Patent ID: 7511475

Claim:
A speed sensor for a moving member, the sensor comprising means for constituting a magnetic singularity on a portion of the moving member, and a sleeve slidably receiving said portion and including annular coils and a tubular body having two magnetic assemblies mounted in opposition to each other on a common axis, which assemblies are separated by a ferromagnetic spacer, each having one of the coils and, on its side remote from the spacer, an annular pole piece in such a manner that the spacer, the coils, and the pole pieces form a housing for slidably receiving the portion of the moving member that presents the magnetic singularity, each magnetic assembly comprises an annular permanent magnet disposed on a common axis between the annular pole pieces and mounted around its coil, the magnetic singularity, the coils, and the permanent magnets being arranged so that the coils provide a linear signal that is independent of the position of the moving member.