1、BRITISH STANDARD BS2062-2: 1960 Specification for Gear hobs Part2: Hobs for gears for turbine reduction and similar drivesBS2062-2:1960 This BritishStandard, having been approved by the MechanicalEngineering IndustryStandards Committeeand endorsed bytheChairman of the Engineering Divisional Council,
2、was published undertheauthority of theGeneralCouncil on 23 December1960 BSI01-2000 First published December1953 First revision December1960 The following BSI references relate to the work on this standard: Committee reference MEE/127 Draft for comment A(MEE)3057 ISBN 0 580 35989 1 Co-operating organ
3、izations The Mechanical Engineering Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty* Gas Council Air Ministry High Commission of India
4、 Associated Offices Technical Committee Institute of Marine Engineers Association of Consulting Engineers Institute of Petroleum (Incorporated) Institution of Civil Engineers British Chemical Plant Manufacturers Institution of Gas Engineers Association Institution of Heating and Ventilating British
5、Compressed Air Society Engineers British Electrical and Allied Manufacturers Institution of Mechanical Engineers Association* Institution of Mechanical Engineers British Engineers Association (Automobile Division) British Gear Manufacturers Association* Institution of Production Engineers* British I
6、nternal Combustion Engine Locomotive and Allied Manufacturers Manufacturers Association Association of Great Britain British Iron and Steel Federation Machine Tool Trades Association* British Railways, The British Transport Ministry of Labour (Factory Inspectorate) Commission Ministry of Power Crown
7、 Agents for Oversea Governments and Ministry of Transport Administrations Ministry of Works D.S.I.R.National Engineering Laboratory* National Coal Board Electricity Council the Generating Board and National Physical Laboratory (D.S.I.R.) the Area Boards in England and Wales Radio Industry Council En
8、gineering Equipment Users Association War Office The Government departments and scientific and 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 standard: Board of Trade P
9、arsons and Marine Engineering Turbine Milling Cutter and Reamer Association Research and Development Association North East Coast Institution of Engineers and Society of Motor Manufacturers and Traders Shipbuilders Manufacturers of gear hobs Amendments issued since publication Amd. No. Date Comments
10、BS2062-2:1960 BSI 01-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Terms and notation 1 3 Dimensions 1 4 Gashes 1 5 Keys and keyways 1 6 Permissible errors 1 7 Marking 1 8 Ordering instructions 1 Appendix A 5 Appendix B 6 Appendix C Marking of hobs 7 Appe
11、ndix D Ordering instructions 7 Appendix E 8 Appendix F Keys and keyways 9 Appendix G Approximate metric equivalents 10 Figure 1 Gear hob terms 1 Figure 2 20 pressure angle basic rack tooth profile in terms of unit normal diametral pitch 5 Figure 3 16 pressure angle basic rack tooth profile in terms
12、of unit diametral pitch 6 Figure 4 Profile of hob teeth of unit pitch and 16 flank angle in axial plane of hob 7 Figure 5 Section of hob teeth on a developed helix 8 Figure 6 Hob keyway dimensions in inches 9 Figure 7 Hob arbor and keyway dimensions in inches 9 Table 1 Permissible errorsgrade AA hob
13、s (Expressed in ten-thousandths of an inch) 2 Table 2 Recommended basic dimensions for hobs for cutting gears with a20 pressure angle basic rack tooth profile (Figure 1 of BS1807-2) and a16 pressure angle basic rack tooth profile (Figure 2 of BS1807-2) 5 Table 3 Recommended basic dimensions for hobs
