| 摘要 |
PURPOSE:To make it possible to obtain a speaker which does not generate proper tone and is very superior in tone quality, by constituting a diaphragm with a free edge consisting of the resin sheet, which has not the skin layer dependent upon vacuum forming. CONSTITUTION:Resin sheet 3 is clamped by clamp frame 21 and is heated by heater 10. Next, mold 13 is raised to bring softened sheet 3 into contact with mold 13 in the airtight state. Mold 13 is produced with sintered metal so that internal air permeability may be good. Next, sheet 3 is sucked through mold 13 by vacuum to form sheet 3 into a shape along upper face 13a. Next, sheet 3 is taken out and has the center removed. A center cap is produced similarly. Next, a cone part is connected to the free edge and the center cap obtained in this manner. As a result, the free edge, which has not a skin layer, and so on can be obtained. |
