Research On The Load Distribution Between The Travelling System And Final Drive Of Crawler Bulldozer

The crawler bulldozers are widely used, and they play a vital role in the construction ofthe national economy.The travelling system and the final drive system are importantcomponents of crawler bulldozers, the qualities of their structure and performance will affectthe performance of the complete machine directly.In Engineering practice, multiple sets finaldrive of some series crawler bulldozers have failure destruction when used. It is hard todetermine the failure reason.Through the mechanical analysis and strength checking to thefinal drive, it can be found that the strength of other parts of the final drive is sufficient, onlythe strength check of the large gear ring wheel hub and the half axle of the final drive isdifficult, leading to the destroyed reasons can’t be further analyzed, which is the engineeringproblem to be solved.The bottleneck of the problem is that the load from travelling system inwhat proportion to the large gear ring wheel hub and the half axle of the final drive fordelivery can’t be determined. Thus the key to solve this problem is to research on the loaddistribution between travelling system and final drive.This dissertation was supported by theinternational science and technology cooperation project of the national ministry of scienceand technology, that is the introduction of the key-technology of dual-use all-terrain andall-weather water and land multipurpose transport vehicle (No.2009DFR80010) anduniversity-enterprise cooperation project, that is the analysis of travelling and final drivesystem of some series crawler bulldozers. The load distribution between the travelling systemand the final drive of crawler bulldozers has been researched in this paper.This paper elaborated the background and significance of the research that the loaddistribution between the travelling system and the final drive of tracked bulldozers and madedetailed analysis of the main structure and motion principle of the travelling system and final drive. After that the paper found that the large gear ring wheel hub and the half axle of thefinal drive can be seen as a rigid body together as a whole.So the deformation of the largegear ring wheel hub and the half shaft of final drive is consistent in the same location.Therefore the mechanical analysis model of load distribution is put forward. And on this basis,according to the curvature of curved neutral layer is equal when the beam is bent, A simplemathematical model of stiffness distribution method of load distribution between thetravelling system and the final drive of tracked bulldozers is established.The integrated use ofdeformation compatibility condition of interference contact statically indeterminate structureand the energy method of unit load method and Moore integral graph multiplication, a precisemathematical model of deformation coordinate method that dealing with load distribution isestablished. The establishment of the mathematical model dealing with the load distributionbetween the travelling system and the final drive makes up for the shortage of the research ofthe domestic and foreign on the load distribution between the travelling system and the finaldrive of crawler bulldozers and solves the failure of final drive and the problem of final driveoptimization in engineering practice.In order to further study the load distribution between the travelling system and the finaldrive of crawler bulldozers and verify the correctness of the mathematical model, this paperhas carried on the virtual prototype simulation analysis.Firstly, the RecurDyn multi-bodydynamics simulation analysis was utilized to extract the load that the travelling systemtransfering to the final drive. Secondly, that data was added into ProE/Mechanica finiteelement analysis software. Thirdly, the finite element simulation analysis was carried out afterinputting the load and the constraint. Then the stress and strain of the large gear ring wheelhub and the half axle was gotten. Finally, by comparing the result with the theoreticalcalculation analysis, the correctness of mathematical model was verified. At the same time avirtual prototype model and joint simulation analysis method to solve the problem ofcaterpillar bulldozers’ load distribution was gotten.In order to further validate the reliability and validity of the mathematical model and the virtual prototype simulation analysis model of load distribution between the travelling systemand the final drive of tracked bulldozers, we conducted the real vehicle stress tests experimentof the crawler bulldozer.The nSoft software will process and analysis the experiment datacoming from experiment under various operating conditions rationally. Then the stress of thefinal drive half shaft was calculated, which was compared with the result of the theory andsimulation analysis. The comparison results showed that the results of the theory andsimulation of load distribution between the travelling system and the final drive werebasically identical with the experimental results. Thus, it provided two alternative theoreticalmethods to solve track-type travelling system and the final drive load distribution forengineering practice, a reliable method of virtual prototype simulation analysis. It also offereda feasible stress and strain test experimental method to conduct load distribution.In this paper, a more comprehensive and systematic analysis to the result of themathematical model, virtual prototype simulation analysis model and real vehicle experimentof load distribution between the travelling system and the final drive has been conducted. Bythe result of mathematical model and virtual prototype model of load distribution, we foundthat the safety factor of the final drive’s large gear ring wheel hub is too low, which is easy tocause the failure of the final drive. Therefore, when the large gear ring wheel hub’s design hasbeen improved and optimized, it made the final drive’s structure of crawler dozer morereasonable. No failure damage phenomenon has been found yet. The results proved that theload distribution between the large gear ring wheel hub and the half axle of the final drive ismainly related to the stiffness of both. Thus the cooperated design criteria have been summedup between the travelling system and the final drive. When designers are designing trackedvehicle, they can consider the load transferring mechanism to design the stiffness of trackedvehicle’s parts to make the tracked vehicle’s structure more reasonable. Solving the problemthat the load distribution between the travelling system and the final drive provided theoreticalbasis to improve and optimize the final drive, and it’s also helpful to solve the problem ofengineering vehicle’s load distribution.