1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 21.100.10 ISBN 0-626-15703-X SANS 3548:2005Edition 1ISO 3548:1999Edition 2SOUTH AFRICAN NATIONAL STANDARD Plain bearings Thin-walled half bearings wi
4、th or without flange Tolerances, design features and methods of test This national standard is the identical implementation of ISO 3548:1999 and is adopted with the permission of the International Organization for Standardization. Published by Standards South Africa 1 dr lategan road groenkloof priv
5、ate bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 3548:2005 Edition 1 ISO 3548:1999 Edition 2 Table of changes Change No. Date Scope Abstract Specifies tolerances, design features and test methods for thin-walled ha
6、lf bearings with integral flange up to an outside diameter of D0 of 250 mm and without flange up to an outside diameter of D0of 500 mm. Keywords bearings, bushings, dimensional tolerances, dimensions, measurements, plain bearings, tolerances (measurement). National foreword This South African standa
7、rd was approved by National Committee StanSA TC 5120.02, Bearings, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. AReference numberISO 3548:1999(E)INTERNATIONALSTANDARDISO3548Second edition1999-12-01Plain bearings Thin-walled half bearin
8、gswith or without flange Tolerances, designfeatures and methods of testPaliers lisses Demi-coussinets minces ou sans collerette Tolrances, caractristiques de conception et mthodes dessaiISO 3548:1999(E) ISO 1999All rights reserved. Unless otherwise specified, no part of this publication may be repro
9、duced or utilized in any form or by any means, electronicor mechanical, including photocopying and microfilm, without permission in writing from the publisher.International Organization for StandardizationCase postale 56 CH-1211 Genve 20 SwitzerlandInternet isoiso.chPrinted in SwitzerlandiiForewordI
10、SO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISOmember bodies). The work of preparing International Standards is normally carried out through ISO technicalcommittees. Each member body interested in a subject for which a technical com
11、mittee has been established hasthe right to be represented on that committee. International organizations, governmental and non-governmental, inliaison with ISO, also take part in the work. ISO collaborates closely with the International ElectrotechnicalCommission (IEC) on all matters of electrotech
12、nical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.Publication as an International Standard requires approval b
13、y at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this International Standard may be the subject ofpatent rights. ISO shall not be held responsible for identifying any or all such patent rights.International Standard ISO 3548 was p
14、repared by Technical Committee ISO/TC 123 Plain bearings, SubcommitteeSC 3 Dimensions, tolerances and construction details.This second edition cancels and replaces the first edition (ISO 3548:1978) and also ISO 6864:1984 the technicalcontent of which is now incorporated in this International Standar
15、d.Annex A forms a normative part of this International Standard.INTERNATIONAL STANDARD ISO ISO 3548:1999(E)1Plain bearings Thin-walled half bearings with or withoutflange Tolerances, design features and methods of test1 ScopeThis International Standard specifies tolerances, design features and test
16、methods for thin-walled half bearings withintegral flange up to an outside diameter of Doof 250 mm and without flange up to an outside diameter of Doof500 mm. Due to the variety of design it is, however, not possible to standardize the dimensions of the half bearings.Half bearings according to this
17、International Standard are predominantly used in reciprocating machinery andconsist of a steel backing and one or more bearing metal layers on the inside.In reciprocating machinery, flanged half bearings may be used in connection with half bearings without flange.Alternatively to serve as a flanged
18、half bearing, it is possible to use a half bearing without flange together with twoseparate half thrust washers in accordance with ISO 6526; or a half bearing with assembled flanges.NOTE All dimensions and tolerances are given in millimetres.2 Normative referencesThe following normative documents co
19、ntain provisions which, through reference in this text, constitute provisions ofthis International Standard. For dated references, subsequent amendments to, or revisions of, any of thesepublications do not apply. However, parties to agreements based on this International Standard are encouraged toin
