معى اليوم احبتى فى الله
كتاب
Fluid Power Circuits And Controls Fundamentals And Applications
Contents
Preface .......................................................................................................v
1. Brief Overview of Fluid Power
...................................................... 1
1.1 Introduction..........................................................................................1
1.2 Concept of Fluid Power ......................................................................1
1.2.1 Basic Circuits ............................................................................2
1.2.2 Basic Circuit Analysis..............................................................7
1.2.3 Efficiency.................................................................................10
1.3 Summary.............................................................................................11
2. Fluid Power Basics
........................................................................ 15
2.1 Introduction........................................................................................15
2.2 Fluid Statics.........................................................................................16
2.2.1 Hydrostatic Pressure .............................................................16
2.2.2 Conservation of Mass............................................................22
2.3 Functions of a Working Fluid ..........................................................24
2.4 Fluid Properties..................................................................................26
2.4.1 Viscosity ..................................................................................26
2.4.2 Bulk Modulus.........................................................................30
2.4.3 Specific Gravity ......................................................................31
2.4.4 Other Fluid Properties ..........................................................31
2.5 Flow in Lines ......................................................................................34
2.5.1 Reynolds Number..................................................................35
2.5.2 Darcy’s Equation....................................................................37
2.5.3 Losses in Fittings....................................................................43
2.6 Leakage Flow......................................................................................45
2.7 Orifice Equation .................................................................................48
2.7.1 Analysis to Illustrate Use of Orifice Equation ...................50
2.7.2 Use of Orifice Equation to Analyze Pressure
Reducing Valve ......................................................................54
2.8 Summary.............................................................................................61
A2.1 Data for Selected Hydraulic Fluids .................................................65
3. Pressure Control
............................................................................ 67
3.1 Introduction........................................................................................67
3.2 Review of Needed Symbols .............................................................68
3.3 Relief Valve.........................................................................................69
3.3.1 Direct-Acting Relief Valve....................................................69
3.3.2 Pilot-Operated Relief Valve..................................................75
3.3.3 Example Circuits Using Pilot-Operated Relief
Valves ......................................................................................77
3.4 Unloading Valve ................................................................................81
3.5 Sequence Valve and Pressure-Reducing Valve .............................88
3.5.1 Sequence Valve ......................................................................88
3.5.2 Pressure-Reducing Valve......................................................89
3.6 Counterbalance Valve and Brake Valve.........................................92
3.6.1 Counterbalance Valve ...........................................................92
3.6.2 Brake Valve.............................................................................94
3.7 Summary.............................................................................................95
4. Creation and Control of Fluid Flow
.......................................... 101
4.1 Introduction......................................................................................101
4.2 Fixed Displacement Pumps............................................................103
4.3 Fixed Displacement Pump Circuits...............................................104
4.4 Variable Displacement Pump Circuits .........................................109
4.4.1 Vane Pump ...........................................................................110
4.4.2 Piston Pump .........................................................................114
4.4.3 Improvement in Efficiency with Load Sensing ...............117
4.5 Comparison of Pump Performance Characteristics for
Three Main Designs.........................................................................124
4.5.1 Gerotor Pump.......................................................................124
4.5.2 Vane Pump ...........................................................................130
4.5.3 Axial Piston Pump...............................................................132
4.6 Multiple Pump Circuits ..................................................................137
4.7 Pump Mounts...................................................................................138
4.8 Flow Control Valves........................................................................140
4.8.1 Flow Dividers .......................................................................143
4.9 Circuits Using Flow Control Valves .............................................144
4.10 Summary...........................................................................................146
5. Rotary Actuators
.......................................................................... 153
5.1 Introduction......................................................................................153
5.2 Stall Torque Efficiency ....................................................................157
5.3 Typical Performance Data for a Gear Motor ...............................159
5.4 Comparison of Motor Performance Characteristics for
Three Main Designs.........................................................................161
5.4.1 Gear Motor............................................................................161
5.4.2 Vane Motor ...........................................................................162
5.4.3 Piston Motor .........................................................................162
5.5 Performance Characteristics of Low-Speed, High-Torque
Motors................................................................................................164
5.5.1 Geroler Motor (Disc Valve) ................................................164
5.5.2 Vane Motor (Low-Speed, High-Torque) .........................165
5.6 Design Example for Gear Motor Application..............................167
5.6.1 Functional Requirements....................................................168
5.6.2 Other Design Considerations.............................................168
5.7 Interaction of Pump and Motor Characteristics..........................168
5.8 Bent Axis Motors..............................................................................172
5.8.1 Design Considerations for Bent Axis Motors ..................175
5.8.2 Performance Advantage of Bent Axis Design .................176
5.9 Radial Piston Motors .......................................................................179
5.10 Motor-Gearbox Combinations.......................................................180
5.11 Oscillating Actuator.........................................................................183
5.12 Summary...........................................................................................185
A5.1 Curve Fitting Technique .................................................................187
6. Hydrostatic Transmissions
