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| Illustration 1 | g00559297 |
Engine compartment (1) Gear pump (brake and pilot) | |
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| Illustration 2 | g00559303 |
Gear pump (brake and pilot) (1) Gear pump (brake and pilot) (2) Bearing cover (3) Intermediate plate (4) Housing (5) Drive gear (6) Intermediate plate (7) Bearing cover (8) Shaft seal (9) Bolt (10) Compressed oil (11) Drive shaft (12) Bearing bushings (13) Intake port (14) Output port (15) Support plates (16) Driven gear (17) Bearing support (18) Tooth chamber (19) Pressure chamber | |
Gear pump (1) is a gear type pump. The pump is mounted on the front of the engine and the pump is driven by the timing gear.
The gear pump provides oil flow for the brake accumulators at a maximum pressure of 15000 kPa (2175 psi). The gear pump also provides oil flow to the pilot manifold. The pilot manifold directs oil flow to the pilot circuit at a rate of 15 L/min (4 US gpm). The remainder of the oil is supplied to the attachments.
The gear pump includes gears (5) and (16) in housing (4). The front bearing cover is used as the pump mounting flange. Drive shaft (11) is sealed by shaft seal (8) .
The rotation of shaft (11) creates a vacuum in the tooth chamber (18) from the gears. This vacuum and the atmospheric pressure on the oil in the tank cause the oil to flow to the brake pump. The oil will fill the tooth chambers. The oil is moved from intake port (13) to output port (14). From the pump, the oil flows through the wheel brake valve to the wheel brake lines.
When the wheel brake accumulators are charged to 15000 kPa (2175 psi), the accumulator charging valve switches to neutral flow. This allows the pump oil to flow from port "N" of the accumulator charging valve to the pilot manifold.
Note: There is a low flow pressure relief valve in the line to the pilot flow control valve. The low flow pressure relief valve is set to 17000 kPa (2460 psi).
When the pressure in the wheel brake accumulators is 12000 kPa (1745 psi) the accumulator charging valve moves to the charging position. The gear pump now delivers flow in order to fill the accumulators to a pressure of 15000 kPa (2175 psi).