Rotational direction detection device for a motor or the like
First Claim
1. A rotational direction detection device comprising a single permanent magnet rotatable in response to the rotation of a rotary shaft of a rotary object for generating a rotating magnetic field in a first plane substantially perpendicular to the rotary shaft;
- a magnetic field sensor disposed in a second plane parallel to and adjacent said first plane and spaced from said shaft, and having a plurality of ferromagnetic magnetoresistive elements lying in said second plane so as to be responsive to said rotating magnetic field for generating an output representative of the rotation of said rotary shaft, at least two of said elements being arranged within said second plane to form an angle other than 0 degree, 90 degrees, 180 degrees and 270 degrees; and
a rotary condition detector responsive to the output of said magnetic field sensor for determining the rotational direction of said rotary shaft.
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Accused Products
Abstract
A rotational direction detection device is disclosed which has a single permanent magnet rotatable in response to the rotation of a rotary shaft. A magnetic field sensor is composed of a plurality of magnetic field detecting elements responsive to a rotating magnetic field produced by the rotation of the permanent magnet for generating an output representative of the rotation of the rotary shaft. The magnetic field detecting elements are arranged so that signals developed by at least two such elements differ in phase by a phase angle of other than 0 degree and 180 degrees. A rotary condition detector is responsive to the output of the magnetic field sensor for determining the rotational direction of the rotary shaft.
104 Citations
5 Claims
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1. A rotational direction detection device comprising a single permanent magnet rotatable in response to the rotation of a rotary shaft of a rotary object for generating a rotating magnetic field in a first plane substantially perpendicular to the rotary shaft;
- a magnetic field sensor disposed in a second plane parallel to and adjacent said first plane and spaced from said shaft, and having a plurality of ferromagnetic magnetoresistive elements lying in said second plane so as to be responsive to said rotating magnetic field for generating an output representative of the rotation of said rotary shaft, at least two of said elements being arranged within said second plane to form an angle other than 0 degree, 90 degrees, 180 degrees and 270 degrees; and
a rotary condition detector responsive to the output of said magnetic field sensor for determining the rotational direction of said rotary shaft. - View Dependent Claims (2, 3, 4, 5)
- a magnetic field sensor disposed in a second plane parallel to and adjacent said first plane and spaced from said shaft, and having a plurality of ferromagnetic magnetoresistive elements lying in said second plane so as to be responsive to said rotating magnetic field for generating an output representative of the rotation of said rotary shaft, at least two of said elements being arranged within said second plane to form an angle other than 0 degree, 90 degrees, 180 degrees and 270 degrees; and
Specification
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- Resources
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Current AssigneeNippon Electric Company Limited (NEC Corporation)
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Original AssigneeNippon Electric Company Limited (NEC Corporation)
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InventorsNagao, Morimasa, Ito, Susmu
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Primary Examiner(s)Smith, Alfred E.
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Assistant Examiner(s)O'Hare, Thomas P.
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Application NumberUS06/031,094Time in Patent Office846 DaysField of Search324/165, 324/173, 324/207, 324/174, 324/208, 324/252, 338/12, 338/32 R, 338/32 H, 340/672US Class Current324/165CPC Class CodesG01P 13/04 Indicating positive or nega...
