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| Illustration 1 | g00943015 |
Vibratory pump (1) Servo piston (2) Direction control valve (3) Makeup and relief valve (4) Port plate (5) Charge pump (6) Barrel Assembly (7) Piston (8) Swashplate (9) Drive shaft (AA) Charge pressure (AB) Sump (AC) Activated components | |
The vibratory pump is similar to the propel pumps. A few differences exist for the vibratory pump. The vibratory pump has a direction control that is a solenoid operated valve. There is no feedback link for the swashplate control. The vibratory pump contains an integral charge pump. The combination valve in the pump contains no function for towing.
The vibratory pump is controlled by two solenoids. One solenoid controls the high amplitude, and one solenoid controls the low amplitude. When a particular control solenoid is energized, charge oil is directed into the corresponding chamber for the servo piston, and the opposite chamber for the servo piston is open to the pump case. The swashplate moves to the maximum angle in order to provide flow to the vibratory motor.
High Pressure Relief Valve
The high pressure relief valve provides two functions for the vibratory circuit:
- High pressure relief valve
- Makeup check valve
The maximum working pressure of each loop line of the closed circuit is limited to 35000 ± 3000 kPa (5075 ± 435 psi) by these valves. This valve is a direct acting type. The valve limits the main circuit pressure to specified values above the charge pressure.
High Pressure Relief Valve
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| Illustration 2 | g00943019 |
Relief valve cross section (1) Locking cap (2) Relief valve (3) Conical spring (4) Collar (5) Spindle (6) Spring (7) Collar | |
Oil from the vibratory pump flows through relief valve (2) at the oil passage. High pressure oil enters the passage and the oil acts on the collars (4) and (7). The force of spring (6) keeps the valve closed until the oil pressure in the high pressure side of the main loop circuit reaches relief pressure. After the relief pressure is reached, the pressure moves spindle (5) downward while the pressure compresses spring (6). The relief oil flows from the high pressure side to the low pressure side of the main loop. The oil flows through the gap between spindle (5) and collar (7). The arrows show this flow in illustration 2. High pressure oil enters the low pressure side of the main loop circuit until the force of spring (6) seats spindle (5) and collar (7) .
Makeup Check Valve
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| Illustration 3 | g00943067 |
Makeup valve cross section (1) Locking cap (2) Relief valve (3) Conical spring (4) Collar (5) Spindle (6) Spring (7) Collar | |
Oil from the vibratory pump flows through relief valve (2) at the oil flow passages. The force of spring (3) and the oil pressure in the passage keeps collar (7) closed. Charge pressure acts on the bottom of collar (7) and spindle (5). When the oil pressure in the passage drops below the charge pressure, collar (7) and spindle (5) move upward compressing spring (3) .
The charge oil flows through the gap. The closed loop circuit will be replenished with the makeup oil. The arrows show this flow in illustration 3. Charge oil continues to replenish the low pressure side of the circuit with the make up oil until the pressure in the oil passage becomes greater than the charge pressure.
Vibratory Control Valve
Solenoid Valve
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| Illustration 4 | g00943283 |
(1) Springs (2) Solenoid (3) Valve spool (4) Solenoid | |
The control valve is attached to the vibratory pump. The valve is a three-position solenoid. The valve is a four-way directional control valve. The solenoid control valve directs oil to the servo circuit of the vibratory pump.
When current is supplied to either solenoid (2) or (4), the solenoid moves valve spool (3). The controlled oil passes across valve spool (3). The oil exits the passage to the hydraulic servo.
When the vibratory circuit is not activated, current flow to the solenoid (2) or (4) is interrupted. The force of springs (1) moves valve spool (3) to the center position. The force of each spring (1) is identical. Springs (1) balance each other. The springs also maintain the center position of valve spool (3) .
Servo Piston Assembly
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| Illustration 5 | g00943284 |
Section View Of The Vibratory Pump (5) Drive shaft (6) Pump housing (7) Joint pin (8) Servo housing (9) Servo piston (10) Solenoid valve (11) Barrel (12) Swashplate (13) Bearing | |
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| Illustration 6 | g00943285 |
Section View Of The Servo Piston (8) Servo housing (9) Servo piston (14) Locknut (15) Stroke limiter screw (16) Piston rod (17) Springs (centering) | |
The servo control assembly controls swashplate angle (12) of the vibratory pump. Servo housing (8) is an integral part of the vibratory pump. The servo housing contains the servo piston (9) .
The charge circuit supplies control oil to control valve (10) on the vibratory pump. The control valve regulates the servo piston (9) by directing the oil flow which enters the servo housing. The control valve also acts on servo piston (9). Linear movement of the servo piston mechanically controls the rotational movement of swashplate (12) with joint pin (7). When the servo piston moves, the angle of the swashplate changes in the pump.
The flow of the pump output is zero when the swashplate angle is zero. The swashplate angle is zero when the servo piston is in the center position. The servo piston will return to the center positions when the control valve (10) is not energized. The servo piston is mechanically centered by springs (17). The center position of the servo piston can be adjusted by loosening locknut (14) and turning piston rod (16) .
The pump flow is controlled by the servo piston. The maximum pump output is determined when the swashplate is at the maximum angle. The maximum swashplate angle is controlled by limiting the travel of the servo piston. Adjust stroke limiter screw (15) in order to control the travel of the servo piston. There are two stroke limiter screws. The stroke limiter screws are located on each end of the servo housing.