hbk akram مهندس فعال جدا
عدد المساهمات : 275 التقييم : 621 تاريخ التسجيل : 15/10/2012 العمر : 36 الدولة : egypt العمل : student الجامعة : benha
| موضوع: كتاب Basics of Hydraulic Systems الأربعاء 02 أكتوبر 2013, 8:55 pm | |
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أخوانى فى الله أحضرت لكم كتاب Basics of Hydraulic Systems Second Edition By Qin Zhang
و المحتوى كما يلي :
Table of Contents Preface ix Preface to the Second Edition .xi About the Author xiii 1. Introduction to Hydraulic Power .1 1.1 Power Transmission and Hydraulic Systems 1 1.1.1 Power Transmission in Machinery Systems 1 1.1.2 Hydraulic Power Systems on Mobile Equipment 2 1.1.3 Hydraulic Components and System Schematics .4 1.2 Fundamentals of Hydraulic Power Transmission 6 1.2.1 Multiplication of Force 6 1.2.2 Conservation of Energy 8 1.2.3 Continuity of Fluids 11 1.3 Energy and Power in Hydraulic Systems 12 1.3.1 Energy Conversion in Hydraulic Systems 12 1.3.2 Hydraulic Power and Efficiency 13 1.4 Standard Graphical Symbols for Hydraulic System Schematics 15 1.5 Units and Unit Conversion in Hydraulic Systems . 18 References .21 Exercises 22 2. Hydraulic Power Generation 25 2.1 Hydraulic Pumps 25 2.1.1 Overview of Hydraulic Pumps 25 2.1.2 Principle of Positive Displacement Pumping 26 2.1.3 Gear Pumps 27 2.1.4 Vane Pumps 32 2.1.5 Piston Pumps 34 2.2 Control of Hydraulic Power Generation 41 2.2.1 Corner Power and Pump Efficiency 41 2.2.2 Pressure Limiting 45 2.2.3 Load Sensing with Pressure Limiting 47 2.2.4 Torque Limiting .48 References .51 Exercises 52 3. Hydraulic Power Distribution .55 3.1 Hydraulic Control Valves .55 3.1.1 Overview of Hydraulic Valves .55 3.1.2 Fundamentals of Valve Control .57 3.1.3 Pressure Control Valves 64 3.1.4 Directional Control Valves .71 3.1.5 Flow Control Valves . 76vi Table of Contents 3.1.6 Electrohydraulic Control Valves 81 3.1.7 Programmable Electrohydraulic Valves .87 3.1.8 Select Appropriate Control Valves 89 3.2 Hydraulic Manifolds 91 3.2.1 Overview of Hydraulic Manifolds 91 3.2.2 Modular-Block Manifolds . 91 3.2.3 Single-Piece Hydraulic Manifolds . 91 3.3 Hydraulic Lines .93 3.3.1 Major Components of Hydraulic lines 93 3.3.2 Hydraulic Hoses .93 3.3.3 Metal Tubes and Pipes 96 3.3.4 Designing Hydraulic Lines 98 3.3.5 Hose Routing and Installations . 101 3.4 Energy Losses and Heat Generation in Power Distribution . 103 References .105 Exercises 107 4. Hydraulic Power Deployment 109 4.1 Hydraulic Power Deployment Components . 109 4.1.1 Hydraulic Actuators 109 4.1.2 Principle of Hydraulic Actuating 109 4.2 Hydraulic Cylinders . 113 4.2.1 Classification of Hydraulic Cylinders . 113 4.2.2 Operating Parameters of Hydraulic Cylinders 114 4.2.3 Hydraulic Cylinder Cushions 120 4.2.4 Hydraulic Cylinder Power Transmission . 121 4.2.5 Hydraulic Cylinder Applications 123 4.3 Hydraulic Motors 126 4.3.1 Classification of Hydraulic Motors 126 4.3.2 Operating Parameters of Hydraulic Motors 126 4.3.3 High-Speed Hydraulic Motors . 129 4.3.4 Low-Speed High-Torque Motors . 135 4.3.5 Oscillating Rotary Actuators . 138 4.3.6 Speed Control and Power Transmission of Hydraulic Motors . 140 4.4 Hydrostatic Transmission 146 4.4.1 Overview of Hydrostatic Transmission 146 4.4.2 Configurations of Hydrostatic Transmission 148 4.4.3 Control of Hydrostatic Transmission 153 4.4.4 Applications of Hydrostatic Transmission . 159 References .163 Exercises 164 5. Hydraulic Power Regulation 167 5.1 Overview of Power Regulation . 167 5.1.1 Regulating Hydraulic Power 167 5.1.2 Commonly Used Power-Regulating devices . 168 5.2 Power-Absorbing Devices 170 5.2.1 Hydraulic Shock Absorbers 170 5.2.2 Hydraulic Fluid Springs 173Table of Contents vii 5.3 Power Storage Devices . 176 5.3.1 Functions of Hydraulic Accumulators 176 5.3.2 Operation Principles of Hydraulic Accumulators 178 5.3.3 Sizing Hydraulic Accumulators 181 5.3.4 Mounting Hydraulic Accumulators 183 5.4 Power Regeneration Devices . 185 5.4.1 Functions of Hydraulic Power Regeneration . 185 5.4.2 Hydraulic Pressure Intensifiers . 186 5.4.3 Two-Speed Hydraulic Cylinders . 188 5.4.4 Hydraulic braking chargers . 189 References .191 Exercises 192 6. Hydraulic Fluids and Fluid-Handling Components . 195 6.1 Hydraulic Fluids 195 6.1.1 Functions of Hydraulic Fluids . 195 6.1.2 Hydraulic Fluid Properties . 196 6.1.3 Types of Hydraulic Fluids 200 6.2 Hydraulic Fluids Reservoirs 202 6.2.1 Functionality of Fluid Reservoirs 202 6.2.2 Fluid Reservoir Components .203 6.2.3 Fluid Reservoir Sizing .206 6.3 Hydraulic Fluid Filters .208 6.3.1 Hydraulic Fluid Contamination 208 6.3.2 Fluid Cleanliness Measurements 210 6.3.3 Hydraulic Fluid Filters 211 6.4 Other Components 215 6.4.1 Heat Exchangers 215 6.4.2 Seals . 