Projekthandbuch. Project Manual Industriehydraulik. Industrial Hydraulics RE 00846/ Trainee's manual. Schülerhandbuch

Transcription

1 Electric Drives and Controls Hydraulics Linear Motion and Assembly Technologies Pneumatics Service Projekthandbuch Project Manual Industriehydraulik Industrial Hydraulics RE 00846/04.07 Schülerhandbuch Trainee's manual

2 Electric Drives and Controls Hydraulics Linear Motion and Assembly Technologies Pneumatics Service Introduction Introduction Imparting knowledge through project work Project designation with short description of the industrial application Overview of components Safety aspects A Project tasks B Hydraulic power unit 02 Hydraulic pump/variable displacement pump characteristic curve 03 Single-rod cylinder/pressure intensification 04 Single-rod cylinder/ flow 05 Hydraulic motor 06 4/3 directional valve 07 Check valve 08 Check valve, pilot operated 09 Throttle valve, adjustable 10 Throttle check valve 11 Flow control valve 12 Pressure relief valve, direct operated 13 Pressure relief valve controls 14 Pressure reducing valve 15 Pressure switch 16 Pressure switch/hysteresis 17 Hydraulic accumulator 18 Regenerative circuit 19 Rapid speed/creep speed control 20 Valve circulation control 21 Commissioning, inspection, maintenance, troubleshooting, repair Annex RE General product information about hydraulic products from Bosch Rexroth AG C

3 Introduction 1 Introduction In July 2004 the Federal Minister for Economics and Labor passed the new regulations for vocational training in industrial metalworking professions. Framework curriculum Specialist qualification Core qualification Training objectives Project management Project steps Basic training for the entire field of professions, the structure and objectives of vocational training are termed framework curriculum. Skills and knowledge (qualifications) are to be imparted with reference to practical needs. To be capable of carrying out qualified work, the trainees are to be trained in particular in independent planning, execution and checking as well as acting in the overall operative context. Profession-specific specialized qualifications, e.g. the manufacture, assembly and disassembly of assemblies and systems, are to be acquired in conjunction with core qualifications, e.g. planning and organizing the work. The training contents for the profession-specific specialiized qualification include, among others, business processes and quality assurance systems in the relevant field of activity. The present Project Manual Industrial Hydraulics is intended to help acquire the required specialist knowledge in the field of hydraulic control technology in practice-oriented applications. Through the logically structured projects to 21, specifically the contents listed below can be learnt: Physical laws and technical interrelationships (area, pressure, force, work and power) Structure and function of hydraulic equipment, practical operating characteristics and possible applications of electrohydraulic components Reading and understanding symbols and circuit diagrams and preparation of simple hydraulic circuit diagrams Assembly of electrohydraulic units according to circuit diagrams prepared on a projectrelated basis Types, properties, requirements and application of hydraulic fluids The execution of projects is a successful instrument/tool for meeting customer requirements and executing customer orders in a target-oriented manner. Project management in trade and industry follows 4 phases: Definition phase (objective and boundary conditions), Planning phase (possibly coping with difficulties and preparing a time schedule), Execution phase (processing), Retrospective (conclusion and analysis). On this basis, projects to 21 of the present Project Manual Industrial Hydraulics are to be worked off in 6 project steps. The pictograms that are shown as recurring symbols refer to important information in a simplified graphical representation. 1. Informing The requirements of the customer are described in a project definition. Based on the relevant, detailed project definition, the trainee is to get a clear idea of the finished solution, including any required details. This is achieved through a systematic analysis of the project documentation and, if required, by asking the project manager/trainer, e.g.: Which hydraulic component/system is to be dealt with? 2. Planning Detailed planning and the organization of the individual project steps greatly contribute to the success, i.e. to meeting the customer requirement. Planning also means the theoretical preparation and anticipation of the concrete execution. Comparable applications in the own company are helpful in planning.

