Device for detecting the position of a moveable magnet to produce a magnetic field
US6346806B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 1999 |
| Grant date | Feb 12, 2002 |
| Priority date | — |
| Expiry date | Sep 13, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a device for detecting the position of a magnet which is positioned so that it is moveable (3, 23, 24) to produce a magnetic field (6) through a ferromagnetic wall (1, 29), a magnetic field sensor (10, 21, 21′) being situated in front of said wall. When said magnet (3, 23, 24) is moved in relation to said wall (1), the lines (6) of the field build up a useful flux (6) which progresses in said wall (1, 29). Said useful flux has magnetic remanence (7) which is retained after the magnet (3, 23, 24) has passed by, is aligned along the movement axis of the magnet (3, 23, 24) in accordance with the polarity, and builds up a fringing flux (12) to the front side of the wall (1, 29) where the magnetic field sensor (10, 21, 21′) is positioned. Outside of said wall, the fringing flux (12) is opposed and is aligned with the useful flux (6). The magnetic field sensor is a magnetic field sensor element (10, 21, 21′) located at a short distance from the wall (1, 29) and detects the field direction of the fringing flux (12); when the magnet (3, 23, 24) passes by, the fringing flux is superposed by the field (6) of the magnet (3, 23, 24). The magnetic fiel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.