Study On Optimizing Grader Ring Gear Shape And Materials Heat Treatment Technology

Gear transmission has many advantages, such as high efficiency, compactstructure and reliable operation. It has been widely used in the transmission ofconstruction machinery. The service life of gear plays an important role in geartransmission. And the forms of gear failure directly affects the service life of the gear,such as broken teeth, tooth wear, tooth surface pitting, tooth bonding and plasticdeformation. Thereby, it can affect the entire production process.The background of this paper is the research trends of gear material at home andabroad. Combining with the structures and the various mechanical propertyrequirements of grader ring gear, taking the actual using environment of grader ringgear into account, this paper want to provide the best ring gear material after selection.At the beginning, this paper analyses the grader ring gear problems in using process.Through comparing the original ring gear shape and another designed ring gear shapein meshing performance and contact stress, we get the better ring gear shape, and thenoptimize it. Different material used for ring gear will bring different results inmachining performance and service life. So it’s important to choose the right materialcarefully according to the use of working environment. This paper tests three kinds ofsteels, which are18MnMoNb steel, Q345steel, Q550steel, in process performance,mechanical properties and other performances. We want to find the more suitablematerial through contrasting the different performances. We did a lot of standardtensile tests for different material, and obtained the tensile strength data andelongation data. After comparing, we find that Q345steel is good at tensile strength550MPa and elongation performance34.2%. We also did a lot of impact toughnesstest at different temperatures. Through analyzing the wear test data, we calculatedthe wear volume in the design life of the three kinds of materials. We find that Q345steel has the best wear resistance, and Q550steel has the worst wear resistance. Afterstudying on the gear roots’ bending fatigue life data and the tooth surface contactfatigue life data, we find that18MnMoNb steel and Q345steel have the similarfatigue performance, they are much better than Q550steel in fatigue performance. Atlast, in order to improve the tooth surface hardness and wear resistance further, wetried to develop a suitable surface induction hardening process. We made a surfaceinduction hardening device, and used it to harden the18MnMoNb gear and the Q345 gear. We find that Q345steel is better at uniformity and stability inhardness distribution.Optimizing the design of the ring gear shape by the large general finite elementsoftware ANSYS. Comparing the process performance, mechanical properties andeconomic efficiency, we ultimately confirm the Q345steel is the best steel for ringgear in the three kinds of steel. And we provide a good surface induction hardeningprocess for strengthen the grader ring gear. This paper provides a theoretical andexperimental evidence for making grader ring gear.