Tai ngay!!! Ban co the xoa dong chu nay!!! Machine Elements • Analysis and Design This textbook provides undergraduate students with a basic understanding of machine element theory, and introduces tools and techniques to facilitate design calculations for a number of frequently encountered mechanical elements The material in the book is appropriate for one or two courses in Machine Elements and/or Mechanical Engineering Design The material is intended for students who have passed first and second year basic courses in engineering physics, engineering mechanics and engineering materials science The book is organized into 13 separate chapters, which in principle can be read independently The covered subjects are: Tolerances, springs, bearings, shafts, shaft-hub connections, threaded fasteners (bolts), 2D Joint Kinematics, couplings, clutches, brakes, belt drives, gear geometry and strength of gears About the authors Peder Klit and Niels L Pedersen are both professors in machine elements at the Department of Mechanical Engineering, the Technical University of Denmark, DTU Peder Klit & Niels L Pedersen MACHINE ELEMENTS ANALYSIS AND DESIGN Machine Elements Analysis and Design By Peder Klit and Niels L Pedersen © 2014 Polyteknisk Forlag 2nd edition, 2014 ISBN 978-87-502-1068-9 Cover design by Anne Bjørlie Printed by Livonia Printed in Latvia 2014 All rights reserved No part of the contents of this book may be reproduced or transmitted in any form or by any means without the written permission of the publisher Polyteknisk Forlag Anker Engelundsvej DK-2800 Lyngby Phone: +45 7742 4328 Fax: +45 7742 4354 E-mail: forlag@polyteknisk.dk www.polyteknisk.dk Side iii Preface to the second edition This book is intended to provide undergraduate students with basic understanding of machine element theory, and to introduce tools and techniques facilitating design calculations for a number of frequently encountered mechanical elements The material in the book is appropriate for a course in Machine Elements and/or Mechanical Engineering Design for students who have passed first and second year basic courses in engineering physics, engineering mechanics and engineering materials science At the end of each chapter in the book, references, which may be useful for further studies of specific subjects or for verification, are given Students who wish to go deeper into the general theory of machine elements may find the following textbooks inspiring: • Norton, R L., "Machine Design, an integrated approach", Prentice-Hall, 2014 • Shigley, J E and Mischke, C R., "Mechanical Engineering Design", McGraw-Hill, 2004 Students are encouraged to find supplement information from other sources such as International and National Standards, Internet Catalogues and information provided by companies (online or paper based) Those who are in command of the German language will find numerous German textbooks of very high standard Outstanding in quality is the textbooks by Niemann and co-authors • Niemann, G., Winter,H., Hohn, B "Maschinenelemente", Springer Verlag, Band I, 2005 • Niemann, G., Winter,H., "Maschinenelemente", Springer Verlag, Band II, 2003 • Niemann, G., Winter,H., "Maschinenelemente", Springer Verlag, Band III, 1983 • Decker, K., "Maschinenelemente, Funktion, Gestaltung und Berechnung", Carl Hanser Verlag, 2011 and an overall mechanical engineering reference book can be recommended as helpful during the study, and afterwards in your professional engineering life as well: • DUBBEL: Taschenbuch fiir den Maschinenbau, Springer Verlag, 2014 In this second edition of the book the misprints in the first edition have been corrected and some chapters have been extended A new chapter on 2D joint kinematics has also been added to the book Copenhagen, June 2014 Peder Klit and Niels L Pedersen Side iv Side v Contents Preface to the second edition iii Contents v Limits, fits and surface properties 1.1 Introduction 1.2 Geometrical tolerances 1.2.1 Specifying geometrical tolerances 1.2.2 Toleranced features 1.3 1.4 1.5 Surface texture 1.3.1 Surface Texture Parameters 1.3.2 Surface Texture Parameters Tolerances on lengths, diameters, angles 1.4.1 Dimensions and tolerances 10 1.4.2 Fits 11 1.4.3 The quality function deployment 12 1.4.4 Functional dimensioning 12 1.4.5 Dimension chains 15 The ISO-tolerance system 17 1.5.1 Introduction 17 1.5.2 Field of application 17 1.5.3 Terms and definitions 17 1.5.4 Tolerances and deviations 19 1.5.5 Preferred numbers 20 1.5.6 Standard tolerance grades IT1 to IT16 21 1.5.7 Formula for standard tolerances in grades IT5 to IT16 22 1.6 Nomenclature 23 1.7 References 24 Springs 25 2.1 Introduction 25 2.2 The design situation 25 2.3 Helical springs 26 2.3.1 Formulas for helical springs 27 2.3.2 Stress curvature correction factor 29 2.3.3 Material properties 30 2.3.4 Relaxation 30 2.3.5 Types of load 30 2.3.6 Dynamic loading 31 2.3.7 Optimization 32 Side vi 2.4 2.5 2.6 2.3.8 Compression springs 34 2.3.9 Growing mean diameter of helix 34 2.3.10 Natural frequency 34 2.3.11 Buckling of spring 34 2.3.12 Statically loaded cold-formed compression spring 36 2.3.13 Statically loaded hot-formed compression spring 36 2.3.14 Dynamically loaded cold-formed compression spring 37 2.3.15 Dynamically loaded hot-formed compression spring 37 2.3.16 Extension springs 37 2.3.17 Initial tension 38 2.3.18 Statically loaded cold-formed extension springs 38 2.3.19 Statically loaded hot-formed extension springs 38 2.3.20 Dynamically loaded cold-formed extension springs 38 2.3.21 Dynamically loaded hot-formed extension springs 39 2.3.22 Ends of extension springs 39 Belleville springs or coned-disk springs 40 2.4.1 40 Formulas for Belleville springs Helical torsion springs 42 2.5.1 Methods of loading 42 2.5.2 Binding effects 43 2.5.3 Formulas for helical torsion springs 44 Spiral springs 45 2.6.1 Clamped outer end 45 2.6.2 Simply supported outer end 47 2.7 Supplementary literature 49 2.8 Nomenclature 49 2.9 References 51 Rolling element bearings 53 3.1 Introduction 53 3.2 Bearing types 53 3.2.1 Available space 53 3.2.2 Loads 54 3.2.3 Combined load 55 3.2.4 Misalignment 58 3.2.5 Speed 58 3.2.6 Stiffness 58 3.2.7 Axial displacement 58 3.3 Load carrying capacity and life 59 3.3.1 Basic load ratings 59 3.3.2 Life 60 3.3.3 Basic rating life equation 60 3.3.4 Requisite basic rating life 61 3.3.5 Adjusted rating life equation 61 3.3.6 Combination of life adjustment factors