1、Dictionary of Mechanical Engineering Fourth Edition G.H.F. NaylerDictionary of Mechanical Engineering Fourth Edition G.H.F. Nayler MSc, CEng, MIMechE, MRAeS Society of Automotive Engineers, Inc. Warrendale, Pa. Butterworth-Heinemann Oxford Boston Johannesburg Melbourne New Delhi Singapore Copyright
2、1967, 1975, 1985, 1996 G.H.F. Nayler eISBN: 978-0-7680-6208-3First published by George Newnes Ltd, 1967 Second edition 1975 reprinted 1978, 1981 Third edition 1985 Copyright 1967, 1975, 1985, 1996 G.H.F. Nayler Printed and bound in the United States of America. Butterworth-Heinemann Linacre House, J
3、ordan Hill, Oxford OX2 8DP A division of Reed Educational and Professional Publishing Ltd. A member of the Reed Elsevier plc group British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Butterworth-Heinemann ISBN 0 7506 3009 4 All right
4、s reserved. No part of this publication may be reproduced in any material form (including photo- copying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in
5、 accordance with the provisions of the Copyright Designs and Patents Act 1988 or under the terms of a license issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England WIP 9HE. Applications for the copyright holders written permission to reproduce any part of this public
6、ation should be addressed to the publishers. Society of Automotive Engineers, Inc. 400 Commonwealth Drive, Warrendale, PA 15096-0001 Phone: (412) 776-4841 Fax: (412) 776-5760 Library of Congress Cataloging-in-Publication Data Nayler, G. H. F. Dictionary of mechanical engineering / G.H.F. Nayler. - 4
7、th ed. p. cm. ISBN 1-56091-754-7 (hardcover) 1. Mechanical engineering-Dictionaries. I. Title. TJ9.N28 1996 621.03-dc20 95-52297 CIP SAE ISBN 1-56091-754-7 Permission to photocopy for internal or personal use, or the internal or personal use of specific clients, is granted by SAE for libraries and o
8、ther users registered with the Copyright Clearance Center (CCC), provided that the base fee of $.50 per page is paid directly to CCC, 222 Rose- wood Dr., Danvers, MA 01923. Special requests should be addressed to the SAE Publications Group. 1-56091-754-7/96 $.50. SAE Order No. R-156Preface to First
9、Edition This dictionary has been compiled to cover the very large number of me- chanical engineering terms in common use in a handy compact volume. The term “mechanical engineering“ has been interpreted as mainly the produc- tion of, the means for, and the utilization of, mechanical power in engines
10、, transport and mechanisms. It has also been borne in mind that tools, and the making of them, are of first importance, but in order to keep within certain limits those tools that are used by hand have been omitted, except for one or two rare exceptions. As regards power, its production involves the
11、 design and construction of many types of device to enable energy to be developed from fundamental sources and then on to prime movers. As far as possible, terms likely to be found in other dictionaries of the series have been omitted, except where the application of a term is clearly common to more
12、 than one branch of engineer- ing. Consequently, many fields allied to the mechanical engineering indus- try, such as foundry practice, metallurgy, metrology and welding, all of which are vital to the industry but are not in themselves mechanical, have been given only minor attention. In preparing a
13、 work of this kind it is necessary to consult many sources, since the choice of clear and concise definitions is always a difficult task. The selection of terms has been based mainly on the reading of current literature, including the foremost engineering journals. Thus many well known but little us
14、ed terms may not be found. Terms printed in bold italics in the text indicate entries that will provide the reader with additional information. The illustrations are intended to help the less expert and are spread over the large field of mechanical engineering, while avoiding intricate subjects whic
15、h are too complicated for simple line drawings. iiiThe authors are much indebted to Miss E. E. Metcalfe for her valuable assis- tance in the preparation of the line drawings, and to the Publishers staff* for their helpful cooperation at all times during the passage of the dictionary through the pres
16、s. J.L. and G.H.F. Nayler *George Newnes Ltd., London ivPreface to Fourth Edition The dictionary has been further updated and enlarged while retaining practi- cally all of its original contents. With the recent advances in very small size mechanical engineering, micromachining and nanotechnology hav
17、e been in- cluded. Nomenclature used in the manufacture of composites has also been added. Terms which have their main usage on the North American Continent now receive more prominence than previously. Cross-references have always been given full and careful attention and, where relevant, the reader