218 References .221 Exercises 221 7. Hydraulic Circuits 223 7.1 Basic Circuits .223 7.1.1 Pressure Control Circuits .223 7.1.2 Direction Control Circuits 227 7.1.3 Speed Control Circuits 228 7.1.4 Sequencing Control Circuits 233 7.1.5 Synchronizing Control Circuits .234 7.2 Special Function Circuits .234 7.2.1 Pump-Unloading Circuits 235 7.2.2 Cylinder Pressure-Holding Circuits .236 7.2.3 Hydraulic Motors Series-Parallel Circuits 236 7.2.4 Hydraulic Braking Circuits 237 7.2.5 Accumulator Circuits 238 7.2.6 Replenishing and Cooling Circuits . 239 7.2.7 Hydraulic Filtering Circuits . 240 7.3 Integrated Hydraulic Circuits . 240 7.3.1 Hydrostatic Transmission Circuits 240viii Table of Contents 7.3.2 Multibranch Integrated Hydraulic Circuits .244 7.3.3 Programmable Electrohydraulic Circuits 247 References .249 Exercises 249 8. Hydraulic Systems Modeling .253 8.1 Mathematical Model of Hydraulic Systems 253 8.1.1 Building Blocks of Hydraulic System Modeling .253 8.1.2 Model of Simplified Valve-Controlled Systems 257 8.2 System Analysis 261 8.2.1 System Block Diagram and Transfer Function 261 8.2.2 Transfer Function Simplification .266 8.2.3 System State-Space Equations 268 8.2.4 System Performance Characteristics . 269 References .273 Exercises 273 9. Electrohydraulic Systems Control .277 9.1 Concepts of Electrohydraulic System Control 277 9.1.1 Basic Concept of Automatic Controls .277 9.1.2 Open- and Closed-Loop Controls . 278 9.1.3 Transient Response and Steady-State Error . 279 9.1.4 Gain and Feedback 281 9.1.5 Frequency Response and the Bode Diagram .283 9.2 Hydraulic Velocity, Position, and Force Controls .285 9.2.1 Proportional and Servo Actuation in Electrohydraulic Control Valves 285 9.2.2 Velocity Controls 287 9.2.3 Position Controls 289 9.2.4 Force Controls .289 9.3 Basic Methods for Electrohydraulic System Controls 290 9.3.1 Bang-Bang Control .290 9.3.2 Modulated Feedforward Control 291 9.3.3 PID Control . 292 9.3.4 A Few Other Control Methods 293 References .294 Exercises 295 Appendix A: Hydraulic Power Formulas 299 Appendix B: Orifice Area Formulas of a Few Typical Shaped Orifices .303 Appendix C: Some Useful Conversion Factors 305 Appendix D: Solutions to Selected Exercise Problems 307 Index . 311 Index Note: Italicized page numbers refer to figures, bold page numbers refer to tables. A Absolute viscosity, 197 Accumulator circuits, 238–239, 239 Accumulators adiabatic discharging, 182 as auxiliary power source, 176 characteristic states, 180 charging stage, 180 defined, 169, 176 discharging stage, 180 drained stage, 180 empty stage, 180 flow rates, 181 fluid volume insensitive, 178 functions of, 176–177 gas-loaded, 179 isothermal discharging, 181 as leakage makeup source, 177 mounting, 183–184 operation principles of, 178–181 precharged stage, 180 precharged volume, 180 as pulsation absorber, 176 response times, 180 as shock damper, 177 six-stage operating principles, 180 sizing, 181–183, 184–185 spring-loaded, 178–179 as thermal expansion compensator, 177 total volume, 180 weight-loaded, 178 Active zones, 62 Actual output torque, 127 Actuating cylinders, 119 Actuating piston, 186 Actuating pockets, 131 Actuators capacity, 112–113 defined, 109 linear, 109 oscillating rotary, 138–140 principles of, 109–113 rotary, 109 softness, 109 Addendum circles, 27–28 Adiabatic discharging, 182 Air contamination, 209 Air-dissolving rate, 199 All-metal fittings, 97 American National Standards Institute (ANSI), 5, 15 Antifoaming, 199 Antiwear performance, 198 A-port, 73–74 Area, 6 Area ratio, 114 Armature, 82 Automatic control, 277 Automatic direction switching circuits, 227 Automobile transmission fluids, 200 Average current, 83 Axial-piston motors, 134–135 Axial-piston pumps, 34, 35 B Baffling device, 204–205, 205 Balanced vane motors, 131–132 Balanced vane pumps, 33 Balancing circuits, 226 Ball valves, orifice area of, 303 Bang-bang control, 285, 290–291 Bayonet, 96 Bent angle, 36 Bent-axis piston motors, 134 Bent-axis pump, 36 Bernoulli’s equation, 9–10, 172 Beta ratio, 212 Bidirectional motors, 126 Biodegradeable fluids, 100 Black box, 261 Bleed-off circuits, 229 Bleed-recharge circuit, 226–227, 227 Block diagram, 261–266 of basic feedback control system, 281 of basic modulated feedforward control systems, 291 Block diagram transformations, 262, 263–264 Bode diagram, 283–285 Bode plot, 283 Boosting piston, 186312 Index Boundary lubrication, 195 Breakaway force, 122 Breakaway torque, 127 Breather cap, 204 British unit system, 18 Buckling effect, 97 Bulk modulus, 198 C Cam-lock couplings, 96 Cam ring, 32 Cam-type radial-piston motors, 135 Cap end, 109 Cartridge valve, 55 Check valves, 72 Chemical contamination, 209–210 Circuits, 223–249 accumulator, 238–239, 239 basic, 223 cylinder-pressure holding, 236 direction control, 227–228 hydraulic braking, 237–238, 238 hydraulic filtering, 240 hydraulic motors series-parallel, 236–237, 237 integrated hydraulic, 240–249 pressure control, 223–227 pump-unloading, 235–236, 235 replenishing and cooling, 239 sequencing control, 233–234 special function, 234–240 speed control, 228–233 synchronizing control, 234 