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Hydraulic valve device with associated spool displacement transducer

  • US 8,485,497 B2
  • Filed: 02/08/2011
  • Issued: 07/16/2013
  • Est. Priority Date: 02/08/2011
  • Status: Active Grant
First Claim
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1. A hydraulic valve (20), comprising:

  • a valve body (19);

    inner channels (22) within the valve body, the inner channels defining passages for fluid flow;

    at least a spool (21) present in the body, the spool movable axially in order to control the fluid flow in the inner channels (22); and

    at least a sensor (30) attached to said body (19), said sensor (30) movable with the spool (21) to i) sense a current position of the spool, and ii) give out a corresponding electrical signal indicating the current position of the spool,wherein said sensor (30) measures a linear displacement of the spool (21) by sensing an angle of magnetic field lines,wherein said sensor comprises;

    a tube assembly comprising at leasti) a tube (8) resistant to oil pressure, the tube comprising a thread (8A), the sensor mounted on the valve body by the thread so that the tube together with the valve body create a closed space where oil flows, the tube serving as a magnet housing,ii) a moving plunger (1, 2, 4, 5) having an axis (AA),iii) a magnet carrier (5) with a permanent magnet (4) located in an inside of the magnet carrier,iv) a spring (6) placed internal to the tube (8) and acting against the magnet carrier (5), the spring keeping the plunger, with the magnet (4) inside the magnet carrier, in contact with the spool (21),v) an anti-spin device (3) cooperating with the moving plunger and preventing the moving plunger from rotating around the axis (AA); and

    a body assembly comprising at leasti) a connector (9,10,12) for power supply and output signals,ii) a printed circuit board (11) with an integrated circuit serving as magnetic pickup (23),iii) a body (13) supporting the integrated circuit and the tube,iv) a tube and PC board holder (14) within the body,v) a non-magnetic body cover (16), andvi) a seal-lock nut (18) keeping the tube assembly mounted in the body assembly, wherein,said magnet moves along with the spool and creates a variation in a magnetic field during movement with the spool, andthe integrated circuit measures a linear displacement of the spool (21) by sensing a variation in an angle of magnetic field lines of the magnetic field from the permanent magnetic and generates an output signal proportional to the movement of the spool (21).

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