Festo TP 800 User Manual

D (X2)

C (X1)

LS2

LS1

Mobile Hydraulics

Workbook

TP 800

With CD-ROM

Festo Didactic

574166 en

Order no. 574166 Revision level: 03/2013 Authors: Ulrich Schedel, Levent Unan Editor: Christine Löffler Graphics: Doris Schwarzenberger Layout: 03/2013, Susanne Durz, Christine Löffler

+49 711 3467-0 www.festo-didactic.com +49 711 34754-88500 did@de.festo.com

The purchaser shall receive a single right of use which is non-exclusive, non-time-limited and limited geographically to use at the purchaser's site/location as follows.

• The purchaser shall be entitled to use the work to train his/her staff at the purchaser's site/location and shall also be entitled to use parts of the copyright material as the basis for the production of his/her own training documentation for the training of his/her staff at the purchaser's site/location with acknowledgement of source and to make copies for this purpose. In the case of schools/technical colleges and training centres, the right of use shall also include use by school and college students and trainees at the purchaser's site/location for teaching purposes.

• The right of use shall in all cases exclude the right to publish the copyright material or to make this available for use on intranet, Internet and LMS platforms and databases such as Moodle, which allow access by a wide variety of users, including those outside of the purchaser's site/location.

• Entitlement to other rights relating to reproductions, copies, adaptations, translations, microfilming and transfer to and storage and processing in electronic systems, no matter whether in whole or in part, shall require the prior consent of Festo Didactic.

Contents

Intended use _____________________________________________________________________________ VIII Preface ________________________________________________________________________________ IX Introduction ______________________________________________________________________________ XI Work and safety instructions ________________________________________________________________ XII Mobile hydraulics training package (TP 800) _________________________________________________ XIV

Learning objectives _________________________________________________________________________ XV Allocation of learning objectives to exercises __________________________________________________ XVII Equipment set _____________________________________________________________________________ XX Allocation of components to exercises ______________________________________________________ XXVII Notes for the teacher/trainer ________________________________________________________________ XXX Structure of the exercises _________________________________________________________________ XXXI Component designations __________________________________________________________________ XXXI CD-ROM contents ________________________________________________________________________ XXXI

Exercises and solutions: Mobile hydraulics, basic level working hydraulics (TP 801)

Exercise 1-1: Examining performance for a controller using constant displacement pump and fixed pressure limitation _____________________________________________________ 3 Exercise 1-2: Examining performance for a controller using constant displacement pump and adjusted pressure limitation using open-centre load-sensing pressure balance ______ 13 Exercise 1-3: Examining performance of speed control using a 6/3-way proportional valve ____________ 23 Exercise 1-4: Examining energy efficiency of speed control in an open-centre load-sensing system _____ 31 Exercise 1-5: Moving and holding a load with a 6/3-way proportional valve ________________________ 41 Exercise 1-6: Moving and holding a load with a piloted non-return valve ___________________________ 51 Exercise 1-7: Moving and holding a load with a pressure-relief valve as counter pressure _____________ 59 Exercise 1-8: Moving and holding a load with a counterbalancing valve ____________________________ 69 Exercise 1-9: Examining parallel, series and tandem configurations _______________________________ 79

Exercises and solutions: Mobile hydraulics, advanced level steering system (TP 802)

Exercise 2-1: Examining the steering valve in a hydrostatic steering system ________________________ 91 Exercise 2-2: Examining steering when external forces are exerted ________________________________ 99 Exercise 2-3: Examining overload protection for steering _______________________________________ 107 Exercise 2-4: Examining a steering system with priority function _________________________________ 115 Exercise 2-5: Designing a steering system for centre-pivot steering ______________________________ 123

III

Exercises and solutions: Mobile hydraulics, advanced level working hydraulics (TP 803)