14、 with16 flank angle in the axial plane of the hob (Figure 3 of BS1807-2) 6BS2062-2:1960 ii BSI 01-2000 Foreword This standard makes reference to the following BritishStandards: BS1807, Gears for turbines and similar drives Part 2: Tooth forms and pitches. BS2062, Gear hobs Part 1: Hobs for general p
15、urposes1d.p. to20d.p. inclusive. BS2519, Glossary of terms and notation for toothed gearing. This revision of the1953 edition has been carried out under the authority of the Mechanical Engineering Industry Standards Committee in order to bring it into up-to-date relation with BS1807, “Gears for turb
16、ines and similar drives”. The permissible errors given in this edition are very similar to those given in the previous edition, but the layout of the table has been improved to make it comparable with that in BS2062-1:1959, “Hobs for general purposes1d.p. to20d.p. inclusive”. It has not been possibl
17、e to achieve complete agreement on the dimensions of hobs but recommended dimensions are given in Appendix A and Appendix B for the tooth forms and pitches listed in BS1807-2. The dimensions given are suitable for hobs used on the machines generally employed in turbine gear manufacture. It has been
18、agreed to continue the use of the designation Grade AA for this class of hobs as the usage has become well established and any alteration would give rise to confusion. A table of approximate metric equivalents is given in Appendix G. More precise conversions should be based on the tables in BS350, “
19、Conversion factors and tables”. 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 does not of itself confer immunity from legal obligations. Summary o
20、f pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to10 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.BS2062-2:1960 BSI 01
21、-2000 1 1 Scope Part2 of this BritishStandard applies to Grade AA ground profile single-start right-hand and left-hand finishing hobs for gears for marine turbine, land turbine and similar drives. It covers the accuracy requirements of hobs for the production of gears complying with BS1807, “Gears f
22、or turbines and similar drives”, Part1, “Accuracy” and recommends basic dimensions for hobs with the tooth forms and pitches given in BS1807-2, “Tooth forms and pitches”. 2 Terms and notation The general terms used common to gears and hobs are taken from BS2519, “Glossary of terms and notation for t
23、oothed gearing”. Figure 1 illustrates the terms used. 3 Dimensions Recommended basic dimensions for hobs for the production of the tooth forms and pitches given in BS1807-2, “Tooth forms and pitches”, are given in Appendix A and Appendix B. 4 Gashes All hobs shall be gashed so that the cutting faces
24、 are normal to the tooth helix at the datum diameters. 5 Keys and keyways Recommended dimensions and tolerances are given in Appendix F. The error of axial alignment of the keyway shall be such that interference does not occur between the key and keyway at any point throughout the hob length when th
25、e keyway is within the limits of width at all points. 6 Permissible errors The errors shall not exceed those given in Table 1. 7 Marking A recommended system of marking is given in Appendix C. 8 Ordering instructions Recommendations on the instructions to be given in an order are shown in Appendix D
26、. Figure 1 Gear hob termsBS2062-2:1960 2 BSI 01-2000 Table 1 Permissible errorsgrade AA hobs (Expressed in ten-thousandths of an inch) Element No. Illustration Test Axial pitch (inches) 0.2 0.3 0.4 0.5 0.6 0.7 and 0.8 0.9 and 1.0 Diametral pitch 14 12 and 10 8 and 7 6 5 4 3 Hub reference datum surfa
