Hydraulic control system for automatic transmission

Claim 1

IN AN ACCELERATOR CONTROLLED MULTIPLE SPEED VEHICLE TRANSMISSION OF THE TYPE EMPLOYING CHANGE SPEED GEARING CONNECTED BETWEEN AN INPUT SHAFT AND AN OUTPUT SHAFT TOGETHER WITH A PLURALITY OF FLUID OPERATED FRICTION DEVICES OPERABLE TO COOPERATE WITH THE CHANGE SPEED GEARING IN ESTABLISHING AT LEAST ONE RELATIVELY HIGH FORWARD SPEED RATIO, AT LEAST ONE RELATIVELY LOW FORWARD SPEED RATIO AND A REVERSE DRIVE BETWEEN SAID SHAFTS, THE COMBINATION OF (A) A FIRST FLUID PUMP FOR DELIVERING PRESSURIZED FLUID, (B) A SECOND FLUID PUMP FOR DELIVERING PRESSURIZED FLUID, (C) A MODULATOR VALVE CONNECTED TO RECEIVE FLUID FROM SAID PUMPS AND RESPONSIVE TO THE VEHICLE ACCELERATOR TO PROVIDE AN ACCELERATOR CONTROLLED FLUID PRESSURE VARYING IN ACCORDANCE WITH THE ACCELERATOR POSITION, (D) GOVERNOR CONTROLLED VALVING CONNECTED TO RECEIVE PRESSURIZED FLUID FROM THE SAID SECOND PUMP ONLY AND RESPONSIVE TO THE ROTATIONAL SPEED OF THE OUTPUT SHAFT TO PROVIDE A FLUID PRESSURE VARYING IN ACCORDANCE WITH THE ROTATIONAL SPEED OF THE OUTPUT SHAFT, (E) A SERVO REGULATOR VALVE RESPONSIVE TO THE SAID ACCELERATOR CONTROLLED FLUID PRESSURE AND CONNECTED IN CIRCUIT WITH THE SAID FIRST PUMP TO RECEIVE PRESSURIZED FLUID THEREFROM AND PROVIDE A SERVO FLUID PRESSURE VARYING IN ACCORDANCE WITH THE ACCELERATOR POSITION, (F) A PLURALITY OF VALVES CONNECTED IN CIRCUIT WITH THE FLUID OPERATED FRICTION DEVICES FOR CONTROLLING THE DELIVERY OF PRESSURIZED FLUID FROM THE SAID FIRST PUMP ONLY TO THE FLUID OPERATED FRICTION DEVICES AND INCLUDING I. A MANUALLY OPERABLE SELECTOR VALVE SUBJECT TO SERVO FLUID PRESSURE CONNECTED IN CIRCUIT WITH THE SAID SERVO REGULATOR VALVE AND MOVABLE BETWEEN A REVERSE POSITION AND AT LEAST ONE FORWARD POSITION AND II. A PRESSURE REGULATION CUSHIONING VALVE SUBJECT TO SERVO FLUID PRESSURE CONNECTED IN CIRCUIT WITH THE SAID SERVO REGULATOR VALVE AND THE FLUID OPERATED FRICTION DEVICES AND MOVABLE BETWEEN A NON-REGULATING POSITION WHEREIN FULL SERVO FLUID PRESSURE OUTPUT IS APPLIED TO THE FLUID OPERATED FRICTION DEVICES AND A REGULATING POSITION WHEREIN A REDUCED SERVO FLUID PRESSURE OUTPUT IS APPLIED,