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Hydraulics Basic Level Textbook TP 501 Festo Didactic 093281 en 093281_cover_textbook_tp501_en.indd 11.04.2005 17:00:09 Order No.: Description: Designation: Edition: Author: Graphics: Layout: 093281 HYDRAUL.LEHRB D:LB-TP501-1-GB 11/2003 D Merkle, B.Schrader, M Thomes D Schwarzenberger 25.11.2003, M Göttfert, G Heigl, W Schreiner © Festo Didactic GmbH & Co KG, 73770 Denkendorf/Germany, 2003 Internet: www.festo.com/didactic e-mail: did@festo.com The copying, distribution and utilization of this document as well as the communication of its contents to others without expressed authorization is prohibited Offenders will be held liable for the payment of damages All rights reserved, in particular the right to carry out patent, utility model or ornamental design registration Table of contents 1.1 1.2 1.3 Tasks of a hydraulic installation Stationary hydraulics Mobile hydraulics _ 10 Comparison of hydraulics with other control media 11 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 Fundamental physical principles of hydraulics _ Pressure _ Pressure transmission Power transmission Displacement transmission _ Pressure transfer Flow rate _ Continuity equation Pressure measurement _ Temperature measurement Measurement of flow rate _ Types of flow _ Friction, heat, pressure drop Energy and power _ Cavitation Throttle points 13 13 18 19 21 23 25 26 30 31 31 31 35 41 51 53 3.1 3.2 3.3 3.4 Hydraulic fluid Tasks for hydraulic fluids _ Types of hydraulic fluid _ Characteristics and requirements _ Viscosity _ 57 57 58 59 60 4.1 4.2 4.3 4.4 4.5 Components of a hydraulic system _ Power supply section Hydraulic fluid Valves _ Cylinders (linear actuators) Motors (rotary actuators) _ 67 67 67 68 70 71 â Festo Didactic GmbH & Co KG ã TP 501 Table of contents 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 Graphic and circuit symbols _ Pumps and motors _ Directional control valves _ Methods of actuation Pressure valves _ Flow control valves Non-return valves _ Cylinders Transfer of energy and conditioning of the pressure medium Measuring devices _ Combination of devices _ 73 73 74 75 76 78 79 80 82 83 83 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Design and representation of a hydraulic system _ Signal control section Hydraulic power section Positional sketch Circuit diagram Components plus technical data Function diagram Function chart 85 86 87 90 91 92 94 95 7.1 7.2 7.3 7.4 7.5 7.6 7.7 Components of the power supply section 97 Drive 97 Pump _ 99 Coupling 107 Reservoir _ 107 Filters 109 Coolers _ 120 Heaters _ 122 8.1 8.2 8.3 8.4 8.5 8.6 Valves Nominal sizes Design _ Poppet valves Spool valves _ Piston overlap _ Control edges 123 123 125 126 127 129 134 © Festo Didactic GmbH & Co KG • TP 501 Table of contents 9.1 9.2 Pressure valves 137 Pressure relief valves _ 137 Pressure regulators _ 144 10 10.1 10.2 10.3 10.4 Directional control valves 2/2-way valve _ 3/2-way valve _ 4/2-way valve _ 4/3-way valve _ 149 153 157 159 162 11 11.1 11.2 11.3 Non-return valves Non-return valve _ Piloted non-return valve _ Piloted double non-return valve _ 167 168 172 175 12 12.1 12.2 12.3 Flow control valves _ Restrictors and orifice valves _ One-way flow control valve _ Two-way flow control valve _ 179 180 184 185 13 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 Hydraulic cylinders _ Single-acting cylinder _ Double-acting cylinder End position cushioning _ Seals _ Types of mounting Venting _ Characteristics _ Buckling resistance _ Selecting a cylinder _ 193 194 196 199 200 202 202 203 205 207 14 Hydraulic motors _ 211 â Festo Didactic GmbH & Co KG ã TP 501 Table of contents 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 Accessories _ Flexible hoses _ Pipelines Sub-bases Bleed valves _ Pressure gauges _ Pressure sensors _ Flow measuring instruments 16 Appendix _ 233 215 217 223 226 228 229 230 231 © Festo Didactic GmbH & Co KG • TP 501 Tasks of a hydraulic installation What we mean by hydraulics? Hydraulic systems are used in modern production plants and manufacturing installations By hydraulics, we mean the generation of forces and motion using hydraulic fluids The hydraulic fluids represent the medium for power transmission The object of this book is to teach you more about hydraulics and its areas of application We will begin with the latter by listing the main areas for the application of hydraulics The place held by hydraulics in (modern) automation technology illustrates the wide range of applications for which it can be used A basic distinction is made between: • stationary hydraulics • and mobile hydraulics Mobile hydraulic systems move on wheels or tracks, for example, unlike stationary hydraulic systems which remain firmly fixed in one position A characteristic feature of mobile hydraulics is that the valves are frequently manually operated In the case of stationary hydraulics, however, mainly solenoid valves are used Other areas include marine, mining and aircraft hydraulics Aircraft hydraulics assumes a special position because safety measures are of such critical importance here In the next few pages, some typical examples of applications are given to clarify the tasks which can be carried out using hydraulic systems © Festo Didactic GmbH & Co KG • TP 501 Tasks of a hydraulic installation 1.1 Stationary hydraulics The following application areas are important for stationary hydraulics: • Production and assembly machines of all types • Transfer lines • Lifting and conveying devices • Presses • Injection moulding machines • Rolling lines • Lifts Machine tool construction is a typical application area Lathe In modern CNC controlled machine tools, tools and work pieces are clamped by means of hydraulics Feed and spindle drives may also be effected using hydraulics â Festo Didactic GmbH & Co KG ã TP 501 Tasks of a hydraulic installation Press with elevated reservoir â Festo Didactic GmbH & Co KG ã TP 501 Tasks of a hydraulic installation 1.2 Mobile hydraulics Typical application fields for mobile hydraulics include: • Construction machinery • Tippers, excavators, elevating platforms • Lifting and conveying devices • Agricultural machinery There is a wide variety of applications for hydraulics in the construction machinery industry On an excavator, for example, not only are all working movements (such as lifting, gripping and swivelling movements) generated hydraulically, but the drive mechanism is also controlled by hydraulics The straight working movements are generated by linear actuators (cylinders) and the rotary movements by rotary actuators (motors, rotary drives) Mobile hydraulics 10 â Festo Didactic GmbH & Co KG ã TP 501 ... 25.11.2003, M Gưttfert, G Heigl, W Schreiner © Festo Didactic GmbH & Co KG, 73770 Denkendorf/Germany, 2003 Internet: www .festo. com/didactic e-mail: did @festo. com The copying, distribution and utilization... drives may also be effected using hydraulics © Festo Didactic GmbH & Co KG • TP 501 Tasks of a hydraulic installation Press with elevated reservoir © Festo Didactic GmbH & Co KG • TP 501 Tasks of... overlap _ Control edges 123 123 125 126 127 129 134 © Festo Didactic GmbH & Co KG • TP 501 Table of contents 9.1 9.2 Pressure valves