Komatsu PC500LC-10R Shop Manual page 239

10 STRUCTURE AND FUNCTION
3: Swing valve
4: Boom valve
5: Left travel valve
6: Bucket valve
7: Boom Hi valve
8: Arm Hi valve
9: Service valve
10: Arm valve spool
11: Right travel valve spool
12: Swing valve spool
13: Boom valve spool
14: Left travel valve spool
15: Bucket valve spool
16: Boom Hi spool
17: Arm Hi spool
18: Service spool
19: Pressure compensation valve
20: Suction valve
21: Check valve (for boom regeneration circuit)
22: Check valve (for arm regeneration circuit)
23: Merge-divider EPC valve (for LS spool)
24: Merge-divider EPC valve (for main spool)
25. LS shuttle valve
26: LS bypass plug
27: LS select valve
28: Merge-divider valve
29. Arm quick return valve
30: Arm hydraulic drift prevention valve (if equipped)
31: Self-pressure reducing valve
32: Travel junction valve
33: Variable back pressure valve
34: Variable back pressure solenoid valve
35: Boom hydraulic drift prevention valve
PRESSURE COMPENSATION VALVE OF CONTROL VALVE
FUNCTION OF PRESSURE COMPENSATION VALVE OF CONTROL VALVE
In this machine, the built-in pressure compensation type valve is employed for the travel valve, bucket valve
(cylinder bottom), swing valve, arm Hi-valve (cylinder bottom), and service valve.
PC500LC-10R
COMPONENT PARTS OF HYDRAULIC SYSTEM
36: Boom Hi check valve
37: Main relief valve (boom, left travel, bucket, and at-
tachment)
Set pressure: 35.9 ± 0.25 MPa {366 ± 2.5 kg/cm
(160 ℓ/min)
When digging force is increased: 38.5 ± 0.25 MPa
2
{392.5 ± 2.5 kg/cm } (190 ℓ/min)
38: Main relief valve (arm, right travel, and swing)
Set pressure: 35.9 ± 0.25 MPa {366 ± 2.5 kg/cm
(160 ℓ/min)
When digging force is increased: 38.5 ± 0.25 MPa
2
{392.5 ± 2.5 kg/cm } (190 ℓ/min)
39: Unload valve (boom, left travel, bucket, and at-
tachment)
Cracking pressure: 3.1 ± 0.5 MPa {32 ± 5 kg/cm
40: Unload valve (arm, right travel, and swing)
Cracking pressure: 3.1 ± 0.5 MPa {32 ± 5 kg/cm
41: Suction safety valve
Set pressure: 24.5 ± 0.5 MPa {250 ± 5 kg/cm
42: Suction safety valve
Set pressure: 38.9 ± 0.5 MPa {397 ± 5 kg/cm
43: 2-stage suction safety valve
1st stage set pressure:
2
± 5 kg/cm }
2nd stage set pressure: 20.1 ± 0.5 MPa {205
2
± 5 kg/cm }
44: 2-stage suction safety valve
1st stage set pressure:
2
± 5 kg/cm }
2nd stage set pressure: 14.7 ± 0.5 MPa {150
2
± 5 kg/cm }
45: Suction safety valve for hydraulic drift prevention
valve
Set pressure: 38.9 ± 0.5 MPa {397 ± 5 kg/cm
2
}
2
}
2
}
2
}
2
}
2
}
24.5 ± 0.5 MPa {250
28.4 ± 0.5 MPa {290
2
}
10-145