Dynamic Research And Fault Simulation On Helical Gear

Most of modern machinery is drived by gear transmission devices. In the process of meshing transmission, not only movement is conveyed, but also torque. Currently in the design of the gear, Involutes tooth profile with its smooth transmission and simply designed has been widely used, which lead to the involutes tooth Occupies the main position in the tooth profile. With the rapid development of science, technology and machinery industry, the gear driving is put forward the more strict requirements. These requirements are mainly high bearing capacity, low noise, light weight and high reliability. Reliability relates to the safety in production. Broken teeth is Once appearing, may it cause serious production accidents. So study of gear fault diagnosis method is more and more widely get people’s attention. At present Gear fault diagnosis has developed into a specialized gear research branch of discipline.Compared with the spur gear transmission, helical gear transmission holds the advantages of large coincidence degree, smooth contact and compact structure. It widely used in the transmission system of the modern large-scale mechanical device. But, because of the large load in the transmission process and improper operations, which cause the gear failures. The types of gear failures are a lot of. According to the most common kinds of broken teeth in the production practices, this article takes root crack as the research object. By using computer numerical calculation method-Finite Element Method, this paper researches on the dynamic-characteristics of helical gear transmission system. The ANSYS simulation analysis of the helical gear transmission system greatly improves the computational efficiency, reduces the cost of research. This paper mainly completed the following works:1. The whole thinking and steps of the finite element analysis were Introduced, and the theoretical basis of the finite element method that are the weighted residual method and the variational principle was also discussed.2. Combined with the processes of the finite element analysis, the establishment of geometric model and meshing and loading and constraints of the normal and fault helical gear were Introduced. Finally, we can conclude how the root crack influenced the gear strength.3. Based on the state of helical gear meshing transmission, we do the explicit dynamic analysis of helical gear. By comparing the curve of meshing force of normal gear and fault gear, we can conclude how the root crack influenced the dynamic characteristics of helical gear.4. Through the way of free meshing, the three-dimensional finite element model of helical gear is established. On the basis of this model, we do the finite element modal analysis of helical gear. We got the each order natural frequency and modal shapes of helical gear. Through the analysis of simulation results, we know the circumference vibration is the main vibration mode that leads to the resonance of helical gear.Finally, the root crack can be discovered by the dynamic analysis and contact stress analysis.