3-22
The oil from the P1, P2, P3 pump flows through the neutral oil passage, bypass oil passage and
confluence oil passage in the main control valve. Then the oil goes to each actuator and operates
them. Check valves and orifices are located on these oil passage in the main control valve. These
control the oil from the main pumps so as to correspond to the operation of each actuator and
smooth the combined operation.
INDEPENDENT TRAVEL SYSTEM
This independent travel system for straight travel is provided in the main control valve.
If any actuator(s) on P1 and P2 pump side is operated when traveling, the travel selector spool is
moved to the selected side by the pilot oil pressure.
Consequently, the pressure oil from P1 and P2 pump are supplied to the right and left travel motor
and oil from P3 pump flows into the other operated actuator.
This keeps the straight travel.
1. OUTLINE
A1
A2
A4
A3
S1
S1
BOOM
SWING
Pb5
4
4
1
3
LH
BUCKET
ARM
A2
1
2
3
2
Pa5
Pb10
Pa10
T
A1
A2
RH
IN
OUT
UP
DOWN
OUT
IN
P
Pa3
Pb2
Pb3
Pa2
Pa8
Pb8
Pa10
Dr2
Pb8'
Pa6
Pa7
Pa4
Pa5
Pa3
Pa1
Pa2
Pb10
Pb8
T2
Pb6
Pb7
Pb4
T1
Pb3
Pp1
Pb1
Pb2
LH
1
2
RH
B/SWING
1
2
Pa4
Pb4
2WAY OPTION
ACC
A6
B6
A3
B3
A4
B4
A2
B2
B1
A1
B5
A5
B10
A10
B7
A7
A9
B8
Dr1
Pa8
BU
2
4
3
1
L/H
R/H
Pb6
Pa6 Pb7
Pa7
TRAVEL
DOZER
DOWN
1
2
UP
Pb1
Pa1
PILOT PUMP
LINE FILTER
MAIN CONTROL VALVE
BUCKET CYL
BOOM CYL
DOZER CYL
TURNING JOINT
STOP VALVES
B/SWING CYL
BUCKET
ARM CYL
TRAVEL
SELECTOR
SPOOL
Pb5
P2
P1
P3
Dr1
R1
MAIN PUMP
TRAVEL MOTOR-LH
SWING MOTOR
TRAVEL MOTOR-RH
a1
a2
Ps
T1
T2
R/G
R/H
L/H
T2
a2
a1
T1
Ps
R/G
GB
GA
"R1"
"R2"
DB
P2(BW)
P1(FW)
P2(FW)
P1(BW)
B(CCW)
A(CW)
Mu
PB
BOOM
TRAVEL-RH
TRAVEL-LH
ARM
PTO
DOZER
SWING
BOOM
SWING
GROUP 5 COMBINED OPERATION
R35Z73HC30