Circular cylinder rotor, 132 Closed-center speed control circuits, 231 Closed-center valve, 74, 87 Closed circuits, 151–152 Closed-loop closed-circuit HST, 154–155, 154 Closed-loop controls, 278–279, 279 Closed-loop system analysis, 284–285 Closed-relief valve, 152 Commutator, 131 Compound hydraulic springs, 174 Conduct lines, 16 Constant power control, 50 Constant-power transmissions, 146 Constant-pressure-reducing control, 67–68 Constant-torque HST, 243 Constant-torque transmissions, 146 Constant velocity force, 122 Continuous feedback, 291 Continuous rotation motors, 126 Control valves, 57–90 central (neutral) position, 60 directional, 71–76 electrohydraulic, 81–87 flow control valves, 76–80 hydraulic orifice, 57 hydraulic resistance, 57 orifice area, 57 pressure control valves, 64–71 selecting, 89–90 Conversion factors, 305–306 energy, 305 force, 305 gravity, 306 mass, 306 power, 305 pressure, 306 torque, 306 velocity, 306 volume, 305 Cooling circuits, 239 Cooling fan, 206 Corner power, 42, 153–154 Corrosion prevention, 199 Counterbalance valves, 69–70, 70 Cracking points, 62 Cracking pressure, 64 Critically damped system, 280 Cubic centimeters (cc) per revolution, 126 Cubic inches per revolution, 126 Cushion(s), 120–121 pressure, 121 velocity, 121 Cylinder-pressure holding circuits, 236 Cylinders, 113–126 applications, 123–126 area ratio, 114 body, 113 classification, 113–114 components of, 113 cushions, 120–121 defined, 109 differential extension, 115 double-rod, 116, 116 extension cycle, 114 extension operation, 109 hydraulic stiffness of, 268 natural frequency of, 111 operating parameters, 114–119 in parallel systems, 124–126 power transmission, 121–123 ram, 116–117, 117 retraction cycle, 114Index 313 retraction operation, 109 single-acting, 116 single-rod double-action cylinder, 109, 113 speed, 299 spring-return single-acting, 116 stiffness of, 109 telescopic, 117–118, 117 two-speed, 169, 188–189 D Damper, 253 Deadband, 89–90, 270 Dead zones, 62 Dedendum circles, 27–28 Dial adjustment approach, 143 Differential equation, second-order, 255 Differential extension, 115 Diffusers, 205 Direct-acting relief valves, 64–65 Direct drive gerotor motor, 130 Directing states, 73 Directional control valves, 16, 71–76, 285–286 Direction control circuits, 227–228 Discrete feedback, 290 Disk valves, orifice area of, 303 Displacement, 7 Double-acting intensifiers, 187–188 Double-rod cylinder. See also Cylinders configuration of, 116 defined, 116 system load, 272 Double shutoff lock-ball-type coupling, 95 Double-vane actuators, 139 Drilled-type manifolds, 92 Dual gain, 90 Dual-parameter control, 48 Dynamic resistance, 127 E Effective bulk modulus, 198 Effective current, 83 Efficiency, 13–14 hydraulic power and, 13–14 mechanical, 43, 112, 127 motor, 14–15 overall, 112, 129 power, 43 pump, 14, 43 spool valve, 260–261 stall torque, 112, 155 torque, 44 volumetric, 43, 112, 128 Electrical power transmission, 1–2 Electrohydraulic control valves, 81–87 electromechanical drivers for, 81 on-off, 81 programmable, 87–88, 88 proportional, 81 solenoid-controlled pilot-operating design, 84–85, 85 solenoid drivers, 81–83 Electrohydraulic systems control, 277–294 automatic control, 277 bang-bang control, 285, 290–291 basic methods for, 290–294 Bode diagram, 283–285 closed-loop controls, 278–279, 279 concepts of, 277–285 continuous feedback, 291 critically damped system, 280 directional control valves, 285–286 discrete feedback, 290 feedback, 281–282, 282 feedforward controls, 279, 279, 291 feedforward-plus-PID control, 293–294 force controls, 289–290 frequency response, 283–285 gain, 280 gain-scheduling control, 291–292 modulated feedforward control, 291 open-loop controls, 278–279, 279 overdamped system, 280 overshoot, 279–280 PID control, 292–293 position controls, 289 proportional and servo actuation in, 285–287 proportional control valves, 285–286 response time, 280 rise time, 279–280 schematics of, 278 servo control valves, 285–286 settling time, 279 solenoid control valves, 286 steady-state error, 279–281 transient response, 279–281 underdamped system, 280 velocity controls, 287–288 Electronic control unit, 158 Energy, conversion factors, 305 Energy conservation, 8–11 law, 172 method, 158 Energy conversion, 12–13314 Index Energy loss, 103–105, 158 English unit system, 18 Entrained air, 199, 209 Exhaust pockets, 131 Extension cycle, 114 Extension operation, 109 External gear motor, 129 External-gear pumps, 27 External power regenerators, 185 F Fabric-reinforced hoses, 93 Feedback, 281–282, 282 Feedforward controls, 279, 291 Feedforward-plus-PID control, 293–294 Filler cap, 204 Filters, 211–215 circuits, 240 dirt-holding capacity, 214 efficiency, 212–213 high-pressure, 211 low-pressure, 211 ratings, 212, 214–215 Fire-resistant hydraulic fluids, 201 Fitting nut, 97 Fixed-displacement motor, 241 Fixed-displacement pumps, 16, 33, 241 Fixed-pressure-reducing