Exercise 3-1: Examining a hydraulic system with load-sensing-controlled variable displacement pump _ 133 Exercise 3-2: Examining the load hold function _______________________________________________ 143 Exercise 3-3: Remotely controlling proportional directionalcontrol valves using a hydraulic joystick ___ 151 Exercise 3-4: Setting a (volumetric) flow rate independent of load _______________________________ 159 Exercise 3-5: Setting the volumetric flow rate using a load-sensing-controlled pump unit ____________ 169 Exercise 3-6: Examining a load-sensing system with upstream pressure balance ___________________ 179 Exercise 3-7: Examining a load-sensing system with downstream pressure balance _________________ 191

Exercises and worksheets: Mobile hydraulics, basic level working hydraulics (TP 801)

Exercises and worksheets: Mobile hydraulics, advanced level steering system (TP 802)

Exercises and worksheets: Mobile hydraulics, advanced level working hydraulics (TP 803)

Exercise 3-1: Examining a hydraulic system with load-sensing-controlled variable displacement pump _ 133 Exercise 3-2: Examining the load hold function _______________________________________________ 143 Exercise 3-3: Remotely controlling proportional directional control valves using a hydraulic joystick ___ 151 Exercise 3-4: Setting a (volumetric) flow rate independent of load _______________________________ 159 Exercise 3-5: Setting the volumetric flow rate using a load-sensing-controlled pump unit ____________ 169 Exercise 3-6: Examining a load-sensing system with upstream pressure balance ___________________ 179 Exercise 3-7: Examining a load-sensing system with downstream pressure balance _________________ 191

