1、BRITISH STANDARD BS EN 22768-1:1993 ISO 2768-1: 1989 General tolerances Part 1: Tolerances for linear and angular dimensions without individual tolerance indications The European Standard EN 22768-1:1993 has the status of a British Standard UDC621.713.12:744.4BSEN22768-1:1993 This British Standard,
2、having been prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee, was published under the authority of the StandardsBoard and comes into effect on 15 November 1993 BSI 12-1998 The following BSI references relate to the work on this standard: Committee refe
3、rence MTE 24 Announced in BSI News, October 1993 ISBN 0 580 22604 2 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichi
4、sches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological I
5、nstitute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin
6、 Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBS EN22768-1:1993 BSI 12-1998 i Contents Page Cooperating organ
7、izations Inside front cover National foreword ii Foreword 2 Introduction 3 1 Scope 3 2 General 3 3 Normative references 3 4 General tolerances 3 5 Indications on drawings 4 6 Rejection 4 Annex A (informative) Concepts behind general tolerancing of linear and angular dimensions 5 Annex ZA (normative)
8、 Normative references to international publications with their relevant European publications 6 Table 1 Permissible deviations for linear dimensions except for broken edges 4 Table 2 Permissible deviations for broken edges 4 Table 3 Permissible deviations of angular dimensions 4 National annex NA (i
9、nformative) Committees responsible Inside back cover National annex NB (informative) Cross-reference Inside back coverBSEN22768-1:1993 ii BSI 12-1998 National foreword This British Standard has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee and
10、is the English language version of EN 22768-1:1993 General tolerances Part 1: Tolerances for linear and angular dimensions without individual tolerance indications, published by the European Committee for Standardization (CEN). It is identical with ISO 2768-1:1989 published by the International Orga
11、nization for Standardization (ISO). This standard supersedes BS 4500-3:1973, which is withdrawn. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard doe
12、s not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendmen
13、ts incorporated. This will be indicated in the amendment table on theinside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 22768-1 April 1993 UDC 621.713.12:744.4 Descriptors: Machine components, dimensional tolerances, angular tolerances, untoleranced dimensions, dimensional devia
14、tions, specifications English version General tolerances Part 1: Tolerances for linear and angular dimensions without individual tolerance indications (ISO 2768-1:1989) Tolrances gnrales Partie 1: Tolrances pour dimensions linaires et angulaires non affectes de tolrances individuelles (ISO 2768-1:19
15、89) Allegemeintoleranzen Teil 1: Toleranzen fr Lngen- und Winkelmae ohne einzelne Toleranzeintragung (ISO 2768-1:1989) This European Standard was approved by CEN on 1993-04-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Eu
16、ropean Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (Engli
17、sh, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Fi
18、nland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050
19、Brussels 1993 Copyright reserved to CEN members Ref. No. EN 22768-1:1993 EEN22768-1:1993 BSI 12-1998 2 Foreword In1991, the International Standard ISO2768-1:1989 General tolerances Part1:Tolerances for linear and angular dimensions without individual tolerance indications was submitted to the CEN Pr
20、imary Questionnaire procedure. Following the positive result of the CEN/CS Proposal, ISO2768-1:1989 was submitted to the Formal Vote. The result of the Formal Vote was positive. This European Standard shall be given the status of a national standard, either by publication of an identical text or by
21、endorsement, at the latest by October1993, and conflicting national standards shall be withdrawn at the latest by October1993. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany
22、, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. NOTEThe European references to international publications are given in annex ZA (normative).EN 22768-1:1993 BSI 12-1998 3 Introduction All features on component parts always have
23、 a size and a geometrical shape. For the deviation of size and for the deviations of the geometrical characteristics (form, orientation and location) the function of the part requires limitations which, when exceeded, impair this function. The tolerancing on the drawing should be complete to ensure
24、that the elements of size and geometry of all features are controlled, i.e. nothing shall be implied or left to judgement in the workshop or in the inspection department. The use of general tolerances for size and geometry simplifies the task of ensuring that this prerequisite is met. 1 Scope This p
25、art of ISO 2768 is intended to simplify drawing indications and it specifies general tolerances for linear and angular dimensions without individual tolerance indications in four tolerance classes. NOTE 1The concepts behind the general tolerancing of linear and angular dimensions are described in an
26、nex A. It applies to the dimensions of parts that are produced by metal removal or parts that are formed from sheet metal. NOTE 2These tolerances may be suitable for use with materials other than metal. NOTE 3Parallel International Standards exist or are planned, e.g. see ISO 8062 1)for castings. Th
27、is part of ISO2768 only applies for the following dimensions which do not have an individual tolerance indication: a) linear dimensions (e.g. external sizes, internal sizes, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges); b) angular dimensions, includin
28、g angular dimensions usually not indicated, e.g. right angles (90), unless reference to ISO 2768-2 is made, or angles of uniform polygons; c) linear and angular dimensions produced by machining assembled parts. It does not apply for the following dimensions: a) linear and angular dimensions which ar
