FORMING METHOD FOR TOOTH SURFACE OF GEAR BY PRECISION COLD FORGING

摘要

PURPOSE:To uniformly apply pressure to the whole face width, and to execute cold forging forming with high accuracy by pushing a movable die into which a gear is pushed into a fixed die and sliding it along a taper, bringing the movable die to elastic deformation to the inside and finishing precisely the tooth surface. CONSTITUTION:A gear 2 formed by cold forging is set with a chamfer 4 upward and by aligning a tooth 3 with a gear surface 5 of a movable die 6. When a punch 11 is depressed in this state, the gear 2 is pushed into the movable die 6 until the punch 11 hits against the upper face of the movable die 6 first. The punch 11 is allowed to descend by a prescribed stroke. In this case, the movable die 6 slides and descends along a taper 8 to a fixed die 7, pushed to the inside and deformed within an elastic range, the gear surface 5 is reduced, and in the teeth 3, a counter taper 13 can be formed by cold forging. In this case, the tooth 3 of the gear 2 is pressed uniformly to the inside by the movable die 6 extending over the whole face width, and the tooth surface having the counter taper 13 of high accuracy can be obtained.