Right Turn Position
STEERING CONTROL VALVE IN RIGHT TURN POSITION
1. Tank return passage.
11. Outlet to cylinders
(for left turn).
14. Outlet to cylinders
(for right turn).
3. Outlet to tank.
8. Outer spring.
15. Ball resolver valve.
4. Flow control valve.
9. Inner spring.
13. Narrow slots.
5. Pilot valve.
10. Wide slots.
When the steering wheel is turned to the right a few
degrees (SLOW RIGHT TURN), spool (6) is moved out
of the valve body a small amount. This causes
compression of inner spring (9). Pump oil flows from
inlet (2) through narrow slots (13) on the valve spool.
The oil flows into outlet (14) and then to the steering
cylinders. The force of the oil in the cylinders causes
the machine to turn slowly to the right.
If the steering wheel is turned against the stop
(FAST RIGHT TURN), spool (6) will move out of the
valve body some more. There is compression of both
the inner and outer springs (9) and (8). When
compression of the outer spring starts, there is an
increase in the force needed to turn the steering wheel.'
This lets the operator feel the spool move to the FAST
When the spool is in the FAST TURN position, the
pump oil, flows from inlet (2) through wide slots (10) in
the spool. These large slots. let more oil flow to the
cylinders than the small slots. The result is a FAST
Return oil that is pushed from the steering cylinders
is sent into the control valve through outlet (I 1). The oil
is sent through slots in the valve spool into return
passage (1). The oil then flows through outlet (3). From
the outlet, the oil flows back to the filter and hydraulic
The pressure of the oil to the cylinders is also felt
through passage (16). When oil goes into passage (16),
the pressure moves ball resolver valve (15). The
pressure of: the oil to the cylinders is then felt against
pilot valve (5) and flow control valve: (4).
If an outside force keeps the machine from turning,
the pressure in outlet (14) and passage*(16) will
increase. This pressure increase is also felt against the
pilot valve and flow control valve. The pressure against
the flow control valve causes it to move to the left. This
lets more oil flow to the cylinders. If the pressure goes
above the relief valve setting of 2000 ± 25 psi (-140.6 ±
1.8 kg/cm2) (13 790 ± 172 kPa), the, pilot valve will