A displacing device is incorporated in a displacement control valve. The
displacing device includes a first pressure chamber, a second pressure
chamber, a second bellows, a transmission rod, and an urging spring. The
second pressure chamber communicates with a suction chamber. The interior
of the second pressure chamber is a suction pressure zone. When the
pressure in the suction pressure zone is less than or equal to a
predetermined reference pressure, the transmission rod moves an actuation
rod (valve body) to open a valve hole. Therefore, a variable displacement
compressor is prevented from operating with a large displacement when
there is insufficient amount of refrigerant or when the speed of the
compressor is high.