1、BRITISH STANDARD BS5208:1975 Specification for Dimensions of power take-off driving shafts and mounting faces for small internal combustion engines UDC 621.43181.423:621.82/.83BS5208:1975 This BritishStandard, having been approved by the MechanicalEngineering IndustryStandards Committee,was publishe
2、d underthe authority of theExecutive Board on 30June1975 BSI12-1999 The following BSI references relate to the work on this standard: Committee reference MEE/123/2 Draft for comment72/35589 DC ISBN 0 580 08673 9 Co-operating organizations The Mechanical Engineering Industry Standards Committee, unde
3、r whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Associated Offices Technical Committee Department of Trade Association of Consulting Engineers Electricity Supply Industry in Engl
4、and and Association of Hydraulic Equipment Wales Manufacturers Ltd* Engineering Equipment Users Association Association of Mining Electrical and Federation of Manufacturers of Construction Mechanical Engineers Equipment and Cranes British Compressed Air Society Institution of Gas Engineers British E
5、lectrical and Allied Manufacturers Institution of Heating and Ventilating Association Engineers British Gas Corporation Institution of Mechanical Engineers British Gear Manufacturers Association Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers Man
6、ufacturers Association* London Transport Executive British Mechanical Engineering Confederation Machine Tool Trades Association British Pump Manufacturers Association Ministry of Defence* British Steel Corporation National Coal Board British Steel Industry Process Plant Association Crown Agents for
7、Oversea Governments and Railway Industry Association of Great Britain Administration Royal Institute of British Architects Department of Employment (HM Factory Society of Motor Manufacturers and Inspectorate) Traders Ltd Department of the Environment Telecommunication Engineering and Department of I
8、ndustry Mechanical Manufacturing Association Engineering Department of Industry National Engineering Laboratory The Government department and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee ent
9、rusted with the preparation of this BritishStandard: Diesel Engineers and Users Association Amendments issued since publication Amd. No. Date of issue CommentsBS5208:1975 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Dimensions 1 4 T
10、olerances on assembled engines 1 5 Screw threads 1 6 Stress concentrations on stepped shafts 1 Appendix A Information on stress concentrations on stepped shafts 7 Figure 1 Cylindrical shaft with keyway and threaded hole 2 Figure 2 Cylindrical shaft with threaded end 3 Figure 3 Cylindrical shaft with
11、 conical end (1 in 5 on diameter) andthreadedhole 4 Figure 4 Cylindrical shaft with conical (1 in10on diameter) and threaded end 5 Figure 5 Composite mounting face 6 Figure 6 Typical relief grooves for stepped shafts 7 Publications referred to 8BS5208:1975 ii BSI 12-1999 Foreword This BritishStandar
12、d has been prepared under the authority of the Mechanical Engineering Industry Standards Committee to facilitate the production and interchangeability of various attachments for small internal combustion engines. The dimensions given are in metric units and whilst being close to, they are not interc
13、hangeable with existing components in imperial units. The preparation of this standard was undertaken in the recognition that with the current changeover to the metric system, industry would benefit from a metric based standard for guidance in future design. A British Standard does not purport to in
14、clude 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 cover, pag
15、esi andii, pages1 to8, an inside back cover 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.BS5208:1975 BSI 12-1999 1 1 Scope This BritishStandard specifies the dim
16、ensions of power take-off driving shafts and mounting faces for small internal combustion engines, generally up to15kW power output. NOTEIt is pointed out that the power take-off driving shafts and mounting faces specified in this standard are not related to the main power take-off assemblies specif
17、ied in BS3092. 2 References The titles of the BritishStandards referred to in this standard are listed on page 8. 3 Dimensions 3.1 The dimensions of power take-off driving shafts shall be as shown in the following figures. Figure 1 Cylindrical shaft with keyway and threaded hole. Figure 2 Cylindrica
18、l shaft with threaded end. Figure 3 Cylindrical shaft with conical end(1in5on diameter) and threaded hole. Figure 4 Cylindrical shaft with conical(1in10on diameter) and threaded end. 3.2 The dimensions of the mounting faces shall be as shown in Figure 5. Mounting faces may incorporate either or both
