The control block diagram of the Kobelco excavator boom recovery and sequential confluence system is shown in Figure 3.7
1. Regeneration control (normal regeneration position) @ When performing the arm recovery operation, the pilot pressure is switched twice to switch the arm spool, and at the same time, it is input to the low pressure sensor (SE-7).
2. The output voltage of the low-pressure pressure sensor is input to the electromechanical controller, and the pilot signal processing is performed internally to output the command current corresponding to the input voltage to the small arm variable regeneration proportional valve (PSV-A) O@小臂变. The regenerative proportional valve switches the arm variable regenerative spool with the pressure of the proportional valve corresponding to the command current from the electromechanical controller twice.
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 the 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 processing is performed internally to output the command current corresponding to the input voltage 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 2 times pressure), and switch the arm variable regeneration spool by current hydraulic command (proportional valve 2 times pressure). In this way, the return oil on the small chamber side of the arm cylinder is regenerated into the discharge oil of the P2 pump and supplied to the large chamber side.
6. During the arm recovery operation, 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.
The operation state of the variable regeneration spool of the arm is shown in Figure 3.8.
Under the E/G no-load condition, the arm variable regeneration spool inputs the command current from the electromechanical controller to the arm variable regeneration proportional valve (PSV-A), and the arm variable regeneration spool returns to "usually Regeneration'' position.
When the recovery pressure of the arm reaches 32MPa or more, the variable regeneration spool of the arm returns to "regeneration cut"
Location.
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 pump output 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 small arm variable regeneration proportional valve.
0 The arm variable regeneration proportional valve outputs the secondary pressure proportional to the command current from the electromechanical controller, and the arm variable regeneration spool returns to the "regenerative cut" position again. 3. Sequence merge control (regenerative cut position) @小臂 Recovery operation, the load is higher, when the discharge pressure of the P2 pump reaches more than 28MPa, the output pressure of the high-pressure pressure sensor of the P2 pump is processed by the pilot signal inside the electromechanical controller, and the system command current corresponding to the input voltage is output to go straight Proportional valve (PSV-C) and PI shut-off proportional valve (PSV-D) a@Straight travel proportional valve and PI shut-off proportional valve output proportional valve 2 times pressure corresponding to the command current from electromechanical controller, switch straight travel spool and PI Cut off the proportional valve spool.
The spool of the 0PI cut-off proportional valve changes the negative pressure control pressure by switching. This pressure is input to the PI negative pressure sensor (SE-26), the output voltage is input to the electromechanical controller, and the negative pressure control signal is processed internally. The command current corresponding to the input voltage is output to the PI pump proportional valve (PSV-PI).
The 0PI pump proportional state changes the discharge volume of the PI pump with the secondary pressure of the proportional valve corresponding to the command current from the electromechanical controller.
0 Straight proportional valve spool is switched to make the PI side parallel circuit and P2 parallel circuit conductive, and by switching off the PI cut proportional valve spool, the oil from the PI pump and P2 pump is merged. This is the combined control of the arm recovery sequence.
The occasions when the sequential confluence control is released are: walking operation: when the secondary arm recovery pilot pressure is less than 6MPa; bucket hoisting operation: when the pressure of the P2 pump remains below 28MPa for more than 0`2s: lifting switch When it is "ON".
