Torque sensor for electrical power steering system has elastic part between two shafts, ferromagnetic part, weakly magnetic part forming variable flux density magnetic circuit and magnetic sensor

摘要

The device has an elastic part between and fixed to two shafts so the shafts and elastic element are coaxial and a magnetic flux density sensor. The element is twisted elastically when torsion is applied to the shafts. A ferromagnetic part produces a magnetic field. A weakly magnetic part forms a magnetic circuit whose flux density varies when the rotational offset of the weakly magnetic and ferromagnetic parts varies with elastic part rotation. The device has an elastic part between and fixed to the first and second shafts so the shafts and elastic element are mutually coaxial and the elastic element is twisted elastically when torsion is applied to the shafts, a ferromagnetic part that produces a magnetic field, a weakly magnetic part in the magnetic field to form a magnetic circuit whose flux density varies when the rotational offset of the weakly magnetic part relative to the ferromagnetic part varies according to the rotation of the elastic part and a magnetic sensor for detecting the flux density. Independent claims are also included for the following: (a) an electrical power steering system with an inventive device (b) and a method of assembling a torque sensor.