1. During the bucket recovery operation of the Kobelco excavator, the bucket spool will be pressure converted twice.
2. The change of the negative pressure control pressure caused by the switching of the bucket valve core is input to the PI side negative music control sensor Qiao E. 26) and back pressure sensor (SE-28
3. The output voltage of the PI side negative pressure control sensor and back pressure sensor is input to the electromechanical integrated controller, and the negative pressure control signal processing is performed internally, and the output is output to the PI pump proportional valve (PSV-PI). As shown in Figure 3.19, the negative pressure control signal processing is shown in Figure 20.
4. The PI pump proportional valve outputs the secondary pressure of the proportional valve corresponding to the command current of the electromechanical controller to control the pump discharge.
5. The bucket valve core is switched by the pure hydraulic command (pilot pressure twice), and the discharge volume of the PI pump is controlled with negative pressure.
