Torque Sensor
The torque sensor converts steering torque input and its direction to voltage signals, in conjunction with interface.
A torsional force caused by steering operation is converted to an axial movement of a slider core. See Figure . A variable differential transformer is installed around slider core. Within transformer are three coils, primary coil on inside, and two secondary coils, one for right turns and one for left turns.
Alternating current is passed through primary coil when system is energized. The amount of mutual induction from primary coil to secondary coils changes depending on position of slider coil. The input shaft and slider are one piece. Rotation of shaft moves slider in a circular direction. The pinion is turned via torsion bar. The slider core is installed on pinion shaft on grooves, and turns with pin ion shaft.
When there is little resistance, input shaft torsion bar, pinion shaft, and slider core turn together to same angle. The slider core does not move up/down.
When there is resistance on input shaft (hard to steer situation), and slider pin is turned at an angle by steering wheel, torsion bar is twisted due to resistance. Accordingly, pinion shaft turns at a smaller angle. The difference in turning angles changes position of slider pin in groove, forcing slider core upward or downward, depending on direction of direction of turn. See Fig 1 .