According to the mutual position and motion relationship between the cutter head, shaking table and the workpiece, the mathematical model of normal gear cutting is established. This chapter studies the key parameters that affect the meshing characteristics of Cycloid Bevel Gears and hypoid gears, and on the premise of ensuring that the position of the reference point and the spiral angle and pressure angle at the reference point are the theoretical design values, Two methods for controlling the meshing characteristics of tooth surfaces are proposed:
(1) Through the pre control of the long axis of the instantaneous contact ellipse at the reference point, which is one of the important evaluation indexes of the load-carrying capacity of Cycloid Bevel Gears and hypoid gears, the pre control of the load-carrying capacity is realized. In the calculation of gear cutting adjustment, the design requirements for the length coefficient of the tooth surface contact area are taken as the judgment conditions, and the cutter inclination angle is taken as the variable to accurately control the length of the instantaneous contact area, so as to realize the pre control of the bearing capacity of the gear pair.
Taking the cycloid hypoid gear pair as an example, set multiple groups of tooth surface contact area length coefficient values for gear cutting adjustment calculation and TCA analysis, and obtain the accurate inclination of large and small wheel cutters. At the same time, from the TCA results, it is obtained that with the increase of the instantaneous contact area length, the transmission error gradually decreases, and when ct=1, it is close to the line contact, The constant transmission ratio can be achieved approximately, but it is extremely sensitive to errors.
(2) By controlling the directional angle of the contact trace at the reference point of Cycloid Bevel Gear and hypoid gear, the control of the tooth surface contact trace is realized. Through analysis, it is found that changing the tool position angle affects not only the position of the contact trace, but also the angle between the contact trace and the direction of the tooth line. Therefore, in the calculation of gear cutting adjustment, the tool position angle is taken as the variable, and the directional angle of the contact trace at the reference point of the working face and non working face is taken as the judgment condition to realize the control of the contact trace. Similarly, taking the example of cycloid tooth hypoid gear as an example, set multiple groups of directional angle scale factors for the contact trace of working face and non working face, analyze the symmetry of the contact trace of working face and non working face, and carry out TCA analysis when the factor is 1, From the TCA results, the directional angle of the contact trace at the control reference point can effectively control the direction of the contact trace and change the contact quality and transmission performance of the tooth surface.
Based on the research on the pre control method of the meshing characteristics of Cycloid Bevel Gears and hypoid gears, a comprehensive spirac gear cutting adjustment calculation method with preset contact area length coefficient and contact trace directional angle is finally obtained, which eliminates the edge contact, reduces the transmission noise, and reduces the transmission ratio error, The movement stability and transmission accuracy are improved, and the forward and reverse transmission consistency of the gear pair is realized. Taking a pair of cycloid hypoid gear pairs used on the rear axle of pickup truck as an example, the tooth contact analysis results obtained by the comprehensive spirac method with preset contact area length coefficient and contact trace directional angle and the existing spirac method are compared. The results show that the comprehensive spirac method effectively controls the meshing characteristics of the tooth surface.
The research on the meshing characteristics of Cycloid Bevel Gears and hypoid gears not only further improves the existing spirac gear cutting adjustment calculation, but also lays a theoretical foundation for the subsequent research on the new semi generative machining method of Cycloid Bevel Gears and hypoid gears.