Meshing principle and geometry of tooth profile for offset enveloping cylindrical worm drive

Abstract

The offset cylindrical worm drive plays an important role in aviation and aerospace fields. It can reduce the vibration, noise, and overall size of the aircraft gearbox, making a significant contribution to the rapid development of this field. However, the existing types of grindable offset cylindrical worm drives are few and the basic research is not sufficient, which prevents the optimal performance of the offset cylindrical worm drives. For this reason, this paper puts forward a new type of worm drive, namely, the offset enveloping cylindrical worm drive, and develops its whole meshing theory system. Using the tooth surface equation, the analytical expression of the reference point coordinate is deduced and the geometry of the asymmetry tooth profile is analyzed detailed. Besides, the conjugate region and contact lines on the tooth surfaces are determined by solving the nonlinear equations iteratively. And the numerical results of sliding angle and induced principal curvature show that the lubrication weakness is non-existent on the tooth surface and the bearing capacity is excellent.