When the spool of the main control valve is suddenly removed from the neutral position (to the working position), the reverse adjustment pressure will drop (the pressure drop is inversely proportional to the amount of spool movement). As the reverse adjustment pressure decreases, the flow rate of the hydraulic pump will increase sharply. Therefore, the speed of the hydraulic cylinder is changed rapidly, so that the entire excavator generates strong vibration.
In order to prevent this kind of vibration phenomenon, it is necessary to reduce the change speed of the hydraulic pump flow rate.
When one of boom lifting, stick, swing and walking movements is performed, the pilot hydraulic control circuit
The contact of the pressure switch is closed (CLOSE). At this time, the EPOS-Gong controller will provide current (700mA, 3.2MPa) to the reverse control priority valve (electromagnetic proportional pressure reducing valve), and then gradually reduce its current value, reaching 150mA (OMPa) after about 1s
Shuttle Valve selects the higher of the reverse pressure from the control valve (slow drop when the spool valve moves) and the pressure from the reverse control priority valve to supply to the hydraulic pump regulator, This reduces the rate of change of hydraulic pump flow.
Reverse control priority valve settings are shown in Table 16-6, and the change curve of hydraulic pump flow is shown in Figure 16-20.
