US 11,953,395 B2
Magnetic field differential linear torque sensor
Alexander Latham, Harvard, MA (US)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
Filed on Mar. 18, 2022, as Appl. No. 17/655,469.
Prior Publication US 2023/0296459 A1, Sep. 21, 2023
Int. Cl. G01L 3/10 (2006.01)
CPC G01L 3/104 (2013.01) 28 Claims
OG exemplary drawing
 
1. A differential magnetic field torque sensor, the sensor comprising:
a multipole magnet assembly configured for coupling to a first rotatable shaft having a first axis of rotation;
first and second magnetic field directors positioned adjacent the multipole magnet assembly and configured to affect magnetic flux from the multipole magnet assembly, wherein the first and second magnetic field directors are configured for coupling as a unit to a second rotatable shaft having a second axis of rotation aligned with the first axis of rotation;
first and second magnetic field concentrators configured to concentrate the magnetic flux from the multipole magnet assembly, wherein each magnetic field concentrator has first and second offset sections that are offset from one another in a direction transverse to the first axis of rotation, wherein the first and second offset sections of the first magnetic field concentrator are at different positions respectively in a direction parallel to the first axis of rotation, and wherein the first and second offset portions of the second magnetic field concentrator are at different positions respectively in a direction parallel to the first axis of rotation;
first and second interdigitated section pairs, each including an offset section of the first magnetic field concentrator configured with an offset portion of the second magnetic field concentrator in a respective orientation, and wherein the second interdigitated section pair has a reversed orientation relative to that of the first interdigitated section pair; and
a magnetic field sensor having first and second magnetic field sensing elements, each configured to measure magnetic flux and to produce an output signal based on measured changes in magnetic flux due to relative angular motion between the multipole magnet assembly and the first and second magnetic field directors, wherein the output signal is indicative of torque applied to the first or second rotatable shafts;
wherein each of the first and second interdigitated section pairs is configured to receive a respective magnetic field sensing element.