| 摘要 |
PROBLEM TO BE SOLVED: To provide main body fittings keeping high accuracy and lengthen the life of a mold. SOLUTION: In a first process, by extrusion-molding a first cylindrical work W1 in the axis direction, a second work W2 comprising a small diameter part 6 and a large diameter part 7 coaxially integrated with the small diameter part 6 is formed. In a second process, by extrusion-molding the second work W2 in the axial direction, the whole outer circumferential surface of the large diameter part 7 is made parallel to the axial direction and the cross sections vertical each other in the axial direction form a hexagon, and a third work W3 forming a first axial hole 18b pierced from the opposite side to the small diameter part 6 and positioning the tip part having a distance from the small diameter part 16 to form a large diameter corner part 18 is formed in the large diameter part 7. In a third process, by extrusion-molding the third work W3 in the axial direction, a remaining part 19b other than a main part 19a of the large diameter corner part 18 is swelled in the diameter direction and a fourth work W4 forming a flange part 29b directly connecting the remaining part 19b to the small diameter part 16 is formed, while the shape of the main part 19a on the opposite side to the small diameter part 16 of the large diameter corner part 18 is held. COPYRIGHT: (C)2006,JPO&NCIPI
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