control, 68 Fixed pump-fixed motor HST, 148, 241–242 Fixed pump-variable motor HST, 149, 241 Flared fittings, 97 Flareless fittings, 98 Flat-face couplings, 95 Float-center valve, 75, 87 Flow capacity, 62, 291 Flow continuity, 255, 257 Flow control orifice, 255 Flow control orifice equation, 256 Flow control valves, 16 flow-dividing, 79–80 noncompensation, 77 pressure-compensated, 78–79 Flow dividers, 79–80 Flow-dividing control valves, 79–80 Flow gain, 62–63 Flow-passing rate, 90 Flow-sensing control, 46–47 Flow variation index, 28 Flow velocity angle, 60 Fluid continuity, 11–12, 172 Fluid density, 196 Fluid-level gauge, 205 Fluid power transmission, 2 Fluid reservoirs, 202–207 capacity, 206 components of, 203–206 configuration of, 203 dimension, 206 functionality, 202–203 material, 206 sizing, 206–207 Fluid subsystem, 253 Force, 6 conversion, 255, 256 conversion factors, 305 multiplication of, 6–8 Force controls, force controls, 289–290 Forced-open check valves, 72 Force motor, 81 Formulas, 299–301 hydraulic cylinder speed, 299 hydraulic force in cylinder, 300 hydraulic power, 301 hydraulic pump/motor speed, 299–300 hydraulic torque in pump and motor, 300 mechanical power in cylinders, 301 mechanical power in pump or motor, 301 Newton’s law of motion, 299 orifice equation, 300 Pascal’s law of pressure, 299 Four-way three-position valve, 74 Free air, 209 Free-piston assembly, 119 Free water, 209 Frequency response, 283–285 Full-film lubrication, 195 Full-flow pressure, 64 G Gain, 281–282 Gain-scheduling control, 291–292 Gas contamination, 209 Gas-loaded accumulators, 179 Gear motors, 129 Gear pumps, 27–32. See also Pump(s) addendum circles, 27–28 dedendum circles, 27–28 external, 27 flow variation index, 29 internal, 27 mesh overlap index, 29 theoretical flow rate, 31 volumetric displacement, 31 volumetric efficiency, 31–32Index 315 Gerotor pumps, 31 Gravity, conversion factors, 306 H Head end, 109 Heat contamination, 209 Heat exchangers, 215–218 Heat generation, 103–105 High-pressure filters, 211 High-speed state, 119 Hose connectors, 95 Hose fittings, 95 Hoses, 93–96 connectors, 95 fittings, 95 hydraulic hoses, 93–96 inside diameter, 93 leak-free connections, 100 outside diameter, 93 polytetrafluoroethylene (PTFE), 93–94 routing and installations, 101–103, 102 sizing, 101 Hydraulic accumulators adiabatic discharging, 182 as auxiliary power source, 176 characteristic states, 180 charging stage, 180 defined, 169, 176 discharging stage, 180 drained stage, 180 empty stage, 180 flow rates, 181 fluid volume insensitive, 178 functions of, 176–177 gas-loaded, 179 isothermal discharging, 181 as leakage makeup source, 177 mounting, 183–184 operation principles of, 178–181 precharged stage, 180 precharged volume, 180 as pulsation absorber, 176 response times, 180 as shock damper, 177 six-stage operating principles, 180 sizing, 181–183, 184–185 spring-loaded, 178–179 as thermal expansion compensator, 177 total volume, 180 weight-loaded, 178 Hydraulic actuators capacity, 112–113 defined, 109 linear, 109 oscillating rotary, 138–140 principles of, 109–113 rotary, 109 softness, 109 Hydraulic braking chargers, 189–190 Hydraulic braking circuits, 237–238, 238 Hydraulic circuits, 223–249 accumulator, 238–239, 239 basic, 223 cylinder-pressure holding, 236 direction control, 227–228 hydraulic braking, 237–238, 238 hydraulic filtering, 240 hydraulic motors series-parallel, 236–237, 237 integrated hydraulic, 240–249 pressure control, 223–227 pump-unloading, 235–236, 235 replenishing and cooling, 239 sequencing control, 233–234 special function, 234–240 speed control, 228–233 synchronizing control, 234 Hydraulic control valves, 55–90, 57–90 central (neutral) position, 60 directional, 71–76 electrohydraulic, 81–87 flow control valves, 76–80 hydraulic orifice, 57 hydraulic resistance, 57 orifice area, 57 overview, 55–57 pressure control valves, 64–71 selecting, 89–90 Hydraulic cylinders, 113–126 applications, 123–126 area ratio, 114 classification, 113–114 components of, 113 cushions, 120–121 defined, 109 differential extension, 115 double-rod, 116, 116 extension cycle, 114 extension operation, 109 natural frequency of, 111 operating parameters, 114–119 in parallel systems, 124–126 power transmission, 121–123 ram, 116–117, 117 retraction cycle, 114316 Index retraction operation, 109 single-acting, 116 single-rod double-action cylinder, 109, 113 speed, 299 spring-return single-acting, 116 stiffness of, 109 telescopic, 117–118, 117 Hydraulic damping ratio, 268 Hydraulic energy storage devices, 167 Hydraulic fluids, 195–202 antifoaming property of, 199 antiwear performance, 198 bulk modulus, 198 cleanliness, 210–211 contamination of, 208–210 demulsibility of, 199 density, 196 dissolved gases in, 195 dynamic viscosity (absolute viscosity), 197 effective bulk modulus, 198 environmentally safe, 200 filters, 211–215 fire-resistant, 201 fluid density, 196 