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Hydraulic control system for a continuously variable transmission

  • US 20010023217A1
  • Filed: 03/14/2001
  • Published: 09/20/2001
  • Est. Priority Date: 03/17/2000
  • Status: Active Grant
First Claim
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1. A hydraulic control system for a continuously variable transmission comprising a transmission mechanism which includes a set of adjustable first and second pulleys having first and second cylinder chambers, respectively, width of respective pulleys being variable according to hydraulic pressure applied to said cylinder chambers, and a belt provided between the pulleys so as to transmit torque therebetween;

  • means for producing a line pressure and continuously supplying the line pressure to said second chamber;

    a shift control valve adapted to be operated under the action of an actuator associated therewith to supply a pressure which is reduced from said line pressure to the first cylinder chamber; and

    shift control means for generating a shift command to the actuator depending on a driving condition and modifying the line pressure, characterized in that said shift control means includes means for determining whether or not said shift is accomplished, said shift control means being operable to raise the line pressure from a first level to a second level when said determining means determines that the shift to the HI side is not accomplished.

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