A Six Axles All-terrain Crane Steering Mechanism Optimization Design

In recent years,with the continuous investment in the domestic infrastructure construction,as well as the hoisting demand of wind power and petrochemical industry,the construction crane has achieved rapid development.The operation environment of wind power industry is bad,the road condition is poor,and the construction of large-scale wind farm in China greatly stimulates the development of large tonnage truck crane,especially all terrain crane.All terrain crane has strong bearing capacity,good steering maneuverability,and strong cross-country ability,at the same time,all terrain crane could easily transfer working area,also have high working efficiency;under the condition of temporary construction road,The powerful pass-through and flexible steering mode gives all terrain crane unparalleled advantages compare with ordinary truck crane.The research object of this paper is a steering system of a six axles all-terrain crane chassis.After launching this model on the market,two problems are found,one is the premature wear of the wheel,the other is the deformation of the steering rod.After the redesigning and analysing on the steering system,two design issues of steering mechanism were found,one is steering wheels are not according to the same circle during steering operation,sideslip of steering wheels exacerbated wear of tire;Secondly,the stiffness of the steering rod was designed and matched unreasonably,and the stiffness of individual steering rod is obviously lower than others,which causes the steering rod deformation when driving on the bad road.This paper introduces the Ackerman principle and deduces the steering angle function of the multi-axle steering vehicle.The calculation of the chassis steering center of the six axles all-terrain crane is carried out,and the conclusion is the steering center of chassis is at the center of the fourth axle.The main components of the steering mechanism of the six axles vehicle are introduced,and the connection and constraint relationship of each component are defined.The steering mechanism model of the six axles vehicle is established in the ADAMS.Using the steering angle error between the actual rotation angle of the wheel and the theoretical rotation angle as goal,the steering mechanism is simulated and analyzed for tire wear problem.The hinge point arrangement of the steering rod system is optimized by the optimization design method.The interference between the suspension guiding mechanism and the steering mechanism is considered,and the matching between them is analyzed,and the best matching effect is given.In view of the problem that the steering rod is eas ily to be deformed,three different bad driving conditions that the vehicle may encounter are extracted,and the pressure of the steering system under each working condition is calculated,The force was simulated and analyzed under different working conditions,and the safety factor of the steering rod under different working conditions was obtained.The position of the problem rod in the original design was found,which laid a theoretical foundation for the subsequent design improvement of the rod stiffness.Based on the application of ADAMS simulation software,this paper optimizes the angle error between the actual rotation angle and the oretical rotation angle of the wheel based on the Ackerman principle.Through the experimental verification and the feedback of the market,the improvement of the hinge point of the steering rod is proved effective.The solution has improved the wear problem of the wheels in the original design.For the problem that the tie rod is easily deformed,especially the frequent deformation on the eighth steering rod,problem was found through simulation,and the cross-sectional area of the eighth steering rod is increased to make the rigidity of the whole set rod more balanced.The deformation problem of the eighth steering rod under extreme working conditions is well solved.This paper analyzes and improves the two problems existing in the six axles all-terrain crane chassis steering system.The theoretical introduction and example calculations are taken as ideas.In the process of analyzing and solving problems,a practical set of design tools and optimization methods was provided for steering system designing.It has a good engineering application value in shortening the development cycle and improving the design accuracy,and the design essentials and design process that should be considered in the conventional design were sorted out.