| 摘要 |
PROBLEM TO BE SOLVED: To easily expedite a mold assembling, to mold a product having excellent inner surface shape, and to hold a core die length constant regardless of a bending angle by setting a crack of a cylindrical split piece obliquely, rotating the piece at a predetermined angle around a central axis, and engaging it with the crack. SOLUTION: This miter bend has split pieces 11, 12 of a cylindrical shape with split crack 13 as oblique crack of an angleαdeg.. The core die for molding the tube having the angle of 2αdeg. is obtained by rotating the pieces 11, 12 at 180 deg. around a central axis to the core die to a linear core die, and engaging the crack 13. That is, the core die for molding the tube is obtained by rotating the linear core die at 0 to 180 deg. around the central axis of the pieces 11, 12 and used as the bending core die having a bending angle of 0 to 2αdeg.. In such a rotation, the pieces are rotatably symmetrical at the central axis as a center, and hence a length of the core die along the central axis is constant. |
