Komatsu PC130-7, Руководство по ремонту, Страница: 296 / 342

20-506
PC130-7
TROUBLESHOOTING
H-1 Speed or power of whole work equipment, swing, and travel is low
Trouble • Speed or power of whole work equipment, swing, and travel is low.
Related
information
• Carry out the troubleshooting in working mode A.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1 Defective unload valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Control levers Unload pressure
All levers in neutral
2.4 – 3.4 MPa
{25 – 35 kg/cm
2
}
2
Defective adjustment or
malfunction of main relief
valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting
Control levers Main relief pressure
Arm-IN circuit relieved
33.6 – 37.0 MPa
{343 – 378 kg/cm
2
}
If the oil pressure does not become normal after adjustment, the main
relief valve may have a malfunction or a defect in it. Check the main
relief valve directly.
3
Defective self-reducing
pressure valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting
Control levers Control circuit basic pressure
All levers in neutral
2.84 – 3.43 MPa
{29 – 35 kg/cm
2
}
4
Defective adjustment or
malfunction of PC valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting
Measured pump
discharge pressure
Measurement
conditions
Oil pressure ratio
Pump discharge
pressure
Swing lock switch:
LOCK
Arm-IN circuit relieved
1
PC valve output
pressure
0.6 (3/5)
If the oil pressure does not become normal after adjustment, the PC
valve may have a malfunction or a defect in it. Check the PC valve
directly.
5
Defective adjustment or
malfunction of LS valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting
Measured pump
discharge pressure
Oil pressure ratio
All levers in neutral
Either track shoe
driven idle (Full stroke)
Pump discharge
pressure
Almost same pressure
1
LS valve output
pressure
0.6 (3/5)
If the oil pressure does not become normal after adjustment, the LS
valve may have a malfunction or a defect in it. Check the LS valve
directly.
6 Malfunction of servo piston The servo piston may have a malfunction. Check it directly.
7 Defective piston pump
If none of above causes is the cause of the trouble, the cause may be
lowering performance, malfunction, or internal defect of the piston
pump.
H-1
(1)