Effects of machine-tool parameters on geometry and contact pattern for face hobbed hypoid gears

Machine-tool parameters (MTP) were one of the most relevant factors on the design of the tooth surface topography (TST) and meshing characteristics for face hobbed hypoid gears. In this paper, the tooth surface mathematical model has been solved based on the cutting trace of the gear blank, meshing equation, kinematic association and tooth surface discretization. The influence of MTP on the TST and magnitude of deviation from midpoint has been researched by the discrete points on the tooth surface. Furthermore, a finite element model (FE model) has been developed to study, in detail, the effect of MTP deviation on the contact pattern. The results show that the diagonal, tooth direction and composite are three main forms of TST for the changing MTP. The deformation direction of radial distance and sliding base is tooth direction and that of work offset is composite. Others MTP are diagonal. Meanwhile, the movement direction of contact pattern is divided into three categories, such as diagonal, tooth profile and tooth direction. The movement direction of contact pattern is diagonal including the tile angle, work offset, machine root angle, horizontal and the radial distance. The tooth profile direction involves the swivel angle and initial cradle angle. The sliding base is in the tooth direction.