Kubota M108S, Workshop Manual

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8-M5
M108S, WSM HYDRAULIC SYSTEM
[2] CONTROL VALVE
■
Neutral
Pressurized oil from the P port, pushes and opens
unload poppet 1 (4) and returns to tank from T1 port.
The oil in the chamber A behind the unload poppet 1
(4) returns to the tank through the E of spool (3) and
control valve body. The oil in the hydraulic cylinder does
not flow out because the circuit is cut off by the actions of
poppet 1 (1) and poppet 2.
This allows the implement to be kept at a steady
height.
W1020421
■
Lifting
When the control lever is moved to “UP” position,
spool (3) is pulled by the spool operating lever, forming a
circuit with the P port and chamber A.
The pressurized oil thus flows into the chamber A and
closes unload poppet 1 (4).
The pressure in the circuit slowly rises, pushing open
poppet 1 (1), and the hydraulic oil flows into the hydraulic
cylinder from the C port, lifting the implement.
W1020747
(1) Poppet 1
(2) Poppet 2
(3) Spool
(4) Unload Poppet 1 P : Pump Port
C : Cylinder Port
T1 : Tank Port 1
T2 : Tank Port 2
T3 : Tank Port 3
E : Groove
A : Chamber A
(1) Poppet 1
(2) Poppet 2
(3) Spool
(4) Unload Poppet 1 P : Pump Port
C : Cylinder Port
T1 : Tank Port 1
T2 : Tank Port 2
T3 : Tank Port 3
A : Chamber A
KiSC issued 06, 2007 A