1、BRITISH STANDARD BS EN 22768-2:1993 ISO 2768-2: 1989 General tolerances Part 2: Geometrical tolerances for features without individual tolerance indications The European Standard EN 22768-2:1993 has the status of a British Standard UDC 621.713.14:744.4BSEN22768-2:1993 This British Standard, having b
2、een prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 July 1993 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference MTE/2
3、4 Draft for comment 87/78364 DC ISBN 0 580 21934 8 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 Oesterreichisches Normungsins
4、titut 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 Institute of Icela
5、nd 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 Espaola de Norma
6、lizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN22768-2:1993 BSI 03-1999 i Contents Page Cooperating organizations Inside fr
7、ont cover National foreword ii Foreword 2 Introduction 3 1 Scope 3 2 General 3 3 Normative references 3 4 Definitions 3 5 General geometrical tolerances 3 6 Indications on drawings 5 7 Rejection 5 Annex A (informative) Concepts behind general tolerancing of geometrical characteristics 6 Annex B (inf
8、ormative) Further information 7 Annex ZA (normative) Normative references to international publications with their relevant European publications 10 Figure B.1 Principle of independency: maximum permissible deviations on the same feature 7 Figure B.2 Examples of general tolerances on circularity 8 F
9、igure B.3 Parallelism deviation equal to the numerical value of the size tolerance 8 Figure B.4 Parallelism deviation equal to the numerical value of the straightness tolerance 8 Figure B.5 Examples of general tolerances on symmetry 8 Figure B.6 Example of general tolerances on a drawing 9 Table 1 G
10、eneral tolerances on straightness and flatness 4 Table 2 General tolerances on perpendicularity 4 Table 3 General tolerances on symmetry 4 Table 4 General tolerances on circular run-out 5 National annex NA (informative) Committees responsible Inside back coverBSEN22768-2:1993 ii BSI 03-1999 National
11、 foreword This British Standard has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee and is the English language version of EN22768-2:1993 General tolerances Part 2: Geometrical tolerances for features without individual tolerance indications, pub
12、lished by the European Committee for Standardization (CEN). It is identical withISO2768-2:1989 published by the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible
13、for their correct application. Compliance with a British Standard does 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, theEN title page, pages 2 to 10, an inside back cover and a back cover. This sta
14、ndard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 22768-2 April 1993 UDC 621.713.14:744.4 Descriptors: Machine components, geometrical toler
15、ances, machining tolerances, dimensional deviations, specifications English version General tolerances Part 2: Geometrical tolerances for features without individual tolerance indications (ISO 2768-2:1989) Tolrances gnrales Partie 2: Tolrances gomtriques pour lments non affects de tolrances individu
16、elles (ISO 2768-2:1989) Allgemeintoleranzen Teil 2: Toleranzen fr Form und Lage ohne einzelne Toleranzeintragung (ISO 2768-2:1989) 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 gi
17、ving this European 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 ver
18、sions (English, 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,
19、 Denmark, Finland, 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
20、 36, B-1050 Brussels 1993 Copyright reserved to CEN members Ref. No. EN 22768-2:1993 EEN22768-2:1993 2 BSI 03-1999 Foreword In 1991, the International Standard ISO 2768-2:1989 General tolerances Part 2: Geometrical tolerances for features without individual tolerance indications was submitted to the
21、 CEN Primary Questionnaire Procedure. Following the positive result of the CEN/CS proposal, ISO 2768-2:1989 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 tex
22、t or by endorsement, at the latest by October1993, and conflicting national standards shall be withdrawn at the latest by October1993. In accordance with the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, F
23、rance, Germany, 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).EN22768-2:1993 BSI 03-1999 3 Introduction All features on component part
24、s always have 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 comple
25、te to ensure 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
26、 Scope This part of ISO 2768 is intended to simplify drawing indications and specifies general geometrical tolerances to control those features on the drawing which have no respective individual indication. It specifies general geometrical tolerances in three tolerance classes. This part of ISO 2768
27、 mainly applies to features which are produced by removal of material. Its application to features manufactured by other processes is possible; however, special examination is required to ascertain whether the customary workshop accuracy lies within the general geometrical tolerances specified in th
28、is part ofISO2768. 2 General When selecting the tolerance class, the respective customary workshop accuracy has to be taken into consideration. If smaller geometrical tolerances are required or larger geometrical tolerances are permissible and more economical for any individual feature, such toleran
29、ces should be indicated directly in accordance with ISO 1101 (see clause A.2). General geometrical tolerances in accordance with this part of ISO 2768 apply when drawings or associated specifications refer to this part of ISO2768 in accordance with clause 6. They apply to features which do not have
30、respective individual geometrical tolerance indications. General geometrical tolerances apply to all geometrical tolerance characteristics, excluding cylindricity, profile of any line, profile of any surface, angularity, coaxiality, positional tolerances and total run-out. In any event, general geom
31、etrical tolerances in accordance with this part of ISO 2768 should be used when the fundamental tolerancing principle in accordance with ISO 8015 is used and indicated on the drawing (see clause B.1). 3 Normative references The following standards contain provisions which, through reference in this
32、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 t
33、he standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 1101:1983, Technical drawings Geometrical tolerancing Tolerancing of form, orientation, location and run-out Generalities, definitions, symbols, indications on drawings. ISO 2768-1
34、:1989, General tolerances Part 1: Tolerances for linear and angular dimensions without individual tolerance indications. ISO 5459:1981, Technical drawings Geometrical tolerancing Datums and datum-systems for geometrical tolerances. ISO 8015:1985, Technical drawings Fundamental tolerancing principle.