fluid incompressibility, 109 functions of, 195–196 incompressible, 195 kinematic viscosity, 197 lubricity, 198 operating temperature, 199, 199–200 oxidation stability of, 199 petroleum-based, 200 properties of, 196–200 relative density (specific gravity), 197 reservoirs, 202–207 rust and corrosion prevention, 199 saturation level, 209 seal compatibility of, 200 synthetic-based fire-resistant, 201 thermal stability of, 199 types of, 200–202 viscosity index, 197 water-based, 201–202 Hydraulic fluid springs, 173–175 compound, 174 defined, 169 simple orifice type, 173 tension type, 174 Hydraulic force in cylinder, 300 Hydraulic hoses, 93–96 connectors, 95 fittings, 95 hydraulic hoses, 93–96 inside diameter, 93 leak-free connections, 100 outside diameter, 93 polytetrafluoroethylene (PTFE), 93–94 routing and installations, 101–103, 102 sizing, 101 Hydraulic jack, 6–7 Hydraulic lines, 93–103 components of, 93 designing, 98–101 hydraulic pipes and tubings, 93 metal tubes and pipes, 96–98 Hydraulic manifolds, 91–92 drilled-type, 92 laminar-type, 92 modular-block, 91 single-piece, 91–92 Hydraulic motors, 126–146 classification of, 126 defined, 109, 111 high-speed, 129–135 load-limit function, 112 low-speed high-torque motors, 135–138 operating parameters, 126–129 overall efficiency, 129 piston-type, 133–135 power transmission, 140–145 rolling-vane, 135, 136 sizing of, 145–146 speed control, 140–145 Hydraulic motors series-parallel circuits, 236–237, 237 Hydraulic orifice, 57 Hydraulic power calculating, 13–14 defined, 14, 145 efficiency and, 13–14 formula, 301 Hydraulic power deployment, 109–163 actuators, 109–113 components, 109–113 cylinders, 113–126 hydrostatic transmission, 146–163 motors, 126–146 Hydraulic power formulas, 299–301 hydraulic cylinder speed, 299 hydraulic force in cylinder, 300 hydraulic power, 301 hydraulic pump/motor speed, 299–300 hydraulic torque in pump and motor, 300 mechanical power in cylinders, 301 mechanical power in pump or motor, 301 Newton’s law of motion, 299Index 317 orifice equation, 300 Pascal’s law of pressure, 299 Hydraulic power generation control of, 41–50 corner power, 42 load-sensing control, 47–48 power regeneration devices, 185–191 pressure limiting, 42 pressure-limiting compensation, 45–47 pump efficiency, 41–45 speed-boosting, 190–191 torque limiting, 48–50 Hydraulic power regulation, 167–191 devices, 168–169 overview, 167–168 power-absorbing devices, 170–175 power storage devices, 176–185 Hydraulic power systems, 2 geometric shape formation, 4 on mobile equipment, 2–4 power-to-weight ratio, 4 system schematics, 4–5, 5 Hydraulic power transmission, 6–12 energy conservation, 8–11 fluid continuity, 11–12 force multiplication, 6–8 hydraulic fluids and, 195 Hydraulic pressure intensifiers, 186–188 double-acting, 187–188 single-acting, 187 Hydraulic pumps, 25–41 gear pumps, 27–32 maximum speed, 25 minimum speed, 25 overview, 25–26 piston pumps, 34–41 positive displacement pumping, 26–27, 26 rated speed, 25 speed, 299–300 vane pumps, 32–34 Hydraulic resistance, 57 Hydraulic shock absorbers, 170–173 annular clearance type, 170 configurations of, 170, 171 defined, 169 multiple-orifice type, 170 operations, 175 orivis type clearance type, 170 simple orifice type, 170 spear-type, 170 stepped spear type, 170 tapered spear type, 170 Hydraulic springs, 167 Hydraulic stiffness, 266–267 Hydraulic systems components of, 4–6 electrohydraulic systems control, 277–294 energy and power in, 12–15 energy conversion in, 12–13 graphical symbols, 15–18 hydraulic circuits, 223–249 hydraulic fluids, 195–221 hydraulic power deployment, 109–163 hydraulic power distribution, 55–105 hydraulic power generation, 25–50 hydraulic power regulation, 167–191 mobile equipment, 2–4 modeling, 253–272 power transmission, 1–2, 6–12 system schematics, 4–6 units and units conversion in, 18–20 Hydraulic systems modeling, 253–272 building blocks, 253–257 fluid subsystem, 253 mathematical models, 253–272 mechanical subsystem, 253 simplified valve-controlled systems, 257–261 system analysis, 261–272 Hydraulic torque in pump and motor, 300 Hydrodynamic sealing, 30 Hydrostatic pumps, 25–26, 27 Hydrostatic transmission (HST), 146–163 advantages of, 146 all-wheel drive, 161 applications of, 159–163 base speed, 163 circuits, 240–244 closed circuits, 151 closed-loop closed-circuit, 154–155, 154 configurations, 148–153 constant-torque, 243 control of, 153–158 critical speed, 151 defined, 146 fixed pump-fixed motor, 148, 241–242 fixed pump-variable motor, 149, 241 inline configuration, 159–160, 159 mass, 156 natural frequency of, 155 open circuits, 151 open-loop closed-circuit, 153 open-loop open-circuit, 156 overview, 146–147 pump-to-motor passages, 157 pump-to-pump passages, 157 response time, 153318 Index split configuration, 160–161, 160 split-torque power transmission, 162 stiffness of, 155 torque-to-speed ratio, 151 variable pump-fixed motor, 