Radius of curvature analysis of oscillating follower cylindrical cam’s expansion pitch curve

Abstract

The currently used method to calculate radius of curvature of a cylindrical cam’s planar expansion pitch curve produces errors. Therefore, there is an urgent need to find an accurate method for cylindrical cam design. This research utilizes the three-dimensional expansion curve coordinates of the follower’s motion track and establishes the planar expansion pitch curve equation with the consideration of deviation angle, which can be easily used to analyze and design an oscillating follower cylindrical cam. The deduced equation of radius of curvature is based on motion law of the mechanism and prime cylinder radius of the cam. The relation curve between minimum radius of curvature and prime cylinder radius, which takes into consideration that planar expansion pitch curve varies with prime cylinder radius in the event of certain motion law, is described by MATLAB, and specific minimum radius of prime cylinder is generated for each allowable radius of curvature according to the relation curve. Thus, geometric parameters of a cylindrical cam can be designed. The feasibility of our methodology is validated with a specific example.