# US 6,720,763 B1 · Compact rotary magnetic position sensor having a sinusoidally varying output > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,720,763 B1 - Document ID: US6720763B1 - Status: Granted - Kind: B1 - Application number: 09/655,035 - Filed: 2000-09-05 - Granted: 2004-04-13 - Earliest claimed: 1999-09-09 - Assignees: Delphi Technologies, Inc. - Inventors: Thomas Wolfgang Nehl; Thaddeus Schroeder; Nady Boules; Rassem Ragheb Henry - Web page: https://patentgrep.com/patent/US6720763B1 ## CPC - G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)} - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract A rotary position sensor featuring a magnetized rotor which produces a magnetic flux density that varies sinusoidally with respect to the angular position of the rotor, which may be either a selectively magnetized ring or disk. The magnetic flux density produced by the rotor is measured by a sensor that responds in a linear fashion to the magnitude of the radial component of the magnetic flux density. Typical embodiments would use magnetic flux density sensors, as for example either linear Hall sensors or magnetoresistive type sensors. The measured magnetic flux densities are then used as in a traditional resolver to compute position or used to directly generate control signals to operate, for example, a motor. ## Claims ### Claim 1 A rotary position sensor comprising: a magnetized disk rotatable about a rotation axis; an outer core of a ferromagnetic material nonrotatable about the rotation axis, said outer core being concentrically disposed relative to said axis of rotation; an air gap located between said outer core and said magnetized disk; at least one magnetic flux density sensor selectively located at said air gap in stationary position with respect to said outer core; wherein the magnetization of said disk provides a magnetic field oriented in a plane perpendicular to said rotation axis; and wherein said disk is tangentially magnetized with at least one pair of poles. ### Claim 2 (depends on 1) The rotary position sensor of claim 1, further comprising an annulus located between said outer core and said disk, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus. ### Claim 3 (depends on 1) The rotary position sensor of claim 1, wherein said disk is tangentially magnetized with a plurality of pairs of poles. ### Claim 4 (depends on 3) The rotary position sensor of claim 3, further comprising an annulus located between said outer core and said disk, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus. ### Claim 5 A rotary position sensor comprising: a magnetized ring rotatable about a rotation axis; an outer core of a ferromagnetic material nonrotatable about the rotation axis, said outer core being concentrically disposed relative to said axis of rotation; an annular air gap located concentrically between said outer core and said magnetized ring; and at least one magnetic flux density sensor selectively located at said air gap in stationary position with respect to said outer core; wherein the magnetization of said ring provides a magnetic field oriented in a plane perpendicular to said rotation axis; wherein said ring is tangentially magnetized with at least one pair of poles. ### Claim 6 (depends on 5) The rotary position sensor of claim 5, further comprising an annulus located between said outer core and said ring, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus. ### Claim 7 (depends on 6) The rotary position sensor of claim 6, further comprising an inner core of ferromagnetic material disposed between said axis of rotation and said ring. ### Claim 8 (depends on 5) The rotary position sensor of claim 5, wherein said ring is tangentially magnetized with a plurality of pairs of poles. ### Claim 9 (depends on 8) The rotary position sensor of claim 8, further comprising an annulus located between said outer core and said ring, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus. ### Claim 10 (depends on 9) The rotary position sensor of claim 9, further comprising an inner core of ferromagnetic material disposed between said axis of rotation and said ring. ### Claim 11 (depends on 8) The rotary position sensor of claim 8, wherein said plurality of pairs of poles comprise a plurality of pairs of mutually spaced apart magnetic arcuates. ### Claim 12 A rotary position sensor comprising: a magnetized ring rotatable about a rotation axis; an outer core of a ferromagnetic material nonrotatable about the rotation axis, said outer core being concentrically disposed relative to said axis of rotation; an annular air gap located concentrically between said outer core and said magnetized ring; an annulus located between said outer core and said ring; and at least one magnetic flux density sensor selectively located at said air gap in stationary position with respect to said outer core; wherein the magnetization of said ring provides a magnetic field oriented in a plane perpendicular to said rotation axis; wherein said ring is radially magnetized with at least one pair of poles; and wherein said annulus is composed of a nonmagnetic material, said at least one magnetic flux density sensor being embedded in said annulus; wherein said rotary position sensor further comprises an inner core of ferromagnetic material disposed between said axis of rotation and said ring. ### Claim 13 (depends on 12) The rotary position sensor of claim 12, wherein said ring is radially magnetized with a plurality of pairs of poles. ### Claim 14 (depends on 13) The rotary position sensor of claim 13, wherein said plurality of pairs of poles comprise a plurality of pairs of mutually spaced apart magnetic arcuates. ### Claim 15 A rotary position sensor comprising: a magnetized disk rotatable about a rotation axis; an outer core of a ferromagnetic material nonrotatable about the rotation axis, said outer core being concentrically disposed relative to said axis of rotation; an air gap located between said outer core and said magnetized disk; at least one magnetic flux density sensor selectively located at said air gap in stationary position with respect to said outer core; and an annulus located between said outer core and said disk, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus; wherein the magnetization of said disk is homogeneously magnetized and provides a magnetic field oriented in a plane perpendicular to said rotation axis. ### Claim 16 A rotary position sensor comprising: a magnetized ring rotatable about a rotation axis; an outer core of a ferromagnetic material, said outer core being concentrically disposed relative to said axis of rotation; an air gap located between said outer core and said magnetized ring; and at least one magnetic flux density sensor selectively located at said air gap; wherein the magnetization of said ring provides a magnetic field oriented in a plane perpendicular to said rotation axis; and wherein said ring is homogeneously magnetized; and wherein said rotary position sensor further comprises an inner core of ferromagnetic material disposed between said axis of rotation and said ring. ### Claim 17 (depends on 16) The rotary position sensor of claim 16, further comprising an annulus located between said outer core and said ring, said annulus being composed of a nonmagnetic material, said at least one sensor being embedded in said annulus.