PURPOSE: To prevent the fluctuation of an output torque by a method wherein a vacuum delay valve, connecting the vacuum chamber of a vacuum diaphragm device, controlling the opening and closing of an air bleed port, to a suction air path, is provided.
CONSTITUTION: The opening and closing control valve 14 is secured to a diaphragm 11 to effect the operning and closing control of the air bleed port 9. The vacuum delay valve 16 is arranged in a vacuum introducing pipe 15 connected to the vacuum chamber 12 of the diaphragm device 10. The vacuum delay valve 16 is consisting of a non-return valve 20 and a throttle valve 21. When a vacuum in the suction air path 2 becomes smaller than a set value, the non- return valve 20 is opened and the opening and closing control valve 14 closes the air bleed port 9. When the vacuum of the suction air becomes larger than the set value, the non-return valve 20 is closed and air in the vacuum chamber 12 cannot be flowed out gradually through the throttle valve 21, therefore, the opening and closing control valve 14 continues to close the air bleed port 9. According to this method, the fluctuation of torque may be prevented.
YAMADA TOSHIO
MATSUSHITA SOUICHI
INOUE TOKUTA
