Motor-driven throttle valve device with inductive throttle sensor and inductive throttle sensor for detecting rotation angle of throttle shaft of motor-driven throttle valve device

An inductive throttle sensor for detecting the rotation angle of a throttle shaft of a motor-driven throttle valve device, the motor-driven throttle valve device including:

• a throttle body which has an intake path;
• a throttle shaft that extends through the intake path in a direction intersecting the flow of air;
• a butterfly throttle valve which is fastened to the throttle shaft to open and close the intake path;
• a motor which drives the throttle shaft;
• a train of reduction gears which transmits the rotation of the motor to the throttle shaft and includes an output gear fastened to a rotor shaft of the motor, a final stage gear fastened to the throttle shaft, and an intermediate gear positioned between the output gear and the final stage gear;
• a gear cover which is mounted on the throttle body to cover the reduction gear train and is made by resin;
• a retainer which is positioned between the gear-side surface of the gear cover and an end face of the intermediate gear to prevent the axial separation of the intermediate gear;
• a motor terminal connection which is mounted on the gear-side surface of the gear cover and electrically connected to a motor terminal projecting from the motor;
• a connector which is mounted on the gear cover and connected to an external wiring plug;
• and
• a plurality of connector terminals mounted on the connector;
• wherein the plurality of connector terminals include a motor connector terminal connected to the motor terminal connection and a sensor connector terminal connected to the sensor circuit;
• wherein a sensor connection conductor section for connecting the sensor circuit to the sensor connector terminal extends toward the motor terminal connection, and insert-molded into the seat cover, joins with a motor connection conductor section for connecting the motor terminal connection to the motor connector terminal, and is wired to the connector;
• wherein the retainer, which prevents the axial separation of the intermediate gear, is positioned between the motor terminal connection and plural connections between the sensor circuit and the sensor connection conduction section;
• the inductive throttle sensor comprising:
• an excitation conductor which is mounted on the throttle shaft;
• a circuit board which is mounted on the gear cover;
• a receiver coil/exciting coil section which includes a receiver coil and an exciting coil and is mounted on the circuit board;
• and
• a sensor circuit which is mounted on the circuit board to detect a change in the inductance between the excitation conductor and the receiver coil and determine the rotation angle of the throttle shaft;
• wherein the sensor circuit is installed between the retainer which prevents the axial separation of the intermediate gear, and the receiver coil/exciting coil section;
• wherein the plural connections are located concentratedly on one side of the circuit board;
• and
• wherein the connection between the sensor circuit and the sensor connection conductor is disposed in a decentralized manner on both sides of the retainer which prevents the axial separation of the intermediate gear.