Hyundai HL955 Manual page 472

4) WHEN THE RCV LEVER IS IN THE DUMP POSITION
Bucket Boom
Aux
4
5
Control unit
(Electro-Hydraulic & Joysick steering)
EH18 EH20 EH19 EH22 EH21
EH17
6
4 6(4)
1 3(2) 5(3)
To MCV
a3 b3 a1 b1 a2 b2
Steering valve
(EHPS) EF port
Steering valve
(EHPS) LS port
Return line
1
29
PS
Steering system
B1
S1
·
If the RCV lever (4, bucket) is pushed right, the bucket spool is moved to dump position by pilot oil
pressure from EH control block (6).
·
The oil from main pump (1) flows into main control valve (3) and then goes to the small chamber of
bucket cylinder (14) by pushing the load check valve of the bucket spool.
·
The oil at the large chamber of bucket cylinder (14) returns to hydraulic tank (22).
·
When this happens, the bucket is dumped.
·
When the dumping speed of bucket is faster, the oil returned from the large chamber of bucket
cylinder combines with the oil from the pump, and flows into the small chamber of the cylinder.
This prevents cylinder cavitation by the negative pressure when the pump flow cannot match the
bucket dump speed.
P
3
LS
Joystick
4' Pst
T
T
P
2(1) ( ) : 2 Spool
Regeneration
check valve
28 28 11
12
S1
X1 X2
P1 T
X3
X1 X2
B2
L2 S2 L4 L3
L1
14
40
a1
B1
A1
Bucket
b1
A1
Return line
23
25
24
26
22
Fan & brake pump
6-8
13
LH RH
29
29
a2 a3
B3
A2 B2 A3
Boom Aux
b2 b3
757F6WE06