1、BRITISH STANDARD BS 4823:1972 Guide to The selection of fitment bores for cylindrical shaft endsBS4823:1972 This British Standard, having been approved by the MechanicalEngineering IndustryStandards Committee,was published underthe authority of the Executive Board on 31 July 1972 BSI 12-1999 The fol
2、lowing BSI references relate to the work on this standard: Committee reference MEE/-/12 Draft for comment 71/30962 ISBN 0580 07135 9 Co-operating organizations The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representat
3、ives from the following Government departments and scientific and industrial organizations: The industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Associa
4、tion of British Correspondence Colleges Associated Offices Technical Committee Engineering Equipment Users Association* Association of Consulting Engineers Gas Council Association of Hydraulic Equipment Institution of Civil Engineers Manufacturers Ltd. Institution of Gas Engineers Association of Min
5、ing, Electrical and Institution of Heating and Ventilating Mechanical Engineers Engineers British Compressed Air Society Institution of Mechanical Engineers British Electrical and Allied Manufacturers Institution of Mechanical Engineers Association (Automobile Division) British Gear Manufacturers As
6、sociation* Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers Manufacturers Association Locomotive and Allied Manufacturers British Mechanical Engineering Confederation Association of Great Britain British Pump Manufacturers Association* London Tran
7、sport Executive British Steel Industry Machine Tool Trades Association Crown Agents for Oversea Governments and Ministry of Defence Administrations Ministry of Defence, Army Department Department of Employment (H.M. Factory National Coal Board Inspectorate) National Physical Laboratory (Department o
8、f Department of the Environment Trade and Industry) Department of Trade and Industry Process Plant Association Department of Trade and Industry National Royal Institute of British Architects Engineering Laboratory Telecommunication Engineering and Electricity Council, the Central Electricity Manufac
9、turing Association Generating Board and the Area Boards in Water-tube Boilermakers Association England and Wales Amendments issued since publication Amd. No. Date CommentsBS4823:1972 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Classes of nominal
10、fit 1 3 Tolerances 1 Table 1 Fitment bores for cylindrical shaft ends 2BS4823:1972 ii BSI 12-1999 Foreword This standard makes reference to the following British Standards: BS 4235, Metric keys and keyways Part 1: Parallel and taper keys. BS 4500, ISO limits and fits. BS 4506, Shaft ends. Since the
11、introduction of BS4506, “Shaft ends”, based on the corresponding ISO Recommendation ISO/R775 1) , a need has become apparent for guidance on tolerances for the bores of shaft fitments, e.g.couplings and pulleys. For cylindrical shaft ends in the range of sizes commonly encountered, this guidance is
12、given in this British Standard. Although the “hole” basis has been adopted for the ISO system of limits and fits, it is clearly unrealistic to obtain different fits by varying the diameter of the shaft as this usually forms part of the larger item, e.g.an electric motor as compared with a coupling,
