1、ANSI/AGMA 2111-A98Metric Edition of ANSI/AGMA 2011-A98Reaffirmed December 2004American National StandardCylindrical WormgearingTolerance and InspectionMethods (Metric)ANSI/AGMA2111-A98iiCylindrical Wormgearing Tolerance and Inspection Methods (Metric)ANSI/AGMA 2111-A98(Metric Edition of ANSI/AGMA 20
2、11-A98)Approval of an American National Standard requires verification by ANSI that the require-ments for due process, consensus and other criteria for approval have been met by thestandards developer.Consensus is established when, in the judgment of the ANSI Board of Standards Review,substantial ag
3、reement has been reached by directly and materially affected interests.Substantial agreement means much more than a simple majority, but not necessarily una-nimity. Consensus requires that all views and objections be considered, and that aconcerted effort be made toward their resolution.The use of A
4、merican National Standards is completely voluntary; their existence does notin any respect preclude anyone, whether he has approved the standards or not, frommanufacturing, marketing, purchasing or using products, processes or procedures notconforming to the standards.The American National Standards
5、 Institute does not develop standards and will in nocircumstances give an interpretation of any American National Standard. Moreover, noperson shall have the right or authority to issue an interpretation of an American NationalStandard in the name of the American National Standards Institute. Reques
6、ts for interpre-tation of this standard should be addressed to the American Gear ManufacturersAssociation.CAUTION NOTICE: AGMA technical publications are subject to constant improvement,revision or withdrawal as dictated by experience. Any person who refers to any AGMATechnical Publication should be
7、 sure that the publication is the latest available from theAssociation on the subject matter.Tables or other self-supporting sections may be quoted or extracted. Credit lines shouldread: Extracted from ANSI/AGMA 2111-A98, Cylindrical Wormgearing Tolerance and In-spection Methods, with the permission
8、 of the publisher, the American Gear ManufacturersAssociation, 1500 King Street, Suite 201, Alexandria, Virginia 22314.Approved October 1, 1998ABSTRACTThis standard describes and defines variations that may occur in unassembled wormgearing. It displays mea-suring methods and practices, giving suitab
9、le warnings if a preferred probe cannot be used. The applicability ofsingle or double flank composite testing is discussed, using a reference gear. Tooth thickness measurement isshown using direct measurement as well as the use of measurements over wires or pins. Equations for themaximum variations
10、are given for the stated ranges, as a function of size, pitch and tolerance grade.Published byAmerican Gear Manufacturers Association1500 King Street, Suite 201, Alexandria, Virginia 22314Copyright 1998 by American Gear Manufacturers AssociationAll rights reserved.No part of this publication may be
11、reproduced in any form, in an electronicretrieval system or otherwise, without prior written permission of the publisher.Printed in the United States of AmericaISBN: 1-55589-717-7AmericanNationalStandardANSI/AGMA 2111-A98AMERICAN NATIONAL STANDARDiiiContentsPageForeword iv.1 Scope 12 Symbols, terms
12、and definitions 1.3 Manufacturing and purchasing considerations 5.4 Measuring methods and practices 75 Equations for worm and wormgear tolerances 20.Tables1 Symbols used 2.Figures1 Functional part of the profile - cutoff points, drop-off region 42 Lead and lead form variation 43 Worm thread runout i
13、nspection, Vr17.4 Worm pitch variation inspection, Vp1- method A 8.5 Worm pitch variation inspection, Vp1- method B 9.6 Worm thread profile inspection, V1107 Worm thread profile tolerance band, VT1108 Worm thread lead inspection, Vl1119 Wormgear tooth runout, Vr212.10 Location of probe - wormgear pi
14、tch variation, Vp213.11 Two probe device 13.12 Schematic of single probe device 14.13 Relationships of pitch variation, Vp2, and accumulated pitch variation, Vap21514 Pitch variation, Vp2, graphical data from two probe device 1515 Pitch variation Vp2, and accumulated pitch variation, Vap2: graphical
15、 datafrom single probe device 15.16 Schematic of a double flank wormgear tester 17.17 Schematic of a single flank wormgear tester 1718 Thread thickness measurement by means of a gear tooth caliper 1819 Thread thickness measurement over pins 18AnnexesA Inspection tolerance tables 21.Bibliography 43.A
16、NSI/AGMA 2111-A98 AMERICAN NATIONAL STANDARDivForewordThe foreword, footnotes and annexes, if any, in this document are provided forinformational purposes only and are not to be construed as a part of ANSI/AGMA Standard2111-A98, Cylindrical Wormgearing Tolerance and Inspection Methods (Metric).The p
17、urpose of this standard is to establish geometrical accuracy communication betweena manufacturer and purchaser of unassembled cylindrical wormgearing with axes at rightangles.AGMA 390.02 September 1964 was a replacement for AGMA 234.01 for fine pitchwormgearing. ANSI/AGMA 2000-A88 is a partial revis
