Magnetoelastic torque sensor

US6330833A · kind A · utility

Assignee

• Mannesmann VDO AG · DE

Inventors

• John E. Opie · Stony Creek, US
• Brian Kilmartin · Cheshire, US

Key dates

• Filing date: Dec 31, 1998
• Grant date: Dec 18, 2001
• Expiry date: Dec 31, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L3/105
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A magnetoelastic torque sensor for measuring the magnitude of torque applied to a member, comprising a magnetoelastic element which is disposed on and encircles the member, an outer flux guide extending across the magnetoelastic element in an axial direction and adjacent to the opposite end regions thereof, and an inner flux guide located between the first and second end regions, wherein the inner and outer flux guides provides a magnetic path to an axial component of the magnetic field produced by the magnetoelastic element in response to a non-zero value of torque. The inner flux guide is formed by cutting or etching an amorphous metal foil in a flat annular configuration with symmetrically projecting coil core tabs. The one-piece inner flux guide is supported by a support assembly comprising base and cover pieces. When assembled, the coil core tabs are sandwiched between two complementary semi-cylindrical mandrel portions projecting from the cover and base pieces, around which sense coil wires are wound. An electronic detector is coupled to the coil wires to measure the strength of the axial component of the magnetic field emanating from the magnetoelastic element as torque is a…