MASSEY FERGUSON 5400 - General

Massey Ferguson 5400 - Issue 1.b
09E01.3
Auxiliary spool valve
A . General
The Rexroth SM12 auxiliary spool valves are fitted on
the high flow rate circuit. They are fed by oil coming
from the trailer braking valve or the closing plate fitted
in its place (depending on version).
When the spool valves are not activated, the oil is
available for the lift control valve fitted downstream.
The auxiliary spool valves are mounted on a support
which is itself fitted to the rear of the lift cover.
Quick-disconnect couplings are fitted directly on the
spool valve body. To obtain sufficient distance
between couplings, the spool valves are fitted with
blocks serving as spacers. These blocks are also used
to let the oil flow to the next spool.
Characteristics
Functions: Double acting; Single and double acting
(convertible)
These functions are also recognised via the abbrevia-
tions SA and DA.
Positions : Three; Four with one in floating position.
Return to neutral: By spring or by an automatic
system.
Zero leak: With or without.
Each spool valve is activated by a lever in the cab and
it has three phases of travel:
- 35% reduced flow rate;
- 45% progressive increase of flow rate and pressure;
- 20% full flow rate.
The progressive increase of flow rate and pressure
ensures uniform operation of the implements.
This characteristic also allows two spool valves to be
activated simultaneously, the total flow rate being
shared. The flow rate to each quick-disconnect
coupling is proportional to the position of the control
lever.
The spool valve placed against the flow divider is spool
valve No. 1.