Bending strength assessment of chemically-heat-strengthened Novikov gearing

¹ Don State Technical University, pl. Gagarin, 1, Rostov-on-Don, 344010, Russia
² South Federal University, Bolshaya Sadovaya Str. 105/42, Rostov-on-Don, 344006, Russia

^* Corresponding author: besk-an@ya.ru

Abstract

The article is devoted to the refinement of the flexural strength assessment of surface-strengthened gears with Novikov’s engagement. For standard involute wheels the results that were calculated in accordance with existing regulations and experiments could differ by an order of magnitude, or even more, then for Novikov’s transmissions, only partial recommendations based on experiments are relatively reliable. The influence of several factors, such as the possible initiation of flexural fractures under the action of contact stresses on the tooth’s leg, as well as the peculiarities of cyclic loading of gear teeth with two lines of engagement, have not been studied in practice. The purpose of this article is to assess the influence of tensile stresses on the boundary of the instantaneous contact spot in the conditions of reducing the plastic properties of the material due to thermal (chemical-thermal) treatment. The presence of a dangerous cross-section on the border of the active and transitional sections of the tooth profile is presented, which may not coincide with the area of action of the maximum tensile stresses, in which two essentially different types of stress-strain state will alternate, which considerably complicates the assessment of accumulation of fatigue damages.