Numerical Simulation Of Thermo-Mechanical Coupling In Plastic Helical Gear Meshing

Gear drive is a kind of transmission that was widely used, its function mainly havetwo parts: transfer power and movement. For it possessed with many meris that waswidely applied into our daily life and production, such as high transmission ratio, highaccuracy, efficiency, operation smoothness, long service life, compact structure, highsafety and reliability.With the development of material science and high demand of the lightweightindustrial products,plastic was more and more applied in production. Compared with thetraditional steel gear,plastic gear possessed with a lot of advantages,but for it also havea limitation of material properties, plastic gear would exposes some drawbacks inpractical use. Plastic itself with a high sensitive to heat and low fatigue intensity, socompared with traditional steel, plastic helical gear is easier to cause problems like gearfault, fatigue deformation, and agglutination. This article is mainly to study the frictionalheating characteristic of plastic helical gear pair under the situation of uniform meshingprocess. Main contents and conclusions of this dissertation are as follows:1．This paper primitively introduces the transmitting characteristics of plastichelical gear, research studies at home and abroad, finite element method of thedevelopment and its basic principle, a few of finite element software widespread usedand its characteristics in current market. Make sure to use LA-DYNA procedures toconduct the meshing process of plastic helical gear pair and dynamic simulation offrictional heating.2．This paper analysis the contact principle and friction heat mechanism in themeshing process of plastic helical gear pair, finished the calculation of tooth flankcontact stress, established the modal of friction heat flow of helical gear pair, discussedthe heat transfer analysis principle and finite element in theory, also made a introductionof finite element method and its contact theory, friction and heat transfer analysisprinciple, and the solving process. Completed a set of effective method in solving theproblems of the gear surface friction, thermo-mechanical coupling in meshing process ofplastic helical gear pair.3．Comprehensive use a variety of CAD/CAE software to finish the finite elementanalysis of gear surface friction that occurred in the meshing process of plastic helicalgear pair.Use SolidWorks to build a three-dimensional geometry model and accomplishits assembly, and completed the finite element model of the gear helical pair friction in HyperMesh software, finally finished the frictional dynamic simulation of helical gear inthe uniform meshing process under the situation of of dry friction. At the time ofcompleting the data transmission between each software efficiently, it promoted theefficiency and accuracy of finite element method,provided solutions and reference forengineers to solving the other engineering problems by the means of finite elementmethod.4．While the speed of driving wheel reaches60r/min and the resisting moment ofdriven gear is10N m,this paper would make a detailed analysis of the flash temperaturedistribution and changes of helical gear meshing. Temperature rise were mainly focus ongear teeth surface, furthermore,MC nylon itself with a low thermal conductivity, so theheat spread slowly. obtained the temperature distribution and its variation with time afterhaving been conflicted with the helical face gear. Finding that each gears has slightlydifferent when producing heat flow in the meshing process, as a result,it caused surfacetemperature very close.The heat flow that produced by approach point and recess pointof tooth mesh was far greater than the heat flow that produced by its other position,sothe highest transient temperature rise of the gear surface appeared near approach pointand recess point,and the highest and reasonable temperature should be0.74K.5．Under the condition of different rotate speed of a driving gear and resistingmoment of the follower gear to dynamic simulation,so as to further considered the risingsurface temperature that influenced by the speed of driving gear and resisting momentwhich influenced to the process of MC nylon gear meshing.Calculation result show thatincrease of driving gear’s rotational speed and follower’s resistance moment can lead toflash temperature increasing of the gear surface, only the range increased falls a littleduring the process, and the effect of follower gear’s resistance moment is more apparent.