| 摘要 |
PURPOSE:To reduce the cost of manufacturing a diaphragm with bellows by a method in which a cap-shaped molding having a thin horizontal stage portion in its tiered portions is formed, and the molding is folded at the horizontal stage portions to form the bellows. CONSTITUTION:Molding is made by using a cap-shaped mold having tiered portions 21 formed by stretching bellows 11 and thin horizontal stage portions 21a to be folded in the tiered portions 21. When the thickness of an uprising wall 21b is 0.6mmt, that of the horizontal stage portion 21a is 0.4-0.3mmt. The tiered portions 21 are folded at the horizontal stage portions 21a to obtain a diaphragm 10 with the bellows 11. Since the portions 21a are of a small thickness, top and bottom portions 11a and 11b can be exactly and easily formed at given positions. The upper and lower molds 26 and 27 may have staged projections 26a and staged recessions 27a for each, which are easily formed by cutting the molds. |
