ELECTRONIC EXPANSION VALVE WITH OPPOSED SPRING STRUCTURE BELLOWS

摘要

PURPOSE: An electronic expansion valve which has bellows of opposition spring structure is provided to improve the hysteresis characteristic by making the hysteresis characteristic between a top bellows and a bottom bellows. CONSTITUTION: An electronic expansion valve comprises a valve main body(5), a positioner(41), a valve part(7) and a bellows. The valve body comprises reduction gears consisting of the electric-powered step motor and plurality of gears. The positioner changes the rotational motion of the reduction gears into the linear motion. The valve part is connected in the valve main body and has the linear motion of the positioner. The valve part is composed of a valve rod(71) and a valve head(72) in order to open and close an outlet(54) and an inlet(53). The bellows seals between the valve rod and valve room. The bellows prevents the refrigerant from flowing into a case(1) from the valve room.