| 摘要 |
PURPOSE:To expand a piston oscillation frequency area, by raising the rigidity of a vibration diaphragm, and also reducing its density. CONSTITUTION:In order to raise a value of E (Young's modulus)/rho (density) of synthetic resin which becomes a base body, polypropylene, a copolymer mainly composed of propylene, polyethylene a copolymer mainly composed of ethylene, etc., or their mixture are selected. Also, as for a reinforcement, a glass fiber, a glass flake, a carbon fiber, etc., whose Young's modulus is comparatively high, or these mixture are selected. For instance, when 20wt% a glass fiber is mixed in polypropylene, a film of rho=1.05, E=5X10<4>kg/cm<2> is obtained. When it is compared with polypropylene, a value of E/rho of about 2 times is obtained. |
