A Study on Finish Hobbing with Carbide Hob : Improvement of Gear Accuracy Using New Hobbing Machine

Abstract

This paper deals with the improvement of gear accuracy which has been obtained through the pracical use of a newly developed hobbing machine.The carbide hob used for finishing large hardened gears has recently become very populat.A cutting with a rake angle of -30° degrees is fixed slantly to the cutting direction.The hob was characterized by its performance of finishing only tooth surface of a gear without chipping the cutting edge on a univarsal hobbing machine.However, accuracy of a gear with a higher hardness was poor.Especially, a tooth profile error appeared largely.Therefore, the new CNC hobbing machine with higher rigidity and the backlash eliminator has been developed for large gears.From the experimental results, the new machine was found to be effective in finishing of hardened gears.