| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a diaphragm coating the inner peripheral surface of a through hole with rubber without exposing the cross section of foundation cloth. SOLUTION: This method is for manufacturing the diaphragm made of a molded body provided with a front surface layer and a back surface layer made of rubber and an intermediate layer made of foundation cloth and having one or two or more through holes formed. The method includes (1) a process for preparing a laminated sheet provided with the front surface layer and back surface layer made of unvulcanized rubber and the intermediate layer made of foundation cloth, (2) a process cutting the laminated sheet to obtain a molding material formed with at least a through hole, and (3) a process for pressing/vulcanizing the molding material in a state of a pin provided on a metal mold corresponding to the through hole inserted into the through hole. When the diameter of the through hole of the molding material and the outside diameter of the pin inserted into the through hole are taken D and d, respectively, a value of (D/d) is not less than 1.1. After filling unvulcanized rubber into a gap of the inner peripheral surface of the through hole of the molding material and the outer peripheral surface of the pin provided on the metal mold, the rubber is pressed/vulcanized. |
