
2 minute read
5. Option Pilot Valve (remote control valve
from Sumitomo SH350LC-5 SH350HD-5 SH370HD-5 Hydraulic Excavator Service Text Manual WLST3505-01T - PDF
Multi-purpose circuit (2 pumps flow crusher)
When the 2 pumps flow select switch in the cab is flipped to the 2 pumps flow side, the ON signal (24 V) is output from the computer A to the 2 pumps flow solenoid valve to switch the valve.
When the multi-purpose circuit switch is flipped to the crusher side, the crusher circuit is formed without outputting a signal from the computer A to the option switchover solenoid valve and without switching the valve.
At this time, the pilot signal does not go to the 3-direction valve or to the shut-off valve and the 3direction valve forms the A ⇔ B circuit.
By operating the option remote control valve to the crusher close side, the pilot pressure oil is fed to the control valve pa2 port and switches the option spool.
At the same time, the pilot pressure oil flows from the solenoid valve for 2 pumps flow B2 port to the
A2 port and is fed to the control valve pcc port and the control valve neutral cut valve is switched.
The discharge oil from hydraulic pump A2 enters the control valve P2 port and goes through the center bypass oil path and since the neutral cut valve has closed the port to the tank, the oil goes from the P3 port via the P4 port and merges on the upstream side of the option spool.
The discharge oil from hydraulic pump A1 is fed from the control valve P1 port through the parallel oil path and fed to the option spool. Switching the spool lets the oil flow from the shut-off valve A port through the B port and into the crusher.
At this time, the option pilot pressure switch signal is detected, the P1 flow control proportional valve is controlled by the output signals from the computer A to adjust the discharge flow.
The return oil from the crusher returns from the 3-direction valve A port through the B port and the option spool and returns to the hydraulic oil tank.
Because the crusher operating flow can be set to 5 levels on the service support screen of the monitor display, the optimum operating flow can be selected.
Pressure line Tank line Pilot pressure line Pilot tank line Electric line
1 3-direction valve 10 Monitor display 19 5 stack solenoid valve 2 Shut-off valve 11 Computer A 20 Console lever lock switch 3 Crusher 12 Multi-purpose circuit switch 21 Horsepower control proportional valve 4 Option switchover solenoid valve 13 2 pumps flow select switch 22 P1 pressure sensor 5 2 pumps flow solenoid valve 14 Control valve 23 P2 pressure sensor 6 Option remote control valve 15 Neutral cut valve 24 N1 negative control pressure sensor 7 Check valve 16 Travel pilot pressure sensor 25 N2 negative control pressure sensor 8 Oil cooler 17 Upper pilot pressure sensor 26 P1 flow control proportional valve 9 Option pilot pressure switch 18 Lever lock 27 Hydraulic pump
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Enlarged View