Toro Reelmaster 5510 Series, Руководство по обслуживанию

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Lift Circuit (5610-D)
A 4-section gear pump is coupled to the piston (traction) pump. The gear pump
section (P4) supplies hydraulic flow to the lift control manifold and ultimately for
the lift cylinders. The gear pump takes its suction from the hydraulic reservoir.
The lift control manifold includes 4 electrically operated solenoid valves. The
solenoid relief valve (SVRV) located in the lift control manifold limits the lift circuit
pressure to 13,800 kPa (2,000 psi). The 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-energized. The valve (SV2) is used to direct fluid flow to
retract the lift cylinders when energized or extend them when de-energized. The
valve (SV1) allows hydraulic flow to the front lift cylinders when energized. The
valve (SV3) allows hydraulic flow to the rear lift cylinders when energized.
The lift circuit pressure can be monitored at the lift control manifold port G4.
The Toro Electronic Controller (TEC) uses inputs from various machine switches
to determine when the lift manifold solenoid valves (SV1, SV2, SV3, and SVRV)
are to be energized. The TEC also provides a partial raise position of the front
outside cutting units.
During the conditions of not raising or lowering the cutting units (joystick in the
neutral (center) position), all 4 lift manifold solenoid valves (SV1, SV2, SV3, and
SVRV) are de-energized. The hydraulic flow from the gear pump section (P4)
bypasses the lift cylinders to the oil cooler and then to the hydraulic reservoir.
Raise the Cutting Units
When the joystick is moved to the raise position with the engine running, the
solenoid valve (SVRV) energizes along with solenoid valves (SV1), (SV2), and
(SV3). The energized solenoid valves direct gear pump section P4 fluid flow to
the rod end of the lift cylinders. The hydraulic pressure against the rod side of the
cylinders causes the shafts to retract, and raises the cutting units. Fixed orifices
in the lift control manifold (C1L, C4L, C5L, and C23L) control the lifting speed by
providing a restriction for the return flow from the lift cylinders.
When the joystick is returned 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 (C1L, C4L, C5L, and
C23L) prevent the lift cylinders (and cutting units) from dropping after they have
been raised.
Hydraulic System: Hydraulic Flow Diagrams (5610-D) Page 6–38 Reelmaster ® 5410/5510/5610 Series
15216SL Rev C