| Space beveloid gear pairs are the gear mechanism for space transmission.Theirs tooth backlash can be adjusted to reduce the retrace tolerance and improvethe transmission accuracy. Moreover, these gear pairs can achieve small axis angletransmission. The contact form of beveloid gears can be made into the line contactafter profile modification, which can improve the loading capacity of gear pairs,effectively reduce the vibration and noise, and enhance the stability in driving. Atpresent, the batch processing method of space beveloid gear is rarely reported. Aswell as, the non-involute beveloid gear can not be directly machined by traditionalgear cutting machines. Therefore, it is necessary to find a practical and low-costway to machine non-involute beveloid gears.Based on the meshing features of space beveloid gear pairs, the tooth profileequations of involute beveloid gears and non-involute beveloid gears are derived bymeans of space meshing theory and differential geometry. Then, thethree-dimensional models of space beveloid gear pairs are presented by simulatingthe enveloping movements of gear pairs, which lays the foundation for studying theprocessing technology of space beveloid gears.According to the geometric characteristics of beveloid gears, the relationshipsbetween hob and gear in the process of machining are built, and the tooth surfaceequations are derived by analyzing the equation of hob helicoid. Then, through theanalyses of the relative motions between the bevoloid gear, public rack and the hob,the formulas calculating the processing parameters are derived. By using therelationships between the gear parameters and machine tool parameters, thebeveloid gears people need can be calculated and processed quickly. In order toobtain a pair of non-involute beveloid gears, comparative analyses of two kinds oftooth surfaces, namely the tooth surface of involute beveloid gear and the toothsurface of non-involute beveloid gear, are made in this thesis. Then, a method ofusing common gear grinding machines to process non-involute beveloid gear isstudied. By means of the analyses of the relative motions between the grindingwheel, imaginary rack and gear, the tooth modification surface equations generatedby grinding wheel are deduced. Through analyzing the influence of grindingparameters on the modified tooth surfaces, the shape parameters and the feed ofgrinding wheel are optimized to get the ideal profiles. The results reflect thefeasibility of this method, and provide a new way to machine the non-involutebeveloid gears. |