148–149, 241 variable pump-variable motor, 149–151, 242 Hysteresis, 63 I Ice crystals, 209 Ideas gas law, 179 Incompressible fluids, 195 Inline axial-piston motors, 134 Inline-piston pumps, 34, 35 Inner tubes, 93 Inside diameter, 93, 99 Integrated hydraulic circuits, 240–249 hydrostatic transmission circuits, 240–244 multibranch, 244–247 programmable electrohydraulic circuits, 247–249 Internal gear motor, 129 Internal-gear pumps, 27 Internal leakage, 30 Internal power regenerators, 185 Internal temperature gauge, 206 International Standards Organization (ISO), 5, 15, 197, 210–211 Inverse valve transform, 291 Inverse water solubility, 201 Isothermal discharging, 181 J Joint Industrial Council (JIC), 15, 202 K Kinematic viscosity, 197 Kinetic energy, 255 L Laminar-type manifolds, 92 Laplace transform, 262 Leak-proof seal, 98 Limited rotation motor, 126 Linear actuators, 109 Linear differential equation, 262 Linear displacement transducer (LDT), 291 Linear system, 253 Linear variable differential transformer (LVDT), 89 Line-relief circuit, 223, 224 Live swivel, 103 Load, 7 Load area, 258 Load flow rate, 258 Load-limit function, 112 Load pressure, 258 Load-sensitive system, 245 Lobe pumps, 31 Low-pressure filters, 211 Low-speed high-torque motors, 135–138 Lubrication, 195 Lubricity, 198 M Magnetic drain plug, 205 Main lines, 16 Main relief, 65–66 Manifolds, 91–92 blocks, 55 drilled-type, 92 laminar-type, 92 modular-block, 91 single-piece, 91–92 Margin pressure, 25, 47 Mass, 253 conversion factors, 306 Mass flow rate, 77 Maximum discharge pressure, 25 Maximum flow velocity, 99 Maximum inlet pressure, 25 Maximum motor speed, 128 Mechanical efficiency, 43, 112, 127 Mechanical power, 14 in cylinders, 301 in pump or motor, 301 Mechanical power transmission, 1 Mechanical subsystem, 253, 255 Mesh overlap index, 29 Metal tubes and pipes, 96–98 Meter-in, 77 Meter-in circuits, 229 Metering control, 57 Metering notches, 57 Metering point power, 42 Meter-out, 77 Meter-out circuits, 229 Microbial contamination, 210 Minimum discharge pressure, 25 Minimum motor speed, 128 Mobile equipment hydraulic power systems in, 2–4 hydraulic steering system, 4 Modeling, 253–272 building blocks, 253–257Index 319 fluid subsystem, 253 mathematical models, 253–272 mechanical subsystem, 253 simplified valve-controlled systems, 257–261 system analysis, 261–272 Modular-block manifolds, 91 Modulated control, 291 Modulating gain, 270 Modulating zones, 62 Modulation gains, 291 Modulation sensitivity, 62, 83 Moisture-removing filters, 204, 204 Motor(s), 126–146 classification of, 126 defined, 109, 111, 126 displacement, 126 efficiency, 14–15 fixed-displacement, 241 high-speed, 129, 129–135 hydraulic, 111 internal leakage, 112 load-limit function, 112 low-speed high-torque motors, 135–138 maximum speed, 128 mechanical efficiency of, 112 minimum speed, 128 operating parameters, 126–129 oscillating, 111 overall efficiency, 112, 129 piston-type, 133–135 power transmission, 140–145 pump-controlled, 240 rolling-vane, 135, 136 sizing of, 145–146 slippage of, 128 speed control, 140–145 stall, 112 variable-displacement, 241–242 volumetric efficiency of, 112 Multibranch integrated hydraulic circuits, 244–247 load-sensitive system, 245 multipressure setting circuit, 245 prioritized, 244 priority function, 245 Multipressure setting circuit, 245 N National Aeronautics and Space Administration (NASA), 210 National Fluid Power Association (NFPA), 5, 202 National Institute of Standards and Technology (NIST), 210 Natural frequency, 267 Needle valves, 77 orifice area of, 303 Newtonian shear stress equation, 197 Newton’s law of motion, 299 Newton’s second law of motion, 172 Noncompensation flow control valves, 77 Nonlinear valves, 63 No-spill couplings, 96 O Oil-in-water emulsion, 202 On-off control valves, 81 Open-center speed control circuits, 230 Open-center valve, 74–75, 87 Open circuits, 151 Open-loop closed-circuit HST, 153 Open-loop controls, 278–279, 279 Open-loop open-circuit HST, 156 Operating torque, 127 Orbiting gerotor motor, 130 Orifice area, 57, 90 of disk valves, 303 formulas, 303 of needle valves, 303 of round holes, 303 of simple ball valves, 303 of simple spool valves, 303 Orifice coefficient, 58, 257 Orifice equation, 10–11, 58, 300 O-ring seals, 219–220 O-ring type fittings, 97 Oscillating motors. See also Motor(s) defined, 111, 126 operating parameters, 139–140 Oscillating rotary actuators, 138–140 Outlet filters, 205–206 Outlet line strainer, 205–206 Output reaction, 261 Outside diameter, 93, 96 Overall efficiency, 112, 129 Overall pump efficiency, 43 Overdamped system, 280 Overlapped valves, 61, 89 Overshoot, 279–280 Oxidation stability, 199 P Partial priority, 76 Pascal, Blaise, 6 Pascal’s law of pressure, 6–8, 299 Petroleum-based fluids, 100, 200320 Index Phosphate esters, 201 Pilot-operated check valves, 72 Pilot-operated solenoid valves, 83 Pilot relief, 65–66 