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제9장 유압회로
9. Hydraulic Circuit Design & Analysis
Description of the operation of hydraulic circuitsdrawn using graphical symbols for all components
d d l d i i i f i li dspeeds and load-carrying capacities of regenerative cylindersmechanical-hydraulic servo systems
Troubleshoot hydraulic circuitsto determine causes of malfunctions
Analysis of hydraulic circuitsto evaluate the safety of operationto evaluate the safety of operationto perform a desired functionincluding the effects of frictional lossesthe speed control of hydraulic cylinders
Fluid Power Symbols- 1 - Fluid Power 유압공학
Fluid Power Symbols
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유압 시스템 기본 구성
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9.1 Introduction
Hydraulic circuita group of components such as pumps, actuators, control valves, and conductors arranged so that will perform a useful task
Three important considerationsSafety of operationy pPerformance of desired functionEfficiency of operation
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유압 회로도
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Hydraulic Circuit of Hydrostatic Transmission
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Control of Hydraulic Cylinders
Control of single acting hydraulic cylinder
Control of double acting hydraulic cylinder
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Regenerative Cylinder Circuit
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Regenerative Cylinder
Cylinder extending speed Ratio of extending & retracting speeds
Q Q Q= +T P RQ Q Q= +
P T RQ Q Q= − ret
PP
P r
QvA A
=−
( )ext extP P P r PA v A A v= − −
Q/
/( )extP P r
v Q Av Q A A
=−
ext
PP
r
QvA
=/( )
retP P P r
P r
v Q A A
A AA
−
−=
Load-carrying capacity during extension
rA
1extP Pv A
= −extension 1retP rv A
extload rF pA=
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Drilling Machine Application
The spring-centered position gives rapid spindle advancespindle advance (extension)The left envelope mode gives slow feed (extension) when the drill starts to cut into the workpieceThe right envelope mode retracts the pistonmode retracts the piston
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Pump-unloading Circuit
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Double-pump Hydraulic System
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Counterbalance Valve Application
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Hydraulic Cylinder Sequence Circuit
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Automatic Cylinder Reciprocating System
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Locked Cylinder using Pilot Check Valves
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Cylinder Synchronizing Circuits
Cylinder Connected in Parallel
Cylinder Connected in Series
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Analysis of Cylinders hooked in Series
continuity equation
( 1) ( 2)out cyl in cylQ Q=( ) ( )y y
1 2( ) ( )
( )eff cyl eff cylA v A v
A A v A v
=
− =for synchronization ( )
1 1 21 2( )P R PA A v A v− =
P R PA A A− =1 2v v=
summing force on cylinder 11 1 2P R P
1 1 11 2 1( )P P Rp A p A A F− − =summing force on cylinder 2
2 2 22 3 2( )P P Rp A p A A F− − =
desired result
1 1 2Pp A F F= +
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11 1 2Pp
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Fail-Safe Circuits
Fail-safe circuit
Fail-safe circuit with overloadprotection
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p
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Two-Handed Safety Circuit
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Meter-in Speed Control of Hydraulic Cylinder
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Meter-out Speed Control of Hydraulic Cylinder
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Analysis of Extending Speed Control
flow-rate to the cylindercyl pump PRVQ Q Q= −
flow-rate through the flow control valve (FCV)y p p
1 2p p pΔ −
pressure p2
1 2FCV v v
p p pQ C CSG SGΔ
= =
pressure p2
extending speed of the cylinder2 piston loadp A F= 2 /load pistonp F A=
extending speed of the cylinder/ /cyl cyl piston FCV pistonv Q A Q A= =
/PRV load pistonvcyl
piston
p F ACvA SG
−=
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piston
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Speed Control of Hydraulic Motor
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Hydraulic Motor Braking System
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Closed-circuit One-direction HST
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Closed-circuit Reversible-direction HST
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Air-over-oil Circuit
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Example: Analysis of Hydraulic System
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Mechanical-hydraulic Servo System
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9.A Fluid Power Symbols
Line & Line Functions
PumpsMotorsCylinders
Miscellaneous Units
Basic Valve SymbolsValve ExamplesValve Examples
Methods of Operation- 30 - Fluid Power 유압공학
Methods of Operation
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Lines & Line Functions
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Pumps, Motors & Cylinders
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Miscellaneous Units
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Basic Valve Symbols
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Valve Examples
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Methods of Operation
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㉿ 한국공업규격
유압용어: KS B 0119
유압.공기압도면기호: KS B 0054
Report #9KS 유공압관련규격찾아볼것
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Report
Text Problems9-169-289-45
Due date: 2주후
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