course-komatsu-wb93r5-wb97r5-backhoe-loaders-hydraulic-system.pdf

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Hydraulic System : Main Principle

FLOW: dete deterr mi n es the th e speed of th e work wor k equi equi pment. pment. Speed of work equipment is determined by the amount of pump flow. Greater the pump flow the greater the speed. Lesser pump flow creates slower speeds. Pump flow rate is determined by the pump swash plate angle and rpm.

PRESSURE: dete deterr mi nes the th e amoun amou n t of force the th e work wor k equi pment pment can can exer xer t.









Hydraulic System : Main Principles

Pump RPM When the pump rotation speed increases, increases , the pump flow increases. This is directly effected by engine rpm. When the pump rotation speed decreases, decreases , the pump flow decreases.

Pump Swash Plate Angle Angle As the pump swash plate angle increases increases more fluid can fill each chamber increasing the flow.

As the pump swash plate angle decreases decreases less fluid can fill each









Hydraulic System : Flow/Pressure Relationship Relationship

The The rela relati tio onship ship betw etween een flow low and and press ressu ure is sho shown in the the Hydr ydrauli aulicc Outp utput Cur Curve. ve. With all hydraulic equipment the relationship between flow and pressure is inversely proportional: as pressure increases flow decreases and as pressure decreases flow increases.

Flow (Q) Hydr. POWER is constant =

Q x P









Hydraulic System : Variable Displacement Pump

BASIC PRINCIPLE 1. Cont Contro roll of of pum pump p swa swash sh plat plate e ang angle le The pump swash plate angle (pump  discharge amount) is controlled so that LS differential differential pressure PLS (the difference between pump (discharge) pressure PP and control valve outlet port LS pressure PLS) PLS) load pressure of actuator) is constant. (LS pressure PLS=Pump PLS=Pump discharge pressure PP-LS PP-LS pressure PLS) PLS)









Hydraulic System : Variable Displacement Pump

) D t n e m Q e e c g a











Hydraulic System : Speed Up









Hydraulic System : Compensators

FLOW CONTROL

P

S

FLOW CONTROL









Hydraulic System : Compensators THE INNOVATIVE

CONVENTIONAL SYSTEM

SYSTEM INSTALLED ON THE

Flow division without pressure compensator

NEW KOMATSU BACKHOE LOADERS

Flow division with










Light load

Heavy load PLS1

PLS1 > PLS2 Main spool

PLS2










2.Light load (Compensated (Compensated side)

PLS2 < PLS1

1.Heavy load (Compensating side)











Hydraulic System : Lay Out



























Hydraulic System : Control Valve









Hydraulic System : Control Valve



























course-komatsu-wb93r5-wb97r5-backhoe-loaders-hydraulic-system.pdf

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