Performance Evaluation of SCORF Systems Using Lubrication and Undercutting Indices

The objective of this study is to present the theory and asystematic performance evaluation procedure for the Spherical Cam-Oscillating Roller-Follower (SCORF) systems by introducing two new indices, namely, the lubrication and the undercutting indices. The dynamic characteristics of the SCORF systems are of great importance in association with the performance of system operations, and thus directly affecting the overal efficiency of the production machine in operation. By taking advantage of a spatial coordinate transformation and the theory of surface meshing contact, the kinematic motion in terms of meshing requirements are derived in vectorial form. The meshing characteristics of the system including the pattern of linear line contact, curvature interference avoidance, the relative sliding behavior between the cam and the roller, and the conditions for a dynamic oil film formation, are carefully examined. Two evaluation criteria, namely, the lubrication angle and the undercutting interference avoidance checking indices, are developed and used to validate the proposed approach. The performance of the SCORF mechanism and the associate design evaluation criteria developed in this paper is shown to be useful, practical and can be extended for the design and analysis of other spatial cam systems.