IV © Festo Didactic 574166

Basics of mobile hydraulics

1 Introduction _______________________________________________________________________ I-5

2 Fundamentals of hydraulics __________________________________________________________ I-7

2.1 Basic principles of pressure and flow control valves _______________________________________ I-7

2.2 Pressure drop _____________________________________________________________________ I-10

2.3 Heat generation due to the pressure drop ______________________________________________ I-13

3 Closed hydraulic circuit (hydrostatic system) __________________________________________ I-15

3.1 Setting up a closed hydraulic circuit ___________________________________________________ I-15

3.2 Hydraulic pumps for closed hydraulic circuits ___________________________________________ I-17

3.2.1 Mechanically resetting the hydraulic pump _____________________________________________ I-17

3.2.2 Hydraulically resetting the hydraulic pump _____________________________________________ I-18

3.3 Feed pumps _______________________________________________________________________ I-20

3.4 Flushing valves ____________________________________________________________________ I-20

3.5 Shock valves ______________________________________________________________________ I-21

4 Load-sensing systems ______________________________________________________________ I-23

4.1 Attributes of load-sensing systems ____________________________________________________ I-23

4.1.1 Open-centre load-sensing systems ____________________________________________________ I-23

4.1.2 Closed centre load-sensing systems ___________________________________________________ I-25

4.2 Energy efficiency of the hydraulic pressure supply _______________________________________ I-30

4.2.1 Loss of energy _____________________________________________________________________ I-30

4.2.2 Pressureless pump recirculation circuit ________________________________________________ I-32

4.2.3 Flow rate control in systems with constant displacement pump ____________________________ I-34

4.2.4 Flow rate control in systems with variable displacement pump _____________________________ I-36

4.2.5 Flow rate control in open-centre load-sensing systems ___________________________________ I-38

4.2.6 Flow rate control in closed centre load-sensing systems __________________________________ I-40

5 Variable-displacement pumps _______________________________________________________ I-42

5.1 Types of variable displacement pumps ________________________________________________ I-42

5.2 Vane pump________________________________________________________________________ I-42

5.3 Axial piston pump __________________________________________________________________ I-44

6 Two-pump system with shut-off valve _________________________________________________ I-46

6.1 Requirements of a pump system for mobile machines ____________________________________ I-46

6.2 Example of a two-pump system with shut-off valve ______________________________________ I-47

7 Flow dividers ______________________________________________________________________ I-48

7.1 Synchronicity of drives ______________________________________________________________ I-48

7.2 Flow divider (50/50 slide valve) ______________________________________________________ I-48

7.3 Rotation flow valve _________________________________________________________________ I-50

7.4 Rotation flow valve for pressure boosting ______________________________________________ I-51

8 Valve manifold for mobile hydraulics _________________________________________________ I-49

8.1 Setup of valve blocks _______________________________________________________________ I-53

8.2 Circuit symbol of proportional directional control valves in valve modules ___________________ I-55

8.3 Setup of valve modules _____________________________________________________________ I-56

8.4 Valve slides of proportional directional constant valves ___________________________________ I-57

8.4.1 Design of valve slides _______________________________________________________________ I-57

8.4.2 Influence of control notches on flow rate characteristics __________________________________ I-58

8.5 Input module of a valve manifold _____________________________________________________ I-59

8.5.1 Design of an input module ___________________________________________________________ I-59

8.5.2 Input module in combination with an open-centre valve module ___________________________ I-60

8.5.3 Input module in combination with a closed-centre valve module ___________________________ I-61

8.6 Shock and anti-cavitation valve _______________________________________________________ I-62

9 Circuits with open-centre valves _____________________________________________________ I-64

9.1 Open-centre valves _________________________________________________________________ I-64

9.2 Design of an open-centre 6/3-way valve _______________________________________________ I-66

9.3 Parallel connection _________________________________________________________________ I-69

9.4 Tandem configuration_______________________________________________________________ I-70

9.5 Series connection __________________________________________________________________ I-71

10 Load-independent flow rate control with proportional valves _____________________________ I-72

10.1 Proportional flow control valve _______________________________________________________ I-72

10.2 Upstream pressure balance __________________________________________________________ I-74

10.3 Downstream pressure balance _______________________________________________________ I-78

11 Holding and safe lowering of load ____________________________________________________ I-82

11.1 Application example ________________________________________________________________ I-82

11.2 Piloted non return valve _____________________________________________________________ I-83

11.3 Pressure-relief valve ________________________________________________________________ I-84

11.4 Counterbalancing valve _____________________________________________________________ I-85

12 Hydraulic pilot control ______________________________________________________________ I-88

12.1 Hydraulic pilot control with a joystick __________________________________________________ I-88

13.2 Hydraulic joystick (manually-operated pilot control) _____________________________________ I-88

13.3 Electronic joystick (electro-hydraulic pilot control) _______________________________________ I-90

13 Prioritising consuming devices ______________________________________________________ I-92

13.1 Necessity of prioritising consuming devices ____________________________________________ I-92

13.2 Pressure sequence valve ____________________________________________________________ I-92

13.3 Circuit prioritisation ________________________________________________________________ I-93

13.4 Way valves with prioritisation ________________________________________________________ I-94

13.5 Static prioritity valve ________________________________________________________________ I-94

13.6 Dynamic priority valve ______________________________________________________________ I-95

13.7 3-way flow control valve _____________________________________________________________ I-96

VI © Festo Didactic 574166

14 Hydrostatic steering _______________________________________________________________ I-98

14.1 Design and characteristics of hydrostatic steering _______________________________________ I-98

14.2 Design of steering valves ____________________________________________________________ I-98

14.2.1 Rotary slide valve and bush __________________________________________________________ I-99

14.2.2 Proportioning pump (Orbitrol pump) _________________________________________________ I-100

14.3 Versions of steering valves _________________________________________________________ I-101

14.3.1 Open-centre steering valves ________________________________________________________ I-101

14.3.2 Closed-centre steering valves _______________________________________________________ I-102

14.3.3 Load-sensing steering valves ________________________________________________________ I-103

14.3.4 Reaction and non-reaction steering valves _____________________________________________ I-103

14.4 Types of steering systems __________________________________________________________ I-104

14.4.1 Ackermann steering system with axle journal steering ___________________________________ I-105

14.4.2 Articulated steering system _________________________________________________________ I-105

Picture credits ___________________________________________________________________________ I-107

VII

Intended use

The mobile hydraulics basic and advanced level training packages are only to be used:

• for the intended purpose in teaching and training applications

• when their safety functions are in flawless condition

The components in the training packages are designed in accordance with the latest technology as well as recognised safety rules. However, life and limb of the user and third parties may be endangered, and the components may be impaired, if they are used incorrectly.

