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| Illustration 1 | g06131744 |
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Vibratory System OFF (1) Vibratory motor assembly (2) Flushing spool (3) Vibratory motor (4) Solenoid "B" (5) Solenoid "A" (6) Combination valve (7) Relief valve (8) Makeup valve (9) Passage to shift valve (10) Thermal bypass return manifold (11) Passage from axle motor (12) Oil cooler (13) Tank (14) Relief valve (15) Thermal bypass valve (16) Passage from drum pump (17) Servo piston (18) Vibratory pump (19) Hydraulic oil temperature sensor (20) Combination valve (21) Relief valve (22) Makeup valve (23) Passage from charge filter (24) Charge relief valve | |
When the engine is operating, return oil from the fan and steering hydraulic systems flows through the charge filter and into passage (23).
Inside vibratory pump (18), charge oil flows to the following locations:
- Charge relief valve (24)
- Makeup valve (22) in combination valve (20) for port"MA"
- Makeup valve (8) in combination valve (7) for port"MB"
- Pump displacement control
- Out port"PS" of vibratory pump (18) and into the passage to shift valve (9)
When the engine is operating, the input shaft of vibratory pump (18) rotates. However, when neither pump solenoid is energized, both sides of pump servo piston (17) are open to the pump case drain. In this case, the servo piston moves the pump swashplate to the neutral position.
Charge pressure acts on charge relief valve (24). When charge pressure is greater than the setting of the valve, the oil pressure overcomes the spring force, and the charge relief valve opens. An orifice limits the amount of flow through the charge relief valve.
The pressure setting of charge relief valve (24) in vibratory pump (18) is less than the pressure setting of the charge relief valve in the propulsion pump. This fact ensures that oil is sent through the case drain of the vibratory pump under normal operating conditions. Since the orifice limits the oil flow through the charge relief valve on the vibratory pump, the charge relief valve on the propulsion pump controls charge pressure.
Charge pressure acts against makeup valves (8) and (22). If the pressure in either side of the hydrostatic loop falls below charge pressure, the corresponding makeup valve opens. This action allows charge oil to flow into the loop.
Since the vibratory system is not operating, vibratory motor (3) is not rotating, and flushing spool (2) remains in the center position.
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| Illustration 2 | g06131772 |
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High Amplitude Operation (1) Vibratory motor assembly (2) Flushing spool (3) Vibratory motor (4) Solenoid "B" (5) Solenoid "A" (6) Combination valve (7) Relief valve (8) Makeup valve (9) Passage to shift valve (10) Thermal bypass return manifold (11) Passage from axle motor (12) Oil cooler (13) Tank (14) Relief valve (15) Thermal bypass valve (16) Passage from drum pump (17) Servo piston (18) Vibratory pump (19) Hydraulic oil temperature sensor (20) Combination valve (21) Relief valve (22) Makeup valve (23) Passage from charge filter (24) Charge relief valve | |
When the vibratory system is operating, solenoid"A" (5) is energized. In this case, charge oil enters the high amplitude cavity of servo piston (17). The pressure in the cavity overcomes the spring force. The pump servo moves, and the angle of the swashplate changes.
When solenoid"A" (5) is energized, supply oil flows from port"A" of vibratory pump (18) to port"B" of vibratory motor assembly (1). The supply oil causes the motor to rotate. After turning the motor, reduced pressure oil returns to port"B" of the vibratory pump. The returning oil completes the circuit.
Pump supply oil also flows to combination valve (20) and to flushing spool (2). As long as the pressure in the high-pressure circuit is greater than charge pressure and less than relief pressure, makeup valve (22) remains seated. In this case, relief valve (21) also remains closed.
When pressure in the high-pressure side of the loop is greater than relief pressure, relief valve (21) in the combination valve opens. This action directs oil from the high-pressure loop into the charge system. When pressure in the high-pressure side of the loop decreases below the relief pressure, the relief valve closes.
When pressure in the low-pressure side of the loop is less than charge pressure, makeup valve (8) is open. This situation allows charge oil to flow into the low-pressure side of the loop. If the pressure in the low-pressure side of the loop rises above charge pressure, this makeup valve closes.
Oil in the high-pressure side of the loop acts against one side of flushing spool (2). Oil in the low-pressure side of the loop acts against the other side of the flushing spool. The difference in pressure moves the flushing spool. This movement directs oil from the low-pressure side of the loop through an orifice to the vibratory motor case drain line. The flow of flushing oil through the case cools the motor.