jcb JS70 Service Manual

31 - 4
Operation
The control valve is constructed with the 4-spool and 5-
spool sides overlapping and integrated into one.
When all spools are neutral
1. Neutral passage (Refer to Fig. 1, 2)
The oil delivered by port 4P passes through the 4-spool
passage to the neutral passage (a) and flows out from ports
T1 and T2.
The oil delivered from port 5P enters the passage (11) from
the 5-spool neutral passage (A), passes through the 4-spool
passage and flows from ports T1 and T2.
2. Signal Passage (Refer to Fig. 2, 12)
The oil from the signal hydraulic source enters port PP, flows
through the filter (1), the restriction (2) and is guided to the
pilot chamber (42) of the shuttle (straight travel spool).
The oil then enters passages (20) and (2) from the signal land
part of each spool on the 5-spool side, the signal land port
of each spool on the 4-spool side and tank passage from
the signal land (7) of the bucket spool.
Part of the oil flow from port PP passes through filter (1), the
restriction (46) and into port PT. The flow then enters the
passage (12), the land (4, 5 and 6) and flows to the tank
passage Ta.
Section E Hydraulics
9803/6020
Section E
31 - 4
Issue 1
Control Valve
289760
Fig. 1
B
A
C
E
G
J
D
F
H
A Swing
B Arm 1
C Arm 2
D Boom 2
E Boom 1
F Reverse
G Bucket
H Travel (Left)
J Travel (Right)

jcb JS70 Specifications

General

Brand	jcb
Model	JS70
Category	Excavators
Language	English