Toro 03781, Руководство по обслуживанию

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Reelmaster 7000−D Hydraulic System Page 5 − 21
Lower Cutting Units
A four section gear pump is coupled to the piston (trac-
tion) pump. Gear pump section P4 supplies hydraulic
flow to both the lift control manifold and the steering con-
trol valve. Hydraulic flow from this pump section is deliv-
ered to the circuits through a proportional flow divider
located in the fan control manifold. Maximum lift/lower
circuit pressure is limited to 1700 PSI (117 bar) by a relief
valve (RV1) in the lift control manifold. Lift circuit pres-
sure can be monitored at the test fitting in lift control
manifold port G.
A joystick (lower mow/raise control lever) on the console
arm is used to raise and lower the five (5) cutting units
(Fig. 13). The joystick acts as an input to the Toro Elec-
tronic Controller (TEC) which sends electrical outputs to
appropriate lift control manifold solenoid coils in order to
raise or lower the cutting units.
When the cutting units are in a stationary position (not
raising or lowering), lift circuit flow from gear pump sec-
tion P4 bypasses the lift cylinders through the lift control
manifold solenoid valve S1 (de−energized). Return flow
from the manifold is routed to the oil filter and traction
charge circuit.
Cutting Unit Lower
NOTE: The operator must be in the operator seat and
the mow speed limiter in the LOW speed (mow) position
in order to lower the cutting units.
When the joystick is moved to the lower position, sole-
noid valve S1 along with solenoid valves S3, S4 and S5
are energized by the TEC. To allow the front cutting units
to be lowered before the rear cutting units, the controller
slightly delays energizing solenoid S5 after the joystick
is moved to the lower position
. The energized solenoid
valves direct gear pump oil flow to the piston end of the
lift cylinders. Hydraulic pressure causes the lift cylinder
shafts to extend, and lower the cutting units.
The flow to the front lift cylinders is restricted by a series
of control orifices in the lift junction manifold. The first set
of control orifices restricts the flow to each front lift cylin-
der in both the lower and raise direction. Three (3) pi-
loted check valves in the junction manifold are shifted by
hydraulic pressure to allow return flow from the extend-
ing front lift cylinders. The return flow passes through a
second set of control orifices in the junction manifold
providing additional cylinder speed control while lower-
ing the cutting units.
A flow control orifice in the lift control manifold (port C3)
controls the rear cutting unit lowering speed by provid-
ing a restriction for the return flow from the lift cylinders.
Because cutting unit weight assists in extending the lift
cylinders when lowering the cutting units, less hydraulic
pressure is necessary during the cutting unit lowering
operation. Lift circuit lower relief valve (RV2) allows lift
circuit pressure to be limited to 500 PSI (34 bar) while
lowering the cutting units.
NOTE: Adjustment of lift circuit lower relief valve (RV2)
is not recommended.
When the joystick is released, solenoid valves S1, S3,
S4 and S5 are de−energized and the lift cylinders and
cutting units are held in position.
1
2
Figure 13
1. Console 2. Joystick
(lower mow/raise
control lever)
Figure 14
CUTTING UNIT LOCATIONS
#4 #1 #5
#3 #2
Hydraulic
System