Hydraulic Fluid Power. Andrea Vacca

      4 Chapter 4Figure 4.1 Flow through a sharp orifice.Figure 4.2 Orifice area for a poppet needle valve. (a) Entire popper valve. ...Figure 4.3 Theoretical and experimental trends of the flow coefficient vs. t...Figure 4.4 Orifice equation plotted in a (p, Q) layer for different area ope...Figure 4.5 Hydraulic symbol of two valves and equivalent orifice networks.Figure 4.6 Orifice in parallel and in series.

      5 Chapter 5Figure 5.1 Control volume (CV) and bounding control surface (CS).Figure 5.2 Constant section pipe with uniform velocity profile.Figure 5.3 An orifice connected to upstream and downstream lines is a pure r...Figure 5.4 Impedance model for a hydraulic line. (a) Real system, (b) Lumped...Figure 5.5 Lumped distributive model for a hydraulic line. (a) Real system, ...Figure 5.6 Conceptual representation of using of a hydraulic accumulator for...

      6 Chapter 6Figure 6.1 Power flow in a hydraulic system.Figure 6.2 Representation of power flow and input‐output energy parameters i...Figure 6.3 Plunger pump with port selection spool.Figure 6.4 Commutation points for a plunger pump, starting from the bottom l...Figure 6.5 Ideal working cycle of the plunger pump.Figure 6.6 Wobble plate pump (a) and ISO pump symbol (b).Figure 6.7 Displacement chamber volume as a function of the shaft angular po...Figure 6.8 Procedure for assembling a pump symbol. The factors to be conside...Figure 6.9 ISO symbols of the most common pumps.Figure 6.10 Symbol breakdown for a hydraulic motor (top) and ISO symbols of ...Figure 6.11 Displacing cycle of an ideal hydrostatic machine with compressib...Figure 6.12 Examples of external leakage and internal leakage.Figure 6.13 Effect of turbulent losses: (a) pump; (b) motor.Figure 6.14 Incomplete filling.Figure 6.15 Trends for the volumetric losses.Figure 6.16 Trends for the hydraulic-mechanical losses.Figure 6.17 Qualitative representation of volumetric, hydraulic-mechanical, ...Figure 6.18 Qualitative representation of volumetric, hydraulic-mechanical, ...Figure 6.19 Swashplate‐type axial piston machine vertical cross‐section.Figure 6.20 Swashplate‐type axial piston machine horizontal cross‐section.Figure 6.21 Valve plate geometry example for a bidirectional motor.Figure 6.22 Pressures in a swashplate axial piston machine.Figure 6.23 Three lubricating interfaces in swashplate‐type axial piston mac...Figure 6.24 Bent axis‐type axial piston machine.Figure 6.25 Radial piston machine.Figure 6.26 External gear machine: (a) view of the lateral bushing surface f...Figure 6.27 External gear machine lateral bushing.Figure 6.28 Internal gear machine.Figure 6.29 Gerotor cross‐section.Figure 6.30 Vane pump cross‐section.Figure 6.31 Vane pump port flow.Figure 6.32 Single stator vane machine.

      7 Chapter 7Figure 7.1 Linear actuator architecture and ISO symbol.Figure 7.2 ISO symbols of various linear actuators.Figure 7.3 Cylinder areas, forces, and pressure. The sign convention for the...Figure 7.4 Definition of resistive and overrunning loads for a hydraulic cyl...Figure 7.5 Schematic for the definition of volumetric efficiency for a hydra...Figure 6 Conceptual cross‐section of a two‐stage single acting telescopic cy...Figure 7 Conceptual cross‐section of a two‐stage double acting telescopic cy...

