Research On Plane Envelop Hourglass Worm's Mechanical Characteristics Basing On Finite Element Method

Planar enveloping hourglass worm gears has been widely used, and it is characterized by strong duty-bearing capacity, good wear resistance and long service life. But so far, the design method basing on strength is immature, and no design formula has been widely accepted by the academic community. This paper researches the mechanical characteristics such as load sharing among teeth and contact load distribution along contact lines. This work lays foundation for establishing the design formula of the planar envelope hourglass worm gears.In this thesis, based on the principles of gear meshing, computer aid design, gear tooth contact analysis and nonlinear finite element method analysis theory, by means of computer aid design and finite element simulation, the method of establishing precise 3D geometry model of planar envelope hourglass worm gears has been presented, and the contact mechanical characteristics have been researched deeply.The major content is as follows:①Based on the principles of gear meshing, the equations of contact lines and the work surfaces of the planar first envelope worm have been deduced, and the precise geometry model of the worm gears has been established. By the advantage that the working surface is a ruled surface, a new method has been proposed. Using UG, the precise model could be established easily.②A method of establishing the 3D geometry of planar double envelope worm gears has been proposed. Basing on the gear tooth generating principle, the virtual machining method was proposed to establish the worm gear's geometry model. Using the develop language of UG, the UG/Open GRIP, the program of creating the planar double envelope worm gear has been developed. So the geometry model of the planar double envelope worm gears could be established easily.③The mechanical characteristics of the planar first envelope worm drive have been researched by finite element method. It is found that the contact load decreases from the mesh-in tooth to mesh-out tooth. And the influence of theβon load sharing among teeth is researched. It is found that if the non-contact zone doesn't exist on the gear surface of the worm, the higher the value ofβis, the more smoothly the contact load distributes.④Using adaptive remeshing technique, the contact load distribution along the contact lines has been researched. It is found that the contact load at the ends of the contact lines is higher, and the contact load at the central part is lower and smoother.⑤Basing on the nonlinear finite element method, The mechanical characteristics of the planar double envelope worm gears have been researched. Same as the first envelope worm gears, the contact load decreases from the mesh-in tooth to mesh-out tooth. Each tooth has two contact lines, and similar as the first envelope worm gears, the contact load at the ends of the contact lines is higher, and the contact load at the central part is lower and smoother.