DIE FOR FORMING GEAR AND EXTRUSION-FORMING APPARATUS WITH DIE FOR FORMING GEAR

摘要

PROBLEM TO BE SOLVED: To provide a die for forming a gear with which in an extrusion-forming process of a gear, the strength and the durability of the gear can be ensured and the wear resistance at the root portion of the gear can be ensured. SOLUTION: The die 100 for forming the gear is provided with a cylindrically formed container 110 and a mandrel 120 formed into columnar shape. In the lower part of an inner circumferential surface of a penetrating hole 112 of the container 110, a forming tooth 116 constituted of a preliminary forming tooth 117 forming a smaller tooth than the tooth of the intended gear and a finish-forming tooth 118 forming the tooth of the intended gear are formed. The thickness 117b of the tooth tip part in the preliminary forming tooth 117 is formed into the thickness equal to the width of a tooth space at a position (tooth flank) where a depth from the tooth tip of the intended gear is equal to the projecting amount 117a (tooth depth) of the preliminary forming tooth 117. The thickness 118b of the tooth tip part of the finish-forming tooth 118 is formed into the thickness equal to the width of the tooth space at the tooth root of the intended gear to be formed by the tooth tip part of the finish-forming tooth 118. COPYRIGHT: (C)2009,JPO&INPIT