| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce material input and to improve strength. <P>SOLUTION: A fiber flow of a hub ring 2 is formed along the axial direction against an inner diameter section 23 in a state where it is gently inclined toward a punched inner diameter section (partition wall) A from a shoulder part 22 as a position of an outer wall surface 24 of the punched inner diameter section (partition wall) A is molded by entering the inner side more than a position of the shoulder part 22 in an inside diameter punching process in a forging process. Consequently, the fiber flow of an inner peripheral surface 27 on which serration of the hub ring 2 after the inner diameter punching is formed comes to be in a state roughly along the axial direction, rotary bending fatigue and strength such as impact bending strength, etc. on the shoulder part 22 are improved, and it is possible to improve the strength and durability of the serration. Additionally, it is possible to set thickness of a small-diameter step section 26 thin to the minimum and to reduce the material input. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
