EFFECT OF TOOTH DEFLECTION AND CORNER CONTACT ON BACKSIDE SEPARATION (BACKLASH) OF GEAR PAIRS

Because plastic materials have moduli that are much lower than those of metals, the deflections of loaded plastic gears are much greater than those of steel gears. This paper presents an evaluation of tooth deflections and the effect of load on the backlash of these gears using a finite element program that has an accurate contact deflection analysis embedded within it. In addition to deflection analysis, the effect of tip modification on the contact regime and loads along the edges of the plastic gears is presented. An example spur gear pair and an example helical gear pair are used to demonstrate the analysis methodology. The results of the analysis show that backside tooth contact does not occur as tooth deflections in plastic gears increase with increasing load. In fact, the backside gap actually increases with increasing load.Copyright © 2003 by ASME