COMPUTERIZED DESIGN OF WORM GEAR DRIVES WITH IMPROVED CONDITIONS OF MESHING AND BEARING CONTACT

摘要

A new geometry of a cylindrical worm gear drive is proposed for: (ⅰ) reduction of sensitivity of the drive to errors of alignment, and (ⅱ) observation of a favorable bearing contact. The basic ideas of new geometry are as follows: (ⅰ) the worm-gear is generated by a hob that is oversized in comparison with the worm of the drive and has a parabolic profile in normal section; (ⅱ) the tooth surface of the worm of the drive is a conventional one. Due to deviation of the hob thread surface, the bearing contact of the worm and the worm-gear is localized. Reduction of sensitivity to misalignment and improved conditions of meshing are confirmed by application of TCA (Tooth Contact Analysis). Formation of bearing contact has been investigated by finite element method applied in 3D for more than one pair of contacting teeth. Developed ideas may be applied for various types of cylindrical worm gear drives.