Modification of involute gear pair with fewer teeth based on equal bending strength

To solve the problem of the weak strength of involute gear pair with fewer teeth, research is done on the selection of its addendum modification coefficient and tangent modification coefficient, taking the planar involute gear pair with fewer teeth as the research object with the designing intention of enhancing the bending strength of pinion and obtaining the same or approximately bending strength of gear pair. By the analyzing the maximum bending stress of gear pair, it is deduced that addendum modification coefficient and tangent modification coefficient of gear pair should be related functionally. Two factors must be considered for the selection of addendum modification coefficient, i.e. undercut and no lateral clearance meshing. The addendum modification coefficient of pinion must meet the condition that undercut is avoided, and the sum of addendum modification coefficients of gear pair must be in a certain functional relation. The selection of tangent modification coefficient need to consider the mutual influence between tangent modification and meshing of gear pair and bending strength. If the tangent modification coefficient of the pinion is excessively big, the tooth thickness of gearwheel will be reduced, its bending strength be weakened, and the tooth profile and root of the pinion be interfered. According to the above conditions, for involute gear pair with fewer teeth with ascertained tooth number and modulus, the optimum modification coefficients are found based on equal bending strength through establishing the mathematical model for solving the modification coefficients. ©, Tianjin University. All right reserved.