Reservoir having a ventilating structure

Abstract

The reservoir includes a tank having an inlet, and a cap for covering the inlet. The cap further comprises an outer portion, an inner portion, a labyrinth, a protruding portion, a vent hole and a check valve. The inner portion is arranged in the outer portion to define the labyrinth therebetween. The labyrinth is opened to outside of the tank. The protruding portion is formed on the center of the inner portion to protrude in a direction of the inside of the tank, in which the vent hole is formed to communicate between inside of the tank and the labyrinth. The check valve is arranged on an upper end of the vent hole, and is constructed to permit the communication of air through the vent hole and to prevent a leak of the fluid through the vent hole.

What is claimed is:  
     
         1 . A reservoir for reserving fluid, comprising: 
 a tank having an inlet; and    a cap for covering the inlet, wherein the cap comprises; 
 an outer portion,  
 an inner portion arranged in the outer portion,  
 a labyrinth defined by at least one of the outer portion and the inner portion, and opened to outside of the tank,  
 a protruding portion formed at a center of the inner portion and arranged to protrude in a direction toward the inside of the tank when the cap covers the inlet,  
 a vent hole formed in the protruding portion to communicate between the inside of the tank and the labyrinth, and  
 a check valve arranged on an upper end of the vent hole, and constructed to permit communication of air through the vent hole and to prevent a leak of the fluid through the vent hole.  
   
     
     
         2 . A reservoir for reserving fluid according to  claim 1 , wherein the check valve is made of an elastic material.  
     
     
         3 . A reservoir for reserving fluid according to  claim 2 , wherein the check valve comprises: 
 a valve-sheet having a center hole therein and attached on the inner portion;    a boss inserted in the center hole of the valve-sheet;    a flange formed at an upper end of the boss and closing a clearance between the boss and the center hole of the valve-sheet;    a through hole formed in the boss; and    a valve portion formed at a lower end of the boss to elastically close a lower end of the though hole.    
     
     
         4 . A reservoir for reserving fluid according to  claim 3 , wherein 
 the flange is adapted to elastically deform to permit air in the tank to flow out when a pressure in the tank is higher than a pressure outside of the tank; and    the valve portion is adapted to elastically deform to permit air outside of the tank to flow in when the pressure in the tank is lower than the pressure outside of the tank.    
     
     
         5 . A reservoir for reserving fluid according to  claim 2 , wherein the check valve comprises: 
 a boss inserted in the vent hole,    a plural number of grooves formed on a periphery of the boss;    a flange formed at an upper end of the boss and closing an upper end of the vent hole;    a through hole formed in the boss; and    a valve portion formed at a lower end of the boss to elastically close a lower end of the though hole.    
     
     
         6 . A reservoir for reserving fluid according to  claim 5 , wherein 
 the flange is adapted to elastically deform to permit the air in the tank to flow out when a pressure in the tank is higher than a pressure outside of the tank; and    the valve portion is adapted to elastically deform to permit air outside of the tank to flow in when the pressure in the tank is lower than the pressure outside of the tank.    
     
     
         7 . A reservoir for reserving fluid, comprising: 
 a tank having an inlet; and    a cap for covering the inlet, wherein the cap comprises; 
 an outer portion,  
 an inner portion arranged in the outer portion,  
 a labyrinth defined by at least one of the outer portion and the inner portion, and opened to outside of the tank,  
 vent means for communicating between the inside of the tank and the labyrinth, and  
 check valve means for permitting the communication of air through the vent means and preventing leakage of the fluid through the vent means.  
   
     
     
         8 . A vehicle having a reservoir for reserving fluid, comprising: 
 a tank reserving a fluid to be supplied to the vehicle, the tank having an inlet; and    a cap for covering the inlet, wherein the cap comprises a vent hole, and check valve means for permitting communication of air through the vent hole and for preventing a leak of the fluid through the vent hole to outside of the tank.