Model for load sharing and transmission error for helical gears with tip relief

Abstract

The start of contact, at the driven tooth tip, of each transverse section of a helical tooth occurs under different load conditions, since the length of contact varies along the meshing cycle, and therefore the meshing stiffness and the load per unit length vary accordingly. This results in a different teeth deflection, and therefore a different advance of the effective start of contact for each transverse section. This means that whatever the tip relief, it will be suitable to absorb the teeth deflection at the start of contact only for one -or a few- transverse sections, but it will be small or too large for all the rest. In this work a simple model is presented for the calculation of mesh stiffness, load distribution and teeth deflection for helical gears with tip relief, which includes the simulation of the start of contact in the transverse sections in which the relief depth does not adjust to the instantaneous load conditions.