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3-22
3-22
When the travel levers are pushed forward or reverse position, the travel spools in the main control
valve are moved to the forward or reverse travel position by the pilot oil pressure from the remote
control valve.
The oil from the each pump flows into the main control valve and then goes to the each travel motor
through the turning joint.
The return oil from both travel motors returns to the hydraulic oil tank through the turning joint and
the travel spools in the main control valve.
When this happens, the machine moves to the forward or reverse.
8. TRAVEL FORWARD AND REVERSE OPERATION
PS
(P4)
(P3)
N2
Pca
Dr3
P2c2
Ba
Aa
PAa
PBa
Bo
Ao
PAo
PBo
(Ck2)
Drb
PBb2
PSp
Dra
Bs
As
PAs
PBs
Dr4
Pns
Br
Ar
PAr
PBr
R3
TRAVEL(RH)
SWING
BOOM 2
T1
Pa
P2
P1 P1g
P2g
R4
(PTb)
PS
PL1
Py
PBL
PAL
Px
P
PBb
PAb
Ab
Bb
P2c1
Dr3'
PBc
PAc
PAcs
Bc
Ac
PBa2
PAa2
Pcb
N1
OPTION
ARM 1
ARM 2
BUCKET
BOOM 1
TRAVEL(LH)
B
PS
PS
PS
PS
PS
A
B
C
TRAVEL
P
T
RCV PEDAL
(2)
PBr
(1)
PAr
(4)
PBL
(3)
PAL
BOOM
P
T
BUCKET
ARM
P
T
SWING
c
e2
d1
h1
h2
P2c1
PAb
(4)
PBc
Pca
PAc
PAcs
PBb2
PBb
PAa2
P2c2
PAa
PBa2
PBa
PBs
PAs
PSp
Dr#,dr#
T
LINE FILTER
P3
P2
P1
P4
Pns
(MCV)
PL1
(MCV)
P
(T/Joint)
A1
A2
A4
A5
SH
(2)
(1)
(3)
(4)
(2)
(3)
(1)
HYDRAULIC TANK
Dr
LH
RH
Dr
Dr
Dr
Mb
B
A
A
C
P
Dr
D
B
B
A
Pi
Pi
Pi
Pi
N
N
Ma
Ma
Mb
TRAVEL SPEED
SOLENOID VALVE
Pk
Turning joint
TRAVEL MOTOR
SWING MOTOR
ARM
CYLINDER
BUCKET
CYLINDER
BOOM
CYLINDER
PILOT
PUMP
BL
AL
PG(S/Motor)
Pa(MCV)
Psv1(M/PUMP)
P(MCV)
c
a
b
d
e
f
g
h
j
PUMP
A1
PUMP
A2
A
D
E
F
G
H
J
380L3HC18