35、 4 Definitions For the purposes of this part of ISO2768, the definitions for geometrical tolerances given in ISO1101 and ISO5459 apply. 5 General geometrical tolerances (see also clause B.1) 5.1 Tolerances for single features 5.1.1 Straightness and flatness The general tolerances on straightness and
36、 flatness are given in Table 1. When a tolerance is selected from Table 1, it shall be based, in the case of straightness, on the length of the corresponding line and, in the case of flatness, on the longer lateral length of the surface, or the diameter of the circular surface.EN22768-2:1993 4 BSI 0
37、3-1999 Table 1 General tolerances on straightness and flatness 5.1.2 Circularity The general tolerance on circularity is equal to the numerical value of the diameter tolerance, but in no case shall it be greater than the respective tolerance value for circular radial run-out given in Table 4 (seeexa
38、mples in clause B.2). 5.1.3 Cylindricity General tolerances on cylindricity are not specified. NOTE 1The cylindricity deviation comprises three components: circularity deviation, straightness deviation and parallelism deviation of opposite generator lines. Each of these components is controlled by i
39、ts individually indicated or its general tolerance. NOTE 2If, for functional reasons, the cylindricity deviation has to be smaller than the combined effect (see clause B.3) of the general tolerances on circularity, straightness and parallelism, an individual cylindricity tolerance in accordance with
40、 ISO 1101 should be indicated for the feature concerned. Sometimes, e.g. in the case of a fit, the indication of the envelope requirementis appropriate. 5.2 Tolerances for related features 5.2.1 General The tolerances specified in 5.2.2 to 5.2.6 apply to all features which are in relation to one ano
41、ther and which have no respective individual indication. 5.2.2 Parallelism The general tolerance on parallelism is equal to the numerical value of the size tolerance or the flatness/straightness tolerance, whichever is the greater. The longer of the two features shall be taken as the datum; if the f
42、eatures are of equal nominal length, either may be taken as the datum (see clause B.4). 5.2.3 Perpendicularity The general tolerances on perpendicularity are given in Table 2. The longer of the two sides forming the right angle shall be taken as the datum; if the sides are of equal nominal length, e
43、ither may be taken as the datum. Table 2 General tolerances on perpendicularity 5.2.4 Symmetry The general tolerances on symmetry are given inTable 3. The longer of the two features shall be taken as the datum; if the features are of equal nominal length, either may be taken as the datum. NOTEThe ge
44、neral tolerances on symmetry apply where at least one of the two features has a median plane, or the axes of the two features are perpendicular to each other. See examples in clauseB.5. Table 3 General tolerances on symmetry 5.2.5 Coaxiality General tolerances on coaxiality are not specified. NOTETh
45、e deviation in coaxiality may, in an extreme case, be as great as the tolerance value for circular radial run-out given inTable 4, since the deviation in radial run-out comprises the deviation in coaxiality and the deviation in circularity. 5.2.6 Circular run-out The general tolerances on circular r
46、un-out (radial, axial and any surface of revolution) are given inTable 4. For general tolerances on circular run-out, the bearing surfaces shall be taken as the datum if they are designated as such. Otherwise, for circular radial run-out, the longer of the two features shall be taken as the datum; i
47、f the features are of equal nominal length, either may be taken as the datum. Values in millimetres Tolerance class Straightness and flatness tolerances for ranges of nominal lengths up to 10 over 10 up to 30 over 30 up to 100 over 100 up to 300 over 300 up to 1 000 over 1 000 up to 3 000 H 0,02 0,0
48、5 0,1 0,2 0,3 0,4 K 0,05 0,1 0,2 0,4 0,6 0,8 L 0,1 0,2 0,4 0,8 1,2 1,6 Values in millimetres Tolerance class Perpendicularity tolerances for ranges of nominal lengths of the shorter side up to 100 over 100 up to 300 over 300 up to 1 000 over 1 000 up to 3 000 H 0,2 0,3 0,4 0,5 K 0,4 0,6 0,8 1 L 0,6
49、1 1,5 2 Values in millimetres Tolerance class Symmetry tolerances for ranges of nominal lengths up to 100 over 100 up to 300 over 300 up to 1 000 over 1 000 up to 3 000 H 0,5 K 0,6 0,8 1 L 0,6 1 1,5 2EN22768-2:1993 BSI 03-1999 5 Table 4 General tolerances on circular run-out 6 Indications on drawings 6.1 If general tolerances in accordance with this part of ISO 2768 shall apply in conjunction with the general tolerances in accordance with ISO 2768-1, the following information shall be indicated in
