Disclosed is a sensing device comprising: a stator connected to a first shaft; a first gear rotating in engagement with the stator; a second gear rotating in engagement with the first gear; a magnet coupled to the second gear; and a magnetic element disposed corresponding to the magnet, wherein one surface of the magnet disposed facing the magnetic element has an elliptical shape. Accordingly, even when the center of the magnet disposed in the second gear and the center of the magnetic element are not aligned in the axial direction and thus arranged offset, the sensing device can enhance the precision of a steering angle measurement due to the shape of the magnet.

Disclosed herein are a steering angle sensing device and a torque angle sensor module having the same. The steering angle sensing device includes a main gear rotating at the same angle as a steering shaft, a first sub-gear rotatably engaging with the main gear, a second sub-gear rotatably engaging with the main gear and having a number of teeth different from that of the first sub-gear, a third sub-gear rotatably engaging with the main gear and having a number of teeth different from that of each of the first sub-gear and the second sub-gear, a first magnetic sensor detecting a change in magnetic force of the first sub-gear, a second magnetic sensor detecting a change in magnetic force of the second sub-gear, a third magnetic sensor detecting a change in magnetic force of the third sub-gear, and a control device calculating a steering angle from the change in magnetic force detected by each of the first magnetic sensor, the second magnetic sensor, and the third magnetic sensor.

An absolute encoder includes a first drive gear (worm gear 1d) configured to rotate in accordance with rotation of a main spindle, and a first driven gear (worm wheel 2a) that engages with the first drive gear. The absolute encoder includes a second drive gear (worm gear 2b) provided coaxially with the first driven gear and configured to rotate in accordance with rotation of the first driven gear, and a second driven gear provided, in a plan view, on a side opposite the first drive gear with respect to the first driven gear and the second drive gear, the second driven gear engaging with the second drive gear. The absolute encoder includes an angular sensor configured to detect a rotation angle of a rotating body that is rotated in accordance with rotation of the second driven gear.

A multi-turn measurement system includes a plurality of gears, a plurality of pinions engaging the plurality of gears, a plurality of magnets each disposed on one of the plurality of gears, and a plurality of magnetic field sensors. Rotation of the pinions about a center axis drives rotation of the plurality of gears. The magnets each have a magnetic field that changes based on an angular position of the one of the plurality of gears. The magnetic field sensors are each positioned to sense the magnetic field of one of the plurality of magnets.

To correct an error based on a position of a main spindle. An absolute encoder includes a magnet as a permanent magnet provided at a leading end side of a first worm gear part, an angle sensor as an angle sensor configured to detect a rotation angle of the first worm gear part corresponding to a change in a magnetic flux generated from the magnet, a microcomputer configured to output angle position information of a first driving gear in a stopped state, wherein the microcomputer outputs angle error information of the first driving gear corresponding to the angle position information.

An absolute position sensor includes a first gear having a plurality of teeth, a rotational position sensor operatively coupled to the first gear to be configured to detect a rotational position of the first gear, and a second gear including a spiral tooth engaged with the plurality of teeth of the first gear to rotate with the first gear, and having a first end with a first distance from a center of the second gear, and an opposite second end with a second distance from the center of the second gear, the second distance being less than the first distance.

A rotation angle detection device includes a first detection unit, a second detection unit, and a calculation unit. The first detection unit detects a first rotation angle of a steering shaft that rotates with a steering wheel. The second detection unit detects a second rotation angle of a motor shaft coupled to the steering shaft via a speed reduction mechanism. The calculation unit receives the first rotation angle from the first detection unit and the second rotation angle from the second detection unit, and calculates the steering angle of the steering shaft based on a difference angle between the first rotation angle and the second rotation angle.

A sensor device includes a main driving gear, driven gears, an biasing member configured to bias the driven gears toward the main driving gear, a support member configured to support the biasing member, and a sensor configured to generate an electrical signal based on rotation of the driven gears. In a force applied when the biasing member biases the driven gears, assuming that a direction orthogonal to a tangent line at a point of action of the force is set as a first direction, the first direction is different from a second direction.

An absolute encoder includes a first drive gear (worm gear 1d) configured to rotate in accordance with rotation of a main spindle, and a first driven gear (worm wheel 2a) that engages with the first drive gear. The absolute encoder includes a second drive gear (worm gear 2b) provided coaxially with the first driven gear and configured to rotate in accordance with rotation of the first driven gear, and a second driven gear provided, in a plan view, on a side opposite the first drive gear with respect to the first driven gear and the second drive gear, the second driven gear engaging with the second drive gear. The absolute encoder includes an angular sensor configured to detect a rotation angle of a rotating body that is rotated in accordance with rotation of the second driven gear.

A bicycle electric/electronic derailleur has mutually movable components, and a geared motor for controlling the mutual motion of the components. The geared motor includes an electric motor having a drive shaft, an output shaft and a speed reducer including at least one gear between the drive shaft and the output shaft. The output shaft defines at least in part one of the articulation axes. The electric motor is rigidly connected to a first component, and a second component integrally rotates with the output shaft. The derailleur further includes a magnetic rotary encoder for transducing a quantity related to the mutual motion of the components. The encoder includes a permanent magnet and a sensor responding to the changes in the magnetic field of the magnet. The magnet is a disc, cylindrical or annular magnet having diametral magnetization, and is coaxial with and arranged to integrally rotate with the output shaft.