Bionic Research On Wear Resistance And Fatigue Life Of Spur Gears

Gear industry, related to many other industries and being invested very muchmoney, is one of the foundations in equipment manufacturing industry. It is alandmark of China shifting from a manufacturing industry big state to amanufacturing industry powerful nation. There are about200mainstay gearcompanies in China, but the high performance gears are imported only. In order tochange this situation, self-research and self-innovation must be improved andenhanced.There are some methods to improve gears`performance and lifetime, but theycannot solve all of the problems. Bionics discovers that the surfaces of many wearresistance and anti-fatigue organisms, such as pangolin and shell, are non-smooth andsoft and hard alternated. Using the research results of Ministry of Education KeyLaboratory of Bionic Engineering in Jilin University for reference,9stripy bionicsurface morphologies are proposed in this paper based on bionic non-smooth surfacetheory and laser quenching technology. The morphologies are similar to surfaces ofshells, soft and hard alternated, with micro width and depth (width is160-260μm,depth is about3μm), and arrange regularly. Then the best bionic morphology isfabricated on the gear tooth surfaces. Gear meshing test shows that the bionic gear hasbetter wear resistance and anti-fatigue performance. It enlarges the range ofapplication of bionics, and provides theoretical basis for the research on bionics andtransmission technology of gears. This paper`s primary coverage is as follows:Firstly, after considering the non-smooth micro surface morphology of shell,features of gear transmission, dimensions of gear and cylindrical roller, reasons forfatigue failure of gear, and manufacture accuracy of existing equipment,9bionicsurface morphologies with different parameters are designed. In order to save cost andsimplify the experiment, cylindrical rollers are selected to test these different surfacemorphologies instead of gears according to the similarity between gear meshing androllers`rolling so that the best morphology can be found out and fabricated on gears.Secondly, these9different surface morphologies are fabricated on the surfaces ofthe rollers by laser quenching technology so that the bionic rollers are obtained. The2D and3D scan images of the surface morphologies are observed, and the fracturemorphologies, microstructures and microhardness are analyzed. The regular smoothsurface cylindrical rollers, laser quenched rollers and bionic cylindrical rollers are rolled on wear tester. The results show that the bionic rollers have better wearresistance performance. The No.2bionic roller, whose fringe width is185μm, laserscan speed is120mm/s, fringe center distance is457μm, has the best wear resistanceperformance with0.0279%wear rate.Thirdly, the surface morphology on No.2roller is fabricated on the gear surface.The regular gears and bionic gears are tested on the gear tester CL-100A. The wearresistance performance is assessed by comparing the variations of the tooth profiletotal deviation and the spiral line total deviation before and after the test. Theanti-fatigue performance is assessed by comparing the single tooth pitting area ratios.The experiment results show that the variations of the tooth profile totaldeviations of the regular gearwheel and regular pinion before and after the test are25.750μm and9.175μm, and the variations of the spiral line total deviations of theregular gearwheel and regular pinion before and after the test are3.500μm and3.750μm；but the variations of the tooth profile total deviations of the bionicgearwheel and bionic pinion before and after the test are3.825μm and6.500μm, andthe variations of the spiral line total deviations of the bionic gearwheel and bionicpinion before and after the test are2.450μm and3.625μm. The average single toothpitting area ratios of the regular gearwheel and pinion are1.26%and1.55%；but theaverage single tooth pitting area ratios of the bionic gearwheel and pinion are0.58%and1.04%.Thus, the bionic gears have better wear resistance and anti-fatigueperformance. Finally, the wear resistance and anti-fatigue mechanisms of bionic gearare analyzed and discussed.