1、BRITISH STANDARD BS 3733:1974 Specification for Endless V-belt drives for agricultural purposes UDC 621.852.13:631.3BS3733:1974 This British Standard, having been approved by the MechanicalEngineering IndustryStandards Committee, was published under the authorityofthe ExecutiveBoardon 23August1974 B
2、SI 10-1999 First published April 1964 First revision August 1974 The following BSI references relate to the work on this standard: Committee reference MEE/76 Draft for comment 72/34360 DC ISBN 0 580 08265 2 Co-operating organizations The Mechanical Engineering Industry Standards Committee, under who
3、se supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Associated Offices Technical Committee Association of Consulting Engineers Association of Hydraulic Equipment Manufacturers Ltd. Assoc
4、iation of Mining Electrical and Mechanical Engineers British Compressed Air Society British Electrical and Allied Manufacturers Association British Gas Corporation British Gear Manufacturers Association* British Internal Combustion Engine Manufacturers Association British Mechanical Engineering Conf
5、ederation British Pump Manufacturers Association British Steel Industry Crown Agents for Oversea Governments and Administrations Department of Employment (HM Factory Inspectorate) Department of the Environment Department of Trade and Industry Department of Trade and Industry (Marine Division) Depart
6、ment of Trade and Industry National Engineering Laboratory Electricity Council, the Central Electricity Generating Board and the Area Boards in EnglandandWales Engineering Equipment Users Association* Federation of Manufacturers of Construction Equipment and Cranes Institution of Civil Engineers Ins
7、titution of Gas Engineers Institution of Heating and Ventilating Engineers Institution of Mechanical Engineers Institution of Plant Engineers Institution of Production Engineers London Transport Executive Machine Tool Trades Association Ministry of Defence Ministry of Defence, Army Department Nation
8、al Coal Board National Physical Laboratory (Department of Trade and Industry) Process Plant Association Railway Industry Association of Great Britain Royal Institute of British Architects Telecommunications Engineering Manufacturing Association The organizations marked with an asterisk in the above
9、list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Agricultural Engineers Association Ltd. British Rubber Manufacturers Association Ltd. Society of Motor Manufacturers and Traders Ltd. Individual manufacturer Amendme
10、nts issued since publication Amd. No. Date of issue CommentsBS3733:1974 BSI 10-1999 i Contents Page Co-operating organizations Inside front cover Foreword iii 1 General 1 1.1 Scope 1 1.2 Definitions 1 2 V-belts 2 2.1 Materials and workmanship 2 2.2 Cross section dimensions 2 2.3 Determination of bel
11、t pitch length 2 2.4 Matched belts 2 2.5 Marking 2 3 Pulleys for V-belts 13 3.1 Materials 13 3.2 Finish 13 3.3 Tolerances 14 3.4 Balancing of pulleys 14 3.5 Standard dimensions of pulleys 16 Appendix A Recommendations for quarter-turn drives 20 Appendix B Recommendations and drive design examples fo
12、r power application of V-belt drives on agricultural machinery 21 Appendix C Recommended practice for installation tension in V-belt drives and calculation of the resultant forces imposed on the shaft by V-belts 32 Figure 1 Pulleys requiring dynamic balancing 15 Figure 2 Quarter-turn drives 19 Figur
13、e 3 Power rating graph 23 Figure 4 Pitch location with various belt and pulley arrangements 31 Figure 5 Belt deflection measurement 32 Table 1 Cross section dimensions of standard V-belts 3 Table 2 Cross section dimensions of double V-belts 3 Table 3 Cross section dimensions of variable speed V-belt
14、s 4 Table 4 Tolerance and force requirements when measuring new standard V-belts 4 Table 5 Tolerance and force requirements when measuring new double V-belts 5 Table 6 Tolerance and force requirements when measuring new variable speed V-belts 6 Table 7 Dimensions of pulleys for measuring new V-belts
15、 7 Table 8a A section V-belts: standard pitch lengths and permissible length variations 8 Table 8b B section V-belts: standard pitch lengths and permissible length variations 9 Table 8c C section V-belts: standard pitch lengths and permissible length variations 10 Table 8d D section V-belts: standar
16、d pitch lengths and permissible length variations 11 Table 9 Double V-belts: range of pitch length 12 Table 10 Variable speed V-belts: range of pitch length 13 Table 11 Dimensions of standard V-grooved pulleys 16 Table 12 Dimensions of variable speed pulleys 17BS3733:1974 ii BSI 10-1999 Page Table 1