20、vestigate the possibility of applying the most recent editions of the normative documents indicated below. Forundated references, the latest edition of the normative document referred to applies. Members of ISO and IECmaintain registers of currently valid International Standards.ISO 4288, Geometrica
21、l Product Specifications (GPS) Surface texture: Profile method Rules and proceduresfor the assessment of surface texture.ISO 6524, Plain bearings Thin-walled half bearings Checking of peripheral length.ISO 6526, Plain bearings Pressed bimetallic half thrust washers Features and tolerances.ISO 3548:1
22、999(E) ISO23 SymbolsSee Figures 1 and 2 and Table 1.Key1 Joint face 4 Bearing back2 Sliding surface 5 Steel back3 Bearing metalFigure 1 Half bearing without flange(with positive free spread)Figure 2 Flange half bearing(integral or assembled, excluding free spread) ISOISO 3548:1999(E)3Table 1 Symbols
23、 and unitsSymbol Term Unita1Measuring point perpendicular to plane of joint face mmAcalReduced area of cross section (calculated value) of half bearingmm2bHHousing width mmB1Half bearing width (without flange) mmB2Flange half bearing width mmB3Distance between flanges mmC1Outside chamfer mmC2Inside
24、chamferdChDiameter of the checking block bore mmdHHousing diameter mmDflOutside diameter of flange mmDiNominal inside diameter of the half bearing (bearing bore) mmDoNominal outside diameter of the half bearing mmDo,EOutside diameter of the half bearing in the free state (with free spread) mmeBAmoun
25、t of eccentricity mmF Test force NFaxAxial test force for assembled flange bearings Nh Nip (crush, overstand), h = h1+ h2(in checking method B) mmp Amount of free spread mmsflFlange thickness mms1Thickness of the steel backing mms2Bearing metal thickness mms3Half bearing wall thickness mms4Wall thic
26、kness at base of groove mmu Amount of wall thickness reduction for eccentric bearing mm4 Dimensions and tolerances4.1 Housing diameter, half bearing outside diameter and nipThe housing diameter shall be manufactured to tolerance class H6. Thereby the half bearing outside diameter shallbe selected wi
27、th such an oversize that an adequate interference fit is ensured in the housing diameter.In the case of housings made from materials having a high coefficient of expansion or where other factors such ashousing dimensional stability are involved, the housing size may depart from tolerance class H6 bu
28、t shall always beproduced in accordance with a grade 6 tolerance.The half bearing in a free state is flexible so that its outside diameter cannot be measured directly. Instead of this,its peripheral length is determined by means of special checking fixtures. The peripheral length results from theper
29、iphery of the checking block bore and the nip taking into account the reduction under a given checking load perjoint face (see clause 6). For the calculation of the effective interference fit of the half bearings in the housing,see 5.The tolerances given in Table 2 for the nip, apply to half bearing
30、s with machined joint faces. Different materials andhousing design require different interference fits, therefore tolerances only are given in Table 2.ISO 3548:1999(E) ISO44.2 Half bearing wall thickness and bearing boreNominal dimensions to be preferred for the wall thickness of the bearing are giv
31、en in Table 2. Particulars of the wallthickness for each application cannot be specified in general, therefore only tolerances can be given for the wallthickness. These tolerances and the surface roughnesses of the bearing back and the sliding surface of halfbearings with or without electroplated an
32、tifriction layers are given in Table 2.The tolerance for the half bearing wall thickness depends on whether the bearing bore is subject to a finalmachining operation (i.e. “as-machined“) or whether the bearing bore is electroplated without further machining (i.e.“as-plated“).Slight surface deformati
33、ons are acceptable on the outside diameter of the bearing provided that they are notnumerous. However, the measurement of the wall thickness shall not be carried out in these areas.The bearing bore in the fitted state results from the housing bore which is elastically enlarged by the press fit,reduc
34、ed by twice the value of the half bearing wall thickness (see 5).NOTE In certain applications it may be necessary to use plain or flange half bearings with eccentric bores, i.e. the wallthickness of the half bearing decreases uniformly from the crown to the joint faces (see Figures 3 and 4).The ecce
