AGMA-1012-G05-2005.pdf

ANSI/AGMA1012-G05 ANSI/AGMA 1012-G05 Revision of ANSI/AGMA 1012-F90 AMERICAN NATIONAL STANDARD Gear Nomenclature, Definition of Terms with Symbols ii Gear Nomenclature, Definitions of Terms with Symbols ANSI/AGMA 1012-G05 Revision of ANSI/AGMA 1012-F90 ApprovalofanAmericanNationalStandardrequiresverificationbyANSIthattherequire- ments for due process, consensus, and other criteria for approval have been met by the standards developer. Consensusis establishedwhen,inthejudgmentoftheANSIBoardofStandardsReview, substantial agreement has been reached by directly and materially affected interests. Substantialagreementmeansmuchmorethanasimplemajority,butnotnecessarilyuna- nimity.Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. TheuseofAmericanNationalStandardsiscompletelyvoluntary;theirexistencedoesnot in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National StandardinthenameoftheAmericanNationalStandardsInstitute. Requestsforinterpre- tation of this standard should be addressed to the American Gear Manufacturers Association. CAUTION NOTICE: AGMA technical publications are subject to constant improvement, revision, or withdrawal as dictated by experience. Any person who refers to any AGMA technical publication should be sure that the publication is the latest available from the Association on the subject matter. Tables or other self-supporting sections may be referenced. Citations shouldread: See ANSI/AGMA 1012-G05, Gear Nomenclature, Definitions of Terms with Symbols, pub- lished by the American Gear Manufacturers Association, 500 Montgomery Street, Suite 350, Alexandria, Virginia 22314, http:/www.agma.org. Approved September 29, 2005 ABSTRACT This standard lists terms and their definitions with symbols for gear nomenclature. Published by American Gear Manufacturers Association 500 Montgomery Street, Suite 350, Alexandria, Virginia 22314 Copyright © 2005 by American Gear Manufacturers Association All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America ISBN: 1-55589-846-7 American National Standard ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD iii© AGMA 2005 - All rights reserved Contents Forewordiv. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Scope1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Normative references1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Terms and symbols1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Geometric definitions2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1General designations2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2Kinds of gears3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3Principal planes7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4Principal directions9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5Surfaces and dimensions9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6Terms related to gear teeth14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7Terms related to gear pairs26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8Terms related to tooth contact in a gear pair27. . . . . . . . . . . . . . . . . . . . . . . . . . . 5Inspection definitions30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index of terms53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Annexes AAbbreviations41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BGlossary of trade terms42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CTerms and symbols43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD iv© AGMA 2005 - All rights reserved Foreword The foreword, footnotes and annexes, if any, in this document are provided for informational purposes only and are not to be construed as a part of ANSI/AGMA 1012-G05, Gear Nomenclature, Definitions of Terms with Symbols. In 1926 the AGMA adopted a recommended practice for gearing nomenclature, terms and definitions. It included some symbols and abbreviations. A complete revision of terms and definitions by the AGMA Nomenclature Committee was issuedasAGMA112.02inOctober,1948. ThislaterbecameAGMA112.03,andAmerican Standard B6.10-1954, with ASME as a co-sponsor. A separate project dealing with Letter Symbols for Gear Engineering appeared in 1943 as AGMA 111.01, later becoming AGMA 111.03 and American Standard B6.5-1954. AbbreviationsforGearingwasanotherseparateprojectreleasedasAGMA116.01in1955. Most of these abbreviations were already listed in American Standard Z32.13-1950 Abbreviations for Use on Drawings, and it was, therefore, unnecessary to process gearing abbreviations as a separate American Standard. The number of abbreviations used in gearing has intentionally been kept very small to permit memorizing without the need to refer to the standard. AGMAStandard112.04,GearNomenclature(Geometry)Terms,Definitions,Symbolsand Abbreviations, was a complete revision and integration of the three standards previously mentioned. Because of the widespread acceptance of the previous standards, changes werekepttoaminimum. ThestandardinthisformwasapprovedbytheAGMAMembership on April 25, 1965. AGMA 112.05 included several revisions to keep it abreast of the then current gearing techniques. ItwasapprovedbyStandardsCommitteeB6,Gears,theCo-Secretariatsand the American National Standards Institute on February 3, 1976 and designated ANSI B6.14-1976. ANSI/AGMA1012-F90wasarevisionof112.05. Thisrevisionincorporatedthetermsfrom AGMA Standard 116.01 (Oct., 1972), Glossary of Terms Used in Gearing, and terms from ANSI/AGMA 2000-A88, Gear Classification and Inspection Handbook, Tolerances and Measuring Methods for Unassembled Spur and Helical Gears (Including Metric Equivalents). Inaddition,termswhichstartedtobecommonlyusedingearloadratingwere introduced in the annex. ANSI/AGMA 1012-G05 is a revision that updates the style of presentation, reordered the sequence of some terms, added definitions for right and left flank, and modified annexes B and C. The first draft of ANSI/AGMA 1012-G05 was made in June 2002. It was approved by the AGMA membership in July, 2005. It was approved as an American National Standard on September 29, 2005. Suggestions for improvement of this standard will be welcome. They should be sent to the AmericanGearManufacturersAssociation,500MontgomeryStreet,Suite350,Alexandria, Virginia 22314. ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD v© AGMA 2005 - All rights reserved PERSONNEL of the AGMA Nomenclature Committee Chairman: Dwight SmithCole Manufacturing Systems. . . . . . . . . . . . . . . . . ACTIVE MEMBERS M.R. ChaplinContour Hardening, Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . R.L. ErrichelloGEARTECH. . . . . . . . . . . . . . . . . . . . . . . . . . . O.A. LaBathGear Consulting Services of Cincinnati, LLC. . . . . . . . . . . . . . . . . . . . . . . . . . . . T. MillerCST Cincinnati. