Case ih maxxum 120 tractor service repair manual

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HYDRAULIC, PNEUMATIC, ELECTRICAL, ELECTRONIC SYSTEMS - PRIMARY HYDRAULIC POWER SYSTEM

Hydraulic pump Variable displacement pump - Dynamic description (System description CCLS) [13064269] The charge pressure pump draws oil through the charge pump inlet filter. Oil drawn by the charge pump flows through the charge pressure filter to the variable flow piston pump and also through the charge pressure valve to the inlet port of the steering pump. Because output from the charge pump can exceed the combined demand of the steering and variable displacement pumps an open gallery between the inlet side of the charge and steering pumps allows excess flow to the inlet side of the steering. The variable flow closed centre load sensing hydraulic pump operates progressively in 5 modes: • • • • •

Generating Low Pressure Standby pressure Low Pressure Standby High Pressure Circuit Maximum Demand High Pressure Circuit Low Demand Maximum System Pressure (High Pressure Standby)

1 3 5 7 9

Electro Hydraulic Remote (EHR) Valve Load Sensing Line from EHR Valve Load Sensing Line from EDC Valve Load Sensing Line from Trailer Brake Valve Flow Compensating Valve 22 bar (319 psi)

2 4 6 8 10

11 13 15 17 19 21

Variable Displacement Pump Assembly Steering System Supply oil Charge Pressure Bypass Valve 3 bar (44 psi) Main Intake Filter Vacuum Switch Low Temperature Switch 40 °C (104 °F) Charge Pressure Filter

12 14 16 18 20 22

23 25 27 29

Main System Relief Valve 245 bar (3553 psi) Low Pressure Regulating Valve Trailer Brake Valve End Plate with Pressure Regulator Valve for Supply to EHR Pilot Line 20 - 22 bar (290 319 psi) Low pressure Supply to Transmission clutches, Four Wheel Drive, Differential Locks, PTO clutch and PTO Brake

24 26 28 30

Load Sensing Line from High pressure circuit components Gallery to Swash Plate servo piston from flow and compensating valves System pressure supply to low pressure regulating valve System pressure outlet from low pressure regulating valve

B

31

A C E G

D F H

Low Pressure Pilot Line for EHR Control Spool Electronic Draft Control (EDC) Valve Lift Ram Load Sensing Shuttle Valves Pressure Compensating Valve 205 bar (2973 psi) Low Charge Pressure Warning Switch Steering Pump Supplementary lube valve 0.8 bar (12 psi) Main Intake Filter Charge Pump Charge Pressure Filter Dump Valve 6 bar (87 psi) Trailer Brake Valve Outlet Low Pressure Relief Valve 30 bar (435 psi) Low Pressure Regulating Valve Assembly High Pressure Supply to Front Suspension or Mid Mount Remotes, where fitted

Return to Reservoir from flow and pressure compensating valves. System Pressure sensing gallery to flow and pressure compensating valves Regulated Low pressure oil supply Low pressure regulating valve spool sensing gallery

MAXXUM-T3-DRAFT 02/11/2011

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