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| Illustration 1 | g01239023 |
(1) Fan/counterweight pump (2) Steering charge pump (3) Steering pump | |
Fan/Counterweight pump (1) is a fixed displacement gear pump. The pump supplies flow to the fan/counterweight system. When the pump is viewed from the drive end, the pump shaft rotates in a clockwise direction.
Fan/Counterweight pump (1) is mounted on the steering charge pump section (2) of the steering pump (3) on the upper left of the engine flywheel housing.
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| Illustration 2 | g01377948 |
Fixed displacement gear pump (4) Drive gear (5) Idler gear | |
The drive shaft turns drive gear (4). The drive gear forces idler gear (5) to rotate. Oil from the hydraulic tank enters the pump through a port on the side of the pump. The oil fills the space between the gear teeth. The gears turn and the oil is sent out of the pump through another port on the opposite side of the pump. This oil travels to the counterweight control valve.
When the counterweight control valve is in the HOLD position, the oil passes through the valve to the fan motor. If the counterweight control valve is shifted to the EXTEND position or the RETRACT position, the oil is supplied to the counterweight hydraulic cylinder.
The flow rate of oil that is supplied by the pump is controlled by the rate of rotation of the shaft.