......................................................... 193
6.1 Introduction......................................................................................193
6.2 Mechanical Transmissions..............................................................193
6.2.1 Torque Converters...............................................................197
6.2.2 Shift Control of Automatic Transmission ........................199
6.2.3 Summary...............................................................................201
6.3 Introduction to Hydrostatic Transmissions.................................201
6.4 Hydrostatic Transmissions for Vehicle Propulsion ....................203
6.4.1 Comparison of Hydrostatic and Mechanical
Drives.....................................................................................203
6.4.2 Advantages of Hydrostatic Transmissions ......................204
6.5 Different Configurations of Hydrostatic Transmissions
to Propel Vehicles ............................................................................205
6.5.1 Hydrostatic Transmission with Two Wheel Motors.........205
6.5.2 Hydrostatic Transmission with Final Drives...................207
6.5.3 Hydrostatic Transmission with Variable Speed
Motors....................................................................................210
6.5.4 Vehicle with Two Hydrostatic Transmissions.................210
6.5.5 Hydrostatic Drive for Three-Wheel Vehicle ....................212
6.5.6 Hydrostatic Transmission for Four-Wheel Drive
Vehicle ...................................................................................212
6.5.7 Summary...............................................................................215
6.6 Classification of Hydrostatic Transmissions ...............................215
6.7 Closed-Circuit Hydrostatic Transmissions ..................................216
6.7.1 Charge Pump........................................................................216
6.7.2 Shuttle Valve.........................................................................219
6.7.3 Cross-Port Relief Valves .....................................................221
6.7.4 Multipurpose Valves...........................................................222
6.7.5 Summary...............................................................................222
6.8 Closed-Circuit, Closed-Loop Hydrostatic Transmissions .........223
6.8.1 Review of Pump and Motor Operating
Characteristics ......................................................................223
6.8.2 Servo-Controlled Pump ......................................................226
6.8.3 Servo Valve Circuit..............................................................229
6.8.4 Response Time for Closed-Loop Circuit ..........................230
6.8.5 Operation of Closed-Circuit, Closed-Loop
Hydrostatic Transmission ..................................................231
6.9 Hydrostatic Transmission Design .................................................232
6.9.1 Hydrostatic Drive for Sweet Sorghum Harvester...........234
6.9.2 Example Solution for Design of Hydrostatic Drive
for Sweet Sorghum Harvester............................................236
6.10 Summary...........................................................................................251
A6.1 Basic Concepts in Traction..............................................................253
A6.2 Selected Catalog Data for Hydrostatic Transmission
Design Problems ..............................................................................257
7. Linear Actuators
.......................................................................... 271
7.1 Introduction......................................................................................271
7.2 Analysis of Cylinders in Parallel and Series ................................271
7.3 Synchronization of Cylinders ........................................................277
7.3.1 Orifice-Type Flow Divider .................................................279
7.3.2 Gear-Type Flow Divider.....................................................279
7.3.3 Mechanical Coupling ..........................................................279
7.4 Cushioning........................................................................................280
7.5 Rephasing of Cylinders...................................................................281
7.6 Presses ...............................................................................................282
7.6.1 Pilot-Operated Check Valve...............................................284
7.6.2 Load-Locking Circuit ..........................................................286
7.7 Load Analysis...................................................................................286
7.7.1 Analysis of Acceleration of a Load with a Cylinder.......287
7.7.2 One Method for Incorporating the Influence of
Various Factors during Acceleration Event .....................294
7.8 Types of Cylinders...........................................................................296
7.8.1 Cylinder Selection................................................................297
7.8.2 Cylinder Failure ...................................................................297
7.9 Cylinder Construction.....................................................................301
7.10 Summary...........................................................................................303
8. Temperature and Contamination Control
................................. 311
8.1 Introduction......................................................................................311
8.2 Temperature Control.......................................................................311
8.2.1 Methods for Cooling Hydraulic Oil..................................313
8.2.2 Heat Transfer from Reservoir ............................................314
8.2.3 Heat Generated by the System...........................................316
8.2.4 Design Example ...................................................................318
8.2.5 Temperature Control Summary ........................................324
8.3 Contamination Control ...................................................................325
8.3.1 Sources of Contamination ..................................................325
8.3.2 Quantifying Fluid Cleanliness ...........................................326
8.3.3 Effects of Contamination on Various Components ........328
8.3.4 Setting a Target Cleanliness Level.....................................333
8.3.5 Achieving a Target Cleanliness Level...............................335
8.3.6 Monitoring the System Cleanliness Level........................342
8.4 Summary...........................................................................................342
9. Auxiliary Components
................................................................ 349
9.1 Introduction......................................................................................349
9.2 Reservoir ...........................................................................................349
9.2.1 Reservoir Construction .......................................................350
9.3 Hydraulic Lines................................................................................354
9.3.1 Pipe ........................................................................................355
9.3.2 Hydraulic Tubing ................................................................357
9.3.3 Hydraulic Hose ....................................................................362
9.4 Fluid Velocity in Conductors .........................................................365
9.5 Options for Connecting Components...........................................368
9.5.1 Manifolds ..............................................................................370
9.5.2 Quick-Disconnect Coupling...............................................372
9.6 Installation of Lines .........................................................................373
9.6.1 Recommended Practices for Hydraulic Hose..................374
9.6.2 Environmental Issues ..........................................................374
9.7 Design Life of Components............................................................375
9.8 System Integration...........................................................................378
