Refuel-defuel valve

PURPOSE: An oil supply and discharge valve is provided to minimize the weight of an oil valve because oil can be supplied and discharged by one device. CONSTITUTION: An oil supply and discharge valve(100) comprises an upper housing(110), a lower housing(120), and a poppet(130). An oil supply and discharge path(111) is extended upwardly from the top of the upper housing. A first pilot line(115) connected to a high water line valve(500) is formed in one side of the oil supply and discharge path. One or more communication holes communicated with the oil supply and discharge path are formed on the lower part of the lower housing. An outer guide part(122) protrudes upwardly from the center part of the lower housing. A second pilot line(125) connected to a low water level valve(150) is formed in one side of the lower housing. The poppet is arranged inside the upper housing in order to open and close the oil supply and discharge path. A main control line(135) communicated with the oil supply and discharge path is formed in the top side of the poppet. An outer side wall part(132) is coupled to the outer guide part to be vertically movable.