2-16
TRAVEL OPERATION
2)
P1
P2
P1
P2
A6
B6
(A7)
(B7)
Travel motor
Tank passage
Spool changeover
direction
Pilot passage for travel independent signal:
Supply pilot pressure oil via Pp1 port in P3
supply comp.
Operation during travel(Forward)
Pa6
(Pa7)
Pa6
Pa7
R35Z72MCV12
For the travel operation, both Pa pressurization and Pb pressurization are the same on operation so
that only Pa pressurization is explained as follows.
When left (right) travel reverse is operated, the secondary pressure from the remote control valve is
applied to Pa6 [Pa7] port to change over the travel spool. The oil flowed from P2 [P1] port flows
through the supply body into the P2 [P1] side bypass passage. The oil flowed into the P2 [P1] side
bypass passage flows through A6 [A7] port that has been opened by the spool changeover to the
travel motor. On the other hand, the oil returned from the travel motor flows into the control valve
from B6 [B7] port and then to the tank passage has been opened after the spool changeover.
The oil flowed from PP1 port flows through the orifice passage provided in the P3 supply section
into the travel independent signal passage.
Although the travel independent passage (see page 2-15) in the travel section that has been
opened during neutral is blocked after the both travel spools changeover, the travel independent
signal passage is connected to the drain port via the bucket section Accordingly, when the bucket
section has not changed over, the connecting spool in the P3 supply section does not change over
because the pressure in the travel independent signal passage is equal to the drain pressure.
