Inductive angle sensor for a motor vehicle steering system

A torque sensor unit for measuring torque introduced into an upper steering shaft of a motor vehicle, wherein the upper steering shaft is connectable to a lower steering shaft via a torsion bar, wherein the torque sensor unit comprises:

• a first inductive sensor that is connectable to the upper steering shaft to measure a rotary position of the upper steering shaft;
• a second inductive sensor that is connectable to the lower steering shaft to measure a rotary position of the lower steering shaft;
• and
• an evaluation unit configured to process signals from the first and second inductive sensors and calculate torque therefrom based on an angular difference between the rotary positions of the upper and lower steering shafts.

An electromechanical power steering system for a motor vehicle, comprising:

• an upper steering shaft that is connected to a steering wheel;
• a lower steering shaft that is connected to the upper steering shaft via a torsion bar;
• a torque sensor unit that includes
• a first inductive sensor that is connected to the upper steering shaft to measure a rotary position of the upper steering shaft,
• a second inductive sensor that is connected to the lower steering shaft to measure a rotary position of the lower steering shaft, and
• an evaluation unit configured to process signals from the first and second inductive sensors and calculate torque therefrom based on an angular difference between the rotary positions of the upper and lower steering shafts;
• and
• an electric motor for assisting a steering movement, which is received at the steering wheel from a driver, based on the torque measured by the torque sensor unit.

A method for determining torque introduced into an upper steering shaft of a motor vehicle steering system, wherein the upper steering shaft is connected to a lower steering shaft via a torsion bar, wherein a first inductive sensor is connected to the upper steering shaft to measure a rotary position of the upper steering shaft, wherein a second inductive sensor is connected to the lower steering shaft to measure a rotary position of the lower steering shaft, the method comprising:

• measuring an absolute rotary position of the upper steering shaft by way of the first inductive sensor;
• measuring an absolute rotary position of the lower steering shaft by way of a second inductive sensor;
• calculating an angle difference between the absolute rotary positions;
• and
• determining the torque introduced into the upper steering shaft by way of an equation TSTW=c*δ, wherein c is a spring constant of the torsion bar and δ is the angle difference.