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Politecnico di Torino
Academic Year 2009/10
01FNPDS
Fluid power components and systems
Master of science-level of the Bologna process in Mechanical Engineering - Vercelli
Teacher Status SSD Les Ex Lab Tut Years teaching
Rundo Massimo ORARIO RICEVIMENTO A2 ING-IND/08 36 12 8 0 3
SSD CFU Activities Area context
ING-IND/09 5 D - A scelta dello studente A scelta dello studente
Esclusioni:
01FNH; 01FPM
Objectives of the course
The module presents and examines fluid power components and basic systems in terms of their graphical symbols, layout, specific features, construction and operation. Students learn how to identify and interpret fluid power circuits, comprehend and explain their purpose in relation with their constitutive components. Aim of the course is to acquaint students with methods for the analysis and citical evaluation of fluid power components and systems.
Expected skills
Upon completion of this module students should be able to identify the main fluid power components, their specific function and operation, to interpret correctly their purpose within a fluid power system and to determine and contrast from a technical point of view the use of a component or of a whole system in relation to its end use.
Prerequisites
Awareness of concepts covered in, Physics, Fluid Mechanics, 3D Modelling.
Syllabus
The programme addresses the analysis of flow feeding groups, control and utilisation of hydraulic power and of auxiliary components, the analysis of some fixed and mobile plants and an introduction to the working fluids classification and characteristics:
Volumetric Pumps and Motors: their classification, ideal and real characteristics, instantaneous flow rate and torque, flow rate oscillations and pressure ripple, volumetric and mechanical-hydraulic efficiencies, flow and torque losses models. Means of displacement variation control.
Flow Generation units (GA): constant and variable flow rate; constant and approximate pressure, open and closed circuits; ideal and real performance characteristics;
Regulation and Control units (GRC): on-off and proportional directional control valves; flow regulator valves; pressure control valves; ideal and real performance characteristics;
End user units (GU): linear and rotary actuators, stand-still and motion control of resistent and overrunning loads with VCB (counterbalance) and OVC (overcentre) valves, speed control of one or more actuators with constant and variable loads; flow regeneration in linear actuators; synchronised control through flow dividers, characteristics and ideal-real performance; gerotor and orbit principle of operation. Semi-motors.
Auxiliary equipment: accumulators and their dimensioning criteria, rigid pipes and flexible hoses, fittings, heat exchangers, filters, measuring devices, oil leakage control elements (seals)
Working fluid: ISO classification; physical properties (density, viscosity), bulk modulus; contamination and filtration;
Syllabus: more informations
Students attend lectures where they are exposed to the principles of operation of single components and of complete fluid power systems. They also participate to classroom work where they apply what they have learned from lectures and where actual systems are reviewed. In mandatory laboratory hours they acquire a direct experience with components and real systems.
Laboratories and/or exercises
Four two-hours sessions of laboratory work (mandatory) are carried out in teams and topics are selected from the following :
Dismantling and analysis of components: real components of GA, GRC and GU such as pumps of different architectures, linear and rotary actuators, filters, flowmeter devices, accumulators, directional, pressure and flow control valves are dismantled and analysed;
Fluid power valves: some directional, pressure and flow control valves of different manufacturers are disassembled analysed and contrasted to grasp the various underlying principles of operation and how these have been put into effect. Care is taken in interpreting the ISO symbologic representation of the various components;
Dydactic test rig: through direct observation and measurement of some physical quantities (e.g. pressure, flow and velocity) the mode of operation is analysed of different circuits and components assembled on three panels of the test rig. Interactions and characteristics of valves and actuators are appraised. Worth of mention are the practical settings of relief, reducer and sequence valves, implications in series and parallel operation of linear actuators, velocity control of rotary motors with constant and variable loads via variable restrictors and flow regulating valves;
Pumps, motors and linear actuators: Various volumetric pumps (external and internal gear, piston and vane) and motors of different manufacturers are disassembled, analysed and contrasted to understand and appraise their peculiarities and mode of operation;
Steady state characteristics of volumetric units: through direct measurement of pressure, flow, torque and angular speed on either a pump or a motor the steady state characteristics are obtained and critically analysed. Also the volumetric, mechanical-hydraulic and total efficiencies are appraised and scrutinized.
Test rig for overcentre (OVC) valves characterisation: through direct measurement of pressure, flow, and angular speed the steady state characteristics of a winch (orbit motor) loaded with either resistent or overrunning loads are obtained. The winch, subject to overrunning loads, is controlled by an OVC valve, load hold at stand still being granted by an integral multi disc braking system.
Simulation: briefly introducing a simulation environment (AMESim), problems in modelling and simulation of simple components and systems are presented. Students have the opportunity to perform simulations to gain direct experience of the approach and gain perception of the involved potentials.
Bibliography
Will be made available to enrolled students at the Didactic Web site of the Politecnico.
Reference text books:
For additional insight into specific topics reference is made to the following material:
Nervegna, N.: Oleodinamica e pneumatica: Sistemi. Vol. 1, Politeko, Torino
Nervegna, N.: Oleodinamica e pneumatica: Componenti. Vol. 2, Politeko, Torino
Nervegna, N.: Oleodinamica e pneumatica: Esercitazioni. Vol. 3, Politeko, Torino
Gilardino, L.: Esercizi di Oleodinamica
Revisions / Exam
While the module is ongoing, HomeWorks (4 to six) will be progressively proposed on the specific didactic web site of the Politecnico. These Homeworks should be downloaded and solved individually, according to explicit rules, by all students. The purpose of these homeworks is twofold: a self verification of acquired knowledge and competence; a training route toward the final written test. When succesfully registering the exam, each student must present the complete set of his own homeworks.

At the end of the module the final exam is grounded on a two hours written test involving practical numerical evaluations on a proposed problem as well as questions on concepts and principles exposed during the lectures.
For those that reach in the written test marks in the range:
0-14/30 the exam is failed
15 to 20/30 the oral examination is mandatory
21 to 27/30 the oral examination is optional
28 to 30/30 the mark is final and the exam is passed

The oral examination focuses on lectures, classroom work, laboratory topics, written test and homeworks.

Programma definitivo per l'A.A.2009/10
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