An encoder device including: a position detection unit for detecting position information of a moving part; a magnet having a plurality of polarities along a moving direction of the moving part; an electric signal generation unit for generating an electric signal, based on a magnetic characteristic of a magnetosensitive part, the electric signal generation unit having the magnetosensitive part whose magnetic characteristic is changed by a change in magnetic field associated with movement of the moving part and a first magnetic body for guiding magnetic flux lines of the magnet toward the magnetosensitive part; and a second magnetic body for guiding magnetic flux lines of a part having one polarity of the magnet toward a part having other polarity of the magnet, the second magnetic body being disposed between the magnet and the magnetosensitive part.

A system for determining an absolute position of a device includes a high resolution track, a sensor and processing unit associated with the high resolution track, a reference track having a plurality of pole pairs arranged to define a plurality of single-track Gray code segments, and an array of Hall effect sensors associated with the reference track to output a reference signal to the sensor and processing unit indicative of the coarse absolute position of the device over the Gray code segments. A third track has at least one pole pair. At least one sensor associated with the third track outputs a signal used to determine a location within one of the plurality of Gray code segments. The sensor and processing unit combines the third track signal, the reference signal, and the position of the device over the high resolution track to determine an initial, fine absolute position.

A system for determining an absolute position of a device includes a high resolution track (14), a sensor and processing unit (22) associated with the high resolution track (14), a reference track (18) having a plurality of pole pairs arranged to define a single-track Gray code segment, and an array of Hall effect sensors (26) associated with the reference track to output a reference signal to the sensor and processing unit indicative of the coarse absolute position of the device over the single-track Gray code segment. The sensor and processing unit (22) combines the reference signal with the position of the device over the high resolution track to determine an initial, fine absolute position of the device. An up/down hardware counter (34) increments the initial fine absolute position using a signal generated from the high resolution track, and without any further software-based processing, to maintain and continuously update the fine absolute position of the device.

A hollow type rotation detecting device has a 2-pole magnet ring and a multi-pole gear, the 2-pole magnet being coaxially fixed to the outer circumferential surface of the shaft end part of a hollow motor shaft that extends coaxially inside a cylindrical cover. In an annular gap between the cylindrical cover and the 2-pole magnet ring and multi-pole gear, rigid boards are arranged with an orientation facing in a tangential direction at prescribed intervals along the circumferential direction. The rigid boards are electrically connected to one another by flexible printed wiring boards. It is possible to obtain a rotation detecting device suitable to be incorporated into the narrow annular gap between a motor house and the shaft end part of the hollow motor shaft in a hollow motor having a large hollow diameter.

A motor may include a motor main body having a turning shaft and a motor case; a magnet that turns together with the turning shaft; a magnetism sensing element that faces the magnet; a circuit board on which the magnetism sensing element is mounted, the circuit board having a signal ground that is connected to a ground terminal of the magnetism sensing element; a circuit board holder that covers the circuit board from a side of the magnet; and a first shield member that covers the circuit board from a side opposite to the magnet. The first shield member and the circuit board holder are each made of an electrically-conductive material, and electrically connected to the signal ground.

A motor system includes a motor, and a multi-turn absolute encoder that detects a rotation number and an absolute angular position of a rotation shaft of the motor. The multi-turn absolute encoder includes: an absolute angular position detection device that detects the absolute angular position within one rotation period of the rotation shaft; and a storage element that stores the rotation number of the motor. Even if the driving of the multi-turn absolute encoder is stopped while the motor is stopped, the multi-turn absolute encoder detects the multi-turn position of the rotation shaft after startup. Further, the motor has a brake mechanism including: a gear-type brake wheel that rotates integrally with the rotation shaft; an engagement member capable of engaging with the teeth of the gear-type brake wheel; and an actuator which causes the teeth and the engagement member to engage with each other during braking.

A rotation angle detecting device includes: a rotating part rotating integrally with the rotating shaft and including a detected portion; an A-phase detector detecting change of a physical quantity caused by rotation of the rotating part, inside a first detection field over the detected portion and outputting an A-phase signal; and a B-phase detector detecting change of the physical quantity caused by rotation of the rotating part, inside a second detection field located over the detected portion and outputting a B-phase signal that is out of phase with the A-phase signal. The second detection field is shorter than the first detection field with respect to the direction perpendicular to the rotating direction of the rotating part.

A rotary encoder includes a rotor, a stator, and a casting compound. The casting compound has a first surface facing the stator. The first surface has a first predetermined shape and is fixed in relation to the stator. The casting compound has a second surface facing away from the stator, the second surface having a second predetermined shape.

A position detection system for detecting a movement of a machine includes a first and a second position sensor and an evaluation device. The first position sensor is configured to detect a change in a first magnetic field generated by the movement of the machine. The second position sensor is configured to detect a change in a second magnetic field, which differs from the first magnetic field and is generated by the movement of the machine. A detection result from the second position sensor has a lower resolution of a position of an element of the machine to be determined than a detection result from the first position sensor. The evaluation device is configured to evaluate the detection result from the first position sensor and/or the detection result from the second position sensor to determine the position of the element of the machine.

The disclosure provides a position detection system and a method for detecting a movement of a machine. The position detection system comprises a first position sensor configured to detect a magnetic field that forms magnet pole pairs arranged in a row, magnet poles of different polarity being arranged next to one another in each case, a second position sensor configured to detect a magnetic field at an individual magnet arranged in a center of the magnet pole pairs and at a distance from each magnet pole; and an evaluation device configured to evaluate detection results of the first and second position sensors that have been detected based on a movement of an element of the machine relative to the first and second position sensors, the evaluation including identifying a fault based on the detection results of the first and second position sensors.