Noise reducing device

Abstract

A noise-reducing device for water vehicles including: a rigid housing having a fluid-tightly sealed chamber formed therein, and fixable to a vibrating part of the water vehicle to be displaced with the vibrating part; a mass member housed in the rigid housing with a given gap therebetween so that the mass member is freely movable in the vibrating direction relative to the rigid housing, the mass member being adapted to come into collision with a contact part of the housing during input of vibration; and an elastic element formed on at least one surface of contact on the contact part or mass member.

1 . A noise-reducing device for water vehicles in which thrust is provided when water taken in by a jet pump is pressurized and accelerated, and is blasted to the rear by means of a jet nozzle, the noise-reducing device comprising: 
 a rigid housing having a fluid-tightly sealed chamber formed therein, and fixable to a vibrating part of the water vehicle to be displaced with the vibrating part;    a mass member housed in the rigid housing with a given gap therebetween so that the mass member is freely movable in the vibrating direction relative to the rigid housing, the mass member being adapted to come into collision with a contact part of the housing during input of vibration; and    an elastic element formed on at least one surface of contact on the contact part or mass member.    
   
   
       2 . A noise-reducing device according to  claim 1 , wherein the noise-reducing device is formed so as to be attached to the jet pump acting as the vibration source, thereby controlling the vibration of the jet pump.  
   
   
       3 . A noise-reducing device according to  claim 2 , wherein the noise-reducing device is formed so as to be attached to an upper portion of the jet pump.  
   
   
       4 . A noise-reducing device according to  claim 2 , wherein the noise-reducing device is formed so as to be attached to a part by which the jet pump is fixed to a hull of the water vehicle, thereby controlling the vibration of the jet pump.  
   
   
       5 . A noise-reducing device according to  claim 4 , wherein the noise-reducing device is attached to the jet pump using a fixing hole where the jet pump is fixed to the hole with the fixing part.  
   
   
       6 . A noise-reducing device according to  claim 1 , wherein the noise-reducing device is formed so as to be attached to a deck of a hull of the water vehicle, where is subjected to vibration from the jet pump, thereby controlling the vibration of the deck.  
   
   
       7 . A noise-reducing device according to  claim 1 , wherein the rigid housing has a cantilever bar protruding in a direction remote from the fluid-tightly sealed chamber, the cantilever bar being fixable at a protruding end portion thereof to the vibrating part of the water vehicle so that the rigid housing is fixed to the vibrating part in a cantilevered state.  
   
   
       8 . A noise-reducing device assembly for water vehicles in which thrust is provided when water taken in by a jet pump is pressurized and accelerated, and is blasted to the rear by means of a jet nozzle, the noise-reducing device comprising: 
 a plurality of noise-reducing device each including a rigid housing having a fluid-tightly sealed chamber formed therein, and fixable to a vibrating part of the water vehicle to be displaced with the vibrating part; a mass member housed in the rigid housing with a given gap therebetween so that the mass member is freely movable in the vibrating direction relative to the rigid housing, the mass member being adapted to brought into collision with a contact part of the housing during input of vibration; and an elastic element formed on at least one surface of contact on the contact part or mass member;    an attachment bracket having a body portion to which the plurality of noise-reducing device are fixed, and a cantilever bar protruding in a direction remote from the body portion, the cantilever bar being fixable at a protruding end portion thereof to the vibrating part of the water vehicle so that the attachment bracket is fixed to the vibrating part in a cantilevered state.