Illustration 1 | g03233416 |
(1) Supplemental implement gear pump (2) Piston pump |
Supplemental gear pump (1) is used on the 450F to ensure that a sufficient volume of oil is supplied to the implement valve. The gear pump is mounted on the rear of the implement piston pump (2). The outlet for pump (1) is connected to the outlet cover on the implement valve.
When the pump is viewed from the drive end, the pump shaft rotates in a clockwise direction.
Illustration 2 | g01431588 |
Typical fixed displacement gear pump (3) Drive gear (4) Idler gear (A) Outlet (high pressure) (B) Inlet (low pressure) |
A gear pump carries oil from inlet port (B) to outlet port (A) in the spaces between the gear teeth.
The drive shaft turns drive gear (3). The drive gear forces idler gear (4) to rotate. When the gear teeth separate, a partial vacuum is formed. Oil fills in the spaces between the teeth inlet port (B). The gears carry oil around the circumference of the pump to outlet port (A). A seal is formed by the gear teeth against the pump housing. Oil is forced out of the spaces between the gear teeth as the gear teeth mesh together at outlet port (A). Oil will not return to inlet port (B) because the meshing of the gears will fill the spaces between the gear teeth.
The flow rate of oil that is supplied by the pump is controlled by the rate of rotation of the shaft.