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Loading pressure compensation type logic valve

  • US 5,174,329 A
  • Filed: 10/16/1991
  • Issued: 12/29/1992
  • Est. Priority Date: 10/18/1990
  • Status: Expired due to Fees
First Claim
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1. A loading pressure compensation logic valve comprising:

  • a housing;

    a valve poppet slidably fitted in said housing;

    a flow rate control orifice group in a cylindrical portion movable with said valve poppet;

    a loading pressure chamber facing an end of said valve poppet where said cylindrical portion is located;

    a loading pressure inlet port connected to said loading pressure chamber;

    a poppet spring chamber facing an opposed end of said valve poppet;

    an orifice connecting said loading pressure inlet port to said poppet spring chamber;

    a poppet spring in said poppet spring chamber;

    said poppet spring being preloaded to urge said valve poppet toward a poppet seat;

    a flow rate control chamber within said flow rate control orifice group;

    a drain chamber on a side of said poppet seat opposite to said flow rate control chamber;

    a control spool;

    a spool seat in said valve poppet;

    a spool spring effective for urging said control spool into sealing contact with said spool seat;

    means for controlling a force on said control spool in response to an outside pilot pressure;

    said control spool being exposed to a pressure in said poppet spring chamber;

    a pressure transfer spool in said valve poppet for conveying a force developed by pressure from said loading pressure chamber to said control spool;

    a differential pressure compensation orifice in said valve poppet, at a position closer to the loading pressure inlet port than is said flow rate control orifice group;

    a valve spring chamber connecting said differential pressure compensation orifice to said flow rate control orifice group;

    a differential pressure compensation valve radially disposed between said pressure transfer spool and said flow rate control orifice group;

    a valve spring in said valve spring chamber;

    said differential pressure compensation valve being slidable in an axial direction and pushed by said valve spring in a direction effective to open said differential pressure compensation orifice, thereby controlling a degree of opening of said differential compensation orifice;

    a larger diameter pressure chamber adjacent an end of said differential pressure compensation valve, facing in a direction of urging of said valve spring;

    means for connecting said larger diameter pressure chamber to said valve spring chamber; and

    a smaller diameter pressure chamber adjacent another end of said differential pressure compensation valve and connected to said flow rate control chamber through an orifice.

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