Pin-lock couplings, 95 Pintle-type radial pump, 40–41 Piston, 113 actuating, 186 boosting, 186 Piston pumps, 34–41. See also Pump(s) axial, 34, 35 inline, 34, 35 radial-type, 40 Piston shoes, 34 Piston-type hydraulic motors, 133–135 axial, 134–135 radial, 133–134 Pivot joints, 123 Pneumatic power systems, 2 Polyglycols, 200–201 Polytetrafluorethylene (PTFE), 93–94 Poppet valve, 55, 56 Position controls, 289 Positions, 73 Positive displacement pumping, 25, 26–27, 26 Potential energy, 253 Power absorption, 167 conversion factors, 305 defined, 8 efficiency, 43 mechanical, 14 Power-absorbing devices, 170–175 hydraulic fluid springs, 173–175 hydraulic shock absorbers, 170–173 Power deployment components, 17–18, 17 Power deployment subsystem, 2–3 Power distribution components, ISO/ANSI standard symbols for, 17 defined, 2 energy losses in, 103–105 heat generation in, 103–105 Powered lands, 61 Power generation subsystem, 2 Power-matching control, 47 Power regeneration, 167, 185–191 external power regenerators, 185 functions of, 185 hydraulic braking chargers, 189–190 hydraulic power intensifiers, 186–188 internal power regenerators, 185 two-speed hydraulic cylinders, 188–189 Power regulation subsystem, 3 Power storage, 167 components, 18, 18 devices, 176–185 Power-to-weight ratio, 4 Power transmission electrical, 1–2 fluid, 2 hydraulic cylinder, 121–123 hydraulic fluids and, 195 of hydraulic motors, 140–145 in machinery systems, 1–2 mechanical, 1 P-port, 73 Pressure, 6 booster, 186 defined, 306 drop, 90 intensifier, 119, 169 override, 64 overshoot, 40 Pressure-compounded flow control valves, 78–79 Pressure control circuits, 223–227. See also Hydraulic circuits balancing circuits, 226 bleed-recharge circuit, 226–227, 227 defined, 223 line-relief circuit, 223, 224 pressure-reducing circuit, 225–226 two-stage pressure-regulating circuit, 224 Pressure control valves, 16, 64–71 constant-pressure-reducing control, 67–68 counterbalance valves, 69–70, 70 cracking pressure, 64 direct-acting relief valves, 64–65 fixed-pressure-reducing control, 68 full-flow pressure, 64 main relief, 65–66 pilot relief, 65–66 pressure override, 64 sequence valves, 68–69, 69 underloading valves, 70–71 Pressure limiting, 45–46 compensation, 45 defined, 42 flow-sensing control, 46 load sensing with, 47–48 Pressure-reducing circuit, 225–226 Pressure-reducing valves, 66–67 Priority control, 76Index 321 Programmable electrohydraulic circuits, 247–249 Programmable electrohydraulic valves, 87–88, 88 Proportional control valves, 17, 81, 285–286 Proportional directional control valves, 85–86 Proportional-integral-derivative (PID) control, 292–293 Proportional solenoid drivers, 81 Pulsation absorber, 176 Pulse width, 83 Pulse-width modulation (PWM), 82–83, 83 Pump-controlled motors, 240 Pump efficiency, 14 Pump inlet lines, 99 Pump port, 56 Pump(s), 25–41 fixed-displacement, 16, 33, 241 gear, 27–32 maximum speed, 25 minimum speed, 25 overview, 25–26 piston, 34–41 positive displacement pumping, 26–27, 26 rated speed, 25 speed, 299–300 vane, 32–34 variable-displacement, 16, 241–242 Pump slippage, 30 Pump-to-work path, 56 Pump-unloading circuits, 235–236, 235 Q Quick-disconnect coupling, 95 R Radial-piston motors, 133–134. See also Motor(s) cam-type, 135 static balanced, 136–137, 137 Radial-type piston pump, 40 Ram cylinders, 116–117, 117 Rated discharge pressure, 25 Rate flow, 63 Reciprocating-type pump, 27 Recycled fluid, 115 Reference point, 281 Reinforcement layer, 93 Relative density, 197 Relief valve, 204 Replenishing and cooling circuits, 239 Resistance-overcoming torques, 127 Response delay, 62, 291 Response time, 280 Retracting ring, 34 Retraction cycle, 114 Return lands, 61 Return lines, 99 Ring-lock, 96 Rise time, 279–280 Rod, 113 Rod end, 109 Roller-lock couplings, 95 Rolling-vane motors, 135, 136. See also Motor(s) Rotary abutment motors, 139 Rotary actuators defined, 109 oscillating, 138–140 Rotary bladder motors, 139 Rotary cylinders, 126 Rotary-type pumps, 27 Round holes, orifice area of, 303 Running torque, 127 Rust prevention, 199 S Saturated pressure drop, 213 Saturation, 270 Saturation level, 209 Saturation zones, 62 Screw pumps, 31–32 Seals, 113, 218–220. See also Hydraulic cylinders cross-section of, 220 O-ring, 219–220 U-shaped lip seal, 220 V-shaped lip seal, 220 Y-shaped lip seal, 220, 221 Second-order differential equation, 255 Sequence valves, 68–69, 69 Sequencing control circuits, 233–234 Servo, 86 Servo control valves, 285–286 Servo drivers, 81 Settling time, 279 Shock absorbers, 170–173 annular clearance type, 170 configurations of, 170, 171 defined, 167, 169 multiple-orifice type, 170 operations, 175 orivis type clearance type, 170 simple orifice type, 170 spear-type, 170 stepped spear type, 170 tapered spear type, 170322 Index Shock damper, 177 Shuttle check valves, 72 Shuttle valves, 72 Single-acting cylinders, 116 Single-acting intensifiers, 187 