Throttle device for internal combustion engine

摘要

An initial opening degree setting mechanism keeps an initial opening degree of a throttle valve larger than that of a fully closed position thereof when no current is supplied to a motor for driving a throttle shaft for the throttle valve. A throttle lever and a sleeve are inserted into the throttle shaft and secured thereto, and a sleeve integrated with a return lever is fitted over the sleeve so as to permit a relative rotational mevement with respect to the sleeve. The sleeve is urged by a return spring in the direction of closing the throttle valve up to the position of the initial opening degree. With the urging force, the return lever is placed to be engageable with the throttle lever. The throttle shaft has a valve opening force applied by a spring for keeping the initial opening degree of the throttle valve near the fully closed position thereof. Thereby parts belonging to the throttle valve initial opening degree setting mechanism are collectively and rationally arranged, a driving load of the throttle actuator motor is reduced and throttle valve control operation is stabilized.