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

제9장 유압회로

유압 시스템 기본 구성

- 2 - Fluid Power 유압공학

제9장 유압회로

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

- 3 - Fluid Power 유압공학

제9장 유압회로

유압 회로도

- 4 - Fluid Power 유압공학

제9장 유압회로

Hydraulic Circuit of Hydrostatic Transmission

- 5 - Fluid Power 유압공학

제9장 유압회로

Control of Hydraulic Cylinders

Control of single acting hydraulic cylinder

Control of double acting hydraulic cylinder

- 6 - Fluid Power 유압공학

제9장 유압회로

Regenerative Cylinder Circuit

- 7 - Fluid Power 유압공학

제9장 유압회로

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=

- 8 - Fluid Power 유압공학

제9장 유압회로

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

- 9 - Fluid Power 유압공학

제9장 유압회로

Pump-unloading Circuit

- 10 - Fluid Power 유압공학

제9장 유압회로

Double-pump Hydraulic System

- 11 - Fluid Power 유압공학

제9장 유압회로

Counterbalance Valve Application

- 12 - Fluid Power 유압공학

제9장 유압회로

Hydraulic Cylinder Sequence Circuit

- 13 - Fluid Power 유압공학

제9장 유압회로

Automatic Cylinder Reciprocating System

- 14 - Fluid Power 유압공학

제9장 유압회로

Locked Cylinder using Pilot Check Valves

- 15 - Fluid Power 유압공학

제9장 유압회로

Cylinder Synchronizing Circuits

Cylinder Connected in Parallel

Cylinder Connected in Series

- 16 - Fluid Power 유압공학

제9장 유압회로

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= +

- 17 - Fluid Power 유압공학

11 1 2Pp

제9장 유압회로

Fail-Safe Circuits

Fail-safe circuit

Fail-safe circuit with overloadprotection

- 18 - Fluid Power 유압공학

p

제9장 유압회로

Two-Handed Safety Circuit

- 19 - Fluid Power 유압공학

제9장 유압회로

Meter-in Speed Control of Hydraulic Cylinder

- 20 - Fluid Power 유압공학

제9장 유압회로

Meter-out Speed Control of Hydraulic Cylinder

- 21 - Fluid Power 유압공학

제9장 유압회로

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

−=

- 22 - Fluid Power 유압공학

piston

제9장 유압회로

Speed Control of Hydraulic Motor

- 23 - Fluid Power 유압공학

제9장 유압회로

Hydraulic Motor Braking System

- 24 - Fluid Power 유압공학

제9장 유압회로

Closed-circuit One-direction HST

- 25 - Fluid Power 유압공학

제9장 유압회로

Closed-circuit Reversible-direction HST

- 26 - Fluid Power 유압공학

제9장 유압회로

Air-over-oil Circuit

- 27 - Fluid Power 유압공학

제9장 유압회로

Example: Analysis of Hydraulic System

- 28 - Fluid Power 유압공학

제9장 유압회로

Mechanical-hydraulic Servo System

- 29 - Fluid Power 유압공학

제9장 유압회로

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

제9장 유압회로

Lines & Line Functions

- 31 - Fluid Power 유압공학

제9장 유압회로

Pumps, Motors & Cylinders

- 32 - Fluid Power 유압공학

제9장 유압회로

Miscellaneous Units

- 33 - Fluid Power 유압공학

제9장 유압회로

Basic Valve Symbols

- 34 - Fluid Power 유압공학

제9장 유압회로

Valve Examples

- 35 - Fluid Power 유압공학

제9장 유압회로

Methods of Operation

- 36 - Fluid Power 유압공학

제9장 유압회로

㉿ 한국공업규격

유압용어: KS B 0119

유압.공기압도면기호: KS B 0054

Report #9KS 유공압관련규격찾아볼것

- 37 - Fluid Power 유압공학

제9장 유압회로

Report

Text Problems9-169-289-45

Due date: 2주후

- 38 - Fluid Power 유압공학