| 摘要 |
PROBLEM TO BE SOLVED: To highly efficiently generate sound over a wide frequency range by providing a diaphragm to be vibrated under water, forming the diaphragm hollow, filling fluid inside and providing a pressure adjuster for adjusting the fluid pressure. SOLUTION: The inner pressure of an air chamber 3 is changed corresponding to a water depth and a water pressure and the diaphragm 4 is pressure balanced to the water pressure. Also, the inner pressure of the diaphragm 4 is adjusted as well by a hydraulic adjuster 13 and rigidity is held so as not to crush the diaphragm 4 by the water pressure and air pressure. In the state, when the extension/contraction operation of a hydraulic cylinder 6 is performed, the diaphragm 4 is vibrated, the vibration is transmitted and underwater sound is generated. The intrinsic vibration of the diaphragm 4 is arbitrarily changed by adjusting an oil pressure inside a hollow part 12 by the hydraulic adjuster 13. Thus, when the diaphragm 4 is vibrated by the intrinsic vibration, the sound is efficiently generated with less drive power. Further, since the drive power can be less, the hydraulic cylinder 6 can be changed to an electric motor and this device can be more miniaturized, made light in weight and inexpensive.
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