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Automatic transmission with anti creep device

  • US 4,686,872 A
  • Filed: 09/13/1984
  • Issued: 08/18/1987
  • Est. Priority Date: 09/20/1983
  • Status: Expired due to Term
First Claim
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1. An automatic transmission, comprising:

  • (a) a fluid coupling;

    (b) a mechanical transmission mechanism coupled to said fluid coupling, comprising a plurality of power trains and a plurality of friction engagement mechanisms, various ones of said power trains being selectively engageable according to selective supply of actuating fluid pressure to selective ones of said friction engagement mechanisms to provide various speed stages including a lowest speed stage; and

    (c) a transmission control system comprising;

    (d) means for producing a signal representative of engine output; and

    (e) anti creep means for varying the actuating hydraulic fluid pressure for a one of said friction engagement mechanisms which is engaged for providing said lowest speed stage, according to said signal representative of engine output, from a low value when engine output is low upward as engine output increases;

    (f) said anti creep means comprising a hydraulic fluid chamber whose volume alters in relation to the amount of anti-creep action, and means for communicating said hydraulic fluid chamber to a fluid conduit system, said fluid conduit system having a flow resistance which is different in magnitude when said hydraulic fluid chamber is venting from when said hydraulic fluid chamber if filling; and

    (g) said hydraulic fluid chamber decreasing in volume as said anti creep means applies less anti creep action, and said means for communicating said hydraulic fluid chamber to said fluid conduit system provides a flow resistance which is less in magnitude for flow venting said hydraulic fluid chamber than for flow filling said hydraulic fluid chamber.

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