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Stepless belt transmission

  • US 4,717,368 A
  • Filed: 01/23/1986
  • Issued: 01/05/1988
  • Est. Priority Date: 01/23/1986
  • Status: Expired due to Fees
First Claim
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1. A belt-type stepless transmission for an automotive vehicle, comprising:

  • a transmission mechanism which comprises an input pulley and an output pulley of variable effective diameters, each having a movable flange and a stationary flange, a transmission belt stretched between the input and output pulleys, and servomechanisms for varying the effective diameters of the input and output pulleys, and wherein at least one of the servomechanisms being a hydraulic actuator; and

    a control unit operable for supplying the hydraulic actuator with a working fluid or for discharging the working fluid from the hydraulic actuator dependent upon running conditions of the automotive vehicle in order to shift the transmission mechanism, wherein the control unit comprises;

    a supply port for supplying the working fluid to the hydraulic actuator;

    a discharge port for discharging the working fluid from the hydraulic actuator;

    a lead mechanism for changing working fluid pressure internally of the hydraulic actuator by varying an opening degree of the supply port or the discharge port by means of an electric motor controlled independently of the working fluid and dependent upon the running conditions of the automotive vehicle; and

    a follow-up mechanism operatively associated with a movable flange displaced by the changed working fluid pressure for restoring the opening degree varied by the lead mechanism, wherein the supply and discharge of the working fluid for operating the hydraulic actuator is controlled.

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