12.1 INTRODUCTION

In this chapter we submit the dynamic analysis of cam-follower systems that are inherently compliant. A measure of system compliance is the extent of the deviation between the dynamic response and the intended kinematic response, which is the vibration level. This deviation tends to increase (1) as any of the input harmonics of cam motion approaches the fundamental frequency of the mechanism and (2) with the increase of the maximum value of the cam function third-time derivative ( jerk). Also, the deleterious effects of vibration are well known. Vibration causes motion perturbations, excessive component stresses, noise, chatter, wear, and cam surface fatigue. This wear and cam surface erosion feeds back to further exacerbate the problem. For more on the subject of cam system dynamics, the reader is referred to Freudenstein (1960), Chen (1982), Erdman (1993), and Koster (1970).

In designing cam-follower systems, the compliancy of the system can be obtained by (1) the application of mathematical theoretical formulas, (2) testing prototypes, or (3) constructing detailed models. It has been found that the stiffnesses obtained by simple models is more than double the actual stiffness. The analytical inaccuracies are due to differences between assumed and actual stress distributions (largely near the applied loads) and defection modes that were ignored in the analysis.

This chapter presents the analysis of two kinds of systems: (1) high-speed systems and (2) highly compliant systems. The models are:

• models with a rigid camshaft

• models with an...