35、ntricity eBis characterized in a radial plane by the distance between the centre x1of the bearing outside surface andthe centre x2of the bearing bore. eBis not dimensioned specifically. The eccentricity is controlled by the specified reduction uwhich is measured at a vertical distance a1from the pla
36、ne of the joint face. (For guidance of draughtsmen a1is generallyspecified so that the angle a2is approximately 25 from the joint face.) It is subject to agreement between user andmanufacturer.Key1 Crown2 Joint faceFigure 3 Eccentric bearing bore of halfbearingFigure 4 Example of the wall thicknessa
37、t different anglesThe tolerance limit for the behaviour of wall thickness can be calculated according to the following approximateformula:ssuaaa, ,BL actBLsinsin=-3211ssuaaa, ,UL actULsinsin=-3211 ISOISO 3548:1999(E)5whereBLuis thebottom Limit of u;ULu is theupper Limit of u;s3,actis theactual value
38、 of s3;sa,BLis the bottom value of sa;sa,UL is the upper value of sa.An example of calculation is given in annex A.4.3 Width of half bearing, distance between flanges, outside diameter of flange and flangethicknessThe nominal dimension for the half bearing width and the distance between flanges depe
39、nds upon the type ofapplication, the common ratio being B1(B2)/Di1,5 3 s3, but not less than 3 mmaIf b3is less than 2 mm, this area is permitted to be free ofbearing metal over a circumferential length a2to avoid thebreaking of bearing metal when the bearing bore ismachined. The locating nick may al
40、so break into the oilgroove.bThe nick may also be produced at the end of the halfbearing; in this case is b1 = 0.b1 1,5 3 s3, but not less than 3 mmaIf b3is less than 2 mm, this area is permitted to be free ofbearing metal over a circumferential length a2to avoid thebreaking of bearing metal when th
41、e bearing bore ismachined. The locating nick may also break into the oilgroove.Figure 5 Locating nick in a half bearingwithout flangeFigure 6 Locating nick in a flanged half bearingb4()BBb1212-aaSee Figure 4 or Figure 5.Figure 7 Nick recess in the housingISO 3548:1999(E) ISO85.2 Reliefs and chamfers
42、Joint face bore reliefs are normally provided at both sides of the half bearing (with or without flange) on the wholewidth. For guidance it is suggested that the dimension a6be approximatively 1/10 of the inside diameter Di, but theactual value of this dimension will be dependent on the application
43、and is subject to agreement between user andmanufacturer (see Figure 8).Chamfers are provided at both ends of a half bearing without flange (see Figure 9).Flange reliefs are provided at all joint faces (see Figure 10, section A-A) as well as at the edges of the flange slidingsurfaces (see Figure 10,
44、 detail X).For dimensions and limit deviations see Table 3.a6 Di10Figure 8 Bearing bore relief Figure 9 Chamfers ISOISO 3548:1999(E)9a) Joint face relief b) Sliding surface relief for flange bearing.Sliding surface relief for assembled flange bearing to bein accordance with ISO 6526.Figure 10 Flange
45、 reliefs(design at the option of the manufacturer)5.3 Transition between radial part and flangeFigure 11 shows typical examples of the transition region, the actual form used being dependent upon themanufacturing method and the ratio between wall thickness and flange thickness.The transition between
46、 the radial part and flange shall comply with dimension a9in order to avoid cracking.The transition geometry shall be adapted to the form of the shaft in order to avoid fouling of the fillet radius and ofthe housing inside diameter.Figure 12 shows an example of the transition region between half bea
47、ring and the flange of an assembled flangebearing.For assembled flange bearings the prefered dimensions of transition to maximise material for flange attachment areindicated in Figure 12.ISO 3548:1999(E) ISO10Figure 11 Types of transition betweenradial parts of the flanges5 No less than 66 % of half
48、 bearing wall thicknesss6 No less than 50 % of flange thickness but , s4;corner profile should always overlap flange and halfbearing thickness as follows:a10= 0,5 mm min.b5 = 0,25 mm min.Oil groove depth must be clear of half bearing maximumprofile.Key1 FlangeFigure 12 Type of transition between hal
49、f bearing and flange of a assembled flange bearing ISOISO 3548:1999(E)11Table 3 Minimum height (and width) oftransition and relief of the flangesHousingdiameterdHa7a8a9i2i3.0,7 mm. NOTE For tolerance x, see Table 4.Figure 14 Types of oil grooves Figure 15 Position of the oil groove and oil holeFigure 16 Groove form on the flange face ISOISO 3548:1999(E)13NOTE Pocket may be closed or open to the outer flange diameter.Figure 17 Pocket form on the flange faceISO 3548:1999(E) ISO14Table 4
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