9.8.1 Port Connections..................................................................379
9.8.2 Tube or Hose Connections .................................................380
9.8.3 Assembly...............................................................................380
9.9 Summary...........................................................................................380
A9.1 Selected Design Data for Fluid Conductors.................................383
10. Pneumatics
................................................................................... 389
10.1 Introduction......................................................................................389
10.2 Orifice Equation ...............................................................................390
10.3 Compressors.....................................................................................392
10.3.1 Reciprocating Piston Compressor ...................................392
10.3.2 Diaphragm Compressor ...................................................392
10.3.3 Sliding Vane Rotary Compressor ....................................392
10.3.4 Cooling ................................................................................392
10.4 Receiver .............................................................................................394
10.5 Pipelines ............................................................................................394
10.6 Preparation of Compressed Air.....................................................394
10.6.1 Drying of Air ......................................................................394
10.6.2 Air Filtration .......................................................................396
10.6.3 Pressure Regulation...........................................................397
10.6.4 Compressed Air Lubrication............................................398
10.6.5 Service Units .......................................................................398
10.7 Cylinders...........................................................................................399
10.7.1 Single-Acting Cylinders....................................................399
10.7.2 Diaphragm Cylinder .........................................................399
10.7.3 Rolling Diaphragm Cylinders..........................................400
10.7.4 Double-Acting Cylinders..................................................400
10.7.5 Impact Cylinder .................................................................401
10.7.6 Free Air Consumption by Cylinders...............................401
10.8 Motors................................................................................................403
10.8.1 Types of Pneumatic Motors..............................................403
10.8.2 Characteristics of Pneumatic Motors ..............................405
10.9 Additional Actuator Units..............................................................408
10.9.1 Cylinder with Mounted Air Control Block....................408
10.9.2 Hydropneumatic Feed Unit .............................................408
10.9.3 Feed Unit.............................................................................409
10.9.4 Rotary Index Table.............................................................410
10.9.5 Air Cushion Sliding Table ................................................410
10.10 Valves ................................................................................................411
10.10.1 Valve Symbols..................................................................411
10.10.2 Valve Design.....................................................................412
10.10.3 Poppet Valves...................................................................412
10.10.4 Slide Valves.......................................................................413
10.10.5 Other Valves .....................................................................414
10.11 Summary...........................................................................................415
A10.1 Standard Conditions .......................................................................417
11. Servo Valves
................................................................................. 421
11.1 Introduction......................................................................................421
11.2 Concept..............................................................................................422
11.2.1 Feedback..............................................................................425
11.2.2 Programmable Orifice.......................................................426
11.2.3 Control of Pump Displacement .......................................430
11.2.4 Basic Servo Systems...........................................................430
11.3 Servo Valve Construction...............................................................432
11.3.1 Torque Motor .....................................................................432
11.3.2 Methods for Shifting Servo Valve Spool ........................435
11.3.3 Valve Construction ............................................................438
11.4 Valve Performance...........................................................................440
11.4.1 Rated Flow ..........................................................................440
11.4.2 Pressure Drop.....................................................................441
11.4.3 Internal Leakage.................................................................443
11.4.4 Hysteresis............................................................................443
11.4.5 Threshold ............................................................................443
11.4.6 Gain......................................................................................443
11.4.7 Frequency Response..........................................................445
11.4.8 Phase Lag ............................................................................448
11.4.9 Summary.............................................................................450
11.5 Types of Servo Systems...................................................................450
11.5.1 Hydromechanical Servo System......................................450
11.5.2 Electrohydraulic Servo Systems ......................................451
11.6 Servo Amplifiers ..............................................................................457
11.7 Servo Analysis..................................................................................459
11.7.1 Open-Loop Gain ................................................................463
11.7.2 Natural Frequency.............................................................463
11.7.3 Error Terms.........................................................................471
11.7.4 Introduction to the Laplace Domain...............................474
11.8 Summary...........................................................................................480
12. Proportional Valves
..................................................................... 487
12.1 Introduction......................................................................................487
12.2 Types of Proportional Valves.........................................................487
12.2.1 Force-Controlled Proportional Valves............................488
12.2.2 Summary.............................................................................497
12.2.3 Stroke-Controlled Proportional Valves ..........................497
12.3 Analysis of Proportional Directional Control Valve ..................499
12.3.1 Overrunning Load.............................................................501
12.3.2 Resistive Load ....................................................................507
12.3.3 How a Proportional Direction Control Valve
Functions in a Circuit........................................................510
12.4 Comparison of Servo and Proportional Valves...........................513
12.5 Summary...........................................................................................514
A12.1 Summary of Equations....................................................................517
Index
..................................................................................................... 521
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