18、 is guided, as in a thesaurus, to a term of opposite meaning. Clear understandable terminology is essential to efficient, accurate and com- prehensive information distribution and retrieval. It is hoped that this edition will further the above aims worldwide in the field of mechanical engineering. v
19、Acknowledgments I am pleased to record my gratitude to Don Goodsell for his advice and en- couragement and for the use of four figures from his companion Dictionary of Automotive Engineering. I am also grateful to the staff of the Society of Automotive Engineers for their full support in the product
20、ion of this edition, and Butterworth-Heinemann for co-publishing this work. Gordon H.F. Nayler viiA a The symbol for acceleration. Also f. “A“ value An “A“ value is the value above which at least 99% of the sample popu- lation of values is expected to fall with a confidence of 95%. See also allowabl
21、es; stress. The symbol for angular acceleration. ANSI American National Standards Institute. ASME American Society of Mechanical Engineers. ASTM American Society for Testing and Materials. ATE Automatic Test Equipment. AWG American Wire Gauge. acc Acceleration. ablation shield Protection shields att
22、ached to bodies designed to re-enter the earths atmosphere which vaporise in the intense heat and thus keep the main structure at a safe temperature. abradant A material, such as emery and generally in powder form, used for grind- ing. abrasion The wearing or rubbing away of a surface. See also Dres
23、ser. abrasion test A test by means of a scratch on a smooth surface of the material. See Hardness Tests. absorber An auxiliary vibratory system, for modifying the vibration characteristics of the main system, either damped or undamped. absorption dynamometer A dynamometer which measures the work don
24、e by ab- sorbing or dissipating the power, e.g., by the friction of a brake or as in a Froude brake. Cf. Transmission Dynamometer. abutment engine See Engine (Servomotor Types). 1accelerated fatigue test A fatigue test in which the alternating stress level during the test is increased above that exp
25、ected in service in order to reduce the testing time. Accelerated fatigue testing is not an exact science since any assembly does not have a unique S-N curve; nevertheless the technique is widely used in assess- ing equipment performance in a vibration environment. acceleration The rate of change of
26、 velocity (speed) or the average increase of veloc- ity in a unit of time, usually expressed in feet (or centimetres) per second per second. Similarly, “angular acceleration“ is the rate of increase of rotational (an- gular) velocity, usually expressed in radians per second per second. acceleration
27、due to gravity The acceleration of a freely falling body in a vacuum, varying with the distance from the earths centre and having a mean value of 32.2 ft/sec2 or 9.806 m/s2 at sea level. acceleration impedance See effective inertia; effective mass. accelerator (accelerator pedal) (a) A pedal in a mo
28、tor vehicle which acts on the throttle valve and thus controls the power and speed of the engine. (b) A pedal which controls the fuel injection into an oil engine. accelerometer An instrument for measuring acceleration (a) by the movement of a mass supported by a spring, (b) by a simple pendulum in
29、which its period is inversely proportional to the square root of the acceleration being measured, or (c) by the precession rate of a pendulous gyroscope. accessory gearbox A gearbox, driven by and remote from, an engine for mounting accessories such as a hydraulic pump on an aero-engine. acid pump A
30、 pump with the barrel and valves made of glass so as to be resistant to acids. Ackermann steering The arrangement on an automobile whereby the inner axle moves through a greater angle than the outer axle during cornering so as to give approximate true rolling of the respective wheels about the turni
31、ng point. Figure A.1 illustrates that the variation in turning angle of the two wheels is achieved by Figure A.1 Ackermann steering. 2a rod a b c which is shorter in length than the distance between the front wheel pivots. (a) Ackermann steer angle The mean angle through which the wheels of a vehicl
32、e are steered to turn the vehicle on a given radius. (b) Ackermann steer angle (SAE definition) The angle whose tangent is the wheelbase divided by the radius of turn. acme thread A standard American screw thread, with the flanks having an inclined angle of 29, which is used extensively for feed scr
33、ews. It has the same depth as the square thread but is stronger as the bottom of the thread is wider than the square thread. (See Figure T.8(b).) actuator (a) An electric, hydraulic, mechanical or pneumatic device, or combina- tions of these, to effect some predetermined linear or rotating movement.