4 Introduction 2 3. Decision-making After the planning stage, the required aids are to be determined for solving the project task such as: Utilization of possible sources of information such as Internet or colleagues, Overview of hydraulic components, Current technical data sheets possibly required, Prescribed safety instructions. Project tasks 4. Executing The order is to be executed according to the work instructions given in the chapter "order execution", observing all safety notes. Depending on the project order, the possibilities of execution may be limited. This is valid, for example, in the case of costly work in the field of information technology. After having completed the written planning work, you should ask the trainer again, whether the right attempt at a solution was selected. The execution of the order also includes the preparation or the completion of a project sequence chart. Relevant notes are given at the end of the project tasks after the evaluation of work results. Special notes on how to process a project task: The individual project tasks are to be solved through independent understanding, analyzing and working out of objectives in order to that the customer requirements can be met. Hydraulic basic principles are worked out through the preparation of a schematic diagram and the selection of hydraulic components. Through the set-up of electrohydraulic controls on the training system, theoretical basic knowledge is deepened, and the operating characteristics of hydraulic components can be understood. The acquisition of the required system parameters/measured data allows a comparison with manufacturers' documents, which also include component diagrams. In order that possible hazards arising out of plant and machinery can be recognized, safety regulations, product information sheets and operating instructions must be observed (for fundamental safety requirements, see the following chapter and special safety notes in the individual project tasks). 5. Checking Not only final, but also intermediate results should be checked for compliance with the customer requirements as described under the heading "Executing". In some cases, the result can be compared with manufacturers' documents. In measurement experiments, it must be checked whether measurement results are realistic. Also the documentation required by the customer should be finally corrected, improved, and completed. After the completion, the project manager re-checks the result. 6. Evaluating In the final evaluation of the set up electrohydraulic control, measurement and control results are to be compared with project order documents in an external or self-evaluation. A summarized evaluation of work results with regard to the customer requirements must be made at the end of the project step "Order execution". All project steps should be examined and analyzed. What went smoothly, what did not? Where should improvements be made, where should other paths be run?

5 Introduction 3 Faults, if any, and their causes must be analyzed and possibilities discussed as to how faults can be avoided in the future. Project sequence chart The completion of the project work includes the preparation of a project sequence chart. It is recommended that this chart be not completed at the end of the project plan, but in parallel to the individual project steps. The project sequence chart structures the project steps to be executed within a time frame that can be understood by the project manager. When discussing the time sequence, the interrelationships become clear. The order, in which the individual project steps have to be worked out, must be determined. The project sequence chart includes planning steps, sources of information and decision support, but also special points that were observed during project work. Like in everyday practice, the times required for processing the individual project steps must be entered. Notes on the possibilities of improving and optimizing the customer requirement ultimately lead to better customer satisfaction. General learning tips Everybody has the inherent need to eliminate uncertainties, to solve problems and to answer questions. We should give our best attention to the achievability of a target, the challenge of a task and its information content. Please find below some general learning tips. Define the learning objective of the project task and recognize the meaning of the subject matter, which only becomes clear in most of the cases when the objective is obvious. In addition, it is important to have the learning objective in mind and see it always as background when handling the project task. Behind every (learning) objective, there is always a reason, why this objective should be reached. This is the basis that motivates. This reason provides the actual motivation, the drive towards achieving an objective. A precondition for this is that you can recognize a meaning in your action, for example, the reference for the future profession. If the meaning of a project task is unclear, you should not hesitate to ask your project manager/training concretely for the meaning/customer order. Look for practical applications in your company environment. Reflect interrelationships, the structure, relations and cross-connections to other applications in the field of drive technology. Look for a colleague, who is familiar with the problems of hydraulic control technology. Ask him/her, how he/she gained his/her specialist knowledge and which other sources (books, magazines, specialists) he/she knows. Utilize modern information technology such as the Internet. Get feedback at an early stage on whether you proceed correctly in handling the project. Repairs are much easier after individual project steps during processing of the project than at the end of the process/project. Have the nerve to make mistakes instead of anxiously trying to avoid them. Make notes/sketches and utilize the corresponding note pages in the project manual.

