| 摘要 |
PURPOSE:To obtain a loudspeaker diaphragm edge provided with a corrugation conforming to a metal die, by inserting a band-like body consisting of thermoplastic resin between a ring-like lower die having a corrugation shape and a roll metal die, and heating and rolling it. CONSTITUTION:A band-like body 3 having flexibility and consisting of urethane resin being thermoplastic resin is prepared. On the other hand, a ring-like lower die 5 obtained by forming a recessed groove 4 having a ring-like corrugation on an upper face, and a roll metal die 7 of a rotating body structure, which is obtained by forming a projecting line 6 having a sectional shape corresponding to the sectional shape of the recessed groove 4, on the side face are provided. The metal die 7 rolls and slides on the die 5 in a state that a part of the projecting line 6 is fitted into a part of the recessed groove 4. Subsequently, the band-like body 3 is inserted successively from its one end part between the die 5 and 7, and the band-like body 3 is rolled by sliding the metal die 7. In this case, the band-like body 3 is heated together with the dies 5, 7, and a corrugation 8 is formed successively like a circular arc. The end part of the rolled band-like body 3' is matched, and a matched part 9 is connected, by which a loudspeaker diaphragm edge 10 having the corrugation 8 is obtained. |
