Identification of failure modes of a PEEK-steel gear pair under lubrication

Abstract An experimental investigation is conducted to identify the failure modes of the lubricated PEEK gears under different loading conditions through the enclosed power flow test rig, supplemented with the measurements on wear, vibration and the surface micro-topography. The FZG C type gear pair is selected while the mating driving gear is chosen with the material of C45. Experimental results reveal that the pitting-induced tooth breakage occurs under light and moderate loading conditions, while the tooth root breakage dominates under heavy duty loading conditions. The measurement of the wear and the tooth surface micro-topography help to identify that the micro-pits near the pitch line lead to the final tooth breakage under moderate loading conditions. Meanwhile, the insufficiency of the bending strength under heavy loading conditions is the cause of the tooth root fracture.