6 Introduction 4 General notes: For didactic reasons, we refer exclusively to trainees and trainers in the present manual. We expressly point out that these terms include all persons involved in the basic and advanced training: Instructors, teachers, project managers, etc., whether male or female. Procedural knowledge Pictogram In this manual, we do not give notes on procedural knowledge (explanatory knowledge). It is the knowledge of how to achieve a certain result with which measures, procedures or processes - in this case, how the learning target can be reached. The present manual must be understood as a tool for providing the required core and specialist qualification that must be imparted in an integrated form through independent planning, executing and checking according to the regulations for vocational training in industrial metalworking professions. The pictograms, which are used as recurrent symbols, are to transfer important information as quickly as possible in the form of a simplified graphical representation and independently of languages. Notes

7 Introduction 5 Project designation with short description of the industrial application The knowledge of basic principles of hydraulic control technology is to be imparted with relation to practice. The trainer can impart the basic knowledge of hydraulics in 21 individual projects. Together with the customer requirements the detailed project definitions are finally intended to make the function and possible applications of individual system components clear to the trainee during processing of the order. No. Project designation Industrial application (example) Hydraulic power unit Pressure oil supply to a hydraulic cylinder by a hydraulic power unit. Rating of a simple power unit on the basis of parameters specified by the customer. 02 Hydraulic pump, characteristic curve 03 Single-rod cylinder, pressure intensification 04 Single-rod cylinder, flow Typical features of a pressure-compensated vane pump. Understanding the control behavior with the help of a characteristic curve. Safety aspects when using a single-rod cylinder and a meter-out throttle, e.g. for an advance movement. Different traversing speeds when extending and retracting a single-rod cylinder. Application of different types of hydraulic cylinders. 05 Hydraulic motor Powering a hoist with the help of a hydraulic motor for lifting and lowering of a load. 06 4/3 directional valve Controlling the direction of a single-rod cylinder by means of a 4/3 directional valve. It should be possible to position the cylinder at any position. Properties of different directional valve spool shapes and symbols. 07 Check valve Protection of a vertical cylinder with suspended load in a welding in a welding fixture by means of a check valve. When a tool change takes place, lowering of the load at adjustable lowering speed by means of a shut-off valve. 08 Check valve, pilot operated 09 Throttle valve, adjustable Protection of a vertical cylinder with suspended load by means of a pilot operated check valve. Opening the check valve by means of a 4/2 directional valve, adjustable lowering speed. Powering a conveyor belt by means of a hydraulic motor with adjustable output speeds for both directions. 10 Throttle check valve Traversing a tool carriage at different speeds. 11 Flow control valve Rotary drive (hydraulic motor) with constant speed. 12 Pressure relief valve, direct operated 13 Pressure relief valve, controls Preparation of a characteristic curve for the pressure/flow relationship. Possible use of direct operated pressure relief valves. Electrical pre-selection of various pressures (series, parallel circuit) on punching equipment. 14 Pressure reducing valve Swiveling a clamped workpiece by means of a hydraulic motor. 15 Pressure switch Hydraulic pressing of two workpieces with monitoring by a pressure switch.

8 Introduction 6 16 Pressure switch, hysteresis Working out the hysteresis of a mechanical pressure switch. 17 Hydraulic accumulator Moving the tool from the working range of the machine tool using the oil volume stored in the hydraulic accumulator. 18 Regenerative circuit Increasing the velocity by using the oil returning from the single-rod cylinder for extending. 19 Rapid speed/creep speed control Rapid speed/creep speed control for lifting a pallet onto a conveyor belt at load-independent, adjustable creep speed and with fastest return stroke possible. 20 Valve by-pass control Lifting and lowering of a load by a single-rod cylinder, which is controlled by a 4/3 directional valve with blocked central position. Sparing of the hydraulic pump and energy savings through by-pass circuit. 21 Commissioning, inspection, maintenance,... Observing regulations, safety rules and generally recognized technical rules when handling production and hydraulic systems in everyday work.

