| 摘要 |
PROBLEM TO BE SOLVED: To perform a minute flow rate control in an electric expansion valve and to eliminate the leakage in a closed valve. SOLUTION: In this electric expansion valve for opening and closing the opening 13a of a valve seat 13 according to the rotating angle of a valve element 21 rotated by a rotor driven by a pulse motor, the surface to slide on the valve seat 13 of the valve element 21 is formed of a thin metal plate having a throttle groove 21g for performing a minute flow rate control. The throttle groove 21 is half-etched, whereby a groove of optional shape can be extremely precisely formed, the valve opening characteristic of the electric expansion valve is extremely precisely fitted to a design so that the minute flow rate control can be performed. Further, the valve seat 13 is made of a synthetic resin, whereby the leakage in the closing of the valve is eliminated.
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