Computerized design of new type spur, helical, spiral bevel and hypoid gear drives.

摘要

Spur, helical, spiral bevel and hypoid gear drives are widely applied in gear reducers, vehicles, helicopters and other aircrafts. Gear noise and strength are the major concerns of gear industry.; This thesis covers synthesis and analysis of several types of modified gear drives proposed in the thesis: (a) spur and helical gears manufactured by shaving, (b) face-milled formate-cut spiral bevel gears, and (c) face-hobbed hypoid gears.; The goals of research are (i) reduction of vibration and noise, (ii) reduction of stresses (contact stress and bending stress), (iii) reduction of the sensitivity of gear drives to misalignments, (iv) increase of the contact ratio, and (v) avoidance of edge contact. These goals are reached by application of the developed approaches of synthesis and analysis of geometrically modified gear drives mentioned above. The approaches are as follows: (1) Localization of bearing contact by application of double crowning of tooth surfaces that provide a longitudinal path of contact. Application of parabolic generating blades is provided for the purpose of localization. (2) Predesign of function of transmission errors of a small magnitude. An iterative approach of application of modified roll to spiral bevel and hypoid gear drives is developed. (3) An integrated process of local synthesis, simulation of meshing and application of modified roll is developed and applied to face-milled spiral bevel gears. (4) Development of multi-pair-of-tooth finite element method enables to determine the loaded bearing contact and stresses (contact and bending stresses) on gear tooth surfaces. Automatic generations of FEA models are developed for face-milled spiral bevel and hypoid gear drives.; Numerical examples are provided to illustrate the developed approaches.