Case 580SR Service Manual page 616

www.maskinisten.net
26
OIL FLOW OPERATION
All loader/backhoe circuits in neutral
Each control valve section within the backhoe or
loader control valve assemblies contains a spool,
two check valves and a load sensing pressure com-
pensator.
A load sensing gallery connects the compensators in
each control valve section.
When all control valves are in neutral position, the
spools stop the oil flow in each system and the pres-
sure of the load sensing line can bleed to the tank
through the relevant 1 litre/min return-to-tank port in
the inlet cover of the backhoe attachment control
valve.
Because there is no load sense pressure being ap-
plied to the rear face of the flow balancer valve, the
valve will move against the spring and off its seat
when pump pressure reaches 15 bar. Pump flow is
now diverted back to tank and the balancer valve
maintains a stand-by pressure of 15 bar while the cir-
cuits are in neutral.
Pump stand-by pressure 15 bar
Return to oil tank
1. Load sense bleed orifice 1 l/min
2. Load sense limiter (system relief valve)
3. Return to tank
SECTION 35 - HYDRAULIC SYSTEM
1
7
Flow balancer valve operation - All spools in neutral
2
6
4. Load sense line
5. Pump flow balancer (unload) valve
6. Pump flow IN
7. To backhoe control valves
Copyright ©
3
4
5
F29287