Energy-saving valve

An energy-saving valve comprising:

• a main valve body including a first end and a second end as two ends in a direction of an axis, a valve hole extending in the direction of the axis, and an air-supplying port, a first output port, a second output port, and air-discharging ports each being in communication with the valve hole;
• a spool slidably inserted into the valve hole and including channels through which the first output port is in communication with the air-supplying port or the air-discharging port and the second output port is in communication with the air-supplying port or the air-discharging port;
• a spool-driving unit provided to a side of the first end of the main valve body, the spool-driving unit pushing the spool in a direction of the second end to slidably move the spool from a first position at the side of the first end to a second position at a side of the second end;
• and
• a pressure control piston attached to the side of the second end of the spool and having a pressure-receiving surface which enables pressure in the second output port to act in the direction of the second end, the pressure control piston receiving biasing force elastically applied by an elastic member in a direction of the first end, wherein
• in the case where the spool is located at the first position, the first output port is in communication with the air-discharging port, the second output port is in communication with the air-supplying port, supplying compressed air from the air-supply port to the second output port causes the spool to move so as to provide a balance between the biasing force applied by the elastic member to act on the pressure control piston and air pressure in the second output port, the air pressure acting on the pressure-receiving surface of the pressure control piston, and a balance between the biasing force applied by the elastic member and the air pressure acting on the pressure-receiving surface enables the spool to be located at a third position at which the second output port is not in communication with the air-supplying port and the air-discharging port, and
• in the case where the spool is located at the second position, the first output port is in communication with the air-supplying port, and the second output port is in communication with the air-discharging port.