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  • BS 4582-1:1970

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    Specification for fine pitch gears (metric module) Involute spur and helical gears

    Available format(s):  Hardcopy, PDF

    Language(s):  English

    Published date:  27-03-1970

    Publisher:  British Standards Institution

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    Table of Contents - (Show below) - (Hide below)

    Co-operating organizations
    1 General
    1.1 Scope
    1.2 Terminology and notation
    1.3 Standard modules
    1.4 Basic rack tooth profile
    2 Design details
    2.1 Outside diameter and centre distance
    2.2 Modification of addendum and centre distance
    3 Accuracy of gear blanks and gears
    3.1 General
    3.2 Dual flank composite testing - test pressures and
         limits of tolerance
    3.3 Limits of tolerance on blanks and gear elements
    4 Limits and tolerances of assembly
    4.1 Centre distance
    4.2 Depth of engagement
    5 Information to be given on drawings
    5.1 Recommendation
    A Centre distance and addendum modification
    B Examples of calculation
    C Comparable metric modules and diametral pitches
    D Single flank composite testing: limits of tolerance
    E Calculation of measuring pin dimensions for
         external and internal spur gears
    1 Standard modules
    2 Data for spur pinions of unit module having fewer
         than 17 teeth
    3 Centre distances for spur gear pairs of unit module
         for the conditions given in 2.3, para. 1
    4 Forces appropriate to the module suitable for brass
         and steel product gears
    5 Dual flank composite error tolerances
    6 Limits of tolerance on gear blanks
    7 Limits of tolerance on tooth profile
    8 Limits of tolerance on pitch
    9 Limits of tolerance on tooth alignment
    10 Limits of tolerance on radial run-out of teeth
    11 Limits of tolerance on tooth thickness
    12 Tolerance on centre distance of mounting
    13 Minimum depth of engagement for spur gear pairs
         with 28 to 33 teeth (z2 + z1)
    14 Minimum depth of engagement for spur gear pairs
         with more than 33 teeth (z2 + z1)
    1 Basic rack tooth profile for unit normal module
    2 Basic rack tooth profile for unit normal module
         with backlash allowance
    3 Limiting values of addendum modification
    4 Minimum permissible addendum modification
         coefficient for helical pinions (alpha n = 20 deg)
    5 Tolerance zone for profile error
    6 Examples of information to be given on drawings
    7 Chart for normal backlash when x1 + x2 = y

    Abstract - (Show below) - (Hide below)

    Covers gears having modules of 1 mm and less including first and second preferences. Two basic racks (one with backlash allowance); modification of addendum and centre distance to suit various conditions. Four grades of accuracy with elemental and dual flank composite test tolerances. Appendices give information on single flank testing, calculation of measuring pin dimensions and examples of calculations for various design conditions. Metric equivalent of BS 978-1.

    Scope - (Show below) - (Hide below)

    This British Standard relates to involute spur, helical and crossed helical gears, having modules of one millimetre and finer, in four accuracy grades. Examples of application are:

    Class A. Astronomical apparatus and scientific instruments; colour printing machinery; control systems (when multiple trains of gears are involved this grade would generally be used for low speed components where the effect of positional accuracy is important).

    Class B. Navigational instruments; high speed components of control systems where quietness and smooth running are essential; machine tool speed control; photo­ graphic instruments.

    Class C. General purpose instruments; accounting and calculating machinery; counters; clockwork mechanisms.

    Class D. Textile machinery; switch operating gear; clockwork mechanisms where accuracy is not the primary consideration.

    It is recommended that all spur, helical and crossed helical gears for use in horology should be produced to this British Standard, with the possible exception of gears for weight or spring-driven mechanisms in which the pinion is the driven member and has 12 or fewer teeth. In such cases it may be preferable to use cycloidal type spur gears, conforming to BS 978, Part 2†.

    Examples of calculation are given in Appendix B.

    General Product Information - (Show below) - (Hide below)

    Committee MCE/5
    Development Note Reviewed and confirmed by BSI, August 2012. (07/2012)
    Document Type Standard
    Publisher British Standards Institution
    Status Current

    Standards Referenced By This Book - (Show below) - (Hide below)


    Standards Referencing This Book - (Show below) - (Hide below)

    BS 4500(1969) : LATEST
    BS 308(1966) : LATEST
    BS 2519(1954) : LATEST
    BS 978-1:1968 Specification for fine pitch gears. Involute spur and helical gears
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