Research On Simulation Method Of Gear Transmission System Fault

Gear transmission is of the following characteristics, large carrying capacity, high precision of transmission and constant power transmission etc., so be widely used in machinery, motor vehicle, aerospace and other fields to transmit motion and motive power. But because of its complicated structure and bad working environment factors, gear transmission system is easy to be broken down. Some of the factors might cause great influence on production or even serious safety accident. So, it is of the extremely vital significance to avoid the fault of gear transmission. In the fault of gear transmission, up to 60% are caused by the gear failures. Therefore, for avoiding the system failure, the normal operation of gear should be guaranteed.In various forms of gear failure, gear tooth root crack can reduce gear torsional mesh stiffness, make the gear tooth profile deviate the meshing position and gear tooth mesh incorrectly, which increases impact load when the fault gear meshes and takes off mesh. If the situation forms vicious circle, crack will expand rapidly, which eventually led to the teeth broken or other accidents. So, it appears particularly important to master dynamic response of crack when system running. Using the computer to do the dynamic simulation of gear transmission system not only can simulate its operation behavior and working status to offer theoretical basis for fault diagnosis, also can confirm weather this system's functions and properties are available and reliable, which can save manpower and material costs, reduce the product cost in design stage, enhance production efficiency and increase corporate profits. Based on the above reasons, Finite element method and numerical calculation method are adopted to simulate the dynamic behavior of single stage gear transmission in this paper. And mainly completed the following work:1. The common failures, characteristics and influence factors of gear failure are analyzed.2. Using APDL language in ANSYS and adopting the bottom up modeling method to establish the three-dimensional finite element model of two pair standard involutes spur gear respectively, one of which is without crack and the other is with crack. The stress of contact points and gear reverse angle are obtained through finite element analysis.3. Under certain torque, rotating those two gears to make then mesh in different position, the torsional meshing stiffness value of each position in one mesh circle is calculated by using gear reverse angle. The torsional meshing stiffness curves are obtained, the changes and differences of the two curves are compared and analyzed.4. The dynamic model of gear transmission system is built and then solved by using numerical calculation method in MATLAB to get dynamic simulation curve of with and without crack gear system, respectively.5. Design experiment to measure dynamic response of the gear transmission system when running. This simulation method is verified effective and feasible by comparing experiment result and simulation result.The effect caused by root crack on system dynamic response is mastered through dynamic simulation of gear transmission system, which provides a new method for gear fault diagnosis research.