An Experimental and Analytical Investigation of the Dynamic Response of a High-Speed Cam-Follower System. Part 2: A Combined, Lumped/Distributed Parameter Dynamic Model

Abstract

Part 2 describes the development of a dynamic model of a high-speed cam-follower system in which the return spring is modeled as a distributed-parameter element. The dynamic response requires the solution of a coupled set of differential equations, one ordinary and one partial. The dynamic model has the unique capability of faithfully reproducing the effect of the higher harmonics of the cam lift curve on system performance. The model, which has been refined and verified with the aid of the results described in Part 1, is capable of accurately predicting both normal system response as well as pathological behavior associated with the onset of toss, bounce, and spring surge. In comparison, a lumped-parameter dynamic model (differing only in the modeling of the valve spring) does not adequately predict the onset of pathological behavior.