Magnetic torque sensor system
US6904814B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 11, 2001 |
| Grant date | Jun 14, 2005 |
| Priority date | — |
| Expiry date | Sep 11, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L3/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A shaft (40) subject to torque about its axis (A—A) has an axial bore (42). A region (44) of the shaft (40) has a stored magnetisation, the region (44) being permanently magnetised with circumferential magnetisation about the axis (A—A) or an annulus of longitudinal magnetisation which is preferred. The stored magnetisation emanates a torque-dependent field into the bore (42). A magnetic field sensor arrangement (50) is positioned in the bore to produce a torque-dependent signal. The disclosure discusses the relationship between the radial depth (tm) of the permanent magnetisation in region (44) relative to the shaft wall thickness (t). Magnetic sensor placements include axial (52, 54) or offset arrangements of pairs of sensors (52a,b, 54,b). Dependent on the nature of the field to be sensed, sensors (5) may be oriented axially, radially or tagentially with respect to the axis (A—A).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.