Fluid Power Pumps and Motors - GBV
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Fluid Power Pumps and Motors Analysis, Design, and Control Noah D. Manring Mc Graw Hill Education New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto
Transcript of Fluid Power Pumps and Motors - GBV
Fluid Power Pumps and Motors
Analysis, Design, and Control
Noah D. Manring
Mc Graw Hill Education
New York Chicago San Francisco Lisbon London Madrid Mexico City
Milan New Delhi San Juan Seoul Singapore Sydney Toronto
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
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nts
3.4 Conclusion 31 Bibliography 31
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
C o n t e n t s jx
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
X C o n t e n t s
7.3 Volumetrie Flow Consideration 109 7.4 Pump Efficiency I l l 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
C o n t e n t s xi
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
XÜ C o n t e n t s
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
C o n t e n t s
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
