ISO 6336-5:2016 pdf free

ISO 6336-5:2016 pdf free.Calculation of load capacity of spur and helical gears
Allowable stress numbers for bending are derived from the results of testing notched test pieces.Preferably, the ratio of the test piece notch radius to thickness should be similar to that of the fillet radius to the tooth-root chord in the critical section and the surface condition should be similar to that of the tooth root. When evaluating test data, it should be understood that test pieces are usually subjected to repeating bending stress, whereas in the case of a gear tooth, the fillets of the teeth are subjected to combined bending, shear and compressive stresses. Data on the various materials can be obtained from in-house testing, experience or from literature.
Allowable stress numbers for bending are derived from the results of testing un-notched test pieces.See 4.5 for comments on evaluation of test results. In order to take into account the effect of notch sensitivity, it is necessary that actual notch form and notch factors be included in calculations; thus,their results will be influenced by the extreme unreliability of these factors. Data on the various materials can be obtained from known test facilities or from literature.
The values are chosen for 1 % probability of damage. Statistical analysis enables adjustment of these values in order to correspond to other probabilities of damage but such adjustments need to be considered very carefully and may require additional specific tests or detailed documentation of the source of the information used to derive the confidence level of the failure probabilities.
The allowable stress number, OH lim, is derived from a contact pressure that may be sustained for a specified number of cycles without the occurrence of progressive pitting. For the beginning of the long-life area refer to the life factor ZNT for the different materials in ISO 6336-2 (for example case carburized, through hardened, and induction-hardened material 5 × 107, stress cycles are considered to be the beginning for the long life area).ISO 6336-5 pdf free.