| 摘要 |
PURPOSE:To manufacture simply a thin plate, by constituting the thin plate having many hollow projections whose bottom of the projection is punched out, and a surface member. CONSTITUTION:The thin plate 3 has the hollow cylindrical projections 2, which are arranged uniformly in the circumference direction in the concentric form to the center of the diaphragm and are incorporated with the thin plate. Further, the bottom of the projections 2 are punched out. The thin plate 3 is made of metallic sheet such as aluminum or titanium sheet, of plastic sheet such as polypropylene or carbon fiber reinforced polypropylene. Since the diaphragm is formed in multi-layered structure, the bending rigidity is large according to the principles of sandwich construction, and the E/rho (Young's modulus/density) is the same value as that of a conventional honeycomb diaphragm. Since the projections are arranged in concentric form and uniformly in the circumferential direction, the bending rigidity near the circumference of the diaphragm is made uniform and increased and the bending rigidity of the entire diaphragm is made uniform. |
