TM 5-3805-258-24-1
S T E E R I N G S Y S T EM
S U P P L E M E N T A L S T E E R I N G S Y S T EM
S Y S T E M S
O P E R A T I O N
passage (18) to the right end of reversing spool (14).
The force of this oil moves the reversing spool to the
left. Oil from the supplemental pump can then flow
from passage (17) into passage (3). Passage (3) takes
the oil to check valve (11) and diverter spool (1).
If the engine rpm is low, the diverter spool will be
to the left. Oil flow past the diverter spool is stopped.
The pressure of the oil in passage (3) increases until
check valve (11) opens. This lets the oil from the
supplemental pump flow past check valve (11) to
check valve (8). The oil then flows together with the
oil from the primary system and goes through outlet
(5). This combined flow of oil then goes to the steer-
ing control valve.
DIVERTER VALVE SCHEMATIC
(Engine at LOW rpm end Machine in FORWARD Motion)
1. Diverter spool. 2. Return passage to hydraulic tank. 3.
Paasage. 4. Spring. 5. Outlet to steering control valve. 6.
Paaaage. 7. Orifice. 8. Check valve. 9. Passage. 10. Inlet
from primary steering pump section. 11. Check valve. 12.
Supply paasage (for supplemental steering pump). 13.
Spring. 14. Reversing spool. 15. Passaga to left end of
spool. 16. Pasaage. 17. Paaaage. 18. Passage to right end
of spool.
If the engine rpm is high, diverter spool (1) will be
to the right. The oil from the supplemental pump
flows into passage (3). The oil flows around spool (1),
into passage (2), and back to the hydraulic tank.
Only the primary pump flow is sent to the steering
control valve through outlet (5). Check valve (11)
will not let the primary oil flow into passage (3).
If there is a failure of the primary steering pump
section, or if the engine stops there will be a loss of
primary flow. Diverter spool (1) will move to the left.
As long as the machine moves, the flow from the
supplemental pump will provide the oil for the steer-
ing operation. The oil will flow through passage (3),
past check valve (11), and through outlet (5). Check
valve (8) will prevent the loss of flow through inlet
(10), and the stopped primary pump.
When the machine moves in a reverse direction,
the supplemental pump turns in the opposite direc-
tion. The pressure oil from the pump is sent through
passages (16) and (15) to the left end of reversing
spool (14). This causes the spool to move to the right.
The pressure oil can then flow through passage (16)
into passage (3). The rest of the oil flow is the same as
when the machine moves forward.
DIVERTER VALVE SCHEMATIC
(Engine at HIGH rpm and Machine in Forward Motion)
1. Diverter spool. 2. Return passage to hydraulic tank. 3.
Passage. 5. Outlet to atearing control valve. 6. Pas-
sage. 7. Orifice. 8. Check valva. 9. Passage. 10. Inlet from
primary steering pump section. 11. Check valve. 12. Sup-
ply
passage
(for
supplemental
steering
pump).
13.
Spring. 14. Reversing spool. 15. Passage to left end of
spool. 16. Passage. 17. Passage. 18. Passage to right end
of spool.
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