Meshing theory and comprehensive analysis of offset enveloping cylindrical worm drive under point contact

In this paper, the meshing theory and parameter selection strategy of mismatched scheme for the offset enveloping cylindrical worm drive under point contact are investigated to provide the parameter basis for numerical studies on the contact characteristics. Based on the tooth surface contact conditions, the system of contact equations of the point-conjugate tooth surface couple is established and then eliminated. The calculation formulas for geometric parameters, kinematic parameters, and motion errors related to worm angle are derived. Through comprehensively analyzing the requirements of point-conjugate drive pair for mismatched schemes, the methods of grouping mismatch parameters, presetting datum point, and displacing unknowns are proposed. These methods are used to determine the datum point and the two endpoints of the contact path, allowing for the quick acquisition of a reasonable set of mismatched parameters. According to this, a numerical simulation analysis is conducted on the geometry and kinematics characteristics, and the outcomes indicate that the offset point-conjugate drive pair has strong tooth surface bearing capacity and high operational stability.