Fluid Power Pumps and Motors: Analysis, Design and Control / Edition 1

by Noah D. Manring

Overview

Written by an expert in the field of fluid power, this book provides proven methods for analyzing, designing, and controlling high-performance axial-piston swash-plate type machinery. Fluid Power Pumps and Motors: Analysis, Design, and Control offers a comprehensive mechanical analysis of hydrostatic machines and presents meticulous design guidelines for machine components. Detailed diagrams and useful formulas are included throughout. Using the results and techniques employed in this practical resource will reduce product delivery lead-time and costs to increase overall efficiency.

COVERAGE INCLUDES:
Fluid properties | Fluid mechanics | Mechanical analysisPiston pressure | Steady-state results | Machine efficiencyDesigning a cylinder block, valve plate, piston, slipper, swash plate, and shaft | Displacement controlled pumpsPressure controlled pumps

Product Details

ISBN-13:	9780071812207
Publisher:	McGraw Hill LLC
Publication date:	07/19/2013
Pages:	320
Product dimensions:	6.60(w) x 9.20(h) x 1.00(d)

About the Author

Noah Manring is the Glen A. Barton Professor for Fluid Power in the Mechanical and Aerospace Engineering Department at the University of Missouri–Columbia (UMC). Before joining the faculty at UMC, he worked for eight years in the off-highway mobile equipment industry. Dr. Manring holds ten U.S. patents for innovations in the field of fluid power. As a professor, he has received research funding from Caterpillar, Inc., Festo Corp., and the National Fluid Power Association, among others, as well as the U.S. Department of Education, the National Science Foundation, and various private donors. Dr. Manring currently serves as the Associate Dean for Research in the College of Engineering at the University of Missouri. He has done consulting work for several industrial firms, including Moog Inc., FMC Wyoming Corp., Dennison Hydraulics, and Parker Hannifin.