The learning system from Festo Didactic has been developed and produced exclusively for training and continuing vocational education in the field of automation technology. The training companies and/or trainers must ensure that all trainees observe the safety instructions described in this workbook.

Festo Didactic hereby excludes all liability for damage suffered by the trainee, the training company and/or any other third parties as a result of use of these equipment sets outside a purely training situation, unless Festo Didactic has caused this damage wilfully or through gross negligence.

VIII

Preface

Festo Didactic’s training system for automation and technology is geared towards various educational backgrounds and vocational requirements. The learning system is therefore broken down as follows:

• Technology oriented training packages

• Mechatronics and factory automation

• Process automation and control technology

• Mobile robotics

• Hybrid learning factories

The training system for automation and technology is continuously updated and expanded in accordance with developments in the field of education, as well as actual professional practice.

The training packages deal with various technologies including pneumatics, electro-pneumatics, servopneumatics, hydraulics, electro-hydraulics, proportional hydraulics, servohydraulics, mobile hydraulics, programmable logic controllers, sensor technology, electrical engineering, electronics and electric drives.

The modular design of the training system allows for applications which go above and beyond the limitations of the individual training packages. For example, PLC actuation of pneumatic, hydraulic and electric drives is possible.

All training packages feature the following elements:

• Hardware

• Media

• Seminars

Hardware

The hardware in the training packages is comprised of industrial components and systems that are specially designed for training purposes. The components contained in the training packages are specifically designed and selected for the projects in the accompanying media.

Media

The media provided for the individual topics consist of a mixture of teachware and software. The teachware includes:

• Technical literature and textbooks (standard works for teaching basic knowledge)

• Workbooks (practical exercises with supplementary instructions and sample solutions)

• Lexicons, manuals and technical books

(which provide technical information on groups of topics for further exploration)

• Transparencies and videos (for easy-to-follow, dynamic instruction)

• Posters (for presenting information in a clear-cut way)

Within the software, the following programmes are available:

• Digital training programmes (learning content specifically designed for virtual training)

• Simulation software

• Visualisation software

• Software for acquiring measurement data

• Project engineering and design engineering software

• Programming software for programmable logic controllers

The teaching and learning media are available in several languages. They are intended for use in classroom instruction, but are also suitable for self-study.

Seminars

A wide range of seminars covering the contents of the training packages round off the system for training and vocational education.

Do you have tips, feedback or suggestions for improving this workbook?

If so, please send us an e-mail at did@de.festo.com. The authors and Festo Didactic look forward to your feedback.

X © Festo Didactic 574166

Introduction

This workbook is part of the training system for automation technology from Festo Didactic SE. The system provides a solid basis for practice oriented training and vocational education. The mobile hydraulics workbook communicates the basics and fundamental knowledge on the hydraulic systems of mobile work machines. The contents of the workbook are project exercises on the basic level of working hydraulics (TP 801), advanced level steering systems (TP 802) and advanced level working hydraulics (TP 803). The workbook also contains a basic information section on mobile hydraulics.

The basic level working hydraulics (TP 801) is suitable for basic training in mobile hydraulics. Using practice-related problem descriptions, the energy balances of different hydraulic systems (also while loaded) will be examined and evaluated. Control systems with multiple consuming devices are set up in parallel, tandem and series connections and examined in relation to priority, flow rate distribution, and pressure dependency. Further course topics are the behaviour of consuming devices while under loads and the options for safely holding and lowering a load. Basic knowledge of hydraulic device technology is a prerequisite. The advanced level steering system (TP 802) communicates the basics of hydrostatic steering systems with suitable hydraulic controls. The controllers contain typical components of a steering system like steering valve, shock and anti-cavitation valve, steering cylinder and, if required, a secondary consuming device. In the project exercises for advanced level working hydraulics (TP 803), details of the working hydraulics are expanded upon and hydraulic controls with load-sensing controlled variable displacement pump will be set up and examined.

Technical prerequisites for setting up the controllers include:

• A Learnline or Learntop-S workstation equipped with Festo Didactic slotted profile plates.

