Komatsu PC210-8, Руководство по ремонту

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UEN00245-02 40 Troubleshooting
28
PC210, 230, 240-8
H-25 Upper structure overruns remarkably when it stops swinging 1
Trouble (1) Upper structure overruns remarkably when it stops swinging in both directions.
Related
information
• Carry out all troubleshooting in power mode (P) of working mode.
Possible
causes and
standard value
in normal state
Cause Standard value in normal state/Remarks on troubleshooting
1
Defective adjustment or
malfunction of swing motor
(safety valve)
• Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Swing lock switch
Left work equipment
control lever
Swing relief pressure
ON Swing relief
28.9 – 32.9 MPa
{295 – 335 kg/cm
2
}
If oil pressure does not become normal after adjustment, swing
motor safety valve may have malfunction or internal defect. Check
safety valve directly.
2 Defective swing motor
a
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Swing lock switch
Left work equipment
control lever
Leakage from swing
motor
ON Swing relief Max. 10
l
/min
Trouble (2) Upper structure overruns remarkably when it stops swinging in only one direction.
Related
information
• Carry out all troubleshooting in power mode (P) of working mode.
Possible
causes and
standard value
in normal state
Cause Standard value in normal state/Remarks on troubleshooting
1
Malfunction of swing PPC
valve
a
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Left work equipment control lever PPC valve output pressure
Neutral
0 MPa
{0 kg/cm 2 }
Left swing
Right swing
2.84 – 3.43 MPa
{29 – 35 kg/cm
2 }
2
Clogging of swing PPC slow
return valve
Swing PPC slow return valve may have malfunction. Check it
directly.
a
Slow return valves on right side and left side may be checked
by replacing them with each other and seeing change of condi-
tion.
3
Malfunction of swing control
valve (spool) Spool of swing control valve may have malfunction. Check it
directly.
4
Malfunction of swing motor
(suction valve)
Suction valve of swing motor may have malfunction. Check it
directly.
a
Suction valves on right side and left side may be checked by
replacing them with each other and seeing change of condition.
5
Malfunction of swing motor
(check valve)
Check valve of swing motor may have malfunction. Check it
directly.
a
Check valves on right side and left side may be checked by
replacing them with each other and seeing change of condition.