Meshing Theory Study Of Beveloid Internal Gear Enveloping External-rotor Crown Worm Drive

Based on the planar tooth internal gear enveloping crown worm drive and steel planar worm gear enveloping hourglass worm drive,a novel driving device,named beveloid internal gear enveloping external-rotor crown worm drive is proposed in this paper.That is applied for the realization of worm drive with adjustable backlash,small volume and light weight.It’s the drive principle,meshing theory,worm geometric parameters design,meshing performance analysis and three-dimensional solid modeling and so on are studied respectively.The main contents are as follows:The composition structure and working principle of beveloid internal gear enveloping external-rotor crown worm drive are described.Based on differential geometry and space gear meshing theory,the mathematical model and meshing theory system of the beveloid internal gear enveloping external-rotor crown worm drive are established by means of the envelope method of kinematics method.The engagement function,meshing equation,the tooth surface equation and so on are deduced.The calculating formulae of contacting parameters which include induced normal curvature,lubrication angel and relatively entrainment velocity are derived.The characteristics of the worm tooth surface are analyzed by means of numerical calculation tool.The axial section profile of the worm is gained by calculation.The tooth surface structure and characteristics of the beveloid internal gear enveloping external-rotor crown worm drive are studied.The contact line and variable diameter spiral line on worm tooth surface are drawn in MATLAB software.The main geometric parameters associated with gear meshing performance are studied clearly.According to the mesh theory of the drive,based on the numerical calculation software MATLAB,the calculation program of meshing analysis is developed.The main characteristics of the drive and the key parameters on the performance of the drive are analyzed.In accordance with the transmission principle and forming principle of the beveloid internal gear enveloping external-rotor crown worm drive,the example of the beveloid internal gear enveloping external-rotor crown worm drive is designed,which’s center distance and of drive ratio are 100 mm and 60 respectively.Based on the design of non-standard,consulting the design of the planar tooth internal gear enveloping crown worm drive and steel planar worm gear enveloping hourglass worm drive,we work out the calculation formulae of geometry parameters of this new transmission.The three-dimensional solid modeling of the drive is completed by Creo software.The steps of solid modeling are described in detail.In the environment of Creo,two methods of tooth surface generation are researched.And their respective advantages and disadvantages are compared.The static assembly interference and assembly clearance check of the worm gear pair are completed in an environment of Creo/Assembly.The results we obtained demonstrate that the modeling accuracy of digital model is good and the theoretical derivation of mesh analysis is correct.The foundation for the subsequent design work of the beveloid internal gear enveloping external-rotor crown worm drive.