9 Introduction 7 Overview of components Symbol Component designation Type designation Double-acting cylinder with single-sided piston rod ZY 1.3 Double-acting cylinder with single-sided piston rod with load ZY 1.Load Fixed displacement motor with external leakage line and two directions of rotation DM 2.N 4/2 directional valve with solenoid actuation, spring return DW 3E 4/3 directional valve with direct actuation by two solenoids, spring centering of the central position and central position P - T, A, B 4/3 directional valve with direct actuation by two solenoids, spring centering of the central position and central position P, A - B - T 4/3 directional valve with direct actuation by two solenoids, spring centering of the central position and central position P, T, A, B Check valve with spring, flow possible in only one direction, rest position closed, cracking pressure 1 bar DW 4E DW 10E DW 13E DS 2.1 Pilot operated check valve, with spring, pilot pressure enables flow in both directions DS 1.1 Shut-off valve, actuated by turning DZ 2.1 Direct operated pressure relief valve, the cracking pressure can be adjusted by means of a spring DD 1.1

10 Introduction 8 3-way pressure reducing valve DD 2 Pressure switch, electromechanical, adjustable DD 6E Throttle valve, adjustable DF 1.2 Throttle check valve, adjustable, free flow in one direction DZ way flow control valve, adjustable, for one direction of flow, largely independent of viscosity and pressure differential, adjustable, with by-pass check valve DF 3 Accumulator safety block for diaphragm-type accumulator DZ 3.2 Pressure gauge with hose and quick release coupling without check valve DZ 1.4 Hose with quick release coupling with check valve DZ 25.1 Hose VSK 1

11 Introduction 9 Distributor plate with four ports DZ 4.1 Limit switch, inductive DE 2.2 Stopwatch Note: The type designations of the components in the overview of components are Rexroth-specific and adapted for use on the training system DS4.

12 Project : Hydraulic power unit 1 Project : Hydraulic power unit Project definition In a hydraulic system for driving lifting equipment for heavy loads, a hydraulic power unit with a variable displacement pump powered by an electric motor and associated accessories is to be used. The customer wishes to get information about the structure of a hydraulic power unit with pilot operated vane pump. In the list of the hydraulic power unit components he requests the provision of short information about the selected components, including a schematic diagram of the hydraulic system and a parts list. To be able to dimension the hydraulic power unit, the following details are required from the customer: Displacement of the hydraulic pump q V = 20 l/min, Operating pressure p max = 80 bar, Electric motor speed n = 1,500 rev/min, Return line filter with visual-mechanical clogging indicator Drain valve for hydraulic fluid changes as additional option Hydraulic power unit without hydraulic accumulator. Fig..1 Practical example: Hydraulic power unit with hydraulic pump/el. motor and accessories

13 Project : Hydraulic power unit 2 Project information Hydraulics as technology can be assigned to drive technology. The task of drive engineering is to provide a drive for a machine or system that ensures optimum performance of the technological function. This is equally valid for the engine of a passenger car as for the drive of the projects described in this project manual such as the drive of: feed equipment for the vertical transport of workpieces, rope winches for lifting loads, lifting gear for the horizontal transport of loads, conveyor belts for transporting loads, feed carriages for tool transport, punching equipment for punching perforated metal sheets, rotary drives for relocating workpieces, and pressing equipment for workpiece pressing. The drive power is made available by an electric motor or combustion engine. The output torque of the motor or engine is converted by a convertor into a rotary or linear movement as required by the machine. This task is assumed by a transmission - in this case, the hydraulic components such as a hydraulic cylinder or a hydraulic motor. The power is transmitted by the hydraulic fluid. The basic components of a hydraulic system are: Fluid flow generator/pump, fluid flow consumers/hydraulic cylinders and motors, open and closed-loop control equipment/valves, accessories. The components of a hydraulic system listed above can be designed as individual components or, to form a compact assembly, combined in a hydraulic power unit (without consumers). The valves such as directional, pressure and flow control valves are in most of the cases installed separately into a machine. A simple hydraulic power unit consists of: Hydraulic pump with drive motor, reservoir for storing the fluid, instruments for monitoring the fluid level, temperature and pressure, equipment for fluid care such as filters, coolers and heaters, valves for pressure relief functions and, if required, hydraulic accumulators as energy accumulators. In Project you will be made familiar with the general structure of a hydraulic power unit. In the project order, you have to set up the required components on the basis of the given customer requirements.

