COMPONENT OPERATION / Pump Device Increasing Flow Rate (Regulator Operation with Flow Rate Control Pressure Increasing) 1. When pump control solenoid valve (4) is actuated, flow rate control pressure Pi in proportion to the movement of pump control solenoid valve (4) acts on pilot piston (3) and moves spool (2) to the right until spool (2) balances with spring (7). 2. When spool (2) moves to the right, the large chamber of servo piston (11) is connected to the hydraulic oil tank through passage in spool (2). 3.
As own pump delivery pressure P1 is routed into the small chamber of servo piston (11) all the time, servo piston (11) moves to the left and oil in the large chamber is returned to the hydraulic oil tank. 4. As servo piston (11) moves to the left, feedback lever (10) rotates clockwise around pin (9). 5. As the top end of feedback lever (10) is connected to sleeve (1) by pin (8), sleeve (1) moves to the right. Servo piston (11) continues to move until the notches on sleeve (1) and spool (2) are closed completely. 6. With the above operation, the pump displacement angle is increased, and pump delivery flow rate increases.
Increasing amount of pump delivery flow rate is proportional to the that of flow rate control pressure Pi. To Control Valve Psv 5 4 6 Pi 3 7 2 8 9 1 10 P1 11 Pilot Pump T1J1-03-01-006 Main Pump T3-1-8