17、3 Quarter-turn drives: dimensions of deep groove pulleys 18 Table 14 Recommended minimum pitch diameters for tension and guide pulleys 18 Table 15 Quarter-turn drives: offset between shafts and pulleys, dimension Y 21 Table 16 Power correction factors for arc of contact showing proportion of power r
18、ating at 180 arc of contact for V-V and V-flat drives 27 Table 17 Power correction factors for belt pitch length 28 Table 18 Installation and take-up allowances 29 Table 19 Pitch diameter correction factors 30 Table 20 Tension ratio factor R/(R 1) 30 Table 21 Deflection force required for measuring
19、installation tension in V-belt drives 33 Table 22 Values of K to correct for the effect of centrifugal tension 33 Publications referred to Inside back coverBS3733:1974 BSI 10-1999 iii Foreword This British Standard was prepared under the authority of the Mechanical Engineering Industry Standards Com
20、mittee. Its object is to provide standard dimensions for endless V-belts, double V-belts, variable speed V-belts and pulleys for agricultural machines, implements and trailers based on the practical experience of belt and pulley manufacturers, agricultural machinery manufacturers and users. This edi
21、tion in metric units is the result of a comprehensive review of BS3733:1964 and in particular introduces new methods for the pitch length designation and power design calculation of double V-belts. The latter information is under discussion within ISO/TC41. A British Standard does not purport to inc
22、lude 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, page
23、si toiv, pages1to34, 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.iv blankBS3733:1974 BSI 10-1999 1 1 General 1.1 Scope This British Standar
24、d specifies requirements for endless V-belts and V-grooved pulleys for agricultural purposes, including pulleys with movable flanges for variable speed drives Other drives are specified in the following British Standards, BS1440, BS3790, and BS AU150. NOTEThe titles of the British Standards referred
25、 in this standard are listed on the inside back cover. 1.2 Definitions For the purposes of this British Standard the following definitions apply: 1.2.1 V-belt drive a drive which consists of one or more V-belts mounted on grooved pulleys. The profiles of the belts and of the pulley grooves are such
26、that the belts come into contact with the sides of the pulley grooves only and not with the base of the grooves 1.2.2 V-belt a belt in which the outline formed by the base, sides and top of the belt approximates to a trapezium, but which differs from a wedge belt in having a smaller ratio of height
27、to pitch width 1.2.3 double V-belt a belt whose form of cross section is that of two V-belts joined at the long side of the trapezium, and which therefore, being symmetrical, can be mounted in the pulley groove in two senses 1.2.4 angle of a V-belt (A) the included angle obtained by extending the si
28、des of the V-belt 1.2.5 groove angle of a pulley (a) the included angle obtained by extending the sides of the pulley groove 1.2.6 pitch width of a V-belt (l p ) the pitch width is the basic dimension of standardization for the belt and for the corresponding pulley groove, considered as a whole 1.2.
29、7 pitch length of a V-belt (L p ) the circumferential length of a V-belt at the pitch width, determined as specified in2.3 1.2.8 pulley groove pitch width (l p ) the pitch width of the belt associated with the pulley 1.2.9 pulley pitch diameter (d p ) the diameter of the pulley measured at the groov
30、e pitch width 1.2.10 V-flat drive a V-belt drive using both a grooved pulley and a flat pulley 1.2.11 quarter-turn drive a belt drive in which the pulley axes are at right angles to each otherBS3733:1974 2 BSI 10-1999 1.2.12 variable speed drive a belt drive employing pulleys with movable flanges to
31、 permit varying speed ratios between shafts 2 V-belts 2.1 Materials and workmanship The V-belts shall consist of a suitable combination of fabric and/or cord and elastomeric compounds, the whole being bonded together in a uniform manner and shape in accordance with best manufacturing practice. The V
32、-belts shall be suitable for operating at ambient temperatures between 18 C and60 C and shall not be adversely affected under normal operating conditions within this temperature range. 2.2 Cross section dimensions Nominal cross section dimensions and the nominal included angle of V-belts shall be as
33、 shown in Table 1,Table 2 andTable 3. The V-belts shall fit pulley grooves within the limits given in Table 4,Table 5 andTable 6 when mounted on two measuring pulleys made as specified inTable 7. 2.3 Determination of belt pitch length The pitch length of a standard V-belt, double V-belt or variable