18、ion of AGMA 390.03, but does notcover wormgearing. AGMA 390.03a of 1988 still only covered fine pitch wormgearing.ANSI/AGMA 2111-A98 then is a replacement for AGMA 390.03a for fine pitchwormgearing. In addition, it also covers coarse pitch wormgearing.The Cylindrical Wormgearing Committee began work
19、ing on this standard in August, 1993.At that time, it was determined the International Standards Organizations (ISO) method fortolerance grades would be used in this standard.ANSI/AGMA 2111-A98 was approved by the AGMA membership in June, 1998 andapproved as an American National standard on October
20、1, 1998.Suggestions for improvement of this standard will be welcome. They should be sent to theAmerican Gear Manufacturers Association, 1500 King Street, Suite 201, Alexandria,Virginia 22314.ANSI/AGMA 2111-A98AMERICAN NATIONAL STANDARDvPERSONNEL of the AGMA Cylindrical Wormgearing CommitteeChairman
21、: J.R. DeMarais Bison Gear thislevel of accuracy was established during themanufacturing process and is totally independent ofany final inspection.Process control includes elements such asmanufacturing planning, maintenance of machinetools, cutting tool selection and maintenance, heattreatment contr
22、ol and quality assurance programs,as needed, to achieve and maintain the necessarygear accuracy. When properly applied, gearsmanufactured by specific control techniques will befound to have consistent accuracy. Therefore, care-ful manufacturing control at each step of the processshould eliminate the
23、 need for final inspection.However, based on appropriate confidence in theapplied process control, the manufacturer of thatgear must be able to certify that its tolerance grade isat least equal to that of the gears that wereinspected.NOTE: Documentation may be deemed unnecessaryfor products manufact
24、ured under process control wheninspection records are not specified in the purchasecontract.3.3 Inspection methodsGear geometry may be inspected by a number ofmethods as described in clause 4. The selection ofthe particular method depends on the magnitude ofthe tolerance, the size of the gear, the p
25、roductionquantities, equipment available, accuracy of gearblanks and inspection costs.When prior agreement between the manufacturerand purchaser specifies inspection of gears, themanufacturer may select:- the inspection method to be used from amongthe applicable methods described in thisstandard;- t
26、he piece of inspection equipment to be usedby the selected inspection method, provided it isproperly calibrated;- the number of teeth or threads to be mea-sured to assure conformance to the specifiedtolerance grade.3.4 Additional considerationsIn addition to tolerance grade for certain applica-tions
27、, other or special considerations may be re-quired. These may include items such as:- backlash allowances in tooth thickness;- materials furnished by the purchaser;- matching gears as sets;- reference gears for composite measurement;- replacement gearing;- contact pattern.The listed items and other
28、special considerations areto be reviewed and agreed upon by the manufacturerand purchaser.3.4.1 Backlash allowanceAn individual gear does not have backlash. Back-lash is only present when one gear mates withanother. The theoretical backlash of a gear set isbased on the tooth thickness of each member
29、 inmesh, as well as the mounting distance at which thegears are assembled. The actual backlash will alsobe a function of the tolerances on tooth thickness,runout, lead, profile and mounting distance.The methods of determining the backlash requiredfor individual applications are beyond the scope ofth
30、is standard (for additional information see ANSI/AGMA 6022-C93, Design Manual for CylindricalWormgearing).3.4.2 Material furnished by the purchaserGear blanks supplied by the purchaser shall meetthe specifications mutually agreed upon betweenmanufacturer and purchaser to permit the gearmanufacturer
31、to hold the tolerances for the specifiedtolerance grade.3.4.3 Matching gears as setsMatched sets are required in some applications andcan be provided, but usually at extra cost. In suchcases, the purchaser must agree on the details of theadditional specifications concerning how the match-ing is to b
32、e performed and verified. Applicationsrequiring high accuracy gearing may necessitate thematching or modifying of worm and gear profilessuch that the matched set is satisfactory for theapplication.NOTE: This standard provides tolerances for unas-sembled gears only. The inspection of gearing mated in
33、an assembly for a specific application is beyond thescope of this standard. However, for high accuracygearing, the matching process can be fully satisfactoryeven when individual element tolerances areexceeded. The matching process for such gears soldas pairs assumes greater importance than the indiv