Table of Contents

Preface xv

1 Introduction 1

1.1 Introduction 3

1.2 Typical Machine Applications 5

1.3 General Machine Configuration 5

1.4 Conclusion 7

Bibliography 8

2 Fluid Properties 9

2.1 Introduction 11

2.2 Fluid Bulk Modulus 11

2.2.1 General 11

2.2.2 Bulk Modulus for a Liquid 12

2.2.3 Bulk Modulus for a Gas 13

2.2.4 Effective Bulk Modulus 13

2.2.5 Summary 15

2.3 Fluid Viscosity 15

2.3.1 General 15

2.3.2 Viscosity Charts 16

2.3.3 Viscosity Approximations 17

2.3.4 Recommended Viscosities 18

2.3.5 Summary 19

2.4 Conclusion 19

Bibliography 19

3 Fluid Mechanics 21

3.1 Introduction 23

3.2 The Reynolds Equation 24

3.2.1 General 24

3.2.2 Fundamental Equation 24

3.2.3 Linear Flow Conditions 25

3.2.4 Radial Flow Conditions 26

3.2.5 Summary 27

3.3 The Bernoulli Equation 28

3.3.1 General 28

3.3.2 Fundamental Equation 28

3.3.3 Bernoulli Flow Conditions 29

3.3.4 Summary 30

3.4 Conclusion 31

Bibliography 31

4 Mechanical Analysis 33

4.1 Introduction 35

4.2 Cylinder-Block Free-Body Diagram 36

4.2.1 General 36

4.2.2 Time Rate-of-Change of Cylinder-Block Momentum 38

4.2.3 Cylinder-Block Spring Force 38

4.2.4 Shaft Reaction 39

4.2.5 Valve-Plate Reaction 39

4.2.6 Pressure-Clamping Force 40

4.2.7 Piston Reaction 40

4.2.8 Summary 42

4.3 Piston Free-Body Diagram 43

4.3.1 General 43

4.3.2 Time Rate-of-Change of Piston Momentum 44

4.3.3 Slipper Reaction 44

4.3.4 Piston-Bore Pressure Force 45

4.3.5 Cylinder-Block Reaction 45

4.3.6 Summary 47

4.4 Slipper Free-Body Diagram 48

4.4.1 General 48

4.4.2 Time Rate-of-Change of Slipper Momentum 49

4.4.3 Slipper Hold-Down Force 49

4.4.4 Swash-Plate Reaction 51

4.4.5 Slipper-Balance Force 52

4.4.6 Piston Reaction 54

4.4.7 Summary 54

4.5 Swash-Plate Free-Body Diagram 55

4.5.1 General 55

4.5.2 Time Rate-of-Change of Swash-Plate Momentum 56

4.5.3 Slipper Reaction 57

4.5.4 Slipper-Balance Force 58

4.5.5 Control and Containment Forces 58

4.5.6 Summary 59

4.6 Shaft Free-Body Diagram 59

4.6.1 General 59

4.6.2 Time Rate-of-Change of Shaft Momentum 60

4.6.3 Left Bearing Force 61

4.6.4 Right Bearing Force 61

4.6.5 Cylinder-Block Reaction 62

4.6.6 Cylinder-Block Spring Force 62

4.6.7 External Forces 63

4.6.8 Summary 64

4.7 Kinematics of the Piston-Slipper Ball Joint 64

4.7.1 General 64

4.7.2 Motion in the X-Direction 65

4.7.3 Motion in the Y-Direction 66

4.7.4 Motion in the Z-Direction 66

4.7.5 Summary 67

4.8 Symmetry Considerations 67

4.9 Analytical Results 67

4.9.1 General 67

4.9.2 Cylinder-Block Equations 68

4.9.3 Piston Equations 69

4.9.4 Slipper Equations 70

4.9.5 Swash-Plate Equations 71

4.9.6 Shaft Equations 73

4.9.7 Summary 73

4.10 Conclusion 74

Bibliography 74

5 Piston Pressure 75

5.1 Introduction 77

5.2 Control-Volume Analysis 77

5.3 Numerical Solutions 79

5.4 Piston-Pressure Profile 81

5.5 Pressure Carry-Over Angle 82

5.6 Cumulative Pressure Effects 84

5.7 Conclusion 85

Bibliography 85

6 Steady-State Results 87

6.1 Introduction 89

6.2 Cylinder-Block Equations 90

6.3 Piston Equations 95

6.4 Slipper Equations 97

6.5 Swash-Plate Equations 99

6.6 Shaft Equations 101

6.7 Conclusion 103

Bibliography 104

7 Machine Efficiency 105

7.1 Introduction 107

7.2 Internal Friction 108

7.3 Volumetric Flow Consideration 109

7.4 Pump Efficiency 111

7.5 Motor Efficiency 113

7.6 Typical Results 115

7.7 Conclusion 120

Bibliography 121

8 Designing a Cylinder Block 123

8.1 Introduction 125

8.2 Cylinder-Block Geometry 125

8.3 Cylinder-Block Materials 126

8.4 Number of Pistons 128

8.4.1 General 128

8.4.2 Idealized Flow 128

8.4.3 Non-Idealized Flow 133

8.4.4 Summary 135

8.5 Cylinder-Block Layout 135

