MANUFACTURING METHOD FOR BEVEL GEAR, BEVEL GEAR MATERIAL, AND BEVEL GEAR

摘要

PROBLEM TO BE SOLVED: To improve fatigue strength as well as to improve manufacturing efficiency of a gear of a hypoid gear. SOLUTION: A gear raw material 30 is formed by casting a rough raw material. A rounded part is provided on the end 92 of the tooth top surface 84 of the gear raw material 30, and the tooth bottom part 110 has a tooth bottom surface 114, a recessed curved surface 116, and a draft surface 112. The shape and the size of respective parts are selected so that the tooth flank 102 may be smoothly contiguous with the recessed curved surface 116 and a part of the rounded part on the end 92 may remain to function as a chamfer part when a machining allowance 104 is cut and removed in finishing. The recessed curved surface 116 and the tooth bottom surface 114 are provided with skin parts formed in casting and have no step part, and therefore, fatigue strength is improved. The end 92 is not needed to be chamfered by an exclusive machining device, and manufacturing efficiency is improved.