Magnetic speed sensor and method of making the same
AssigneeMagna-Lastic Devices, Inc.
InventorSeong-Jae LEE
Life of this patent
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Abstract
An speed sensor for a rotating shaft includes a plurality of magnetic portions on the shaft that output a magnetic field from each of the magnetic portions, wherein the magnetic portions are integrally formed in the shaft by magnetically polarizing the shaft material itself. At least one magnetic field sensor is positioned proximate to the shaft for detecting the magnetic field from each of the magnetic portions and for outputting a signal corresponding to the angular speed of the shaft as the shaft rotates. The signal is useful for calculating the angular speed of the shaft, and the calculated angular speed value is useful for things like adjusting the angular speed of the shaft, monitoring the performance of the system in which the shaft is used, and for other purposes.
Claims24
A method for forming a magnetic speed sensor for a rotatable shaft comprising the steps of:
- forming a plurality of magnetic spots on the shaft, the magnetic spots outputting a magnetic field detectable by at least one magnetic field sensor as the shaft rotates;
- and
- positioning the at least one magnetic field sensor near the shaft for outputting a signal corresponding to the angular speed of the shaft as the shaft rotates,
- wherein the magnetic spots are integrally formed in the shaft by magnetically polarizing the shaft material itself.
A method for operating an angular speed sensor comprising the steps of:
- receiving an electronic signal from at least one magnetic field sensor corresponding to the angular speed of a shaft as the shaft rotates, wherein the field sensor is fixed relative to the shaft and positioned close to the shaft for detecting a plurality of magnetic fields each emanating from one of a corresponding plurality of magnetic spots on the shaft as each of the plurality of magnetic spots is moved proximate to the magnetic field sensor;
- calculating using the signal an angular speed value for the shaft;
- and
- storing at least temporarily the calculated angular speed value,
- wherein the plurality of magnetic spots are integrally formed in the shaft by magnetically polarizing the shaft material itself.
An apparatus for determining the speed of a rotating shaft comprising:
- a plurality of magnetic spots on a shaft for outputting a magnetic field from each of the plurality of magnetic spots, wherein the plurality of magnetic spots are integrally formed in the shaft by magnetically polarizing the shaft material itself;
- and
- at least one magnetic field sensor positioned proximate to the shaft for detecting the magnetic field from each of the plurality of magnetic spots and for outputting a signal corresponding to the angular speed of the shaft as the shaft rotates.
Dependencies are inferred from the claim text.