34、 One example used in automatic train control is an air-operated differential piston and mechanism mounted on an automatic brake valve to operate at a predetermined brake pipe pressure reduction. (b) A servomotor producing a limited output motion. (c) A complete self-contained servo-mechanism produci
35、ng a limited output motion. See also microactuator. adapter An accessory appliance so that objects of different size can be interchanged such as on a spindle or other fitting. adaptive control A type of control in which an original programmed motion is modi- fied in response to information provided
36、by a sensor system. addendum (a) The radial distance from the reference cylinder (reference adden- dum) or the pitch cylinder (working addendum) to the tip cylinder. (b) Half the difference between the diameter of the pitch circle of a worm wheel and the throat diameter. (c) The distance from the pi
37、tch circle to tip cone measured on the back cone of a bevel gear. (d) In a gear wheel, the radial distance between the pitch circle and the addendum circle. (See Figures H.1, I.3, S.20 and S.21.) In a BS form of tooth it equals 0.3183 times the circular pitch. addendum circle The circle passing thro
38、ugh the tips of the teeth and equal in diameter to the blank or disc from which the wheel is to be cut. Cf . tip cylinder. chordal addendum The radial distance measured as in (a) above but from the chord of the pitch circle. addendum angle The difference between the tip angle and the pitch angle of
39、a bevel gear. addendum (screw threads) The radial distance between the major and pitch cylin- ders (or cones) of an external screw thread; the radial distance between the pitch and minor cylinders (or cones) of an internal thread. See pitch cylinder (cones). (See Figure S.5.) adherend The part that
40、is bonded with adhesive. 3adherents, adhesives In general, glues used for their structural strength. adhesion (adhesive force) The frictional grip between two surfaces in contact, e.g., between the locomotive driving wheel and the rail where it is the product of the weight on the wheel and the frict
41、ion coefficient (0.1 to 0.2 depending on the condition of the rail surface), or that obtained by using an adhesive. adiabatic A change in volume and pressure of the contents of a container without any exchange of heat between the container and its surrounding environment. adjustable pitch propeller
42、A propeller, the pitch of whose blades can be altered on the ground but not in flight. Cf. variable-pitch propeller. adjusting rod A rod with an adjustable clamp for attaching to a fusee or barrel arbor and provided with sliding weights for balancing the pull exerted by the main spring and thus test
43、ing its pull. adjusting screw A screw, usually with a very fine thread, in an instrument or tool by which one part is moved relative to another, to give adjustment in focus, level, tension, etc. adjustment strips Metal strips for the accurate adjustment of the exact bearing loads on sliding surfaces
44、. The precise amount of contact is effected by pressure im- parted to the strips from set or adjusting screws. admission The instant in the working cycle of an internal-combustion or steam en- gine when the inlet valve allows entry of the working fluid into the cylinder. admission corner The corner
45、on an indicator diagram which corresponds with the entry of the working fluid into a cylinder. admission line The side of the indicator diagram which shows the actual condition while steam is entering an engine cylinder. admission port The passage by which steam or the combustible fluid enters an en
46、- gine cylinder. admittance See mechanical admittance. advance (a) Altering the time of ignition of an internal-combustion engine to cause the spark in the cylinder to pass at an earlier point. (b) See angular advance. advance of spark In ignition, turning the contact breaker so that the spark will
47、ignite the charge earlier during the compression stroke. An internal-combustion engine has “advanced ignition“ if the spark has been advanced. advanced ignition See advance of spark. aerial (cable) railway (aerial ropeway) A system of overhead cables with small cars or containers for conveying perso
48、ns or loads, usually over mountainous country. 4aerodynamics A branch of dynamics that deals with the motion of air and other gases. See mechanics. aero engine The power unit of an aircraft, including both piston engine and gas- turbine types. aero-thread insert See thread insert. afterburner That p
49、art of a turbojet engine where extra fuel is burned between the gas turbine and the nozzle. See Figure A.2. Figure A.2 Afterburner. agitators Mechanical stirrers or reverberators for settling concrete, sorting coal or sand, or for mixing molten metals or for rocking fluid paper-pulp on a frame to make the wood fibres interlace. air bearing A shaft bearing maintained wholly by compressed air with no contact between fixed and moving surfaces. air brake (a) A mechanical brake on a railway train or road vehicle which is oper- ated by air pressure acting on a piston. Cf. vacuum brake
