Rectification de dentures de réducteurs nitrurées à l’aide de meules en CBN : mesure des contraintes résiduelles par diffraction X

Grinding of nitrided gear teeth of power transmission system with grinding wheels in CBN : X-ray diffraction measurement of residual stresses

¹ Ingénieur d’Etudes, Centre d’Etude des Structures et Matériaux Navals, DCN Indret
² Technicien Contraintes Résiduelles, Centre d’Etude des Structures et Matériaux Navals, DCN Indret
³ Ingénieur expert Réducteurs, Sous-Direction Etudes Essais, DCN Indret, La Montagne

Abstract

The knowledge of the residual stress levels of nitrided gear teeth of power transmission system provides information for predicting their fatigue lifetime. In the aim of an improvement of our grinding techniques, the influence of both, the finishing pass depth and the loading of CBN (cubical boron nitride) grinding wheel on the residual stress levels was investigated.

The surface residual stresses are in compression and more elevated in the circumferential direction than in the axial one. As the finishing pass depth increases, the residual stresses decrease. The dressing of the grinding wheels during grinding prevent the drop of residual stresses up to 200 N/mm² linked to the loading of the grinding wheels. The depth affected by the grinding is 0.01 mm ; beyond this depth, the profile is equivalent to a nitriding profile.