SYSTEM / Control System Pump Flow Rate Control Purpose: Delivers oil required for the actuator from the main pump according to the control lever stroke. Operation: Control Lever: Operated 1. When the control lever is operated, pressure oil from the pilot valve according to the control pressure acts on each pressure sensor. 2. Each pilot pressure sensor detects this pressure and sends the signal to MC. 3. MC compares with the actual pump swash angle detected by the pump 1 regulator sensor or pump 2 regulator sensor, calculates the required oil amount and drives the pump control solenoid valve. 4.
Consequently, swash angle of the main pump becomes large and delivery flow rate of the main pump increases. Control Lever: In Neutral 1. When the control lever is in neutral, pilot pressure oil to each pressure sensor disappears. 2. Each pilot pressure sensor detects no pressure and sends the signal to MC. 3. MC compares with the actual pump swash angle detected by the pump 1 regulator sensor or pump 2 regulator sensor, calculates the required oil amount and drives the pump control solenoid valve. 4. Consequently, swash angle of the main pump becomes minimum and delivery flow rate of the main pump becomes minimum. NOTE:
The boom is lowered due to own weight by the boom regenerative valve during boom lower operation. Therefore, during boom lower operation, delivery flow rate of the main pump does not increase. T2-2-22