29、e covered by reference to other standards on general tolerances; b) auxiliary dimensions indicated in brackets; c) theoretically exact dimensions indicated in rectangular frames. 2 General When selecting the tolerance class, the respective customary workshop accuracy has to be taken into considerati
30、on. If smaller tolerances are required or larger tolerances are permissible and more economical for any individual feature, such tolerances should be indicated adjacent to the relevant nominal dimension(s). General tolerances for linear and angular dimensions apply when drawings or associated specif
31、ications refer to this part of ISO 2768 in accordance with clauses 4 and 5. If there are general tolerances for other processes, as specified in other International Standards, reference shall be made to them on the drawings or associated specifications. For a dimension between an unfinished and a fi
32、nished surface, e.g. of cast or forged parts, for which no individual tolerance is directly indicated, the larger of the two general tolerances in question applies, e.g. for castings, see ISO 8062 1) . 3 Normative references The following standards contain provisions which, through reference in this
33、 text, constitute provisions of this part of ISO 2768. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 2768 are encouraged to investigate the possibility of applying the most recent editions of
34、the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 2768-2:1989, General tolerances Part2:Geometrical tolerances for features without individual tolerance indications. ISO8015:1985, Technical drawings Fundamental tolerancing princi
35、ple. 4 General tolerances 4.1 Linear dimensions General tolerances for linear dimensions are given in Table 1 and Table2. 4.2 Angular dimensions General tolerances specified in angular units control only the general orientation of lines or line elements of surfaces, but not their form deviations. Th
36、e general orientation of the line derived from the actual surface is the orientation of the contacting line of ideal geometrical form. The maximum distance between the contacting line and the actual line shall be the least possible value (see ISO 8015). 1) ISO 8062:1984, Castings System of dimension
37、al tolerances.EN22768-1:1993 4 BSI 12-1998 The permissible deviations of angular dimensions are given in Table3. 5 Indications on drawings If general tolerances in accordance with this part of ISO2768 shall apply, the following information shall be indicated in or near the title block: a) “ISO 2768”
38、 b) the tolerance class in accordance with this part of ISO 2768. EXAMPLE ISO 2768-m 6 Rejection Unless otherwise stated, workpieces exceeding the general tolerance shall not lead to automatic rejection provided that the ability of the workpiece to function is not impaired (see clause A.4). Table 1
39、Permissible deviations for linear dimensions except for broken edges (external radii and chamfer heights, see Table2) Table2 Permissible deviations for broken edges (external radii and chamfer heights) Table3 Permissible deviations of angular dimensions Values in millimetres Tolerance class Permissi
40、ble deviations for basic size range Designation Description 0,5 aup to 3 over 3 up to 6 over 6 up to 30 over 30 up to 120 over 120 up to 400 over 400 up to 1000 over 1000 up to 2000 over 2000 up to 4000 f fine 0,05 0,05 0,1 0,15 0,2 0,3 0,5 m medium 0,1 0,1 0,2 0,3 0,5 0,8 1,2 2 c coarse 0,2 0,3 0,5
41、 0,8 1,2 2 3 4 v very coarse 0,5 1 1,5 2,5 4 6 8 a For nominal sizes below0,5mm, the deviations shall be indicated adjacent to the relevant nominal size(s). Values in millimetres Tolerance class Permissible deviations for basic size range Designation Description 0,5 aup to3 over3 up to6 over6 f fine
42、 0,2 0,5 1 m medium c coarse 0,4 1 2 v very coarse a For nominal sizes below0,5mm, the deviations shall be indicated adjacent to the relevant nominal size(s). Tolerance class Permissible deviations for ranges of lengths, in millimetres, of the shorter side of the angle concerned Designation Descript
43、ion up to10 over10 up to50 over50 up to120 over120 up to400 over400 f fine 1 030 020 010 05 m medium c coarse 130 1 030 015 010 v very coarse 3 2 1 030 020EN 22768-1:1993 BSI 12-1998 5 Annex A (informative) Concepts behind general tolerancing of linear and angular dimensions A.1 General tolerances s
44、hould be indicated on the drawing by reference to this part of ISO2768 in accordance with clause5. The values of general tolerances correspond to tolerance classes of customary workshop accuracy, the appropriate tolerance class being selected and indicated on the drawing according to the requirement
45、 for the components. A.2 Above certain tolerance values, there is usually no gain in manufacturing economy by enlarging the tolerance. For example, a feature having a35mm diameter could be manufactured to a high level of conformance in a workshop with “customary medium accuracy” Specifying a toleran
46、ce of 1mm would be of no benefit in this particular workshop, as the general tolerance values of 0,3mm would be quite adequate. However, if, for functional reasons, a feature requires a smaller tolerance value than the “general tolerances”, then that feature should have the smaller tolerance indicat
47、ed individually adjacent to the dimension defining its size or angle. This type of tolerance falls outside the scope of general tolerances. In cases where the function of a feature allows a tolerance equal to or larger than the general tolerance values, these should not be indicated adjacent to the
48、dimension but should be stated on the drawing as described in clause5. This type of tolerance allows full use of the concept of general tolerancing. There will be “exceptions to the rule” where the function of the feature allows a larger tolerance than the general tolerances, and the larger toleranc
49、e will provide manufacturing economy. In these special cases, the larger tolerance should be indicated individually adjacent to the dimension for the particular feature, e.g. the depth of blind holes drilled at assembly. A.3 Using general tolerances leads to the following advantages: a) drawings are easier to read and thus communication is made more effective to the user of the drawing; b) th
