Case IH Farmall 105U Pro EP, Service Manual

Page: 668 / 1569

Hydraulic systems - Three-point hitch control valve
Function – lift
SS06M205
2
Color legend
A. High-pressure circuit H. Oil to the tank
B. Pressure drop in high pressure I. Low pressure circuit P1
G. Trapped oil J. Load-sensing line (LS)
The CCU powers the "lift" solenoid valve. The current supply changes in accordance with the control deviation. The
spool
(1) is pushed against the spring (2) of the "lift" solenoid valve. On the one hand, the pressurized oil from duct
(P) can now flow via the open spool (1) through the bore (3) to the spring side of the two-way flow control valve (4) .
On the other hand, the pressurized oil from duct (P) can flow via the shuttle valve (5) into the LS duct and to the pump
regulator. At the same time, the oil flow to output (A) opens poppet valve (6) . The working pressure that is set results
from the device load and the lift speed. The lift speed depends on the electrical current that flows through the "lift"
solenoid valve and that opens the spool
(1) . The spool (1) acts as the adjustable restrictor for the two-way flow control
valve (4) .
This produces the following options:
• A lift speed that is independent of the load flow and pump flow
• Parallel operation of several auxiliary distributors and the linkage. The auxiliary distributors and the linkage work
with various flows and pressures until they reach the pump flow that is currently present
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