Analysis of changes in geometry and kinematics of the gear gears in conditions of abrasive wear

Studies of the reliability of modern agricultural, food and mining machines and mechanisms show that up to 40% of failures occur in transmission units, the performance of which is largely regulated by gears, which are operated in conditions of high air dust and insufficient tightness of internal cavities. As a result of wear on the teeth of the wheels, vibrations appear, and dynamic loads in the drives increase. All this is largely due to the change in gear gearing kinematics during wear. The purpose of this work is to study changes in the geometry and kinematics of gears under conditions of abrasive wear. The objects of research were the evaluation of the distribution of contact stresses and loads, which is a key point in the development of wear-resistant and reliable gears. Additional factors were determined: the influence of operational loads, changes in the shape of teeth during operation and their impact on the accuracy of motion transmission. As a result of the research, analytical dependencies have been developed that make it possible to calculate the geometric, kinematic and qualitative characteristics of the transmission and predict the wear rate of gears and wheels, estimate the magnitude of contact stresses and the coefficient of specific slip along the engagement line of a pair of teeth at various stages of wear. During the wear process, the engagement line bends, and its beginning and end shift in the direction of rotation of the gears. The overlap coefficient gradually decreases, but with a degree of wear above 18-20% it stabilizes in the range of 1.03–1.1. During the abrasive wear of heavily loaded gears, not only the shape of the tooth profiles changes, but also the law of relative movement of the wheels changes.