The Geometric Characteristics And Research Of Non-backlash Double Roller Enveloping Hourglass Worm Gearing

Non-backlash double roller enveloping hourglass worm gearing consists of two pieces of worm wheel and hindley worm, worm gear for each piece of roller can rotate around its own axis, the enveloping worm is enveloped by using worm tooth surface as primary surface, through the automatic backlash adjusting mechanism of half pieces worm wheel body dislocation angle, the double-row roller are respectively connected with the worm tooth surface is always kept in contact with, so as to the backlash of the gear pair transmission can be reconciled and the abrasion value of tooth surface can be compensated, it has the advantages of high transmission efficieny, meshed teeth, strong bearing capacity and so on. In this paper, according to the characreristic of geometry are systematically studied non-backlash double roller enveloping hourglass worm gearing, the mesh geometry, three-demensional accurate model, tooth profile, tooth shape and other geometric properties are systematically analyzed, we optimized the parameters of transmission for the purpose of the longest length of contactline. The main contents of this paper are as follows:According to the theories of differential geometry and gear meshing, combined with the method of moving frames, mesh geometry of non-backlash double roller enveloping hourglass worm gearing is established. We deduced the meshing function of this drive. The contact line equation of worm wheel and hindley worm,worm tooth surface equation and meshing surface equation have been established.Based on the mesh geometry of non-backlash double roller enveloping hourglass worm gearing, we systematically analysed annular helix of the enveloping worm tooth surface, conversion of tooth surface and tooth thickness control principle, established the three-dimensional entity model of worm drive and hindley worm, assembled the transmission. Static global interference inspection and clearance inspection are done by the model analysis function of Pro/E.Based on the gear geometry and3D entity accurate modeling of non-backlash double roller enveloping hourglass worm gearing, enveloping worm tooth surface root tangent, tooth shape, tooth thickness and geometric characteristic of the tooth surface are analysed.Through the analysis of influence factors of no-collateral strength gap of double roller enveloping hourglass worm and service life, we established the optimization design model of transmission for the purpose of the longest length of contactline, The principle of genetic algorithm and the gatool kit in Matlab are used to optimize main geometric parameters of the transmission pair, including roller radius, worm throat diameter para coefficient, roller offset and so on.