8.6 Involute Spline Design 137

8.7 Cylinder-Block Balance 141

8.8 Cylinder-Block/Valve-Plate Leakage 145

8.9 Cylinder-Block Tipping 145

8.10 Cylinder-Block Filling 147

8.11 Conclusion 150

Bibliography 150

9 Designing a Valve Plate 151

9.1 Introduction 153

9.2 Valve-Plate Geometry 153

9.3 Valve-Plate Materials 155

9.4 Sizing Valve-Plate Slots 157

9.4.1 General 157

9.4.2 Constant Area Slots 159

9.4.3 Linearly Varying Slots 162

9.4.4 Quadratically Varying Slots 164

9.4.5 Summary 165

9.5 Checking for Cavitation Potential 166

9.5.1 General 166

9.5.2 Constant Area Slots 169

9.5.3 Linearly Varying Slots 171

9.5.4 Quadratically Varying Slots 172

9.5.5 No Slot Geometry 173

9.5.6 Summary 175

9.6 Line-to-Line Porting 176

9.7 Cross Porting 179

9.8 Trapped Volume Designs 182

9.9 Valve-Plate Indexing 186

9.10 Valve-Plate Clamping 189

9.11 Conclusion 190

Bibliography 191

10 Designing a Piston 193

10.1 Introduction 195

10.2 Piston Geometry 195

10.3 Piston Materials 197

10.4 Piston Stress and Radial Deflection 197

10.4.1 General 197

10.4.2 Stress and Point A 199

10.4.3 Stress at Point B 201

10.4.4 Required Material Strength 202

10.4.5 Radial Piston Deflection 205

10.4.6 Summary 205

10.5 Piston-Length Ratios 205

10.6 Miscellaneous Design Practices 206

10.7 Piston Lubrication 206

10.8 Piston Leakage 208

10.9 Conclusion 208

Bibliography 209

11 Designing a Slipper 211

11.1 Introduction 213

11.2 Slipper Geometry 213

11.3 Slipper Materials 214

11.4 Slipper Stresses 214

11.5 Slipper Design Practices 214

11.6 Slipper Balance 215

11.7 Slipper Leakage 217

11.8 Slipper Tipping 218

11.9 Slipper Hold-Down Devices 218

11.10 Conclusion 220

Bibliography 220

12 Designing a Swash Plate 221

12.1 Introduction 223

12.2 Swash-Plate Geometry 223

12.3 Swash-Plate Materials 224

12.4 Swash-Plate Stresses 224

12.5 Control and Containment Forces 225

12.5.1 General 225

12.5.2 A Transverse-Servo Design 226

12.5.3 An Axial-Servo Design 229

12.5.4 Summary 232

12.6 Swash-Plate Bearings 234

12.7 Conclusion 234

Bibliography 235

13 Designing a Shaft 237

13.1 Introduction 239

13.2 Shaft Geometry 239

13.3 Shaft Materials 240

13.4 Shaft Deflection 240

13.5 Shaft Stress 244

13.6 Shaft Bearings 246

13.7 Conclusion 247

Bibliography 247

14 Displacement Controlled Pumps 249

14.1 Introduction 251

14.2 Pump Description 251

14.3 Analysis 253

14.3.1 General 253

14.3.2 Swash-Plate Equilibrium 253

14.3.3 Discharge Pressure 255

14.3.4 Actuator Pressures 256

14.3.5 4-Way Valve Flow 257

14.3.6 Summary 258

14.4 Dynamic Performance 259

14.4.1 General 259

14.4.2 Time Constant 259

14.4.3 Time Response 260

14.4.4 Bandwidth Frequency 261

14.4.5 Summary 261

14.5 Design 262

14.5.1 General 262

14.5.2 Captured Actuator-Spring Design 262

14.5.3 Actuator Design 263

14.5.4 Dynamic Response Design 264

14.5.5 Summary 265

14.6 Conclusion 265

Bibliography 265

15 Pressure Controlled Pumps 267

15.1 Introduction 269

15.2 Pump Description 269

15.3 Analysis 271

15.3.1 General 271

15.3.2 Discharge Pressure 271

15.3.3 Swash-Plate Equilibrium 273

15.3.4 Actuator Pressures 274

15.3.5 3-Way Valve Flow 275

15.3.6 3-Way Valve Equilibrium 277

15.3.7 Summary 279

15.4 Dynamic Performance 280

15.4.1 General 280

15.4.2 Natural Frequency and Damping Ratio 281

15.4.3 Time Response 282

15.4.4 Bandwidth Frequency 284

15.4.5 Summary 286

15.5 Design 286

15.5.1 General 286

15.5.2 Bias-Spring Design 286

15.5.3 Actuator Design 287

15.5.4 Dynamic Response Design 288

15.5.5 Summary 288

15.6 Conclusion 289

Bibliography 289

16 Conclusion 291

Unit Conversions 295

Selected References 297

Index 301