| Highway construction occupies a very important position in the national economic development.The quality of engineering construction seriously restricts the development of the highway construction.Asphalt paver is a vital engineering machine in highway construction.The performance of crawler walking device is the key factor to determine the quality of pavement.In this paper,the combination of theoretical analysis,simulation analysis and experimental analysis is used to study the wear of track chain rail caused by excessive tension in normal working condition of paver,and the local deformation of track jumping teeth and track frame caused by excessive retreat of guide wheel in extreme working condition.Besides,it provides important theoretical significance and engineering value for the design and optimization of crawler walking device.According to the structure characteristics and driving principle of the crawler walking device,the theoretical calculation model of the crawler walking device is established,and the key dynamic parameters such as driving resistance,driving force,and pre-tensioning force are calculated theoretically,which provides the necessary theoretical basis for the establishment of simulation model and the selection of track tensioning device.Based on the multi-domain co-simulation technology,the mechanical-hydraulic co-simulation model of the crawler walking device is established.We studied the variation of vertical dynamic displacement,dynamic tension and driving torque of loose edge crawler board under different pre-tensioning forces.In addition,we proposed a new method for determining the pre-tension of the track which can more comprehensively alleviate the wear between the track chain rails when the paver is running.Furthermore,the variation law of the pressure in the hydraulic cylinder and the displacement of the piston rod under different is studied.The accumulator parameters suitable for the model are put forward,so that the guide wheel back amount of the crawler walking device is controlled in a reasonable range under the extreme working conditions,and the occurrence of the crawler jumping teeth is avoided.It also provides a theoretical basis for the subsequent improvement test of paver.Based on the rigid-flexible coupling simulation technology,the rigid-flexible coupling simulation model of the crawler walking device is established.The rigidflexible coupling simulation analysis of the crawler frame under different working conditions is carried out,and the stress distribution of the crawler frame under different working conditions is obtained.The main reasons for the local deformation of the crawler frame are analyzed,which provides an improvement direction for the structural optimization design of the crawler frame.According to the conclusion of simulation analysis,the crawler walking device of asphalt paver produced by an enterprise is improved and its driving performance is tested.The internal pressure of the tensioning hydraulic cylinder,the displacement of the piston rod of the tensioning hydraulic cylinder and the pressure of the inlet and outlet of the hydraulic motor are obtained under the conditions of straight and backward steering.The variation law is basically consistent with the simulation results,which verifies the accuracy of the simulation model.After optimizing the pre-tensioning force and accumulator parameters,the tension between the chain rails is effectively alleviated,and the risk of chain rail fracture is reduced.The displacement of the piston rod of the tensioning hydraulic cylinder of the crawler walking device is controlled within 10 mm under extreme working conditions,which avoids the occurrence of tooth jumping when the driving sprocket is engaged with the chain rail,thus verifying the effectiveness of the proposed method for selecting the pre-tensioning force and accumulator parameters. |
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