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| Illustration 1 | g06610194 |
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Vibratory Hydraulic System OFF (1) Vibratory hydraulic pump (2) Front vibratory solenoid (3) Rear vibratory solenoid (4) Interlock valve (5) From charge filter (6) Vibratory solenoid "MA" (7) Vibratory solenoid "MB" (8) Crossover relief valve (9) Servo piston (10) Rotating group (11) Crossover relief valve (12) From propel pump case (13) Rear vibratory motor (14) Flushing spool (15) Flushing orifice (16) Charge relief valve (17) Return manifold (18) Oil cooler (19) Flushing orifice (20) Flushing spool (21) Front vibratory motor (22) Crossover relief valve (23) Rotating group (24) Servo piston (24) Crossover relief valve | |
The vibratory circuit consists of two hydrostatic-drive circuits. One circuit drives the vibratory system on the front drum. The second circuit drives the vibratory system on the rear drum. Each closed-loop circuit has its own rotating group inside a single pump. Each circuit also has its own motor.
The fan system provides charge oil to the vibratory system (and the propel system) when the engine is running. Charge oil from the charge filter flows to port"E" (5) of vibratory pump (1). Inside the vibratory pump, charge oil flows to interlock valve (4) and to charge relief valve (16).
Interlock valve (4) is energized when the engine start switch is in the ON position. When this solenoid is energized, charge oil is available at pump control solenoids (2), (3), (6), and (7).
Displacement of the rotating groups in the pump is electronically controlled. None of pump control solenoids (2), (3), (6), and (7) are energized when the vibratory system is off. In this case, servo pistons (9) and (24) contain oil under equal pressure on both sides of the pistons. The swashplate in each rotating group is at zero angle, and neither rotating group produces flow.
Charge pressure acts on charge relief valve (16). When charge pressure reaches
Charge pressure acts against the makeup valves in each crossover relief valve (8), (11), (22), and (25). If the pressure in either side of either loop falls below charge pressure, the corresponding makeup valve opens. In this case, charge oil flows into the loop.
Since the pressure in each loop is equal when the vibratory system is not operating, flushing spool (14) and (30) in each vibratory motor is in the center position. In this case, the spool prevents flushing oil from flowing into the case drains of the motors.
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| Illustration 2 | g06610215 |
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Vibratory Hydraulic System OPERATING (1) Vibratory hydraulic pump (2) Front vibratory solenoid (3) Rear vibratory solenoid (4) Interlock valve (5) From charge filter (6) Vibratory solenoid "MA" (7) Vibratory solenoid "MB" (8) Crossover relief valve (9) Servo piston (10) Rotating group (11) Crossover relief valve (12) From propel pump case (13) Rear vibratory motor (14) Flushing spool (15) Flushing orifice (16) Charge relief valve (17) Return manifold (18) Oil cooler (19) Flushing orifice (20) Flushing spool (21) Front vibratory motor (22) Crossover relief valve (23) Rotating group (24) Servo piston (24) Crossover relief valve | |
The above schematic shows the vibratory system operating with both drums vibrating at high amplitude. The machine can operate in this configuration with the operator seat facing the front or the rear of the machine.
Note: If only one drum is operating, the vibratory circuit for the idle drum is in the off condition, as previously shown.
When the vibratory system is operating with both drums operating in high amplitude, the machine ECM energizes rear vibratory solenoid (3) and vibratory solenoid"MA" (6). In this case, the rear vibratory solenoid directs charge oil into servo piston (9) and vibratory solenoid"MA" directs charge oil into servo piston (24).
The pressure in the servo pistons causes the corresponding pump servo to move. This movement changes the angle of the swashplate in vibratory rotating groups (10) and (23). The stronger the signal to the solenoid, the greater the swashplate angle, and therefore, the greater the oil flow out of vibratory hydraulic pump (1).
As a swashplate in a rotating group moves, the feedback linkage tends to move the pump solenoid spool back to neutral through a feedback spring. This action prevents the servo piston from tilting the swashplate too far.
In the front drum vibratory circuit, oil from rotating group (23) flows to crossover relief valve (25) and port "A" of front vibratory motor (21). In the rear drum vibratory circuit, oil from rotating group (10) flows to crossover relief valve (8) and port "B" of rear vibratory motor (13).
In each vibratory circuit, the pressure differential between the two sides of vibratory motors (13) and (21) causes the respective motor to turn. After turning the front vibratory motor, oil at a reduced pressure flows to port "C" of vibratory pump (1). After turning the rear vibratory motor, oil at a reduced pressure flows to port "A" of the vibratory pump.
Inside vibratory pump (1), supply oil from rotating group (10) acts against the relief section of crossover relief valve (11). As long as the supply pressure is greater than charge pressure, the makeup valve in the crossover relief valve remains seated. As long as the supply pressure is less than relief pressure, the relief valve in the crossover relief valve remains closed.
Front rotating group (23) operates in a similar fashion to rear rotating group (10). In this case, supply oil acts against the relief valve in crossover relief valve (22).
If pressure in the return side of either loop falls below charge pressure, the makeup valve in the corresponding crossover relief valve opens. In this case, charge oil flows into the low-pressure side of the loop. When pressure in the low-pressure side of the loop rises above charge pressure, the makeup valve closes.
Loop flushing occurs in vibratory motors (13) and (21). In these motors, oil in the high-pressure side of the circuit acts against one side of flushing spool (13) and (20). Oil in the low-pressure side of the circuit acts against the opposite side of the flushing spool. The higher-pressure oil moves the flushing spool. This movement allows oil from the low-pressure side of the circuit to flow across the spool and through respective flushing orifice (14) or (18).
Anytime the pressure in the low-pressure side of the circuit is greater than the setting of the flushing relief valve, the flushing relief valve opens. In this case, oil from the low-pressure circuit flows through an orifice and into the motor case drain line. Acceptable case drain flow for the motor is
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| Illustration 3 | g06610262 |
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Vibratory Hydraulic System OPERATING (1) Vibratory hydraulic pump (2) Front vibratory solenoid (3) Rear vibratory solenoid (4) Interlock valve (5) From charge filter (6) Vibratory solenoid "MA" (7) Vibratory solenoid "MB" (8) Crossover relief valve (9) Servo piston (10) Rotating group (11) Crossover relief valve (12) From propel pump case (13) Rear vibratory motor (14) Flushing spool (15) Flushing orifice (16) Charge relief valve (17) Return manifold (18) Oil cooler (19) Flushing orifice (20) Flushing spool (21) Front vibratory motor (22) Crossover relief valve (23) Rotating group (24) Servo piston (24) Crossover relief valve | |
The above schematic shows the vibratory system operating with both drums vibrating at low amplitude. The machine can operate in this configuration with the operator seat facing the front or the rear of the machine.
Note: If only one drum is operating, the vibratory circuit for the idle drum is in the off condition, as previously shown.
In low-amplitude operation, front vibratory solenoid (2) and vibratory solenoid "MB" (7) are energized. In this case, oil flows out port "A" and port "C" of vibratory hydraulic pump (1). Low-pressure oil returns to port "B" and port"D"
Crossover relief valves (8) and (22) in vibratory hydraulic pump (1) limit the maximum pressure in the hydrostatic loop. Crossover relief valves (11) and (25) in the pump provide makeup oil to the low-pressure side of the loop.
Supply oil is delivered to port "B" of each vibratory motor (13) and (21). The motors rotate so that the shot is captured in the pocket on the "light" side of the eccentric weight.
Flushing spools (14) and (20) shift to allow oil in the low-pressure side of the loop to flow into the motor cases.