Komatsu 830E-AC Shop Manual page 668

Hydraulic oil flows to the closed center steering valve
via the flow amplifier. The flow amplifier is pilot-con-
trolled by the steering valve. Due to large oil dis-
placement in the steering cylinders, the flow amplifier
is incorporated in the steering circuit. The steering
column is connected directly to the steering valve.
When the steering wheel is rotated, oil is directed to
the steering cylinders via the flow amplifier to the
appropriate side of the pistons in the steering cylin-
ders. When steering circuit pressure reaches 17 238
kPa (2500 psi) at the flow amplifier, or during a no
steer situation, flow is blocked at the priority valve
within the flow amplifier.
L4-4
COMPONENT DESCRIPTION
STEERING CONTROL UNIT
The steering control unit is located behind an access
cover on the front of the operator's cab. The steering
control unit is connected directly to the steering col-
umn. The valve incorporates a rotary meter which
ensures the oil volume supplied to the steering cylin-
ders is proportional to the rotation of the steering
wheel.
Operation of the steering control unit is both manual
and hydraulic in effect, providing the operator with
power steering. The valve will be spring returned
automatically to its closed, neutral position when
turning is stopped.
FLOW AMPLIFIER
The flow amplifier (Figure 4-2) is located on the left
inside frame rail just forward of the bleed down mani-
fold. The flow amplifier is required in the steering cir-
cuit due to the large volume of oil displacement
required for steering. The flow amplifier uses the
amount of flow from the steering control valve to
determine the amount of amplified flow to send from
the bleed down manifold to the steering cylinders.
Reference Figures 4-3 through 4-6 for oil flow paths
during the neutral, steering and external shock load
conditions.
Steering Circuit L04048