Fluid power circuits and controls : fundamentals and applications

Title:

Personal Author:

Cundiff, John S.

Series:

Mechanical engineering series

Publication Information:

Boca Raton : CRC Press, 2002

ISBN:

9780849309243

Subject Term:

Hydraulic machinery

Fluid power technology

Available:*

Library	Item Barcode	Call Number	Material Type	Item Category 1	Status
Searching... PSZ JB	30000004522060	TJ840 C85 2002	Open Access Book	Book	Searching... Unknown

Engineers not only need to understand the basics of how fluid power components work, but they must also be able to design these components into systems and analyze or model fluid power systems and circuits. There has long been a need for a comprehensive text on fluid power systems, written from an engineering perspective, which is suitable for an undergraduate-level course in fluid power.

Fluid Power Circuits and Controls: Fundamentals and Applications encourages students to think of the collection of components as a system. The author illustrates each concept with a circuit diagram, and as each component is discussed, immediately places it in a circuit and analyzes its performance. This approach allows students to immediately apply what they have learned and encourages them to think about how the component operating characteristics interact with the rest of the circuit.

Covering all aspects of the industry, this book:

Develops the basic concept for power delivery with fluids
Reviews basic concepts of fluid mechanics and discusses the key properties of the fluids
Discusses the creation and control of flow and the various methods used to control pressure in a circuit
Provides a detailed example of the classic problem of hydrostatic transmission design
Presents characteristics of auxiliary components and applicable SAE standards
Addresses pneumatics, focusing on the difference in power transmission for liquid and gas
Discusses servo valves and proportional valves without requiring a background in automatic controls

The text is richly illustrated, filled with fully worked example problems, and reinforced with exercises in each chapter. Fluid Power Circuits and Controls offers valuable design experience and the background its readers need to approach real-world fluid power problems with confidence.

Author Notes

John S. Cundiff: Virginia Polytechnic Institute and State University, Blacksburg

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

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