Influence of idler misalignment fault on contact and dynamic characteristics of helical gear

Abstract

Due to the advantages of stable helical gear transmission, it is widely used in industry, agriculture, and national defense. Shaft misalignment has a great influence on the vibration, bearing capacity, and life of gear transmission. Based on the idler wheel drive system as the research object, according to the principle of gear meshing, the helical gear time-varying contact wire length model was deduced. The dynamic model of the gear transmission system with faults is established considering the faults of the idler's center distance error and angle error, and the influence law of idler misalignment fault on the vibration of the idler transmission system is revealed. On this basis, the finite element model under angle error is established to analyze the contact stress of the tooth surface under different faults and reveal the contact stress distribution law of the tooth surface. The results show that the misalignment fault will change the length of the helical gear contact line. When the gear shaft misaligns, it will increase the axial force of the gear and increase the axial vibration of the gear. Moreover, the angle error will cause uneven load distribution on the tooth surface of the helical gear, which will reduce the contact area of the gear and increase the contact stress. The phenomenon of off-load of gear accelerates the wear of the gear tooth surface and shortens the life of the gear. The study of idler misalignment fault is of great significance for prolonging the life of gear and providing the basis for gear fault diagnosis.