Patent ID: 7026809

Claim:
Position and/or speed sensor comprising: a mobile target made of a soft material with at least one mobile tooth moving in a direction perpendicular to an axis OZ, a first pair of permanent magnets having a space therebetween, magnetized along a positive or negative OZ axis and defining an air gap with the mobile target, a probe sensitive to direction and intensity of a magnetic induction and mounted in the space between the first pair of permanent magnets, the probe being arranged in the air gap in an XOY extension plane such that its axis of greatest sensitivity is approximately along the OZ axis, and at least one second permanent magnet magnetized along a direction perpendicular to the OZ axis such that a corresponding magnetic induction passes through the probe in the direction opposite to the direction of magnetic induction created by the first pair of permanent magnets and passing through the probe, in the absence of an adjacent tooth, wherein the probe is located on the OZ axis such that when there is no adjacent tooth, the magnetic induction created by the first pair of magnets passes through the probe along a direction opposite to the direction of magnetization and magnetic inductions created by the first pair of magnets and at least one second permanent magnets have approximately equal values but in opposite directions, and wherein in the presence of an adjacent tooth, the absolute value of the variation of the magnetic induction detected by the probe is greater than a trip threshold.