| 摘要 |
PROBLEM TO BE SOLVED: To obtain the diaphragm which is easily manufactured, light-weight, inexpensive, and high in elasticity and superior in linearity, and generates no abnormal sound even at the time of large input and less deforms by joining a synthetic-resin made diaphragm main body tightly to an edge having a cell structure at the time of injection molding. SOLUTION: A formed vulcanized rubber edge 4 is inserted into one mold of a combined mold into a specific shape, which is fitted to an injection molding machine and fixed to the mold by a vacuum chucking device in the mold. The mold is moved to a specific position to leave a specific gap with the other mold and then while a material obtained by adding mica to polypropylene is injected under specific conditions to mold the diaphragm main body 5, it is bonded mainly to the cutting surface 4c of the edge 4. At this time, the adhesion is carried out by welding the materials on each other. Furthermore, the diaphragm main body 5 bites into the cell 4b on the cutting surface 4c of the edge 4 by being made to abut, thus tightly bonded.
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