COMPONENT OPERATION / Pump Device Control by Flow Rate Control Pressure of Pump Control Solenoid Valve Minimum Flow Rate (Regulator Operation with Flow Rate Control Pressure 0) 1. When flow rate control pressure from pump control solenoid valve (4) is 0, spool (2) is pushed to the left by spring (7). 2. As a result, own pump delivery pressure P1 is routed into the large chamber in servo piston (11) through check valve (6), sleeve (1) and spool (2). Although own pump delivery pressure P1 is also routed into the small chamber in servo piston (11), servo piston (11) moves to the right due to the difference in pressure receiving areas. 3.
As servo piston (11) moves, feedback lever (10) rotates counterclockwise around pin (9). 4. As the top end of feedback lever (10) is connected to sleeve (1) by pin (8), sleeve (1) moves to the left. Servo piston (11) continues to move until the notches on sleeve (1) and spool (2) and closed completely. 5. With the above operation, the pump displacement angle becomes the minimum so that pump delivery flow rate become minimum. To Control Valve Psv 5 4 6 3 7 2 8 9 1 10 P1 T1J1-03-01-005 11 Pilot Pump Main Pump T3-1-6