14 Project : Hydraulic power unit 3 Project steps Informing: Accepting and understanding the order, among others, through discussions with the customer. Planning: Planning and organizing the execution of the customer order; among others, through the selection of power unit construction parts from a technical data sheet. Deciding: Hydraulic design and dimensioning of the power unit. Executing: Verifiction of hydraulic circuit diagram Fig..2 and selection of the required drive elements and accessories with short description. Checking: Are all customer requirements met? Evaluating: Are there further possibilities of meeting the customer requirement or simpler ways of project execution? Have unforeseeable problems occurred? Notes

15 Project : Hydraulic power unit 4 Meeting the customer requirement The customer requirement laid down in Project is to be met by dimensioning/providing the hydraulic design of a simple hydraulic power unit. The information/customer requirements necessary for this are listed under the heading of Project definition. The required hydraulic components can be determined on the basis of circuit diagrams and other technical documentation. Also manufacturers' documents such as technical data sheets can be used, with the utilization of modern information and communication media (Internet) being recommended. The control should be set up on the basis of order-oriented planning taking into account applicable safety regulations and product information. The project order is to be analyzed in view of its feasibility. Detailed technical documentation such as: Hydraulic circuit diagram, parts list of hydraulic components, functional description, notes on possibilities of optimization are essential points for fulfilling the customer order. A final evaluation of the work results is to be complemented by: a list of sources of any technical documentation and a project schedule/documentation of work carried out. Note: To be able to recapitulate the work carried out or the order handling, complete the project schedule at the end of the project. Notes

16 Project : Hydraulic power unit 5 Hydraulic circuit diagram Item 9.0 Item 10.0 Item 6.0 Measuring glass Item 2.0 Item 4.0 Item 7.0 Item 8.0 Item 3.0 Item 1.0 Item 5.0 Fig..2 Hydraulic schematic diagram: Drive power unit

17 Project : Hydraulic power unit 6 Component selection with parts list Item Qty Component designation Type designation Symbol Reservoir with cover 100 L/steel Variable displacement pump, pilot operated PV7-1X/ Level control FSK Electric motor 4 KW/1450 rev/ min Shut-off valve, operated by turning Check valve with spring, flow enabled in only one direction; closed at rest position S6-1X/ Filter with by-pass valve and pressure measuring device RF Tank breather filter Connection block with 1/4" coupler plug Measuring glass Table.1 Parts list for hydraulic circuit diagram Fig..2

18 Project : Hydraulic power unit 7 Safety notes Warning Caution To ensure the operability of plant and machinery, and consequently to allow the recognition of potential risks, safety regulations must be observed before and during the execution of the order. Relevant sources of regulations are given in the introduction of the present manual. If work on electrohydraulic components is carried out improperly, risks of injury and a safety risk can arise during operation of the system, including danger to life. Before starting work on the training stand, make sure that electrical ON/OFF switches on the hydraulic power unit are pressed in, that is, that the system is switched off. Check on the system pressure gauge that the system is depressurized. Hydraulic systems can store pressure energy at rest. This can cause injury when the system is opened. Notes

