jcb JS200 Service Manual page 273

Section E
31 - 5
Operation (continued)
* Bucket Spool Selection
Dump: Crowd (Refer to Fig. 11).
When the pilot port P
bR3
the oil delivered from P
n flows through the spool neck and from passage P (q) flows to the cylinder port B
The return oil from the cylinder port A
passage.
II Speed Confluence (Refer to Fig. 11, 12).
When the bucket I spool is selected, (Dump: Crowd: Fig. 11), when pilot port P
12), the oil delivered from P
bucket II spool hole (u), pushes up the poppet (t) and converges in bucket I passage n from passage o (Fig. 1).
Slew Spool Switch (Refer to Fig. 11).
When the pilot port P
bL3
delivered from P port flows through the 5-spool parallel passage B and pushes open the load check valve (s) and flows
L
through the spool neck from passage P and flows from passage R (Q) to cylinder port B
The return oil from cylinder port A
Spare Spool Switch (Refer to Fig. 5).
When the pilot port P
bL2
delivered from the P port flows through the 5-spool parallel passage B and pushes up the load check (r). From passage M, it
L
flows through the spool neck, through the passage o and flows to cylinder port B
to the P port flows through the load check valve (r) passage (q) and converges in passage M.
5
The return oil from cylinder port A
Travel Linearity Spool (Refer to Fig. 18).
When an excavator spool is selected, the signal passage is cut off, but when the travel spool is in neutral, the signal oil is
released to the tank at the travel spool signal land (K) (L) so the pressure of the signal passage (f) does not rise and the travel
linearity spool is in the neutral condition. (Fig. 1)
(When the boom is raised, it is selected to boom II. Fig. 8)
Also, when the spool at the front is switched, the flow to the tank passage of the signal passage (e) is cut off so the P
pressure rises.
(For travel linearity spool selection conditions, refer to the next item, 'Travel Combination Operations').
9803/6400
Control Valve JS200/JS240
(P ) is pressurised and the bucket I spool is selected, the 4-spool neutral passage a is cut off and
aR3
flows through the 4-spool parallel passage b, pushes up the load check valve (v) and from the passage
R
(B ) flows through the spool neck from passage q (P) and is released to the tank
R3 R3
flows into passage Y w from the 5-spool neutral passage A and arm I spool land, flows through the
L
(P ) is pressurised and the spool is selected, the 5-spool neutral passage A is cut off and the oil
aL3
(B ) flows through the spool neck and is released to the tank.
L3 L3
(P ) is pressurised and the spool is switched, the 5-spool neutral passage A is cut off and the oil
aL2
(B ) flows through the spool neck and is returned to the tank.
L2 L2
Hydraulics
aR4
L2
(A ).
R3 R3
is pressurised and bucket II is selected (Fig.
(A ).
L3 L3
(A ). Also, the oil delivered from the outside
L2
Section E
31 - 5
port
f
Issue 2*