1. Regenerative control (normal regeneration position) @When performing arm recovery operation, the pilot pressure will switch the arm spool for the second time, and at the same time, it will be input to the low pressure pressure sensor (SE-7).
2. The output voltage of the low pressure pressure sensor is input to the electromechanical controller, and the pilot signal is processed internally, and the command current corresponding to the input voltage is output to the forearm variable regeneration proportional valve (PSV-A) O@小臂变The regenerative proportional valve switches the arm variable regenerative spool at the secondary pressure of the proportional valve corresponding to the command current from the electromechanical controller.
3. Due to the switching of the arm spool, the negative pressure control pressure changes, and this pressure is input to the P2 negative pressure sensor (SE-27) and back pressure sensor (SE-28).
4. The output voltage of the P2 negative pressure sensor and back pressure sensor is input to the electromechanical controller, and the negative pressure control signal is processed internally, and the command current corresponding to the input voltage is output to the P2 pump proportional valve (PSV-P2) e@P2 The pump proportional valve changes the discharge volume of the P2 pump with the secondary pressure of the proportional valve corresponding to the command current from the electromechanical controller.
5. Switch the arm spool by pure hydraulic command (pilot secondary pressure), and switch the arm variable regeneration spool by electric current hydraulic command (proportional valve secondary pressure). In this way, the return oil on the small cavity side of the arm hydraulic cylinder is regenerated into the discharge oil of the P2 pump and supplied to the large cavity side.
6. When the arm recovery operation is performed, the excitation signal from the electromechanical controller to the rotary parking brake solenoid valve (SV-I) is cut off, and the rotary parking brake is released.
Forearm variable regeneration spool in E/G no-load state, the command current is input from the electromechanical controller to the forearm variable regeneration proportional valve (PSV-A), and the forearm variable regeneration spool returns to "normal" Regeneration'' position.
When the arm recovery load pressure reaches 32MPa or more, the arm variable regeneration valve core returns to the "regeneration cut" position.
2. Regenerative cut-off control (regenerative cut-off position) @ The output voltage of the high-pressure pressure sensor (SE-23) input through the load pressure, in the arm recovery operation, when the P2 pumping pressure reaches 32MPa or more, it is performed in the electromechanical controller Pilot signal processing, output the command current corresponding to the input voltage to the forearm variable regeneration proportional valve.
0 The forearm variable regeneration proportional valve outputs the proportional secondary pressure corresponding to the command current from the electromechanical controller, and the forearm variable regeneration spool returns to the "regeneration cut-off" position again. 3. Sequential merge control (regeneration cut-off position) @小臂 Recovery operation, the load is higher, when the P2 pump discharge pressure reaches more than 28MPa, the output pressure of the P2 pump high pressure pressure sensor is processed by the pilot signal inside the electromechanical controller, and the system command current corresponding to the input voltage is output to the straight line Proportional valve (PSV-C) and PI cut-off proportional valve (PSV-D) a@Straight travel proportional valve and PI cut-off proportional valve output the secondary pressure of the proportional valve corresponding to the command current from the electromechanical controller, switch the direct travel spool and PI Cut off the proportional valve spool.
The 0PI cut-off proportional valve spool changes the negative pressure control pressure by switching. This pressure is input to the PI negative pressure sensor (SE-26), and the output voltage is input to the electromechanical controller, which performs negative pressure control signal processing internally. Output the command current corresponding to the input voltage to the PI pump proportional valve (PSV-PI).
0PI pump proportional country changes the PI pump discharge volume with the secondary pressure of the proportional valve corresponding to the command current from the electromechanical controller.
0 straight-line proportional valve spool through the switch, the PI side parallel circuit and the P2 parallel circuit are connected, and the switching of the proportional valve spool is cut off by PI, the PI pump and the P2 pump are combined. This is the merging control of the forearm recovery sequence.
The occasions when the sequential merge control is cancelled are: walking operation: when the second pressure of the forearm recovery pilot is below 6MPa; when the bucket lifting operation: when the P2 pump pressure is kept below 28MPa for more than 0`2s: lifting switch When it is "ON".
