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Gears Spur and Helical Gears Calculation of Load Capacity

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In line with the International practices for designing of gears, load capacity of cylindrical gears is evaluated based on limitation by contact stresses and bending stresses. Accordingly, the revision is being presented in three parts so that the standard may be utilised more effectively. The Part 1 of this standard deals with the introduction, symbols and general influence factors for design of gears. Detailed step by step calculation procedures for calculation of load factors taking into account the effect of surface durability ( pitting ) is given in Part 2. There is appropriate reference to tables and graphs for arriving at various factors. Part 3 covers the calculation procedure for calculating the load factors with respect to bending strength. These parts have been presented in such a format that the standard may be directly used for arriving at various factors relevant for calculations. In order to help the designer, examples of use of the two sections have been included in the Annex A and B to the standard.

The formulae and tables given in this standard apply to the calculation of load capacity of cylindrical external gears — spur, helical and double-helical; with peripheral speeds less than 50 m/s.

Part 1
1 Scope
2 Symbols, Nomenclature and Units
3 Gbnbeal Influence Factor
3.1 Application Factors, A' A
3.3 Longitudinal Load Distribution Factors, K H \$ and AfrB
3.4 Transverse Load Distribution Factors, k H * and Kw*
3.5 Zone Factor for Contact Stress, Z H
3.6 Elasticity Factor for Contact Stress, Z»
3.7 Contact Ratio Factor for Contact Stress. Z»
3.8 Helix Angle Factor for Contact Stress, Zp
3.9 Life Factor for Contact Stress, Z L
3.10 Lubricant Factor for Contact Stress, Z
3.11 Velocity Factor for Contact Stress, Z v
3.12 Work Hardening Factor for Contact Stress, Z w
3.13 Size Factor for Contact Stress, Z
3.14 Roughness Factor for Contact Stress, Z H
3.15 Reliability Factor, K*
3.16 Life Factor for Bending Stress, Fm
3.17 Form Factor for Bending Stress, Y* %
3 .18 Stress Concentration Factor for Bending Stress, y
3.19 Contact Ratio Factor for Bending Stress, Y*
3.20 Helix Angle Factor for Bending Stress
3.21 Factor of Notch Sensitivity for Bending Stress, Y n
3.22 Factor of Relative Surface Roughness for Bending Stress, Yn
3.23 Size Factor for Bending Stress, F*
3.24 Endurance Limit for the Contact Stress, « u u M
3.25 Nominal Bending Endurance Limit of an Un-notched Specimen at Full Elasticity of the Material, ora

PART 2 METHOD OF CALCULATION OF LOAD FACTORS FOR SURFACE DURABILITY ( PITTING )
1 Scope .
2 Data
2.1 Basic Data
2.2 Supplementary Data
3 FoftMULAB

PART 3 METHOD OF CALCULATION OF LOAD FACTORS FOR BENDING STRENGTH
1 Scope
2 - Data
2.1 Basic Data
2.2 Supplementary Data
3 Formulab
Annex A Examplb for Calculation op Load Factors for Surfacb Durability ( Pitting )
A-l Basic Data
A-2 Supplementary Data
A-3 Formulae
Annex B Example for Calculation of Load Factors for Bbnding Strbngth
B-l Basic Data
B-3 Supplementary Data
B-3 Formulae

Annex A Examplb for Calculation op Load Factors for Surfacb Durability ( Pitting
A-l Basic Data
A-2 Supplementary Data
A-3 Formulae
Annex B Example for Calculation of Load Factors for Bbnding Strbngth
B-l Basic Data
B-3 Supplementary Data
B-3 Formulae