S T E E R I N G S Y S T EM
A M P L I F I E D S T E E R I N G S Y S T EM
spool moves, oil that is pushed from the left end of the
spool flows through metering orifices (1). The oil
flows through passage (3) to the spring end of spool
(12). The spool movement goes on until the orifices
S Y S T E M S O P E R A T I O N
are blocked and flow through them is stopped. This
movement of the spool stops the flow of pressure oil to
the steering cylinders.
STEERING CONTROL VALVE IN RIGHT TURN POSITION
1. Metering orifices.
4. Outlet for left turn.
5. Outlet to tank,
6. Outlet for right turn.
7. Metering orifices.
9. Inlet (from right
15. Inlet (from steering
10. Inlet (from left
16. Ball resolver valve.
16. Flow control valve.
19. Pilot valve (relief valve).
13. Return paaaage.
When the steering wheel is turned to the right,
pilot oil is sent through the right neutralizer valve to
inlet (9). The oil flows into the chamber for spring
(8). There is a pressure increase at inlet (9) which
moves the spool to the left. The amount of spool
movement is controlled by the rotation of the steering
wheel. If there is a slow rotation of the steering wheel,
there will be a low volume of pilot oil and less spool
movement. A slow turn is the result. A faster rotation
of the steering wheel gives a larger volume of pilot oil.
The result is more spool movement, and a faster turn.
Pilot oil flows from the spring chamber across
metering orifices (7). This oil flows through passage
(2) to the left end of the spool. The oil then goes
through inlet passage (10), through the left neutra-
lizer valve to the hand metering unit (HMU). The
HMU lets the oil return to the hydraulic tank.
With the spool moved to the left, oil from the
steering pump section can flow from inlet (15),
through slots in the spool, into outlet (6). This oil
flows to the head end of the left steering cylinder, and
the rod end of the right steering cylinder.
The pressure of this oil moves the cylinder rods and
the machine turns to the right.
When pressure oil enters outlet (6), the pressure
moves ball resolver valve (16). The pressure of the oil
to the cylinders is felt through passage (17), against
pilot valve (19) and flow control valve (18).