Toro Reelmaster 5210 - Page 45

Reelmaster 5010 Series Hydraulic System (Rev. C)Page 4 -- 13
Lift Circuit: Raise Cutting Units
A four section gear pump is coupled to the piston (trac-
tion) pump. Gear pump s ection (P4) supplies hydraulic
flow to the lift control manifold and ultimately for the lift
cylinders. The gear pump takes its suction from the hy-
draulic reservoir. Lift circuit pressure is limited to 2000
PSI (138 bar) by a solenoid relief valve (SVRV) located
in the lift control manifold.
The lift control manifold includes four(4) electrically op-
erated solenoid valves. Valve (SVRV) is used to direct
gear pump flow to the lift cylinders when energized or
bypass pump flow back to the reservoir when de--ener-
gized.Valve ( SV2) isusedtodirectoilflowto retractthe
lift cylinders when energized or extend them when de--
energized.Valve(SV1)allowshydraulicflow tothefront
lift cylinders when energized. Valve (SV3) allows hy-
draulic flow to the rear lift cylinders when energized.
Liftcircuitpressure can bemonitoredatlift controlman-
ifold port G4.
The Electronic C ontrol Module ( ECM) uses inputs from
various machine switches to determine when lift man-
ifold solenoid valves (SV1, SV2, SV3 and SVRV) are to
be energized. The ECM also provides a partial raise
position of the front outside cutting units.
During conditions of not raising or lowering the cutting
units(joystickintheneutral(center)position),allfour(4)
liftmanifoldsolenoidvalves(SV1,SV2,SV3andSVRV)
are de--energized. Hydraulic flow from gear pump sec-
tion(P4)by--passestheliftcylinderstotheoilcoolerand
then to the hydraulic reservoir.
Raise Cutting Units (Fig. 11)
When the joystick is moved to the r aise position, sole-
noidvalve(SVRV)energizesalongwithsolenoidvalves
(SV1),(SV2) and(SV3).The energizedsolenoidvalves
directgearpumpsectionP4oilflowtotherodendofthe
lift cylinders. Hydraulic pressure against the rod side of
thecylinderscausestheshaftstoretract,andraisesthe
cutting units. Fixed orifices in the lift control manifold
(C1L, C4L, C5L and C23L) control the lifting speed by
providingarestriction for the return flow from the lift cyl-
inders.
When the joystick is r eturned to the neutral (center)
position, the solenoid valves are de--energized and the
lift cylinders (and cutting units) are held in the raised
position. Piloted check valves in the lift control manifold
(CV1, CV4, CV5 and CV23) prevent the lift cylinders
(and cutting units) from dropping after they have been
raised.
Hydraulic
System