27、ces 1 Axial run-out 2 2 2 2 2 2 2 2 Radial run-out 3 3 3 3 3 3 3 Outside diameter 3 Radial run-out 10 10 10 10 10 10 10 Tooth lead variation 4 Variation along tooth helix from tooth to tooth 1.5 1.5 2 2 2 2 2 5 Variation along tooth helix in one convolution (cyclic pitch error) 3 3 3 3 3.5 3.5 3.5 6
28、 Departure from design pitch between adjacent tooth forms in same axial plane (adjacent pitch error measured along gash helix) 1.5 1.5 2 2 2 2.5 3 7 Departure from design pitch between any two tooth forms within five pitches in same axial plane (cumulative pitch error) 4.5 4.5 5 5.5 6 7 8BS2062-2:19
29、60 BSI 01-2000 3Table 1 Permissible errorsgrade AA hobs (Expressed in ten-thousandths of an inch) Element No. Illustration Test Axial pitch (inches) 0.2 0.3 0.4 0.5 0.6 0.7 and 0.8 0.9 and 1.0 Diametral pitch 14 12 and 10 8 and 7 6 5 4 3 Tooth 8 Permissible error over the straight flank from the des
30、ign form 1.5 1.5 2 2 2 3 4 9 Thickness (minus only) 10 10 10 10 10 15 15 10 Straightness of each flank (concavity only permissible) 2 2 2 2.5 2.5 3 3.5 11 Length of straight flank 50 50 50 50 50 50 50 12 Start of profile modification (plus or minus) 50 50 50 50 50 50 50 Cutting faces of gashes 13 Ad
31、jacent spacing error 10 10 10 10 10 10 10 14 Cumulative spacing error 20 20 20 30 30 30 30 15 Radial alignment of gash over cutting depth 5 5 5 5 6 10 10BS2062-2:1960 4 BSI 01-2000Table 1 Permissible errorsgrade AA hobs (Expressed in ten-thousandths of an inch) Element No. Illustration Test Axial pi
32、tch (inches) 0.2 0.3 0.4 0.5 0.6 0.7 and 0.8 0.9 and 1.0 Diametral pitch 14 12 and 10 8 and 7 6 5 4 3 Cutting faces of gashes 16 Departure (plusor minus) from angle of gash (expressed as a linear dimension per inch of face width) 6 6 6 6 6 6 6 Bore 17 Diameter (plusonly) 3 3 3 3 3 3 3 Bores shall be
33、 finished straight and parallel, within the tolerances given, for75 per cent of each bearing length. Tooth relief 18 These tolerances apply to new and resharpened hobs. The accuracy of the flank relief and top relief shall be such that the maximum permissible errors specified will not be exceeded wh
34、en the cutting faces are re-ground to the above tolerances. NOTE 1Unless otherwise stated, values represent the full indicator movement. NOTE 2Errors are measured on each set of flanks independently for items4,5,6,7,8,10,11,12. NOTE 3For pitches not given above permissible errors for the next coarse
35、r pitch shall apply.BS2062-2:1960 BSI 01-2000 5 Appendix A Table 2 Recommended basic dimensions for hobs for cutting gears with a20 pressure angle basic rack tooth profile (Figure 1 of BS1807-2) and a16 pressure angle basic rack tooth profile (Figure 2 of BS1807-2) Normal diametral pitch Overall Bor
36、e diameter Hub Length of recess (approx.) Half-round keyway width (diameter) Diameter of bore plus depth of keyway Outside diameter Length Diameter (approx.) Length (approx.) 3 4 5 6 7 8 10 12 14 in 6 1 / 2 6 1 / 4 6 1 / 4 6 6 5 3 / 4 5 3 / 4 5 1 / 2 5 1 / 2 in 8 7 6 5 4 1 / 2 4 3 1 / 2 3 1 / 4 3 in
37、 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 in 4 1 / 8 3 7 / 8 4 1 / 4 4 3 / 8 4 3 / 8 4 3 / 8 4 1 / 2 4 1 / 2 4 1 / 2 in 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 in 2 3 / 4 2 1 / 4 2 1 3 / 4 1 1 / 2 1 3 / 8 1 1 / 4 1 1 / 8 1 in 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8
38、 3 / 8 3 / 8 3 / 8 3 / 8 in 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 NOTE 1Hub diameters are given for guidance but should be as large as possible. NOTE 2For details of keyways see Clause5. Figure 2 20 pressure angle basic rack tooth profile in terms of unit n
