The control block diagram of the Kobelco excavator arm retracting and merging system is shown in Figure 3.16. When the arm retracting and merging operation is performed, the pilot 2 pressure switches the small spool and the forearm merge spool and the forearm T2 spool. At the same time, The output voltage of the low pressure pressure sensor is input to the electromechanical controller, and the pilot signal processing is performed internally, and the command current corresponding to the input voltage is output to the cut-off proportional valve as shown in Figure 3J7.
0PI cuts off the proportional valve to output the secondary pressure of the proportional valve corresponding to the command current of the electromechanical controller. Switching PI cuts off 0 to switch between the arm spool and the PI cut-off spool. The negative pressure controls the pressure change, and this pressure is input to the PI , P2 toilet negative pressure sensor (SE.26, s02 and back pressure sensor.
0PI, P2 side negative pressure sensor and back pressure sensor output voltage is input to the electromechanical controller, internal negative pressure control signal processing, output to the P1 pump proportional valve (PSV-PI) and P2 pump proportional valve (PSV-P2 head As shown in Figure 3.18.
The 0PI pump proportional valve and the P2 pump proportional valve output the secondary pressure of the proportional valve corresponding to the command current of the electromechanical controller, so that the discharge volume of the PI pump and the P2 pump changes.
0 Through pure hydraulic command (pilot 2 times pressure) to switch the small spool and forearm confluence spool and forearm spool, through current hydraulic command (proportional valve 2 times pressure) to switch the PI cut-off spool, in this way, PI pump The discharge oil is merged into the discharge oil of the storage pump. @In addition, there is a large amount of oil in the large cavity of the forearm hydraulic cylinder. A spool for adding fruit will produce back pressure. Therefore, use the forearm spool and the small The arm T2 spool returns the oil return on the side of the human chamber to the tank circuit.
