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Vibration generator

  • US 9,325,230 B2
  • Filed: 04/25/2012
  • Issued: 04/26/2016
  • Est. Priority Date: 05/10/2011
  • Status: Active Grant
First Claim
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1. A vibration generator, comprising:

  • a tubular case made of a magnetic material, the tubular case having a first axial end and a second axial end opposite to the first axial end;

    an end cover arranged to close an opening of the first axial end of the tubular case and to hold a first bearing;

    a second bearing held at the second axial end of the tubular case;

    a movable thrust shaft axially movably inserted through the first bearing and the second bearing and made of a non-magnetic material;

    a coil bobbin made of a resin to accommodate a first coil, a second coil and a third coil, the coil bobbin fixed to an inner circumferential surface of the tubular case such that the first coil, the second coil and the third coil are located in an adjoining relationship with each other;

    an axially-magnetized first tubular permanent magnet and an axially-magnetized second tubular permanent magnet, each arranged within the tubular case and fixed to the movable thrust shaft extending therethrough, the axially-magnetized first tubular permanent magnet being closer to the first axial end than the axially-magnetized second tubular permanent magnet;

    a first annular pole piece arranged within the tubular case and fixed to the movable thrust shaft extending therethrough, the first annular pole piece overlaid on one axial end surface of the first tubular permanent magnet and having an outer peripheral edge facing an inner circumferential surface of the first coil;

    a second annular pole piece arranged within the tubular case and fixed to the movable thrust shaft extending therethrough, the second annular pole piece provided between the axially-magnetized first tubular permanent magnet and the axially-magnetized second tubular permanent magnet, the second annular pole piece facing an inner circumferential surface of the second coil;

    a third annular pole piece arranged within the tubular case and fixed to the movable thrust shaft extending therethrough, the third annular pole piece overlaid on one axial end surface of the second tubular permanent magnet and having an outer peripheral edge facing an inner circumferential surface of the third coil, anda spring means arranged to axially bias the movable thrust shaft with respect to the first axial end or the second axial end of the tubular case wherein both end portions of the movable thrust shaft extend outside the tubular case, the vibration generator further comprising;

    a first weight body fixed to one axial end portion of the movable thrust shaft outside the tubular case; and

    a second weight body fixed to the other axial end portion of the movable thrust shaft outside the tubular case.

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