DANSK DSF/ISO/FDIS 6336-1 PDF

This part of ISO 6336 presents the basic principles of, an introduction to, and the general influence factors for, the calculation of the load capacity of spur and helical gears. Together with the other documents in the ISO 6336 family, it provides a method by which different gear designs can be compared. It is not intended to assure the performance of assembled drive gear systems. It is not intended for use by the general engineering public. Instead, it is intended for use by the experienced gear designer who is capable of selecting reasonable values for the factors in these formulae based on knowledge of similar designs and awareness of the effects of the items discussed. The formulae in ISO 6336 are intended to establish a uniformly acceptable method for calculating the load capacity of cylindrical gears with straight or helical involute teeth. ISO 6336 includes procedures based on testing and theoretical studies as referenced by each method. The methods are validated for: – normal working pressure angle from 15° to 25°; – reference helix angle up to 30°; – transverse contact ratio from 1,0 to 2,5. If this scope is exceeded, the calculated results will need to be confirmed by experience. The formulae in ISO 6336 are not applicable when any of the following conditions exist: – gears with transverse contact ratios less than 1,0; – interference between tooth tips and root fillets; – teeth are pointed; – backlash is zero. The rating formulae in ISO 6336 are not applicable to other types of gear tooth deterioration such as plastic deformation, case crushing and wear, and are not applicable under vibratory conditions where there may be an unpredictable profile breakdown. ISO 6336 does not apply to teeth finished by forging or sintering. It is not applicable to gears which have a poor contact pattern. The influence factors presented in these methods form a method to predict the risk of damage that aligns with industry and experimental experience. They may not be entirely scientifically exact. Therefore, the calculation methods from one part shall not be used in another part unless specifically referenced. The procedures in ISO 6336 provide rating formulae for the calculation of load capacity with regard to different failure modes such as pitting, tooth root breakage, tooth flank fracture, scuffing and micropitting. At pitch line velocities below 1 m/s the gear load capacity is often limited by abrasive wear