Dimensional Synthesis Of A Coaxial Cam-linkage Indexing Mechanism

A novel coaxial cam-linkage indexing cam mechanism has been studied on the demand of higher-speed and higher-precision in automatic machinery. On the basis of detailed description of the structure and transmission principle, the parameterized kinematics model and equivalent mechanical model of the indexing mechanism have been established to analyze the kinematics, dynamic characteristics and static force. By comprehensive consideration of the motion and force transmissibility and the contact stress, set of homogeneous dimensionless parameters can be achieved, with the multi-objective constrained optimization algorithm. The main research content as follows:Firstly, the structure and the transmission principle have been systematically analyzed. On this basis, the working and structure parameters have been defined. According to the transmissibility of the indexing mechanism the structure parameters have been simplified. The profile equations of the conjugate cams and its curvature radius can be derived to analyze the influences of structure parameters on the contour of geometric features.Secondly, the kinematics model and equivalent mechanical model have been established to analyze the kinematics, dynamic characteristics of the indexing mechanism, in order to reveal the influences of structure parameters on the dimensionless motion, inertia moment, equivalent moment of inertia and equivalent moment. Then equations of kinematics constraint can be obtained to serve for the dimensional synthesis of the indexing mechanism.Then, the mechanical model with inertia force has been established to study the variation of constrained forces during a whole period. And the contact stress of the cam has been calculated which was chosen as the statics evaluation index to lay the foundation for the dimensional synthesis, structure design, strength analysis, etc.Finally, according the structural constraint and curvature radius constraint, the optimization design model of the indexing mechanism was established, with the aim to improve the motion and force transmissibility and reduce the contact stress of the cam. Then with the multi-objective constrained optimization algorithm, set of homogeneous dimensionless parameters which can make the indexing mechanism with better motion and force transmissibility and longer service life can be achieved.