BIT & CUTTING EDGE GP 9W0528 - Caterpillar

Ejector Control - HOLD Position
Illustration 1 g06205833
(1) Piston Pump (Steering and Ejector)
(2) Piston Pump (Fan, Brake, and Ejector)
(3) Pump Drive Housing
(4) Cutoff Spool
(5) Flow Compensator Spool
(6) Cutoff Spool
(7) Flow Compensator Spool
(8) Combination Valve
(9) Steering Diverter Valve
(10) Primary Steering Pressure Switch
(11) Signal From Brake and Fan
(12) Backflow Check Valve
(13) Pilot Pressure Reducing Valve
(14) Steering Resolver
(15) Backflow Check Valve
(16) Signal from Steering System
(17) Supply to Steering
(18) Ejector Control Valve
(19) Eject (PRV)
(20) Relief Valve
(21) Load Check Valve
(22) Ejector Control Spool
(23) retract (PRV)
(24) Relief Valve
(25) Ejector Manifold
(26) Ejector Cylinder
(27) Accumulator
(28) Ejector Retract Sensor
(29) Sequence Valve
(30) Check Valve
(31) Load Control Valve
(32) Lower Valve
(33) Tailgate Cylinders
(34) Slow Return Check Valve
(35) Main Hydraulic Oil TankIn the hold position, proportional relief valve (PRV) (19) and (PRV) (23) are de-energized. Ejector control spool (22) remains centered. Oil flow from steering and ejector pump (1) and fan, brake, and ejector pump (2) is blocked from flowing to ejector cylinder (26).Pilot oil supply to the PRV's is provided by fan, brake, and ejector pump (2) via pilot pressure reducing valve (13) installed in combination valve (8). The pilot pressure reducing valve reduces the high-pressure supply oil to pilot pressure. The valve is also designed to drain pilot pressure to the main hydraulic oil tank (28) when the engine is shutdown.Without signal from brake control (11) or ejector control valve (18) to flow compensator spool (7) of the fan, brake, and ejector pump, the pump remains in the standby condition. However, in the scenario above, there is a light signal from steering system (16) being transmitted through steering signal resolver (14) to flow compensator spool (5) of the steering and ejector pump. this signal causes the pump to upstroke and maintain margin pressure above the signal pressure. Backflow check valve (15) prevents the higher pressure from the steering and ejector pump from blending with the oil in the fan, brake, and ejector pump circuit. Relief valve (20) and relief valve (24) protect the ejector system components from excessive high pressures when the ejector is in the full extend or retract position.Ejector Control - Eject Position
Illustration 2 g06205905
(1) Piston Pump (Steering and Ejector)
(2) Piston Pump (Fan, Brake, and Ejector)
(3) Pump Drive Housing
(4) Cutoff Spool
(5) Flow Compensator Spool
(6) Cutoff Spool
(7) Flow Compensator Spool
(8) Combination Valve
(9) Steering Diverter Valve
(10) Primary Steering Pressure Switch
(11) Signal From Brake and Fan
(12) Backflow Check Valve
(13) Pilot Pressure Reducing Valve
(14) Steering Resolver
(15) Backflow Check Valve
(16) Signal from Steering System
(17) Supply to Steering
(18) Ejector Control Valve
(19) Eject (PRV)
(20) Relief Valve
(21) Load Check Valve
(22) Ejector Control Spool
(23) retract (PRV)
(24) Relief Valve
(25) Ejector Manifold
(26) Ejector Cylinder
(27) Accumulator
(28) Ejector Retract Sensor
(29) Sequence Valve
(30) Check Valve
(31) Load Control Valve
(32) Lower Valve
(33) Tailgate Cylinders
(34) Slow Return Check Valve
(35) Main Hydraulic Oil TankIn the Eject condition, the transmission ECM sends a PWM signal to ENERGIZE eject proportional relief valve (PRV) (19). This action allows pilot pressure oil to move ejector control spool (22) to the ejector eject position. The combined oil supply from the steering and ejector pump (1) and fan, brake, and ejector pump (2) flows