IS 8843 : 1978 Accuracy requirements for turbine gears

1 Scope

1.1 This standard specifies basic tooth form modules andaccuracy requirements of high grade helical gears for turbine andsimilar drives. It does not, at present, cover gear loading and IS4460 : 1967 shall be used for rating of these gears. This standardapplies to four classes of gears, designated as Class AO, Class Al,Class A2 and Class B. Class AO is the highest.

1.1.1 The accuracies laid down for Classes AO, Al, and A2 aregenerally appropriate for gears running at pitch line speeds higherthan about 50m/s or where any other factor demands the highestclass. For lower pitch line speeds, the standards of accuracy laiddown for Class B will generally be appropriate.

2 References

IS 2 :1960 Rules for rounding offnumerical values

IS 2458 : 1965Glossary of terms for toothed gearing

IS 2467 : 1963Notation for toothed gearing

IS 2535 : 1978 Basicrack and modules of cylindrical gears for general engineering and heavy engineering

IS 4460 : 1967 Method for rating of machine cut spurand helical gears