mechanism whose contact parts are replaced by permanent magnets exerting repulsive force on each other. The purpose of this study is to investigate the efficacy of the mechanism which can drive without mechanical contact. To evaluate the effectiveness of the mechanism, we constructed an analytical model, derived an equation of motion of the cam follower and conducted numerical calculation of it. Furthermore, we conducted experiments corresponding to the model. As a result, occurrence of superharmonic resonance and collision of the driver and the follower in the neighborhood of the primary resonance point were observed. However, except in occurrence region of them, the rotating motion of the driver was favorably converted into reciprocating motion of the follower without contact. Thus we concluded that a magnetic cam is useful at appropriate rotational speed of the driver.