19、 of the attachment configurations shown in Figure 5 to suit individual applications as required. Power take-off shafts up to and including20mm diameter are generally associated with the50mm diameter spigot bore and90mm PCD. Power take-off shafts over20mm diameter are generally associated with the140
20、mm male spigot and160mm PCD. 4 Tolerances on assembled engines 4.1 Concentricity of the spigot diameters relative to the driving shaft axis shall be within0.13mm total indicator movement. 4.2 The run-out of the driving shaft, measured at the outboard end of the shaft, shall not exceed0.05mm per100mm
21、 of the shaft length, measured from the datum face. 4.3 The squareness of the mounting face to the driving shaft shall be within0.15mm full indicator movement per100mm of face diameter. 4.4 The end of the driving shaft shall be within 0.8mm of the specified dimension from the datum face. This value
22、shall include any endfloat of the shaft. 5 Screw threads Screw threads shall comply with the requirements of BS3643, tolerance class6g for external and6H for internal threads. 6 Stress concentrations on stepped shafts For guidance purposes information on the avoidance of stress concentrations on ste
23、pped shafts is given in Appendix A. BS5208:1975 2 BSI 12-1999 NOTEDatum is mounting face (see Figure 5) Dimensions are in millimetres Diameter D Thread R bmax. Full thread Nominal Tolerance A B C E a F a T L 12 j6 35 30 20 9.5 4 M4 0.7 8 1.0 16 j6 45 40 25 13.0 5 M4 0.7 8 1.0 20 j6 55 50 30 16.5 6 M
24、6 1.0 12 1.0 25 j6 70 60 40 21.0 8 M8 1.25 16 2.0 30 j6 90 80 55 26.0 8 M10 1.5 20 2.0 40 k6 120 110 80 35.0 12 M12 1.75 25 2.0 a Keyway in accordance with BS4235-1. b Minimum radius at the discretion of the manufacturer. Figure 1 Cylindrical shaft with keyway and threaded hole + 0.008 0.003 + 0.008
25、 0.003 + 0.009 0.004 + 0.009 0.004 + 0.009 0.004 + 0.018 0.002 BS5208:1975 BSI 12-1999 3 NOTEDatum is mounting face (see Figure 5) Dimensions are in millimetres Diameter D Thread R amax. Nominal Tolerance A B T C 16 j6 65 56 M16 1.5 20 1.0 20 j6 75 56 M20 1.5 25 1.0 24 j6 100 74 M24 2.0 30 2.0 30 j6
26、 125 88 M30 2.0 38 2.0 a Minimum radius at the discretion of the manufacturer Figure 2 Cylindrical shaft with threaded end + 0.008 0.003 + 0.009 0.004 + 0.009 0.004 + 0.009 0.004 BS5208:1975 4 BSI 12-1999 NOTEDatum is mounting face (see Figure 5) Dimensions are in millimetres Diameter D Datum diamet
27、er Thread R amax. Full thread Nominal Tolerance A B 0.4 C d T L 16 j6 55 45.0 10 14.8 M61.0 12 1.0 20 j6 75 60.0 10 19.0 M81.25 16 1.0 25 j6 100 80.0 10 24.0 M101.5 20 2.0 30 j6 125 100.0 20 29.0 M121.75 25 2.0 40 k6 150 120 20 38.0 M162.0 32 2.0 a Minimum radius at the discretion of the manufacture
28、r Figure 3 Cylindrical shaft with conical end(1in5on diameter) and threaded hole + 0.008 0.003 + 0.009 0.004 + 0.009 0.004 + 0.009 0.004 + 0.018 0.002 BS5208:1975 BSI 12-1999 5 NOTEDatum is mounting face (see Figure 5) Dimensions are in millimetres Diameter D Datum diameter Thread Nominal A B 0.4 d
29、T C 16 38 18.0 15.2 M10 1.25 12 20 51 25.0 19.0 M12 1.25 14 25 62 30.0 24.0 M16 1.5 18 30 88 45.0 28.5 M20 1.5 22 40 122 60.0 38.0 M24 2.0 28 Figure 4 Cylindrical shaft with conical(1in10on diameter) and threaded endBS5208:1975 6 BSI 12-1999 Dimensions are in millimetres Diameter A Diameter B C 139.
30、99 139.96 50.04 50.00 5 Figure 5 Composite mounting faceBS5208:1975 BSI 12-1999 7 Appendix A Information on stress concentrations on stepped shafts Where rotating shafts containing steps in diameter are subjected to bending or to fluctuating torque, there is a danger of fatigue cracks initiating at
31、the toe of the shoulder fillet radius. The transition radius R should therefore be made as large as practicable and be smoothly blended with the smaller diameter portion of the shaft. Parts abutting the shoulder may be suitably chamfered to clear the radius. With a stepped shaft other forms of stres
32、s concentration in the smaller diameter portion of the shaft, such as keyways or screw threads, should be separated from the toe of the shoulder fillet radius by a distance at least equal to that radius, i.e.they should terminate at a distance from the shoulder of at least twice the radius. Typical
33、relief groove possibilities for abutting designs are shown in Figure 6. The surface roughness in the fillet region should be uniform and as low as practicable. Figure 6 Typical relief grooves for stepped shaftsBS5208:1975 BSI 12-1999 8 Publications referred to This standard makes reference to the fo
34、llowing BritishStandards BS3092, Main friction clutches, main power-take-off assemblies and associated attachment for internal combustion engines. BS3643, ISO metric screw threads. BS4235, Metric keys and keyways. BS4235-1, Parallel and taper keys. BS5208:1975 BSI 12-1999 BSI Certification Trade Mar
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