The Tightening Process Parameter Optimization Of A Loader Wheel Rim Bolt

As a detachable connection method, bolt connection is widely used in variousindustrial fields. In order to guarantee the quality of products, it is necessary to makeprecise analyses of process parameters in the process of bolt tightening, so as todetermine the process parameters in the process of bolt tightening.Loader rim bolt is an important part for connection between rims and a wholemachine, and the connection quality will directly influence on the use performance of theloader machine. Because the elastic effect of prestressing force of bolt will influenceeach other, this state will affect the implementation of the unified pre-tightening forcebolt group. This paper presents the study of the tightening order on rim bolt of a loadermachine through the finite element analysis and theoretical calculation and the study forthe realization of the expected pre-tightening force torque required, the main researchwork is as follows:Firstly, use the3D design software UG to establish the models of the steel ring andstar wheel frame, wheel hub which are assembled by the rim bolt, and import theassembly into the finite element software HyperMesh for pre-treatment.Secondly, divide the complex assembly into several parts in HyperMesh, whichhelps to get a excellent grid structure with hexahedron unit and pentahedron unit. Afterdividing the grid on the different parts, the corresponding material properties arerespectively added, meanwhile, the corresponding contact ways between different partsare also set up. Finally, with the help of the corresponding load curves, boltpre-tightening force can be applied by a one-dimensional spring unit SPRING2N as thetwo parts for connecting bolt.Thirdly, by controlling the loading time, the bolt stress curve can be achieved bymathematical operation. By comparing different results of the mean and variance on bolttightening on the conditions of different tightening order, it is concluded that the bestway to tighten is the second way (1-3-5-1-3-5-6-8). Finally, through MOBILE SYSTEMdata acquisition front-end--SADAS SCM05and the corresponding software LMS TestLab9to acquire the results of bolt stress curve in the process of tightening. And by thecomparison of the experiment and simulation results of stress curve, the simulationmodel is validated by the experiment.Fourthly, make a finite element analysis of the nut and the surface of connector inthe bolt connection, and thus the value of the contact stress of each node can bedetermined. By using the MATLAB for the polynomial fitting of the contact stress, the contact stress distribution can be achieved.Fifthly, make a thorough analysis of the formula of moment of torque in tighteningmethod, and then calculate the torqueT pthat produces the prestressing force throughthe geometric relations between the screw thread. Through the mathematicaloperation--integral operation on the stress distribution curve of contact plane, the nutfriction torqueTb that comes from nut and connection plate can be obtained. Witheffective selection of intermediate diameter as a screw thread surface friction radius, it isconcluded that the friction torqueTt which uses to overcome thread frictionTt can beobtained.