Daewoo Solar 225LC-V, Shop Manual

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S0708320
Page 9
Main Pump (With Regulator)
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PUMP OUTPUT DECREASE
When pilot pressure (Pi) increases, the pilot piston (643) shifts toward the right, stopping at that point at
which pilot pressure and the force of the return spring (646) cancel each other out. Movement of the pilot
piston pushes the pin (875) attached to the feedback lever assembly (613, 611, 897) around the "B-point
plug" (614) and the pin (875) on the opposite side of the feedback lever assembly. The pin at the lower end
of the feedback lever is attached to the tilting pin of the swash plate (531/538 in Figure 1).
NOTE: In Figure 6, the circled capital letter "D" at the lower end of the feedback lever shows the
approximate location where the assemblies shown in Figure 1, Figure 6 and Figure 8 react
as the pin (897) at the top of the feedback lever moves and the piston shifts, maintaining
dynamic balance through the valve between pilot pressure (Pi) and discharge output flow
(Q) as shown in Figure 7.
PUMP DISCHARGE DECREASE
The regulator feedback lever assembly is also pin-connected to the outermost spool (652) in the discharge
port (Cl) of the regulator (Figure 8). As that spool moves toward the right, in response to differences in
servo pressure, the servo piston moves to the right, resulting in a decreased swash plate tilt angle and
reduced pump output flow. The system is balanced and control movement of the spool (and servo piston)
stops when the outermost spool (652) and spool sleeve (651) close into each other, shutting off oil
movement.
PUMP DISCHARGE INCREASE
When pilot pressure (Pi) decreases, the pilot piston shifts toward the left and the feedback lever assembly
pivots around point "D" (Figure 6), pushing the spool and servo piston left. Swash plate tilt angle is
heightened and pump output flow begins to increase as a result. Control movement of the spool and servo
piston stops when the feedback lever assembly rotates around point "C" (Figure 6), moving the spool to the
right until it slides into the sleeve (651) and oil movement is blocked.
HORSEPOWER CONTROL
Horsepower control function occurs as each
regulator responds to changes in the output of
the opposite pump. As increases or decreases
in pump output occur (as outlined in the
preceding paragraphs) at one pump, it is
necessary for the output of the remaining pump
to compensate to allow equalizing of the total
discharge rate.
The relationship between changes in pressure
and changes in output flow when the operation
of both pumps (P1 and P2) is measured (Figure
9).
Figure 9