MULTI-TURN ABSOLUTE MAGNETIC ENCODER

摘要

A multi-turn absolute magnetic encoder, comprising the first to the (M+1)th counting units, a single-turn signal processing unit (6) and a multi-turn signal processing unit (12). Each counting unit comprises coded discs (4, 10) with a permanent magnet (14) fixed thereon, and a tunnel magnetic-resistance angular displacement transducer (11). The tunnel magnetic-resistance angular displacement transducer (11) is located within a region in a detection plane of the permanent magnet (14) at a distance is a specific radius range from an axis of a columnar ring of the permanent magnet (14), so that a rotation magnetic field phase angle of a component of a magnetic field generated from the permanent magnet (14) in the detection plane presents a linear variation relationship with the permanent magnet rotating phase angle. The single-turn signal processing unit (6) calculates and outputs codes characterizing the absolute position of an input rotation shaft (3) within a turn based on a sensed signal of the first counting unit; and the multi-turn signal processing unit (12) calculates and outputs the number of rotation turns of the input rotation shaft (3) based on sensed signals of the second to (M+1)th counting units.