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J.M. RinaldoAtlas Copco Comptec, Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD vi© AGMA 2005 - All rights reserved (This page is intentionally blank) -,-,- 1© AGMA 2005 - All rights reserved ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD American National Standard - Gear Nomenclature, Definitions of Terms with Symbols 1 Scope This standard establishes the definitions of terms, symbols and abbreviations which may be used to communicate the technology and specifications of externalandinternalgearteeth. Itprovidesdefinitive meanings by the use of words and illustrations, for commonly used gearing terms. 2 Normative references The following documents contain provisions which, throughreferenceinthistext,constituteprovisionsof the standard. At the time of publication, the editions were valid. All publications are subject to revision, and the users of this standard are encouraged to investigatethepossibilityofapplyingthemostrecent editions of the publications listed. ISO701:1998,Internationalgearnotation- - Symbols for geometrical data. 3 Terms and symbols 3.1 Terms Theterminologyusedinthisstandardisintendedfor use in all AGMA documents and is summarized in the index. Manytermsarelistedintheindexmorethanonceby restating alphabetically with rearranged key words, to aid user look-up of related terms. 3.2 Symbols Thepurposeofstandardsymbolsforgearengineer- ingistoestablishauniformpracticeinmathematical notation for equations and formulas dealing with toothedgearing. Suchequationsandcorresponding calculations may be used in connection with design, application, manufacture, inspection, new methods, and new problems. NOTE: The symbols and definitions used in this stan- dard may differ from other AGMA standards. The user should not assume that familiar symbols can be used without a careful study of these definitions. SI (metric) units of measure, where applicable, are shown in the text.Where equations require a different format or constant for use with SI units, the primary equation has an (M) appended and the secondary expression is shown after the first, indented. Example: d = z m (2M) D = N Pd (2) Symbols must be distinguished from abbreviations which are shortened forms of words often used on drawings and in tables, but not suitable for mathe- matical work (see annex A).For example, the symbol for circular pitch is p, whereas the abbrevi- ation is CP. AGMA is changing to use symbols consistent with symbols used by ISO. In the definition titles, where the old AGMA symbol is still commonly used but differs from the ISO symbol, both symbols are listed with the ISO symbol at the end of the line. Annex C contains an alphabetical list of the old symbols with the new symbols also listed. 3.2.1 Subscripts A subscript following the general symbol may be used to indicate a value applying to a particular gear ortool,oravaluetakenataparticularpositionorina particular direction. For convenience and brevity, it is desirable to use a general symbol without a subscript when only one value of a given kind is involved. Thus, in a spur gear or a straight-tooth bevel gear, there is occasion to consider only one cross section of the teeth, namely, the transverse ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD 2© AGMA 2005 - All rights reserved section, and it is convenient and natural to refer, for instance, simply to the circular pitch, p, and the pressure angle, . In the case of gears with oblique teeth,ontheotherhand,itisusuallynecessarytobe specific and to refer to the transverse pitch, pt, and the transverse pressure angle, t, in order not to leaveanydoubtastowhethervaluesarebeinggiven for the transverse plane or normal plane. 3.2.2 Typography In accordance with the usual practice in published text, symbols, whether upper or lower case, should be printed in serif italic font. This is done to avoid confusion in reading the symbols and to make a distinction between upper and lower case.An exception is Greek capital letters and all subscripts, which are always vertical sans serif font. Numbers appearing as coefficients, subscripts, superscripts, or exponents should be printed in vertical Arabic numerals.Abbreviations should alwaysbeprintedverticalandarenotrecommended for use in formulas. Trigonometric functions should be printed in lower case vertical type. Standard mathematical notation should be followed. 4 Geometric definitions There is an old Chinese proverb that states: The beginning of wisdom is to call things by their right names. Unfortunately,gearingterms andmeanings vary in different offices, shops, textbooks, and among gear authorities. To obtain related continuity, the terms have been grouped in what may be called a textbook arrange- ment in preference to alphabetical order. Many of thedefinitionshavebeenwritteninawaythatmakes them depend on one another, as a logical series. This arrangement leads to a more comprehensive understanding of the concepts and geometrical relations. 4.1 General designations 4.1.1 Gears Gearsaremachineelementsthattransmitmotionby means of successively engaging teeth, see figure 1. 4.1.2 Gear (wheel) A gear (wheel) is a machine part with gear teeth. Of two gears that run together, the one with the larger number of teeth is called the gear, see figure 1. (Wheel per ISO 1122-1:1998). Pinion Gear (wheel) Rack Figure 1 - - Gears 4.1.3 Pinion A pinion is a machine part with gear teeth. Of two gears that run together, the one with the smaller number of teeth is called the pinion, see figure 1. 4.1.4 Worm Awormisagearwithoneormoreteethintheformof screw threads, see figures 2 and 9. Figure 2 - - Worm 4.1.5 Rack A rack is a gear with teeth spaced along a straight line, and suitable for straight line motion. It can be regardedaspartofagearofinfinitelylargediameter, see figure 1. 4.1.6 Basic rack For every pair of conjugate involute profiles, there is abasicrack(see4.7.1). Thisbasicrackistheprofile of the conjugate gear of infinite pitch radius, see figure 3. -,-,- ANSI/AGMA 1012- -G05AMERICAN NATIONAL STANDARD 3© AGMA 2005 - All rights reserved Profile angle Figure 3 - - Basic rack in normal plane 4.1.7 Generating rack A generating rack is a rack outline used to indicate tooth details and dimensions for the design of a generating tool, such as a hob or a gear shaper cutter. 4.1.8 Number of teeth or