Control valve for variable displacement compressor

A control valve for a variable displacement compressor, for varying a discharging capacity of the compressor for compressing refrigerant introduced into a suction chamber and discharging the compressed refrigerant from a discharge chamber, by regulating a flow rate of refrigerant introduced from the discharge chamber to a control chamber, the control valve comprising:

• a body having a main passage through which the discharge chamber and the control chamber communicate with each other, and a sub-passage through which the control chamber and the suction chamber communicate with each other;
• a main valve seat provided in the main passage;
• a main valve element configured to touch and leave the main valve seat to close and open a main valve;
• a sub-valve seat provided in the sub-passage;
• a sub-valve element configured to touch and leave the sub-valve seat to close and open a sub-valve;
• a solenoid configured to generate a drive force in a valve closing direction of the main valve;
• and
• an actuating rod for transmitting the drive force of the solenoid to the main valve element and the sub-valve element,
• wherein power supply to the solenoid is controlled using pulse width modulation, and
• wherein a rate of change in an opening area of the sub-valve becomes higher after a predetermined lift amount of the sub-valve element from the sub-valve seat is reached than before the predetermined lift amount is reached.