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(4)
High pressure stall
1
2
LS pressure oil
System pressure oil
Return oil
1
Drive shaft
2
Swash plate
4
Counter piston
6
Counter spring
10 Control piston
12 Pressure compensator spool
When the hydraulic system stalls under load or when the cylinders reach the end of the stroke, the
main system pressure increases. But LS pressure (19) is regulated by LS relief valve on steering
system and attachment system. The pressure difference between discharged pump and LS
pressure equal to spring (18). It means no flow is necessary. Therefore, discharged pressure push
flow compensator spool (13) left . Supply oil now flows past flow compensator spool (13) and
through passage (23). The oil flows past flow compensator spool (13) and into passage (22). The
oil then flows to control piston (10).
Pump swash plate (2) will be minimum displacement if the operator does not turn the steering
wheel and RCV, then the pump will return to low pressure standby.
14
4
6
10
24
16
17
18
19
20
13 Flow compensator spool
14 Case drain
15 Passage
16 Passage
17 Spring
18 Spring
15
21
22
L
L1
23 13
12
19 LS line from the metering pump
20 Cavity
21 Passage
22 Passage
23 Cavity
6-17
LS pressure
12
13
X
4
10
B
S
75796WE36
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