Single-phase manifolds, 91–92 Single-rod double-action cylinder, 109, 113 Single-vane actuators, 138–139 SI unit system, 18 Society of Automobile Engineers (SAE), 210 Soft-shifting, 57 Solenoid control valves, 286 Solenoid drivers, 81–83 Solid particle contamination, 208–209 Solutions to selected exercise problems, 307–310 Specific gravity, 197 Speed booster, 188, 190–191 Speed control dial adjustment approach, 143 of hydraulic motors, 140–145 Speed control circuits, 228–233. See also Hydraulic circuits bleed-off circuits, 229 closed-center, 231 meter-in circuits, 229 meter-out circuits, 229 open-center, 230 secondary adjustment, 233 speed-increase circuits, 231–232 speed-reducing circuits, 232–233 Speed-increase circuits, 231–232 Speed-reducing circuits, 232–233 Speed response transfer function, 268 Spool shoulders, 57 Spool strokes, 62, 291 Spool valves. See also Valve(s) defined, 56 efficiency, 260–261 flow velocity angle, 60 operating principle of, 57 orifice area of, 303 overlapped, 61 power output, 260–261 spring constant, 60 underlapped, 60 valve flap, 60, 61 valve-transform curve, 62 Spring, 253 compression or stretching of, 253 stiffness of, 253 Spring constant, 60 Spring-loaded accumulators, 178–179 Spring-return single-acting cylinders, 116 Stall torque, 144 Stall torque efficiency, 112, 155 STAMPED procedure, 98, 101 Standard unit system, 18 Standby pressure, 47 Starting torque, 127 Static balanced radial-piston motors, 136–137, 137 Static resistance, 127 Steady-state error, 279–281 Stiffness hydraulic, 266–267 of spring, 253 Stimuli input, 261 Straight runs, 96 Strainers, 211–212 Suction chambers, 27 Suction lines, 99 Summing junction, 261 Summing points, 268 Surface foam, 199 Swash plate, 34 Switch-mode power supplies, 83 Swivel fitting, 103 Swivel joint, 103 Synchronizing control circuits, 234 Synthetic esters, 200 Synthetic hydrocarbons, 201 Synthetic solutions, 202 System analysis, 261–272 closed-loop, 284–285 system block diagram, 261–266 system performance characteristics, 270–272 system state-space equations, 268–269 transfer function, 261–266 transfer function simplification, 266–268 System block diagram, 261–266 of basic feedback control system, 281 of basic modulated feedforward control systems, 291 System load, 272 System performance characteristics, 270–272 System schematics, 4–5, 5 System state-space equations, 268–269Index 323 T Takeoff point, 261 Tandem-center valve, 75, 87 Tandem state, 119 Tank port, 56 Telescopic cylinders, 117–118, 117 Theoretical output speed, 128 Theoretical output torque, 127 Thermal stability, 199 Three-way position valve, 73 Throttling control, 57 Torque conversion factors, 306 defined, 6 efficiency, 44 motor, 86 ripple, 128 stall, 144 starting, 127 theoretical output, 127 torque-limiting compensator, 48–50 torque-to-speed ratio, 151 total, 127 Total pressure-flow coefficient, 267 Total torque, 127 T-port, 73–74 Transfer function, 261–266 of major blocks, 268 simplification, 266–268 of summing points, 268 Transient operating state, 121 Transient response, 279–281 Two-speed hydraulic cylinders, 188–189 defined, 169 flow regeneration mode, 188–189 heavy-load and low-speed mode, 188 light-load and high-speed mode, 188 normal mode, 188 Two-stage pressure-regulating circuit, 224 U Unbalanced vane pumps, 32 Undercondition valve control, 72 Underdamped system, 280 Underlapped spool valves, 60 Underloading valves, 70–71 Unit box, 261 U-shaped lip seal, 220 V Valve-controlled systems, 257–261 hydraulic damping ratio, 268 load area, 258 load flow rate, 258 load pressure, 258 Valve control of motor motion (VCMM), 141–142 Valve-opening areas, 85 Valve(s) control. see Control valves flap, 60, 60 land, 61 plate, 34, 131 ports, 73 spool. see Spool valves transform curve, 291 underloading, 70–71 Valve-transform curve, 62 Vane actuators, 138 Vane motors, 131–132, 131 Vane pumps, 32–34. See also Pump(s) balanced, 32, 33 cam ring, 32 housing, 32 unbalanced, 32, 32 Vapor bubbles, 209 Variable-displacement axial-piston motors, 135 Variable-displacement motors, 241–242 Variable-displacement pumps, 16, 241–242 Variable-power transmissions, 146 Variable pump-fixed motor HST, 148–149, 241 Variable pump-variable motor HST, 149–151, 242 Variable-torque transmissions, 146 Vegetable oils, 201 Velocity controls, 287–288 conversion factors, 306 Vibration, 253–254 Viscosity index, 197 Volume, conversion factors, 305 Volumetric efficiency, 43, 112, 128 Volumetric flow rate, 77 V-shaped lip seal, 220324 Index W Water-based fluids, 201–202, 202 Water contamination, 209 Water glycol, 201 Ways, 73 Weight flow rate, 77 Weight-loaded hydraulic accumulator, 178 Wet-armature solenoid, 82 Winter number, 198 Wire-reinforced hoses, 93 Work, 8 Working lines, 16 Work ports, 56 Work-to-tank path, 56 Y Y-shaped lip seal, 220, 221 Z Zero gain, 90 Zinc dithiophosphate, 199
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