39、ormal diametral pitchBS2062-2:1960 6 BSI 01-2000 Appendix B Table 3 Recommended basic dimensions for hobs with16 flank angle in the axial plane of the hob (Figure 3 of BS1807-2) Figure 3 16 pressure angle basic rack tooth profile in terms of unit diametral pitch Axial pitch of hob Datum diameter of
40、hob Overall Bore diameter Length of recess (approx.) Hub Round keyway width (diameter) Diameter of bore plus depth of keyway Outside diameter (approx.) Length Diameter (approx.) Length (approx.) in 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 in 5.50 5.50 5.50 5.50 5.50 5.50 5.75 5.75 5.75 in 5.72 5.84 5.95
41、6.06 6.18 6.29 6.65 6.76 6.88 in 2 3 / 4 3 1 / 2 4 1 / 4 5 5 3 / 4 6 1 / 2 7 1 / 4 8 8 in 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 2 1 / 4 in 1 1 1 / 4 1 3 / 8 1 3 / 4 2 2 1 / 8 2 3 / 8 2 3 / 4 2 3 / 4 in 4 4 4 4 4 4 4 4 4 in 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 / 2 1 /
42、 2 in 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8 3 / 8 in 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 2 7 / 16 NOTE 1Hub diameters are given for guidance but should be as large as possible. NOTE 2For details of keyways see Clause5.BS2062-2:1960 BSI 01-2000 7 Appendix
43、 C Marking of hobs 1. Where applicable, the following markings shall be used, preferably at one end of the hob. 2. Makers identification mark or number, and material, may also be added if desired. Appendix D Ordering instructions When placing an order the purchaser should state: The number of this B
44、ritishStandard. Quantity required. Normal diametral pitch or axial pitch of hob. Normal pressure angle or flank angle of the hob in the axial plane. Grade. Hand (right-hand or left-hand). Diameter and length. Figure 4 Profile of hob teeth of unit pitch and 16 flank angle in axial plane of hob Exampl
45、es For hob as Appendix A For hob as Appendix B Normal diametral pitch or axial pitch of hob x NDP x AP Normal or axial pressure angle xx NPA xx APA Tooth lead angle x x LA x x LA Cutting depth xxx CD xxx CD for wheels xxx CD for pinions Datum diameter xx DD Gash lead xxx GL xxx GL Right-hand or left
46、-hand RH RH Single start SS SS Number of this BritishStandard BS2062-2 BS2062-2 BS2062-2:1960 8 BSI 01-2000 Bore and keyway. Example: One:6 NDP hob to BS2062-2,20 NPA Grade AA, right-hand,6 in diameter 5 in long,2 1 / 4in diameter bore, half-round keyway. Appendix E Figure 5 Section of hob teeth on
47、a developed helixBS2062-2:1960 BSI 01-2000 9 Appendix F Keys and keyways The error of axial alignment of the keyway shall be such that interference does not occur between the key and keyway at any point throughout the hob length when the keyway is within the limits of width at all points. Figure 6 H
48、ob keyway dimensions in inches NOTEThe recommended arbor diameter limits are:2.2500in. 2.2498in. Figure 7 Hob arbor and keyway dimensions in inchesBS2062-2:1960 10 BSI 01-2000 Appendix G Approximate metric equivalents in mm in mm in mm in mm 0.000 1 0.000 15 0.000 2 0.000 25 0.000 3 0.000 35 0.000 4
49、 0.000 45 0.005 0.000 55 0.000 6 0.000 65 0.000 7 0.000 8 0.000 9 0.001 0 0.001 5 0.002 0.002 0.004 0.005 0.006 0.008 0.009 0.010 0.012 0.013 0.014 0.015 0.016 0.018 0.020 0.023 0.025 0.038 0.051 0.003 0.004 0.005 0.2 0.3 0.378 ( 3 / 8 ) 0.4 0.5( 1 / 2 ) 0.6 0.7 0.8 0.9 1 1 1 / 8 1 1 / 4 1 3 / 8 1 1 / 2 1 3 / 4 0.076 0.102 0.127 5.1 7.6 9.5 10.2 12.7 15.2 17.9 20.3 22.8 25.4 28.6 31.8 34.9 38.1 44.4 2 2 1 / 8 2 1 / 4 2 3 / 8 2 1 / 2 2 3 / 4 3 3 1 / 4 3 1 / 2 3
