Eddy current sensor assembly for shaft torque measurement
AssigneeThe Timken Company
InventorsOrestes Varonis, Duane Carnahan
Life of this patent
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Abstract
The present disclosure provides a device for sensing a torque applied through a shaft 18. The device comprises a magnetoelastic ring 24 press-fitted onto the shaft 18 and an excitation coil 2 placed in close proximity to the ring 24 at only a point along the circumference of the ring 24. The coil 2 is driven by an oscillator 4 for inducing eddy currents inside the material of the ring 24. A sensing coil 8 is also placed in close proximity to the magnetoelastic ring 24 at only a point along the circumference of the ring 24 for sensing the magnetic field generated by the induced eddy currents inside the ring 24. An electrical circuit senses any change in the magnetoelastic ring's 24 electrical conductivity and magnetic permeability.
Claims16
A device for sensing a torque applied through a shaft, the device comprising:
- a magnetoelastic ring press-fitted on the shaft whose torque is measured;
- an excitation coil placed in close proximity to the magnetoelastic ring at only a point along the circumference of the ring, the coil driven by an oscillator for inducing eddy currents inside the material of the ring;
- a sensing coil placed in close proximity to the magnetoelastic ring at only a point along the circumference of the ring for sensing the magnetic field generated by the induced eddy currents inside the ring;
- an electrical circuit for sensing a change in the ring's electrical conductivity and magnetic permeability.
The device of claim 3 further comprising:
- a second excitation coil;
- a second sensing coil, wherein the first and second sensing coils generate signals of approximately equal amplitude and opposite phase;
- and
- wherein the second excitation coil and the second sensing coil
Dependencies are inferred from the claim text.