| 摘要 |
PROBLEM TO BE SOLVED: To prevent a hunting phenomenon while suppressing vibration noise in a temperature type expansion device with a valve element arranged in an upstream side of a valve seat. SOLUTION: A back pressure chamber 12 composed of a cylinder 11 and a piston 10 is provided on a primary pressure chamber 7 introduced with a high pressure refrigerant, and the primary pressure chamber 7 is communicated with the back pressure chamber 12 by a refrigerant passage with a small passage sectional area. The valve element 9 and the piston 10 are integrally formed so as to change in a direction reducing the volume of the back pressure chamber 12 when the valve element 9 moves in a valve opening direction, and a diameter of the piston 10 is formed larger than a diameter of the valve element 9. Since the piston 10 is moved to move the valve element 9 in the valve opening direction by a differential pressure with the back pressure chamber 12 when a positive pressure wave reaches the primary pressure chamber 7, the pressure wave is deflected to a secondary side and damped, and the vibration noise is eliminated. Since a composition giving sliding resistance to a movable part of a valve part is not provided, there is no hysteresis in operation of the valve part, and hunting does not occur. COPYRIGHT: (C)2006,JPO&NCIPI
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