19 Project : Hydraulic power unit 8 Execution of the order Dimensioning of a hydraulic power unit requires fundamental knowledge of hydraulic control technology. This also includes knowledge of the design of hydraulic systems inclusive of the drive power unit. The listing on the next page shows influencing factors that have to be taken into account when rating a hydraulic power unit. In the project order, only simple rules for the rating of power units can be applied. For this, formulas from physical basic principles can be applied (see Fig..3). Any power losses are not considered. Piston area A P Annulus area A A Force Energy converter e.g. cylinder Flow control valve Change in velocity Force = pressure area Pressure differential p Force F v F = force in N p = pressure in bar A = area in mm 2 Velocity v = velocity in s = travel in m t = time in s Directional valve Start, direction, stop Displacement/flow q V = flow in V g = geometric displacement in n = Speed of the pump shaft in η = volumetric efficiency in % Pressure control valve Force/ pressure limitation Energy converter e.g. fixed displacement pump Motor power P M p q V = power in kw = pressure in bar = flow in η total,p = overall efficiency in % Fig..3 Physical basic principles with formulas

20 Project : Hydraulic power unit 9 Factors that have an influence on the rating of a power unit Environment, surroundings - climate Pipe length to the consumer Place of installation: integrated - separate Duty cycle Expected drive power Volume fluctuation Ambient temperatures Heat dissipated by the reservoir Cooling (air, water) Heating Noise - transmitted by pipes and air ducts Acoustic insulation Hoses Compensators Anti-vibration mounts Low flow velocity Pump selection Encapsulation Hydraulic accumulator Silencers etc. Assembly - disassembly - maintenance Factors that have an influence on the rating of a return flow filter Field of application, environment Susceptibility of components (the component with the most stringent requirement determines the filter rating for the entire system!) The required cleanliness class and filter rating must be adhered to. Both must be specified by the component manufacturer. State of art with regard to minimum requirements is, for example, NAS class 9 and a minimum retention rate of ß10 100; ISO 4406 (c) class 20/18/15. A reliable calculation of cleanliness is impossible, because the ingress of dirt in relation to the ß value cannot be determined. Arrangement of filters Type, viscosity and operating temperature of the fluid Operating pressure The flow rate determines the selection of the filter size Permissible Dp across the clean element (Bosch Rexroth selection series: Rated Dp for a pressure filter - 1 bar, return line filter = 0.4 bar) By-pass valve - determined by the filter series, not provided for pressure filters Clogging indicator - a MUST in modern hydraulic systems - visual and/or electrical The tank breather filter must have the same filter rating as the fluid filters.

21 Project : Hydraulic power unit 10 Solutions Hydraulic pump: Electric motor: Hydraulic fluid reservoir: Accessories:

22 Project : Hydraulic power unit 11 As additional aid for rating a hydraulic power unit we recommend the use of a hydraulic slide rule. General note: In contrast to the following project tasks, this order execution does not involve any practical work on the training system. Evaluating the work results in relation to the customer requirement A hydraulic system consists of a, and. A hydraulic power unit accommodates the hydraulic components to form a. The required drive elements and reservoir accessories such as and and can be mounted to or on top of the reservoir. The and of the hydraulic power unit depends on the given conditions and the. Notes

23 Project : Hydraulic power unit 12 Notes

24 Project : Hydraulic power unit 13 Project schedule: Project Last name, first name Project handler Project designation Informing from the project definition. Planning steps Planning of the project objective and the proceeding. Sources of information Decision-making Deciding on and selecting components; complementing the circuit diagram and parts list. (Overleaf)

25 Project : Hydraulic power unit 14 Execution of the order Execution Set-up of the electrohydraulic control and acquisition of required data. Special points? Quality check Checking Are all customer requirements met? Evaluating Optimize project steps (If required, add supplementary sheet) Project Note of completion by confirmation of the project manager/place, date, signature