| 摘要 |
PURPOSE:To improve the strength with a simple constitution, by increasing the foam density of foamed materials in the center, the outside circumferential part, and the concentric part 0.7r distant from the center in the direction of a radius (r) in comparison with the foam density in other parts. CONSTITUTION:In case of a plane (circular) vibration diaphragm, a forming mold 10 for foams in used to charge primary foamed beads of a lower grading in a cente A, an outside circumferential part B, and a concentric circle part C about 0.7r distant from the center in the direction of a radius (r) where enhancement of the strength is required specially, and the foam magnification in these parts is lower than that of other parts, thus forming the diaphragm. Since the center A, the outside circumferential part B, and the concentric circle part C about 0.7r distant from the center where the foam magnification is lower have a density higher than that of other parts, the strength of these parts is enhanced in comparison with other parts as much as possible. |
