| 摘要 |
PROBLEM TO BE SOLVED: To provide an expansion valve in which hunting of a variable capacity compressor with an external control valve is avoided under a low load and oil return is ensured along with a cooling power under a heavy load. SOLUTION: The area ratio Ad/ADd of the orifice area Ad of a valve having an orifice diameter d and the pressure receiving area ADd of a diaphragm 13 having a power element diaphragm diameter Dd is set in a range of 0.019-0.074 and variation rate of a set value is increased for variation of inlet side pressure. Since the set value is high under a low load and open valve state is brought about, hunting with an external control valve is avoided and oil return is ensured. Cooling power is ensured by controlling the inlet side pressure with a large variation rate under a heavy load during full rotation of a compressor. Furthermore, abnormal vibration due to water hammer is suppressed by inclining the shaft contact face of a disc 14 and imparting a transverse load to the shaft 15.
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