US 7,990,136 B2Granted

Variable reluctance position sensor

AssigneeMoving Magent Technologies

InventorsDidier Frachon, Pierre Gandel

Life of this patent

Estimating the term…

Loading patent…

Abstract

A variable reluctance analog position device designed to determine the position variation of a target made from a ferromagnetic material. The device includes at least one magnet, the target and the magnet defining a gap therebetween. A magnetosensitive element detects induction variation produced in the gap by relative movement of the target relative to the magnet. The magnet is magnetized in a direction essentially perpendicular to the front surface of the magnet, which defines one edge of the gap. The magnet includes a cavity open at the front surface thereof and the magnetosensitive element is housed in the cavity. Moreover, the target is provided with a specific geometric configuration determined such that the induction variation according to the position of the target corresponds to a pre-defined function.

Claims17

Dependent claims

A variable-reluctance analog position transducer configured to determine a position of a target, comprising:

a target made of a ferromagnetic material;
at least one magnet, the target and the at least one magnet defining between one another an air gap;
and
a magnetosensitive element detecting a magnetic induction caused by a presence of the target and related to the air gap between the target and the at least one magnet, wherein the at least one magnet has a unidirectional and unipolar magnetization along a direction substantially perpendicular to a front surface of the at least one magnet bounding one edge of the air gap, the at least one magnet having a cavity opening on the front surface of the at least one magnet, the magnetosensitive element being seated in the cavity and sensing a direction and amplitude of the induction of the magnet, the target having a geometric configuration such that the variation of induction as a function of the position of the target corresponds to a predefined linear function while a variation of the air gap is nonlinear with regards to displacement of the target with respect to the magnet.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 12/852,219Filed 6 Aug 2010 · continuation
Priority: FR 02 124257 Oct 2002
Published: US 2011/0043194 A124 Feb 2011
Granted: 2 Aug 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01D 5/147
Using Hall-effect devices: influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed…
G01D 2205/73
Position sensors comprising a moving target with particular shapes, e.g. of soft magnetic targets: targets mounted eccentrically with respect to…
G01D 2205/772
Toothed profiles: sawtooth profiles
G01D 2205/777
Specific profiles: whorl-shaped profiles

Family

PCT/FR03/02949Parent of this continuation · filed 7 Oct 2003
US 2011/0043194 A1Pre-grant publication · published 24 Feb 2011
Application10/530,485Parent of this continuation
US 2006/0125473 A1Published application
US 7,906,959 B2Related patent
US 7,990,136 B2This patent

From the US filing history. Foreign family members aren’t listed.