34、speed V-belt shall be determined when the belt is mounted on a groove measuring fixture having groove dimensions as given inTable 7 with total forces applied and with the belt positioned in the grooves in accordance withTable 4,Table 5 and Table 6 as applicable to the belt section. The total forces
35、shown shall be equally divided between the two strands of the belt and the pulleys shall be rotated at least two revolutions to seat the belt properly. The pitch length shall be calculated by adding the pitch circumference of one of the two equal pulleys to twice the measured centre distance. The le
36、ngth thus determined shall be as given in the appropriate Table and within the limits of variation set out, seeTable 8,Table 9 andTable 10. 2.4 Matched belts In order to avoid uneven distribution of load, belts running on a multi-belt drive shall be matched sets, and shall be within the tolerances o
37、n pitch lengths shown in columns2 and3 of Table 8,Table 9 andTable 10. NOTE 1Age and storage conditions may alter a belt length. NOTE 2It is recommended that belts from different manufacturers should not be mixed on the same drive. 2.5 Marking 2.5.1 Mandatory marking. All V-belts manufactured in acc
38、ordance with this British Standard shall be marked legibly and durably by vulcanizing or printing on the outer non-working face with a symbol indicating the belt cross section and nominal pitch length as given inTable 8,Table 9 andTable 10. 2.5.2 Recommended marking. It is recommended that where man
39、ufacturers mark their belts to indicate pitch length for the purpose of matched belt drives, they should adopt the following system of marking. When the measured pitch length coincides with the nominal pitch length: stamp length code50 on the belt. Each2mm deviation from the nominal pitch length is
40、by definition represented by1 unit, for example: B1760 belt stamped B176050 has a pitch length of 1 760 mm. If it is stamped B176048 it has a pitch length of1 756 mm. If it is stamped B176052 it has a pitch length of1 764 mm. This marking shall appear adjacent to the marking specified in2.5.1. BS373
41、3:1974 BSI 10-1999 3 Table 1 Cross section dimensions of standard V-belts Table 2 Cross section dimensions of double V-belts Cross section symbol Top width, W Height, T Included belt angle, A Pitch width, l p mm mm degrees mm A 13 8 40 11.0 B 17 11 40 14.0 C 22 14 40 19.0 D 32 19 40 27.0 Cross secti
42、on symbol Width, W Height, T Included belt angle, A mm mm degrees AA 13 10 40 BB 17 14 40 CC 22 17 40BS3733:1974 4 BSI 10-1999 Table 3 Cross section dimensions of variable speed V-belts Table 4 Tolerance and force requirements when measuring new standardV-belts (see 2.3) Cross section symbol Top wid
43、th, W Height, T Included belt angle, A Pitch width, l p mm mm degrees mm HI 25 13 30 23.6 HJ 32 15 30 29.6 HK 38 18 30 35.5 HL 45 20 30 41.4 HM 51 22 30 47.3 Groove section symbol Total force applied to belt Position of top face of belt with respect to top of pulley groove, r N mm A 200 + 1.6 1.6 B
44、300 + 1.6 1.6 C 750 + 1.2 2.0 D 1400 + 0.8 3.2BS3733:1974 BSI 10-1999 5 Table 5 Tolerance and force requirements when measuring new double V-belts (see 2.3) Groove section symbol Total force applied to belt Position of top surface with respect to top of pulley groove, r N mm AA 224 5 1.6 BB 335 7 1.
45、6 CC 850 8.5 1.6BS3733:1974 6 BSI 10-1999 Table 6 Tolerance and force requirements when measuring new variable speed V-belts (see 2.3) Groove section symbol Total force applied to belt Position of top surface of belt with respect to top of pulley groove, r N mm HI 500 + 3.2 1.6 HJ 700 + 3.2 1.6 HK 1
46、 000 + 3.2 1.6 HL 1 400 + 3.2 1.6 HM 1 800 + 3.2 1.6BS3733:1974 BSI 10-1999 7 Table 7 Dimensions of pulleys for measuring new V-belts Cross section symbol Pitch diameter, d p Circumference at pitch diameter Distance down fromoutside diameter topitch diameter, b Outside diameter Top width of groove,
47、g Groove depth, d Groove angle, a Pitch width, l p Standard V-belts Double V-belts Variable speed V-belts mm mm mm mm mm mm degrees mm A AA 95.54 300 3.3 102.14 13.00 12.0 34 11.0 + 0.06 + 0.05 + 0.8 0.25 0 0 0 B BB 127.39 400 4.2 135.79 16.55 15.0 34 14.0 + 0.06 + 0.07 + 0.8 0.25 0 0 0 C CC 222.93
48、700 5.7 234.33 22.68 20.0 34 19.0 + 0.10 + 0.09 + 1.2 0.25 0 0 0 D 318.47 1 000 8.1 334.67 32.23 28.0 36 27.0 + 0.16 + 0.13 + 1.6 0.25 0 0 0 mm mm mm mm mm mm degrees mm HI 127.39 400 3.8 134.99 25.34 17.0 26 23.6 + 0.06 + 0.03 + 0.8 0.25 0 0 0 HJ 159.23 500 4.8 168.83 31.79 21.0 26 29.6 + 0.08 + 0.
49、05 + 1.2 0.25 0 0 0 HK 191.07 600 5.7 202.47 38.11 25.0 26 35.5 + 0.10 + 0.05 + 1.3 0.25 0 0 0 HL 222.93 700 6.6 236.13 44.42 29.0 26 41.4 + 0.10 + 0.06 + 1.6 0.25 0 0 0 HM 254.78 800 7.6 269.98 50.77 33.0 26 47.3 + 0.13 + 0.07 + 1.6 0.25 0 0 0BS3733:1974 8 BSI 10-1999 Table 8a A section V-belts: standard pitch lengths and permissible length variations No