34、id-ual absolute measurements.ANSI/AGMA 2111-A98AMERICAN NATIONAL STANDARD73.4.4 Reference gears for compositemeasurementWhen a composite check is specified, a referencegear becomes necessary. The design, accuracy,AGMA tolerance grade validation procedure andcost of a reference gear shall be negotiat
35、ed betweenthe manufacturer and purchaser. A specific refer-ence gear is required for each different productiongear design. The reference gear shall be availablewhen the manufactured gear is to be inspected bycomposite measurements.3.4.5 Contact patternContact pattern is beyond the scope of this stan
36、dard.For information on contact pattern, see ANSI/AGMA6022-C93.3.4.6 Replacement gearingFor replacement gearing, the performance obtainedfrom the previous gearing must be evaluated. Ifsatisfactory, replace with similar material andaccuracy. If improved performance is required,modifications of materi
37、al, heat treatment and toler-ance grade may be considered. Consult with themanufacturer for recommendations.3.5 Acceptance criteriaThe tolerances and definitions contained in thisstandard prevail unless contractual agreementsbetween the manufacturer and purchaser containspecific exceptions.3.6 Evalu
38、ation of tolerance gradeThe manufacturer or the purchaser may wish tomeasure one or more of the geometric features of agear to verify its accuracy. However, a gear which isspecified to an AGMA tolerance grade must meet allthe individual tolerance requirements applicable tothat tolerance grade.4 Meas
39、uring methods and practicesThis section describes the recommended methodsand practices used for the inspection of worms andwormgears. Practices and inspection methodswhich are recognized and accepted throughout thewormgear industry as being reliable are covered andshould provide accurate and repeata
40、ble measure-ments when correctly used. Experienced personnel,using calibrated instruments in a suitable environ-ment, are required. No particular method ofinspection or document is considered mandatoryunless agreed upon by the purchaser andmanufacturer.4.1 Worm thread radial runout, Vr1The worm thre
41、ad radial runout may be measured bypositioning the worm reference bearing diameterson precision V-Blocks on a flat inspection table asshown in figure 3. A shell worm is mounted on aprecision arbor. Using the reference bearing diame-ter or the arbor diameter at each end to establish thereference axis
42、 of the worm, the height of a pin thatcontacts only the thread flanks is measured. Theworm is rotated as many times as necessary until themaximum reading over the pin is obtained. Aminimum of four (4) readings at approximately 90ofrotation of the worm starting from the maximumreading is then recorde
43、d. The radial runout, Vr1,isthe difference between the high and low readings.These measurements should be done first near oneend of the thread and repeated near the other end ofthe thread to assure that the axis of the thread isparallel to the axis of the shaft bearings or arbor.Figure 3 - Worm thre
44、ad runout inspection, Vr1ANSI/AGMA 2111-A98 AMERICAN NATIONAL STANDARD84.1.1 Causes of worm thread radial runout, Vr1The principle cause of radial runout is eccentricitywhich, in turn, is caused by forming the threads fromshaft centers in one machine and turning, grinding,or boring the locating refe
45、rence diameters from shaftcenters in another machine. However, this measure-ment method may include the effects of the follow-ing:- thread thickness variations;- out-of-roundness of either the locating refer-ence diameters or the threads themselves;- thread profile variations;- variations of thread
46、pitch in multiple threadworms;- lead form variations in the threads.4.1.2 Alternative method of determining wormthread runout, Vr1Runout may be measured by indicating the wormroot diameter in a lead checking machine, but only ifthe finishing tool has machined this surface simulta-neously with the th
47、read flanks. This methodmeasures only the eccentricity component of runoutand will not measure the effects of thread thickness,profile or pitch variations.4.2 Worm pitch variation, Vp1This elemental measurement applies to multiplethread worms only.4.2.1 Worm pitch variation, Vp1- method A(recommende
48、d for 2 to 4 threaded worms only)In this test, the probe of the measuring device ispositioned in the plane containing the axis of theworm. The probe is then brought in contact with thefirst thread at the specified diameter so that it readszero on this thread. This establishes the referencethread. (S
49、ee figure 4.) The probe is then displacedin the axial direction by one axial pitch and thereading for the next thread is taken at the samespecified diameter. Measurements are taken paral-lel to the worm axis. The process continues until areading is taken for every thread. An additionalreading is then taken for the reference thread tomake sure it repeats. The maximum differencebetween adjacent thread readings is the maximumpitch variation, Vp1, and should be compared to thepitch variation tolerance, VpT1, values given in thequality equations
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