| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve such problems that a permanent magnet whose N pole and S pole are repeatedly magnetized at a prescribed interval is generally used for a scale of a magnetic linear encoder, however, when a scale is elongated, a production of a long magnet is required, the production of such magnet is difficult and a position detecting accuracy is deteriorated by a temperature rise due to a difference in coefficients of thermal expansion between the magnet and a general metal material. <P>SOLUTION: A detecting part and a magnet are attached to a moving detecting object, a scale is formed of multiple first yoke plates and second yoke plates that are provided alternately at an interval apart, the first yoke plates and the second yoke plates are magnetized to mutually different poles by the magnetized, moving magnet, and the detecting part detects a magnetic field of the magnetized yokes. The multiple yokes are stacked to constitute the long scale so as to dispense with the elongation of the magnet. Furthermore, the yoke is a soft magnetic metal so as to eliminate deterioration of detecting accuracy caused by a difference in the coefficients of the thermal expansion between the magnetic material and the structural metal in the temperature rise. <P>COPYRIGHT: (C)2012,JPO&INPIT |
