Fluid-pressure actuator with a magnetic field sensor

摘要

The piston-cylinder device has an annular permanent magnet (3) attached to the piston (11), cooperating with a magnetic field sensor (2) within the cylinder (10), for detecting the piston position. The permanent magnet is magnetised in the axial direction of the piston-cylinder device and provided by ferromagnetic discs (32,33) for guiding the magnetic flux. The piston has an open groove (31) receiving the permanent magnet, which has an outer dia. only slightly less than the inner dia. of the cylinder, which has a recess receiving a sleeve (21) of a non-magnetic material, incorporating the magnetic field sensor.