13、and is, in any case, generally made first without reference to the details of the fitment. Whilst the standard shafts in BS4506 have, therefore, been selected on a “hole” basis, variations in fit should be obtained by varying the tolerance on the bore of the fitment. A British Standard does not purp
14、ort to include all the necessary provisions of a contract. Users of British Standards are responsible 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 c
15、over, pages i and ii, pages1 to 3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) ISO/R 775, “Cylindrical and 1/10 conical shaft ends”.BS4823:1972 BSI 12-1999 1
16、 1 Scope This British Standard offers guidance in the selection of a suitable shaft fitment bore tolerance for use with the cylindrical standard metric shaft ends of6mm to220mm diameter specified in BS4506. Three classes of nominal fit, viz. interference, close, and free, are considered. Heavy inter
17、ference, or “shrink”, fits where the design torque is transmitted by interfacial friction are not considered as these require detailed individual study. NOTEThe titles of the British Standards referred to in this standard are listed on page ii. 2 Classes of nominal fit The choice of nominal fit in a
18、ny particular case is the designers responsibility and must take due account of the many factors involved including: the transmitted torque (including the magnitude and frequency of any peaks); the type of keying or other means of securing the fitment to the shaft; the need for removal of the fitmen
19、t (e.g.for bearing replacement); the desired standard of reliability. Provision is made in Table 1 for three classes of nominal fit: 1) Interference. Used when it would rarely be necessary to remove the fitment; when service conditions would be likely to be onerous; when the highest standard of reli
20、ability is required. 2) Close. Used when it would be necessary to be able to remove the fitment, e.g.to change a rolling bearing, relatively easily; when service conditions are relatively undemanding, e.g.with infrequent torque variations; when assembly costs must be restricted. 3) Free. Used when t
21、he maximum ease of assembly and dismantling is required; when the engaged length of the bore is great relative to the bore diameter, e.g.belt pulleys; when experience has shown that such a relatively cheaply obtained fit is suitable for the service conditions. Where it is necessary to use a “close”
22、fit, e.g.in order to facilitate the inspection and removal of a rolling bearing, under conditions of torque which would normally suggest an interference fit, it is recommended that a taper key (BS4235-1) be used with the close fit. (It should, however, be noted that the tolerances on keyway widths a
23、re not the same for rectangular and taper keying.) 3 Tolerances Table 1 shows the recommended bore tolerances to give the three classes of nominal fit and also the limits of the fit which will be obtained. The values of the bore tolerances are taken from BS4500. The nominal shaft end diameters and t
24、olerances are from those in BS4506.BS 4823:1972 2 BSI 12-1999 Table 1 Fitment bores for cylindrical shaft ends Limits are given in units of 0.001 mm. Nominal shaft end diameter Shaft end tolerance Bore tolerance to give Limits of resulting fit b Interference fit Close fit Free fit Interference Close
25、 Free Designation Limits Designation Limits Designation Limits Designation Limits mm 6 7 8 9 10 11 12 14 16 18 j6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 8 2 2 2 2 2 3 3 3 3 3 See Note See Note H7 + 12 + 15 + 15 + 15 + 15 + 18 + 18 + 18 + 18 + 18 0 0 0 0 0 0 0 0 0 0 G7 + 16 + 20 + 20 + 20 + 20 + 24 +
