| 摘要 |
PURPOSE:To manufacture cylindrical parts having uniform diameters and shapes, by forming a plate-shaped blank material in a round shape between two rolls in such a way that burrs at the end surface of the material are bitten into the outer circumference of the roll. CONSTITUTION:Burrs 12a, 12a exist while facing mutually in opposite directions, at both end surfaces 12, 12 of a cut plate-shaped blank material 11. The material 11 is so inserted between both rolls 13, 14 that the burr 12a at the end surface of the material 11 faces to an outer circumference roll 14. Then the burr 12a of the material 11 is pinched between both the rolls 13, 14 to be rounded with the rotation of rolls in the direction of the arrows 16, 17, while biting the roll 14. The shape of the material near both ends 12, 12 is slightly straight, but a part 11a having a cylindrical shape as a whole, is obtained by rounding the material 11a into a cylindrical one around the core roll 13. Further, the roll 14 is made of a hard elastic material. |
