Study on Residual Vibration of Indexing Cam Mechanism : 1st Report, Evaluation of Cam Curve

Abstract

This paper deals with a method that evaluates the dynamics on the indexing cam mechanism, given a natural frequency of the output members and a rise time. The amplitude ratio of the residual vibration, as one of the dynamic characteristics and a factor of positioning accuracy is used as a criterion for this evaluation. As most of the items in the specifications such as mass, stroke, timing etc of the cam mechanism operated at high-speed are pre-fixed, a designer wants to select the best motion curve among the several ready-made curves. However, doing to evaluate a motion curve through the experiment, it is more difficult to rightly select the best motion curve due to many factors which are difficult to anticipate. For those reason, a numerical simulation and a quantitative criterion corresponding to the actual vibration without the experiment are perfered. Regarding a cam mechanism as the single degree-of-freedom model, calculating the amplitude ratio of the residual vibration from the equation of motion, this ratio is adopted as the quantitative criterion in this proposed method. Consequently, using the criterion, the positioning error which is affected by the residual vibration for the several motion curve are evaluated. Moreover, the experimental results to verify this method and above simulated results are shown.