Air pressure control valve of an air clutch

摘要

The present invention is an air control valve of an air clutch wherein an air valve assembly interlocking with an operated quantity of a clutch pedal is provided for controlling an air pressure supplied from an air pressure source to the air clutch. Control mechanism is provided for controlling a valve-open pressure of the air valve assembly by a hydraulic pressure from a master cylinder interlocking with the clutch pedal. The control mechanism includes first, second and third spring members of which spring constants gradually decreases in this order, and the valve-open pressure of the air valve body is adapted to be controlled while switching spring forces of the spring members in accordance with the operated quantity of the clutch pedal.