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| Illustration 1 | g00527543 |
Typical example (1) Swing pump regulator (2) Main pump (5) Charging pump (6) Swing pump (7) Main pump regulator | |
The swing pump (6) is a variable displacement piston pump with a swashplate. The pump is driven from the output on the main pump drive.
The swing system is a closed loop system and the pump is designed to upstroke in either direction. In a closed loop system, the swing direction is changed by upstroking the pump in the opposite direction. The swing pump (6) and the swing hydraulic circuit are separate from main hydraulic pump (2) and the circuit.
The swing circuit charging pump (5) is a gerotor type pump that is incorporated in the manifold with a charging relief valve, a crossover relief valve and a cutoff valve. The oil from the charging pump passes an external oil filter before entering the low pressure side of the swing pump.
The pump zero position can be adjusted through mechanical adjustment screws. Swing brake torque can be adjusted at the swing pump regulator by using different brake spools.
Components
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| Illustration 2 | g00817567 |
The swing pump is a swashplate type pump that is used for hydrostatic drives. The pump is driven from the main pump drive output. The pump regulator and the charging pump are mounted on the pump housing.
The swashplate angle is changed by a double servo piston. By directing control oil to either side of the servo piston, the pump swashplate swings to the corresponding direction.
When the swing pump regulator is in the NEUTRAL position, the swashplate is at a zero degree angle and the pump flow is zero. The servo piston is used to upstroke the pump in either direction from the zero degree angle. When the swashplate is passing the zero degree angle, the flow changes the swing direction smoothly.
The charging pump is a gear type pump that is connected to the swing pump housing through a connecting plate. The charging pump is used to keep the swing circuit pressurized with oil.