Terex TS14G, Maintenance Manual

Page: 203 / 376

Section 220-0160
SM 1764 2-99
1
SM - 2139
STEERING SYSTEM - Flow Reversing Valve
Fig. 1 - Cutaway View of Typical Flow Reversing Valve
DESCRIPTION AND OPERATION
Letters in parentheses refer to Fig. 1.
The flow reversing valve distributes the oil to the
steering cylinders and also reverses the flow of oil to
the cylinders, when one of the pistons is pushed into
the housing. The valve is mounted on the rear of the
steering frame between the two cylinders.
In Fig. 1, channel ‘A’ is connected to ‘C’ by the cored
passage ‘B’. Channel ‘C’ is connected to the base of
the right steering cylinder and the rod end of the left
steering cylinder. Channel ‘D’ is connected to the base
of the left steering cylinder and the rod end of the right
steering cylinder.
Channels ‘E’ are connected together by a horizontally
drilled passage, not shown in the illustration. They act
as vent passages for high pressure oil to protect the
seals.
OIL FLOW
Right Turn
Letters in parentheses refer to Fig. 1.
Oil flows into the valve housing through the top left
port (not shown) into channel ‘A'. Oil flows around the
land of the left plunger through channel ‘B’ and into
channel ‘C'. From ‘C’ the oil flow simultaneously into
the base of the right cylinder and into the rod end of
the left cylinder.
In an extremely sharp right turn, the oil flow to the left
steering cylinder is reversed by the left plunger being
pushed 20.638 mm (0.8125 inch) into the valve
housing. Refer to Section 220-0010, STEERING
LINES AND FITTINGS. The lower part of the channel
‘C’ is blocked by the large land of the left plunger.
Channel ‘A’ and the lower part of channel ‘D’ are now
connected, allowing oil to flow into the base of the left
steering cylinder.
TO ROD END OF RIGHT CYLINDER TO BASE OF RIGHT CYLINDER
TO ROD END OF LEFT CYLINDER TO BASE OF LEFT CYLINDER
RIGHT
SPOOL
LEFT
SPOOL
E
E
C
D
B
A
Courtesy of Machine.Market