26、24 + 24 + 24 + 24 + 4 + 5 + 5 + 5 + 5 + 6 + 6 + 6 + 6 + 6 See Note + 14 + 17 + 17 + 17 + 17 + 21 + 21 + 21 + 21 + 21 6 7 7 7 7 8 8 8 8 8 + 18 + 22 + 22 + 22 + 22 + 27 + 27 + 27 + 27 + 27 2 2 2 2 2 2 2 2 2 2 19 20 22 24 25 28 30 + 9 + 9 + 9 + 9 + 9 + 9 + 9 4 4 4 4 4 4 4 M7 0 0 0 0 0 0 0 21 21 21 21 2
27、1 21 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 0 0 0 0 0 0 0 + 28 + 28 + 28 + 28 + 28 + 28 + 28 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 4 + 4 + 4 + 4 + 4 + 4 + 4 30 30 30 30 30 30 30 + 25 + 25 + 25 + 25 + 25 + 25 + 25 9 9 9 9 9 9 9 + 32 + 32 + 32 + 32 + 32 + 32 + 32 2 2 2 2 2 2 2 32 35 38 40 k6 + 18 + 18 + 18 + 1
28、8 + 2 + 2 + 2 + 2 0 0 0 0 25 25 25 25 + 25 + 25 + 25 + 25 0 0 0 0 + 34 + 34 + 34 + 34 + 9 + 9 + 9 + 9 2 2 2 2 43 43 43 43 + 23 + 23 + 23 + 23 18 18 18 18 + 32 + 32 + 32 + 32 9 9 9 9 42 45 48 50 + 18 + 18 + 18 + 18 + 2 + 2 + 2 + 2 N7 8 8 8 8 33 33 33 33 + 25 + 25 + 25 + 25 0 0 0 0 + 34 + 34 + 34 + 34
29、 + 9 + 9 + 9 + 9 10 10 10 10 51 51 51 51 + 23 + 23 + 23 + 23 18 18 18 18 + 32 + 32 + 32 + 32 9 9 9 9 NOTEAn interference fit is not recommended for use with shaft sizes below 19 mm. a Interference is indicated by a minus sign and clearance by a plus sign.BS 4823:1972 BSI 12-1999 3 Table 1 Fitment bo
30、res for cylindrical shaft ends Limits are given in units of 0.001 mm. Nominal shaft end diameter Shaft end tolerance Bore tolerance to give Limits of resulting fit b Interference fit Close fit Free fit Interference Close Free Designation Limits Designation Limits Designation Limits Designation Limit
31、s mm 55 56 60 63 65 70 71 75 80 m6 + 30 + 30 + 30 + 30 + 30 + 30 + 30 + 30 + 30 + 11 + 11 + 11 + 11 + 11 + 11 + 11 + 11 + 11 N7 9 9 9 9 9 9 9 9 9 39 39 39 39 39 39 39 39 39 H7 + 30 + 30 + 30 + 30 + 30 + 30 + 30 + 30 + 30 0 0 0 0 0 0 0 0 0 G7 + 40 + 40 + 40 + 40 + 40 + 40 + 40 + 40 + 40 + 10 + 10 + 1
32、0 + 10 + 10 + 10 + 10 + 10 + 10 20 20 20 20 20 20 20 20 20 69 69 69 69 69 69 69 69 69 + 19 + 19 + 19 + 19 + 19 + 19 + 19 + 19 + 19 30 30 30 30 30 30 30 30 30 + 29 + 29 + 29 + 29 + 29 + 29 + 29 + 29 + 29 20 20 20 20 20 20 20 20 20 85 90 95 100 110 120 125 130 140 150 160 170 180 190 200 220 + 35 + 35
33、 + 35 + 35 + 35 + 35 + 40 + 40 + 40 + 40 + 40 + 40 + 40 + 46 + 46 + 46 + 13 + 13 + 13 + 13 + 13 + 13 + 15 + 15 + 15 + 15 + 15 + 15 + 15 + 17 + 17 + 17 P7 24 24 24 24 24 24 28 28 28 28 28 28 28 33 33 33 59 59 59 59 59 59 68 68 68 68 68 68 68 79 79 79 + 35 + 35 + 35 + 35 + 35 + 35 + 40 + 40 + 40 + 40
34、+ 40 + 40 + 40 + 46 + 46 + 46 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 + 47 + 47 + 47 + 47 + 47 + 47 + 54 + 54 + 54 + 54 + 54 + 54 + 54 + 61 + 61 + 61 + 12 + 12 + 12 + 12 + 12 + 12 + 14 + 14 + 14 + 14 + 14 + 14 + 14 + 15 + 15 + 15 37 37 37 37 37 37 43 43 43 43 43 43 43 50 50 50 94 94 94 94 94 94 108 108 108
35、108 108 108 108 125 125 125 + 22 + 22 + 22 + 22 + 22 + 22 + 25 + 25 + 25 + 25 + 25 + 25 + 25 + 29 + 29 + 29 35 35 35 35 35 35 40 40 40 40 40 40 40 46 46 46 + 34 + 34 + 34 + 34 + 34 + 34 + 39 + 39 + 39 + 39 + 39 + 39 + 39 + 44 + 44 + 44 23 23 23 23 23 23 26 26 26 26 26 26 26 31 31 31 NOTEAn interfere
36、nce fit is not recommended for use with shaft sizes below 19 mm. b Interference is indicated by a minus sign and clearance by a plus sign.BS 4823:1972 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandar
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