• US 20090146650A1
  • Filed: 12/10/2008
  • Published: 06/11/2009
  • Est. Priority Date: 12/11/2007
  • Status: Abandoned Application
First Claim
Patent Images

1. A rotation angle sensor comprising:

  • a gapped magnetic circuit that rotates interlocking with a rotation of a rotating body;

    a magnetic sensing element that senses a gapped magnetic flux of the gapped magnetic circuit; and

    a signal processing unit that outputs the angle of the rotating body by processing a signal from the magnetic sensing element;

    wherein, the gapped magnetic circuit produces a flux that changes its direction and size by the rotation of the rotating body to the magnetic sensing element so that an angle of rotation greater than 360 degrees of the rotating body is detected;

    a rotation angle sensor further comprising;

    a driving gear that is fixed to the rotating body;

    a driven gear having a thread groove on its tooth tips that engages to the driving gear and integrates the gapped magnetic circuit therein, and a magnet and a yoke;

    a screw receiver that engages to the thread groove of the driven gear so that the driven gear is displaced in its axial direction by the rotation of the driven gear; and

    a housing that supports the screw receiver and the magnetic sensing element;

    the driving gear is made up of a scissors gear that is constituted of two gears that are coaxially and relatively rotatably disposed, being adjacent to each other in the axial direction, and having an elastic biasing member that elastically biases the two gears in the directions mutually opposite to the rotating directions;

    wherein, the screw receiver is arranged at a position that regulates the displacement that separates the driven gear from the driving gear by a force applied against the driven gear caused by the elastic biasing member.

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