Sliding means with built-in moving-magnet linear motor

摘要

A sliding means with built-in moving-magnet linear is disclosed, which makes it possible to sense accurately a table(3) position with a magnetic sensor element(34). To this end, a magnetic flux pattern is rectified outside any one N-pole of forward and aft end poles of a field magnet(13). Position of the table(3) is monitored with a magnetic sensor element arranged on the bed(2) in opposition to the field magnet(13). Arranged outside the end pole of the field magnet(13) is an auxiliary magnet(U1) unlike in polarity and made as small as possible in effect on propulsion exerted on the table(3). The auxiliary magnet(13) is to rectify the magnetic flux pattern outside the end pole of the field magnet(13) to the same distribution pattern as found at a boundary between the adjacent poles opposite in polarity in the field magnet(13), thus making it possible to identify the accurate positions of the forward and aft end pole of the field magnet(13). <IMAGE>