Magnetostrictive torque sensor
US4939937A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1988 |
| Grant date | Jul 10, 1990 |
| Priority date | — |
| Expiry date | Jul 21, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L3/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A noncontacting method for sensing torque based on the principle of magnetostriction comprises inducing a primary magnetic flux in a shaft (20) via such means as a primary excitation core/coil(30/32), keeping primary path flux amplitude constant via such means as an auxiliary core/coil (48/50) and appropriate feedback circuitry, and obtaining a torque dependent signal which is a function of a secondary flux via such means as a secondary core/coil(34/36). Signal dependence on RPM, temperature, and material property inhomogeneities is eliminated or minimized, instantaneous torque measurement is possible, and mass production is made feasible. A second embodiment utilizes modified signal processing circuitry to eliminate spurious signal components. A third embodiment comprises a single core/coil(58/60) placed close to a shaft (20) which detects torque by means of voltage or current changes in the coil (60). Embodiment four comprises two single core/coils(58/60 and 59/61) such as those of embodiment three and signal processing circuitry which produces a signal minimally affected by RPM, temperature, and material property inhomogeneities. A fifth embodiment employs a plurality of sensors…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.