      8 Chapter 8Figure 8.1 Generic parameters of springs used in hydraulic components and, i...Figure 8.2 Possible symbols for a check valve.Figure 8.3 Architectures for a check valve. (a) Poppet‐seat type. (b) Ball‐s...Figure 8.4 Flow–pressure characteristic of a check valve.Figure 8.5 Pilot‐to‐open (a) and pilot‐to‐close (b) check valves.Figure 8.6 Symbol and cross‐section of a shuttle valve. Cross section (a) an...Figure 8.7 ISO symbol and its breakdown for a direct acting pressure relief ...Figure 8.8 Direct acting pressure relief valve, poppet type. (a) Cross secti...Figure 8.9 Steady‐state characteristic of a direct acting pressure relief va...Figure 8.10 Pilot operated pressure relief valve.Figure 8.11 Detailed ISO representation of a pilot operated relief valve (a)...Figure 8.12 Steady‐state characteristic of pressure relief valves: qualitati...Figure 8.13 Direct acting pressure reducing and relieving valve: cross secti...Figure 8.14 Ideal (a) and real operating characteristics (b) of a pressure r...Figure 8.15 Pilot operated pressure reducing valve: cross sectional view (a)...Figure 8.16 ISO representation of a two‐way flow control valve: simplified s...Figure 8.17 Cross‐section of a post‐compensated two‐way flow control.Figure 8.18 Detailed ISO symbol for the valve of Figure 8.17.Figure 8.19 Characteristic of a two‐way pressure compensated valve.Figure 8.20 Examples of variable setting two‐way flow control valves.Figure 8.21 Circuit with a two‐way flow control supplied by a fixed displace...Figure 8.22 Detailed (a) and simplified (b) ISO representations of a three‐w...Figure 8.23 Three‐way flow control valve: cross‐section and equivalent symbo...Figure 8.24 Different solutions for adjustable three‐way flow control valves...Figure 8.25 Circuit with a two‐way flow control supplied by a fixed displace...Figure 8.26 Circuit where the three‐way flow control is also used for accomp...Figure 8.27 Three‐way priority flow control valve.Figure 8.28 ISO symbols used for (a) on/off, (b) discrete position, and (c) ...Figure 8.29 Example of a 4/3 spool directional control valve (a): simplified...Figure 8.30 Orifice connections implemented through spool and bore lands.Figure 8.31 Example of opening area vs. spool position for the meter‐in and ...Figure 8.32 Spool with metering notches to obtain fine regulations: cross se...Figure 8.33 Example of possible neutral configurations of a 3/4 DCV: (a) mot...Figure 8.34 Spool actuation principle for a hydraulic pilot operated 4/3 DCV...Figure 8.35 Solenoid basic architecture and operating principle and ISO symb...Figure 8.36 ISO symbols of a DCV with (a) manual and (b) direct solenoid act...Figure 8.37 ISO schematic of a DCV with hydraulic remote pilot actuation con...Figure 8.38 (a) ISO expanded circuit representing an electro‐hydraulic actua...Figure 8.39 Cross‐section and equivalent schematic of a DCV with manual and ...Figure 8.40 Architecture of a servovalve (flapper/nozzle type).Figure 8.41 Spool lapping around the center positions for servovalves. (a) C...Figure 8.42 Opening area (a) and Flow characteristic (b) of a servovalve as...Figure 8.43 Control mechanism of the servovalve (flapper‐nozzle type): (a) i...Figure 8.44 Use of a servovalve for controlling and actuator. Depending on t...Figure 8.45 Parametrization of the servovalve: (a) cross sectional view; (b)...Figure 8.46 Characteristic curve of a servovalve.Figure 8.47 Simplified schematic for understanding the servovalve characteri...Figure 8.48 Characteristic curve of a servovalve (alternative).Figure 8.49 Characteristic curve of a servovalve with positive lapping (clos...Figure 8.50 Characteristic curve of a servovalve with negative lapping (open...Figure 8.51 Valve open at an intermediate position.Figure 8.52 Linearity error in a spool valve.

      9 Chapter 9Figure 9.1 Cross‐section of a spring‐loaded accumulator. The supply port P i...Figure 9.2 Piston‐type gas‐loaded accumulator.Figure 9.3 Diaphragm‐type gas‐loaded accumulator.Figure 9.4 Bladder‐type gas‐loaded accumulator.Figure 9.5 Operating conditions for a bladder accumulator: precharge conditi...Figure 9.6 Simplified circuit for hydraulic brakes.Figure 9.7 Accumulator in a vehicle suspension circuit.Figure 9.8 Use of an accumulator for pulsation dampening.Figure 9.9 Polytropic behavior of the gas inside the accumulator.Figure 9.10 Accumulator for pressure dampening.

      10 Chapter 10Figure 10.1 Control variables for a linear (a) and rotary (b) actuators.Figure 10.2 A cylinder compressing material (a), or a rotary actuator drivin...Figure 10.3 Simple example for understanding resistive and overrunning loads...Figure 10.4 Resistive and assistive loads for linear actuators.Figure 10.5 Resistive and assistive loads for motors.

      11 Chapter 11Figure 11.1 The basic control concepts involved in the control of a single a...Figure 11.2 Control concepts in case of flow supply. Each architecture is re...Figure 11.3 Control concepts in case of pressure supply. Each architecture i...Figure 11.4 Primary control with fixed (a) or variable displacement flow (b)...Figure 11.5 Metering controls with fixed displacement flow supply: the conce...Figure 11.6 Metering controls with variable displacement flow supply. Advanc...Figure