| 摘要 |
PURPOSE:To manufacture a supporting shaft having high strength against the impact from external part by using a female die having the polygonal recessed part regulating the external shape of the flange part of a polygon and a male die having annular projecting part with arcuate cross section along the peripheral edge of the joining part to the lever like part of the flange part. CONSTITUTION:The polygonal recessed part 14 regulating the outer periphery of polygonal flange 3, 23 is formed on the female die 13. The annular projecting part 16 for forming annular recessed grooves 5, 25 with arcuate cross sections is formed along the peripheral edge of the joining part to the lever like parts 3, 23 of the flange parts 2, 22 on the male die 15. Since the polygonal flange parts 2, 22 in the supporting shaft 1 and annular recessed grooves 5, 25 are simultaneously formed by squeezing a bar like metal in the axial line direction by these two dies 13, 15, the sustaining of the metal structure is well continued without destroying it by the annular recessed grooves 5, 25. The joining part to the flange parts 2, 22 and lever like parts 3, 23 can strongly be maintained because of the polygonal shapes 2, 22 being formed by squeezing simultaneously.
|
