Reduced axial movement error in a torque-sensing system

A method for reducing the axial movement error in a torque system comprising a ring press-fit onto a shaft, the ring including a first and a second magnetic field band, the bands having a peak field strength in the center of each band, a first sensor, and a second sensor, the method comprising:

• positioning the first sensor offset from the center of the first band in a first direction;
• positioning the second sensor offset from the center of the second band in a second direction, wherein the second direction is opposite the first direction;
• measuring the magnetic field of each of the bands with its respective sensor;
• determining a total magnetic field from the measured magnetic fields of the first and second bands;
• and
• converting the total magnetic field into torque to obtain an initial torque for the system.

A magnetic torque sensing system for providing a reading indicative of the torque applied to a member about an axially extending axis of a rotatable shaft, the system comprising:

• a magnetoelastic ring press-fit onto the shaft;
• the ring having a cylindrical shape with first and second magnetic field bands magnetized in opposite directions;
• the magnetic field bands each having a peak field strength near the center of the band;
• and
• first and second magnetic sensors operable to measure the magnetic fields of the bands in the ring;
• wherein the first sensor is positioned to one side of the center of the band and the second sensor is positioned to the other side of the center of the band to minimize the error in the torque reading.

A magnetic torque sensing system for providing a reading indicative of the torque applied to a member about an axially extending axis of a rotatable shaft, the system comprising:

• the rotatable shaft having first and second magnetic field bands, each producing a magnetic field with a peak field strength near the center of the band when torque is applied;
• and
• first and second magnetic sensors operable to measure the magnetic fields of the bands;
• wherein the first sensor is positioned to one side of the center of the first band and the second sensor is positioned to the other side of the center of the second band, thereby minimizing error in the sensed torque when the shaft moves in an axial direction.