Motor-driven airflow control device

摘要

The invention discloses a motor-driven airflow control device for controlling a throttle valve (2) fixed to a throttle valve shaft (3) by a motor (20) by transmitting the rotation of the motor (20) to the throttle valve shaft (3) through a reduction gear and providing a rotation angle sensor for detecting the rotational position of the throttle valve shaft (3) at the end on the side of the reduction gear of the throttle valve shaft (3). The rotation angle sensor comprises energizing conductors (3A;3a) for being annularly arranged on the substrate (3;27), and generating magnetic fields by applying a current; an exciting conductor (1D) for being fixed to a rotated detection element and spaced from and not in contact with said energizing conductors (3A;3a) to generate a current according to the rotational position of the rotated detection element through electromagnetic induction; and receiving conductors (3B;3b) for being arranged on the substrate (3;27) to generate currents according to the current flowing in said exciting conductor (1D). The substrate (3;27) is attached to a gear cover (25;29) made of a resin material which covers the reduction gear; and a shield member made of a resin material is provided between said exciting conductor (1D) provided on the rotated detection element and said energizing (3A;3a) and receiving conductors (3B;3b) provided on the substrate (3;27) to cover said energizing (3A;3a) and receiving conductors (3B;3b) to shield said energizing (3A;3a) and receiving conductors (3B;3b) from ambient air.