| 摘要 |
PROBLEM TO BE SOLVED: To prevent excess engagement between a control valve element and a valve seat at the time of positioning control of the control valve. SOLUTION: An expansion valve is driven in an expansion valve control device 28 by outputting drive voltage pulse to the expansion valve which is in an entirely closed state with a valve element being in contact with a valve seat. After drive voltage pulse having been outputted in an expectation of the expansion valve being entirely closed, and when further drive voltage pulse is outputted for driving the expansion valve in a direction of closing the valve, a control circuit 39 changes the voltage value of thus further outputted drive voltage pulse, thereby reducing driving torque of an expansion valve stepping motor 26 for moving the valve element.
|