• A hydraulic power unit with constant displacement pump (volumetric flow rate: 4 l/min) for TP 801 and

TP 802, a hydraulic power unit with constant displacement pump (volumetric flow rate: 4 l/min) and load-sensing controlled variable displacement pump for TP 803.

• A power pack with short-circuit protection (input: 230 V, 50 Hz, output: 24 V, max. 5 A).

• Laboratory safety cables

The practical execution of the nine project exercises for TP 801 requires a TP 801 equipment set. One TP 801 and TP 802 equipment set is required for the practical execution of each of the five project exercises for TP 802. An additional TP 803 equipment set is necessary for the practical execution of the seven project exercises for TP 803. The theoretical fundamentals for understanding these exercises can be found in the following textbooks:

• Hydraulics, basic level

• Electro-hydraulics, basic level

as well as in the appendix to this workbook.

Data sheets for the individual components are also available (cylinders, valves, sensors etc.).

Work and safety instructions

General

• Trainees should only work with the circuits under the supervision of a trainer.

• Electrical devices (e.g. power supply units, compressors and hydraulic power units) may only be

operated in laboratory rooms which are equipped with residual current devices (RCDs).

• Observe specifications included in the technical data for the individual components, and in particular all safety instructions!

• Malfunctions which may impair safety must not be generated in the training environment, and must be eliminated immediately.

• Wear personal safety gear (safety glasses, safety shoes) when working on circuits.

Mechanical system

• Only reach into the setup when it is at a complete standstill.

• Mount all of the components securely onto the slotted profile plate.

• Limit switches may not be actuated frontally.

• Danger of injury during troubleshooting!

Use a tool to actuate the limit switches, for example a screwdriver.

• Set all components up so that activation of switches and disconnectors is not made difficult.

• Adhere to the instructions regarding positioning of the components.

• Always set up cylinders together with the appropriate cover.

Electrical functions

• Use extra-low voltage only (max. 24 V DC).

• Establish or interrupt electrical connections only in the absence of voltage!

• Use only connecting cables with safety plugs for electrical connections.

• When disconnecting connector cables, only pull by the plug, never by the cable.

Hydraulics

• Limit system pressure to 6 MPa (60 bar). Maximum permissible pressure for all devices included in the training package is 12 MPa (120 bar).

• In the case of double-acting cylinders, pressure could be increased relative to the surface area ratio due to pressure boosting. With a surface area ratio of 1:1.7 and a system pressure of 6 MPa (60 bar), it may amount to more than 10 MPa (100 bar).

• Danger of injury due to oil temperatures of greater than 50° C! Hydraulic fluid with an oil temperature of greater than 50° C may result in burns or scalding.

• Danger of injury when switching on the hydraulic power unit! Cylinders may extend and retract automatically.

• Connecting tubing lines – Never connect or disconnect tubing lines when the hydraulic power unit is running, or while under pressure! Couplings must be connected in the unpressurised state. – Set the coupling socket vertically onto the coupling nipple! The coupling socket and the coupling nipple must not be fitted askew. – After each disconnection, make sure that the couplings have closed themselves!

• Hydraulic circuit assembly – The hydraulic power unit and the electrical power pack must be switched off when assembling the circuit. – Before commissioning, make sure that all tank lines have been connected and that all couplings have been securely fitted. – Make sure that tubing lines connected to the cylinder are rinsed with hydraulic fluid, if the volume of oil accommodated by the cylinder is less than the volume which can be contained by the tubing lines.

• Commissioning – Cylinders may only be commissioned with their covers in place. – Switch on the electrical power pack first, and then the hydraulic power unit.

• Dismantling hydraulic circuits – Assure that pressure has been relived before dismantling the circuit. – Switch off the hydraulic power unit first, and then the electrical power pack.

• If connections are decoupled while under pressure, pressure is trapped in the device by the non-return valve in the coupling. This pressure can be vented with the pressure relief unit.

Mounting technology

The mounting boards for the components are equipped with mounting variant A, B or C:

• Variant A, snap-in system Lightweight devices which cannot be subjected to loads (e.g. directional control valves and sensors). Simply clip the components into the slots on the slotted profile plate. Release the components from the slots by actuating the blue lever.

