Siemens Vdo Automotive Corporation

Bernard Genot

Yves Dordet

Luc Jansseune

Michel Boucard

Gerard Mouaici

Laurent Satge

Philippe Morisset

Guy Bonhomme

A contactless angular offset analog sensor, of the magnetic inductance type, includes a first portion forming a detector. The detector includes at least one substrate plate carrying at least one flat spiral winding, and at least one core layer of material with high magnetic permeability and low saturation field over at least one portion of the winding. The detector is adapted to coact with a device for processing the electrical signal measured at the terminals of the winding. The sensor also includes two rotors each having at least one magnet, disposed over a predetermined angular sector. The rotors are movable about a same axis identical to the axis of the winding. Each magnet generates in the plane of the core layer a magnetic field of a value greater than the saturation field of the core layer over at least a portion of the surface of the winding.

Analog sensor for contact-free angular offset sensing

A magnetic sensor includes first and second members movable relative to each other. One of the members is secured to a movable member and the other fixed. The first member defines a magnetic circuit with an air gap provided with a detector sensitive to the magnetic induction prevailing in the air gap. The second member is a permanent magnet in magnetic coupling relation with the first member. The first member has a tubular portion and a rod-shaped portion, the portions being magnetically coupled, at one end, by the permanent magnet with radial magnetization and, at the other end, by elements for concentrating the magnetic flux in the air gap. The air gap is delimited by these concentration elements and the facing end of the rod-shaped portion of the first member.

Magnetic sensor that concentrates magnetic flux in an air gap

A sensor system includes a coil positioned on a thin substrate sandwiched to a layer of mumeta, a high magnetic permeability material. The mumetal acts as an amplifier for the inductance L measured at the terminals of the coil. When a magnet passes in front a sheet of mumetal, its magnetic field locally saturates the mumetal whose magnetic permeability collapses on the saturated surface. The result is a reduction of the inductance factor (L) in proportion with that area of the coil covered by the saturated mumetal. This reduction in inductance is measured at the coil terminals to provide an estimation of that area of the coil that has been covered. By determining a particular layout of the coil, mumetal, and magnet, a predetermined electrical signal of inductance or coupling variations corresponding to movement of the magnet is provided.

Inductive magnetic saturation displacement sensor

Growing community of inventors

St. Marcel Paulel, France

Bernard Genot