Upper Left Pump Stack (Hold)
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| Illustration 1 | g01432013 |
(1) Forward makeup and relief valve (2) To port "E" cooler bypass manifold (3) Charge relief valve (4) Forward makeup and relief valve (5) From port "L1" LH propel (6) Reverse makeup and relief valve (7) Right auger motor (8) To port "D" cooler bypass manifold (9) Right conveyor motor (10) To port "D" cooler bypass manifold (11) Right conveyor pump (12) Direction control valve (13) From port "D" left propel pump (14) Direction control valve (15) Right auger pump (16) Reverse makeup and relief valve | |
The upper left pump stack contains the right conveyor rotating group and the right auger rotating group. When the engine is running, the rotating groups in the material feed pump rotate. The left propulsion pump provides charge oil to the right material feed pump which is in the upper left pump stack.
Inside the material feed pump, charge oil flows to the following valves: the makeup and relief valves, the direction control valves and the charge relief valve.
When the material feed system is in HOLD, the EDCs are not energized. Under these conditions, the direction control valves center the servo pistons. This action opens both sides of the servo piston to the pump case. In this situation, the pump swashplate remains at a minimum angle.
Charge oil that enters the makeup and relief valves acts against the makeup valves. Since the material feed pump rotates during engine operation, normal leakage occurs in the auger circuit and in the conveyor circuit. When pressure in the auger circuit and in the conveyor circuit falls below charge pressure, the makeup valves open. The circuits then fill with charge oil.
When charge pressure increases to the relief setting, the charge relief valve opens. When the charge relief valve is open, charge oil is directed into the pump case drain.
Upper Right Pump Stack (Hold)
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| Illustration 2 | g01431962 |
(1) Reverse makeup and relief valve (2) To port "F" cooler bypass manifold (3) Charge relief valve (4) Reverse makeup and relief valve (5) From port "L1" RH propel (6) Forward makeup and relief valve (7) Left conveyor motor (8) To port "D" cooler bypass manifold (9) To port "B" cooler bypass manifold (10) Left auger motor (11) Left auger pump (12) Direction control valve (13) From port "D" right propel pump (14) Direction control valve (15) Left conveyor pump (16) Forward makeup and relief valve | |
The upper right pump stack contains the left conveyor rotating group and the left auger rotating group. When the engine is running, the rotating groups in the material feed pump rotate. The right propulsion pump provides charge oil to the left material feed pump.
The material feed pump in the upper right pump stack follows the same principles of operation as the material feed pump in the upper left pump stack.
Upper Left Pump Stack (Conveyor Forward)
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| Illustration 3 | g01431966 |
(1) Forward makeup and relief valve (2) To port "E" cooler bypass manifold (3) Charge relief valve (4) Forward makeup and relief valve (5) From port "L1" LH propel (6) Reverse makeup and relief valve (7) Right auger motor (8) To port "D" cooler bypass manifold (9) Right conveyor motor (10) To port "D" cooler bypass manifold (11) Right conveyor pump (12) Direction control valve (13) From port "D" left propel pump (14) Direction control valve (15) Right auger pump (16) Reverse makeup and relief valve | |
When the right conveyor is operating in FORWARD, the forward EDC is energized. In this situation, charge oil flows across the direction control valve and into the forward servo piston cavity. Under these conditions, the swashplate moves and the rotating group produces flow.
The right conveyor rotating group sends flow out of port "C" of the pump housing. This oil flows to port "A" of the right conveyor motor. The pressure differential between the forward and reverse sides of the right conveyor motor causes the motor to turn. After turning the right conveyor motor, oil at a reduced pressure flows out of port "B" of the motor housing to port "D" of the material feed pump. This completes the right conveyor drive circuit.
Loop flushing occurs at the return side of the right conveyor motor. Oil in the return circuit flows through an orifice and into the case of the right conveyor motor. The case drain of the right motor is connected to port "D" of the oil cooler bypass manifold.
As loop flushing occurs, the pressure in the return circuit falls below charge pressure. Charge pressure opens the makeup valve in the reverse makeup and relief valve. Oil from the charge system replenishes the oil which is lost in the circuit due to loop flushing.
As long as the pressure in the forward circuit is greater than charge pressure and less than relief pressure, the makeup valve in the forward makeup and relief valve remains seated. Therefore, the relief valve remains closed. If the forward circuit pressure rises above the relief pressure, the relief valve opens. This action purges excess pressure into the charge circuit.
Note: The right auger rotating group follows the same principles of operation as the right conveyor rotating group. Port "B" is the forward supply port of the right auger pump. Port "A" is the forward port of the right auger motor.
Upper Left Pump Stack (Auger Reverse)
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| Illustration 4 | g01431961 |
(1) Forward makeup and relief valve (2) To port "E" cooler bypass manifold (3) Charge relief valve (4) Forward makeup and relief valve (5) From port "L1" LH propel (6) Reverse makeup and relief valve (7) Right auger motor (8) To port "D" cooler bypass manifold (9) Right conveyor motor (10) To port "D" cooler bypass manifold (11) Right conveyor pump (12) Direction control valve (13) From port "D" left propel pump (14) Direction control valve (15) Right auger pump (16) Reverse makeup and relief valve | |
When the active auger reverse switch is in the RIGHT REVERSE position, the right auger reverse EDC is energized. In this situation, charge oil flows across the direction control valve into the reverse servo piston cavity. Under these circumstances, the swashplate moves and the rotating group produces flow.
Flow is sent out of right auger rotating group through port "A" of the pump housing to port "B" of the right auger motor. The pressure differential between the forward and reverse sides of the right auger motor causes the motor to turn. After turning the right auger motor, oil at a reduced pressure flows from port "A" of the auger motor to port "B" of the material feed pump. This completes the right auger drive circuit.
When the auger is operating in REVERSE, loop flushing occurs at the high pressure side of the right auger motor. Oil in the high pressure circuit flows through an orifice and into the case of the right auger motor. The case drain of the right auger is connected to the oil cooler bypass manifold.
As loop flushing occurs, oil is depleted from the hydrostatic loop. This action causes pressure in the return circuit to fall below charge pressure. Charge pressure then opens the makeup valve in the forward makeup and relief valve. Oil from the charge system replenishes the oil which was lost in the circuit due to loop flushing.
As long as the pressure in the reverse circuit is greater than charge pressure and less than relief pressure, the makeup valve in the reverse makeup and relief valve remains seated. Therefore, the relief valve remains closed. If the reverse circuit pressure rises above the relief pressure, the relief valve opens. In this case, excess pressure is purged into the charge circuit.