• Variant B, rotary system Components with medium load capacity (e.g. hydraulic cylinders). These components are clamped to the slotted profile plate with T-head bolts. The blue knurled nut is used for clamping and loosening. Make sure that the T-head bolts have been turned 90° after tightening.

• Variant C, screw system For devices with high load capacity and devices which are seldom removed from the slotted profile plate (e.g. the hydraulic power unit). These devices are fastened with socket head screws and T-head nuts.

Required accessories

Two digital multimeters are required to evaluate exercises which make use of the flow sensor. The output voltage of the flow sensor is measured with the multimeter.

XIII

Mobile hydraulics training package (TP 800)

The TP 800 training package consists of a multitude of individual training materials. This package refers to components and basic circuits of the hydraulic systems of working machines. Individual components from training package TP 800 may also be included in other packages.

Important TP 800 components

• Permanent workstation with Festo Didactic profile plate

• Equipment sets or individual components (e.g. cylinders, valves and pressure gauges)

• Complete set of laboratory equipment

Media

The teachware for the training package TP 800 consists of one workbook. The contents of the workbook are the project exercises on the basic level of working hydraulics (TP 801), advanced level steering systems (TP 802) and advanced level working hydraulics (TP 803). The theoretical fundamentals for understanding the exercises are described in the textbook attachment. The workbook includes the exercise sheets and worksheets for the project exercise, the solutions to each individual worksheet and a CD-ROM. A set of ready-to-use exercise sheets and worksheets is included in each workbook for all of the exercises.

Data sheets for the hardware components are made available along with the equipment set.

Media

Textbooks Fundamentals of hydraulics and electrohydraulics

Workbooks Mobile hydraulics (TP 800)

Set of posters Hydraulics

Simulation programme FluidSIM® Hydraulic

TP 810 Diagnostic system FluidLab® M

Digital training programme

Overview of media for training package TP 800

Web-based training, hydraulics – Basics of hydraulics principles Web-based training electro-hydraulices – Basics of electro-hydraulics principles

The media are offered in several languages. Further training materials can be found in our catalogues and on the Internet.

Learning objectives

Mobile hydraulics: Basic level working hydraulics (TP 801)

• To know the relationship between pressure, flow rate and power output.

• To be able to calculate the power consumption of a hydraulic system.

• To know that flow division can lead to energy losses in a hydraulic system.

• To know that when using a constant displacement pump, non-decreasing volume flow leads to energy

loss.

• To know how a constant displacement pump with an open-centre load-sensing pressure balance works.

• To know the power-relevant advantages of a constant displacement pump with pressure regulation by

an open-centre load-sensing pressure balance over a constant displacement pump without an opencentre load-sensing pressure balance.

• To be familiar with the mode of operation of a 6/3-way proportional valve.

• To know that proportional directional control valves restrict inflow and outflow.

• To know that a 6/3-way proportional valve with mid-position tank recirculation only generates minor

energy loss in mid-position.

• To know how a shuttle valve works and how to use it.

• To understand the control circuit of an open-centre load-sensing system.

• To know that a proportional directional control valve in connection with an open-centre load-sensing

pressure balance represents a flow control valve.

• To be able to use the cylinder load simulator (loading unit).

• To understand the behaviour of the cylinders under load.

• To know how to use a delockable double non-return valve for the purpose of secure holding.

• To know the advantages and disadvantages of a delockable double non-return valve.

• To be able to use a pressure-relief valve as a counter-pressure valve for secure holding and lowering.

• To know the advantages and disadvantages of counter-pressure valves.

• To be able to use a counterbalancing valve for the secure holding and lowering of a load.

• To know the main difference between a counterbalancing valve and a pressure-relief valve.

• To know that using a counterbalancing valve can reduce energy when lowering a load.

• To know how series, parallel and tandem configurations of 6/3-way proportional valves work.

• To be able to describe the advantages and disadvantages of these configuration types for an

application.

+ 34 hidden pages

Festo TP 800 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual