| In the modernization era of rapid development of construction machinery industry,there are different types of joint friction pairs in working devices such as crane,mining machinery and transportation machinery.In the working process,the hydraulic system provides the power to carry out the digging process,and at the same time,it can bear the alternating load and the contact collision,which cause the joint end face to be easy to wear and lose,thus it has an important influence on the performance of the whole machine.At the same time,because of the processing technology and other reasons,there is a gap in the joint friction pair,which will lead to vibration and bad wear of mechanical power equipment,thus changing the motion characteristics of the mechanism and even failure.Excavators are widely used in infrastructure construction of construction machinery industry,in which the working device is the main working part,as a result of the complexity of various working conditions and the harsh working environment,the end faces of the friction pairs of the three major joints are seriously worn,the invention is respectively the root position where the bucket bucket and the bucket rod are hinged,the bucket rod and the boom are hinged,and the boom and the base rotary platform are hinged.Among them,the bucket and bucket bar hinge joint end friction pair clearance has been extremely serious wear.At present,there is a lack of research on the wear performance of bucket joint friction pair during excavation.In this paper,use a type of excavator bucket joint end face friction pair is studied,Based on the simulation of joint forces under two typical working conditions,the change process and wear mechanism at the clearance of bucket joint end friction pair are studied in depth,and corresponding optimization and improvement schemes are proposed.The main research contents are as follows:Firstly,the working device of excavator is modeled by Lagrange Dynamics,and the force changes of three main joint gaps during operation were analyzed theoretically.Two typical working conditions are selected,and the characteristics of the force and wear of the bucket joint end face are summarized.The dynamic load data of the friction pair gap of the bucket joint end face are obtained by using the virtual prototype technology to simulate the excavation process.Secondly,the finite element model of the bucket joint kingpin was established.Based on the dynamic load data,the dynamic contact stress was analyzed on the end face of the ear plate at the gap,and the normal contact pressure curve at the end face clearance was obtained.The classical Archard wear model was modified,and the end face wear depth value was solved by discrete thinking analysis method combined with ALE redivision technology of finite element mesh surface,and the relationship between wear depth value and wear times was summarized.Finally,wear experiments were carried out on the end surface wear testing machine to verify the wear surface topography of the wear-resistant gasket in the gap.Based on the analysis of the wear mechanism in the clearance of the friction pair of bucket joints,the optimization design scheme of tribology was put forward: The friction pairs of bucket joints are mainly anti-abrasive wear,adhesive wear and improvement of surface lubrication.By designing a new type of wear-resistant gasket based on Powder metallurgy material and improving its structure,the test results show that its wear-resistant performance is better than the traditional wear-resistant gasket,it provides a theoretical reference for improving the wear performance and working efficiency of bucket joints.Figure [59] Table [14] Reference [75]... |
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