1 Scope
This part establishes a system of accuracy relevant to corresponding flanks of individual cylindrical involute gears.
It specifies appropriate definitions for gear tooth accuracy terms, the structure of the gear accuracy system and the allowable values of pitch deviations, total profile deviations and total helix deviations.
This part applies only to each element of a toothed wheel taken individually; it does not cover gear pairs as such.
It is strongly recommended that any user of this part be very familiar with the methods and procedures outlined in GB/Z 18620.1. Use of techniques other than those of GB/Z 18620.1 combined with the limits described in this part may not be suitable.
Annex A (normative) gives formulae for tolerances for tangential composite deviations which are also quality criteria of this part, but are not mandatory inspection items.
Annex B (informative) provides values on Profile and helix form and slope deviations which sometimes serve as useful information and evaluation values but are not mandatory inspection items.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 10095, constitute provisions of this part. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 10095.2-2008 Cylindrical gears - System of accuracy - Part 2: Definitions and allowable values of deviations relevant to radial composite deviations and runout information (ISO 1328-2: 1997, IDT)
GB/Z 18620.1-2008 Cylindrical gears - Code of inspection practice - Part 1: Inspection of corresponding flanks of gear teeth (ISO/TR 10064-1: 1992, IDT)
3 Terms and definitions
For the purposes of this part, the following terms and definitions apply.
For the symbols not explained in this clause, see Clause 4.
3.1 Pitch deviations
3.1.1
single pitch deviation (fpt)
algebraic difference between the actual pitch and the corresponding theoretical pitch in the transverse plane, defined on a circle concentric with the gear axis at approximately mid-depth of the tooth (see Figure 1).
3.1.2
cumulative pitch deviation (Fpk)
algebraic difference, over any sector of k pitches, between the actual length and the theoretical length of the relevant arc (see Figure 1). In theory, it is equal to the algebraic sum of the single pitch deviations of the same k pitches.
Note: Unless otherwise specified, evaluation of Fpk is limited to sectors not larger than one-eighth of the circumference. Hence, allowable values of deviations Fpk apply to sectors of which the number of pitches (k) ranges from 2 to the number nearest to z/8. Generally, evaluation of Fpz/8 is sufficient. If for special applications (e.g. for high-speed gears) smaller sectors are also to be checked, the relevant valuefs) of k should be specified.
3.1.3
total cumulative pitch deviation (Fp)
maximum cumulative pitch deviation of any sector (with k=1 up to k=z) of the corresponding flanks of a gear. It is represented by the total amplitude of the cumulative pitch deviation curve.
Foreword i
ISO Foreword iii
ISO Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and abbreviations
5 Structure of the system of accuracy for gears
6 Formulae for allowable values of gear deviations of accuracy grade
7 Allowable values of gear deviations relevant to corresponding flanks
Annex A (normative) Tolerances for tangential composite deviations
Annex B (Informative) Values of Profile and helix form and slope deviations
Bibliography
