Vacuum pump for vehicle

Abstract

A vacuum pump for a vehicle includes: a pump housing having an internal cylindrical space, an inlet for receiving oil to be supplied to the space, and an outlet for discharging the oil from the space; a rotor eccentrically rotating in the internal cylindrical space of the pump housing; a vane rotating along the inner side of the internal cylindrical space of the pump housing; and a valve maintaining a pressure in the internal cylindrical space of the pump housing at less than a predetermined level.

What is claimed is: 
     
         1 . A vacuum pump for a vehicle, comprising:
 a pump housing having an internal cylindrical space therein, an inlet for receiving oil to be supplied to the internal cylindrical space, and an outlet for discharging the oil from the internal cylindrical space;   a rotor eccentrically rotating in the internal cylindrical space of the pump housing;   a vane rotating along the inner side of the internal cylindrical space of the pump housing; and   a valve maintaining a pressure in the internal cylindrical space at less than a predetermined level.   
     
     
         2 . The vacuum pump of  claim 1 , wherein the valve includes:
 a cylindrical valve case extending to a side of the pump housing to communicate with the internal cylindrical space, the cylindrical valve case having a hole at a top;   an elastic member disposed in the valve case with a first end fixed to a side of the valve case; and   a ball fixed to a second end of the elastic member to block a portion between the valve case and the pump housing when the elastic member is extended.   
     
     
         3 . The vacuum pump of  claim 2 , wherein the elastic member is compressed when pressure over a predetermined level is applied to the ball. 
     
     
         4 . The vacuum pump of  claim 1 , wherein the valve is disposed at a predetermined distance from the outlet in an anti-rotational direction of the vane.