Patent ID: 6771065
Filing Date: 2004-08-03
Classification: G01D

Abstract:
An apparatus for facilitating rotation and sensing angular position, comprising:a sensor magnet arranged on an axis having a north pole and a south pole, the sensor magnet emitting a magnetic field having magnetic flux lines traveling in a return loop from the north to the south pole, the return loop intersecting the axis; a sensor responsive to the magnetic field, the sensor being axially displaced from the sensor magnet and sensing an angle of magnetic flux lines traveling along the return loop, wherein relative rotation about the axis between the sensor magnet and the sensor causes the magnetic flux lines impinging upon the sensor to change angle, the sensor having an output related to the angle of magnetic flux lines and corresponding to relative angular positions between the sensor magnet and the sensor; wherein the north pole and south pole lie transverse to the axis and on opposite sides of the axis, such that the return loop of magnetic flux lines intersect the axis transversely; wherein the sensor is a hall effect detector; and an electrical rotary actuator including a stator having coils surrounding the axis, and a rotor including at least one permanent magnet mounted to the shaft, the actuator having a magnetic leakage field having magnetic flux lines extending axially out of the end of a shaft, the sensor being arranged so as to avoid sensing the magnetic flux lines of the magnetic leakage field, the sensor and the sensor magnet being operable arranged on the rotor and the stator for sensing angular position of the rotor relative to the stator.