Theory of Operation
FLOW COMBINER VALVE OPERATION
increases shifting the flow combiner valve and swing
The function of the flow combiner valve (I) is to ensure
park brake release valve.
machine does not mistrack during combined propel
and dig function operation by routing supply oil from
Actuating the propel function in combined operation
the front pump (D) to the left (A) and right (G) propel
with a dig function now routes the supply oil from the
front pump (J) to the right propel valve (H) and through
the flow combiner valve to the left propel valve (O).
Pilot oil from the pilot pump (F) flows through the
The dig functions, other than bucket, are supplied with
orifice, into dig pilot signal passage (E), past each dig
oil from the rear pump (K). Supply oil for the bucket
function valve spools, and then to the return circuit.
function is through the flow combiner valve. Check
The flow combiner valve (C) and swing park brake
valve (P) prevents back flow through the flow combiner
release valve (D) are connected to the signal passage
between orifice and valve spools. (See Control Valve
Pilot Signal Passages Operation in this group.)
When just the propel function is actuated, the left
propel valve is supplied with oil from the rear pump (K)
When one or more dig functions are actuated, the flow
and the right propel valve is supplied with oil from the
of pilot oil through dig pilot signal passage to return is
front pump (J).
blocked by a valve spool (arm I valve shown) (M). The
pressure in blocked portion of signal passage
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