Abstract: A rotation angle detection device capable of easy selection of detection gears is provided to detect a rotation angle of a main gear. The device includes first and second detection gears each rotatable in conjunction with the main gear, a first magnetic sensor for detecting a rotation angle of the first detection gear, a second magnetic sensor for detecting a rotation angle of the second detection gear, and a microcomputer for detecting the rotation angle of the main gear on the basis of the rotation angle detected by the first magnetic sensor and the rotation angle detected by the second magnetic sensor. The periodicity from the first magnetic sensor and the periodicity of the second magnetic sensor are set to be prime to each other. Further, the teeth number of the first magnetic sensor is set to be a numeric value obtained by multiplying the periodicity of the first magnetic sensor by a predetermined integral number.

Abstract: A rotation angle sensor includes a first and a second detection gears rotatable with a steering shaft, a first detector configured to detect a rotation angle of the first detection gear, a second detector configured to detect a rotation angle of the second detection gear, a processor configured to calculate a rotation angle of the steering shaft based on the rotation angles detected by the first and second detectors and a discriminator configured to discriminate whether the rotational angle of the steering shaft, calculated by the processor, falls in an abnormal value, wherein a least common multiple between a cycle of the first detector and a cycle of the second detector is greater than a steering angle measurement range.

Abstract: A magnetic steering angle detection apparatus includes a magnet rotating in synchronization with a steering shaft mounted on a vehicle, senses a change of a magnetic field from the magnet by use of a hall IC mounted on a column side, and detects a rotation angle of the steering shaft. The magnet has S and N poles arranged on a plane of which normal line is in a substantially axial direction of the steering shaft. The hall IC is disposed such that a sensing direction of the hall IC is set to be a substantially single direction and the sensing direction is made to substantially coincide with the axial direction of the steering shaft.

Abstract: A rotation angle sensor includes a first and a second detection gears rotatable with a steering shaft, a first detector configured to detect a rotation angle of the first detection gear, a second detector configured to detect a rotation angle of the second detection gear, a processor configured to calculate a rotation angle of the steering shaft based on the rotation angles detected by the first and second detectors and a discriminator configured to discriminate whether the rotational angle of the steering shaft, calculated by the processor, falls in an abnormal value, wherein a least common multiple between a cycle of the first detector and a cycle of the second detector is greater than a steering angle measurement range.

Abstract: A rotation angle sensor has first and second detection gears interlinked with and rotatable with a steering shaft, a magnetic sensor to detect a rotation angle of the first detection gear, and a magnetic sensor to detect a rotation angle of the second detection gear. The rotation angle sensor also has a processor to calculate a period number of the first detection gear according to rotational positions detected by the magnetic sensors and compute a rotation angle of the steering shaft according to the calculated period number and detected rotation angle of the first detection gear.

Abstract: A rotation angle detection device capable of easy selection of detection gears is provided to detect a rotation angle of a main gear. The device includes first and second detection gears each rotatable in conjunction with the main gear, a first magnetic sensor for detecting a rotation angle of the first detection gear, a second magnetic sensor for detecting a rotation angle of the second detection gear, and a microcomputer for detecting the rotation angle of the main gear on the basis of the rotation angle detected by the first magnetic sensor and the rotation angle detected by the second magnetic sensor. The periodicity from the first magnetic sensor and the periodicity of the second magnetic sensor are set to be prime to each other. Further, the teeth number of the first magnetic sensor is set to be a numeric value obtained by multiplying the periodicity of the first magnetic sensor by a predetermined integral number.

Abstract: A magnetic steering angle detection apparatus includes a magnet rotating in synchronization with a steering shaft mounted on a vehicle, senses a change of a magnetic field from the magnet by use of a hall IC mounted on a column side, and detects a rotation angle of the steering shaft. The magnet has S and N poles arranged on a plane of which normal line is in a substantially axial direction of the steering shaft. The hall IC is disposed such that a sensing direction of the hall IC is set to be a substantially single direction and the sensing direction is made to substantially coincide with the axial direction of the steering shaft.

Abstract: A second gear rotating at a rotation speed faster than a rotation speed of a first gear while meshing therewith, a magnet provided on the second gear and rotating together therewith, and a small angle detection magnetic sensor disposed in a vicinity of where the second gear is fixed and configured to detect a magnetic line of force of the magnet are provided. Meanwhile, a third gear rotating at a rotation speed slower than the rotation speed of the second gear in synchronization with the first gear, a magnet provided on the third gear and rotating together therewith, and a large angle detection magnetic sensor disposed in a vicinity of where the third gear is fixed and configured to detect a magnetic line of force of the magnet are provided. A rotation angle of a steering shaft is calculated based on angle data detected in the small angle detection magnetic sensor and the large angle detection magnetic sensor.

Abstract: A second gear rotating at a rotation speed faster than a rotation speed of a first gear while meshing therewith, a magnet provided on the second gear and rotating together therewith, and a small angle detection magnetic sensor disposed in a vicinity of where the second gear is fixed and configured to detect a magnetic line of force of the magnet are provided. Meanwhile, a third gear rotating at a rotation speed slower than the rotation speed of the second gear in synchronization with the first gear, a magnet provided on the third gear and rotating together therewith, and a large angle detection magnetic sensor disposed in a vicinity of where the third gear is fixed and configured to detect a magnetic line of force of the magnet are provided. A rotation angle of a steering shaft is calculated based on angle data detected in the small angle detection magnetic sensor and the large angle detection magnetic sensor.