Study On Wear Control And Sealing Characteristics Of Floating Oil Seal Of Chain Wheel Assembly

Scraper conveyors in coal mine gathering enable material transport in large scale coal mines.During coal mine gathering,the coal produced needs to be transported from the coal mining face to the surface or other handling equipment.The scraper conveyor is able to efficiently transport coal from the coal mining face to the designated location through a continuous scraper chain transport system,enabling rapid transfer of large quantities of coal and improving productivity.In harsh environments,the sprocket assembly is susceptible to coal dust and moisture,which can cause problems such as chain rusting,snagging and wear.As an effective sealing device,the floating oil seal can isolate the sprocket assembly from the external environment and prevent the entry of dust,moisture and impurities,thus extending the service life of the sprocket.For this reason it is of great practical value to carry out friction and wear research on floating oil seals to break through their original service life.The specific research contents are as follows:(1)By understanding the(?)ing principle of the floating oil seal,the analysis shows that the rubber seal can provide support and reaction force for the floating seal ring and the floating seal seat to ensure the stable operation of the overall structure.The selection explores the contact stresses generated by different hardness of NBR under different working conditions.In order to find a highly adaptable rubber seal,a comparison of the variation of contact stresses was chosen to analyze the stability of NBR of different hardnesses.The results of the study show that NBR with hardnesses Shore A 60 and Shore A 90 have less fluctuation of contact stress change with increasing friction coefficient at different friction coefficients.Under different lateral pressures.NBR with Shore A 60 and Shore A 70 hardnesses showed less fluctuation of contact stress change with increasing lateral pressure.Based on the above discussion,it is recommended to select rubber seal with Shore A 60 hardness when optimizing the floating oil seal.(2)In order to further optimize the structure of floating oil seal,surface weaving technology is selected to reduce the wear on the contact surface of floating seal ring.In this paper,the surface weave of circular shape is chosen because it is easy to process and has unique isotropic properties among the regular shape weave,and it has more applications in engineering.Considering the processing efficiency,processing cost,and processing accuracy,nanosecond laser processing of surface weaving is chosen in this paper.In order to better process the surface weave,we choose to analyze the influence of laser processing parameters on the surface weave,and the results show that during laser processing,the focal plane should be updated in time with the increase of processing times to ensure that there is a sufficient amount of laser beam hitting the material surface,and the best processing parameters are obtained:laser power 7.2W,laser frequency 25KHz,processing speed 200mm/s～250mm/s,and under this parameter,high quality surface weave can be obtained.Under these parameters,a high quality surface weaving laser processing effect can be obtained,which provides an important basis for the subsequent research on the wear characteristics and friction reduction effect of weaving.(3)A finite element simulation model with and without weaving is established,and commands are inserted in the contact setup,and the equations of the Archard model are written into it to extract the corresponding wear amounts during the simulation.The simulation results show that the wear on the pin surface increases with time and is mainly distributed at the outer circle.Comparing the overall wear of the two models,it is shown that the wear with weave is reduced by 56.8%compared to the one without weave.In order to better understand the effect of each parameter of the surface weave on wear,a control variable approach was taken to study the surface density,weave diameter,and weave depth.The results showed that the increment of wear was smaller as the weave depth increased,indicating that there was a low correlation between weave depth and wear.With the increase of weave diameter and surface density,the increment of wear is higher,which indicates that the weave diameter and surface density have a significant influence on wear.Based on the simulation results,it is concluded that the weaving depth is 100μm,the surface density is 20%～30%,and the weaving diameter is 100μm～200μm,which corresponds to the least amount of wear,and is a reference for the selection of the surface weaving parameters for the pin disk test later on.(4)In order to select the optimal combination of weave parameters and verify the applicability of the simulation,the surface densities of 10%,20%,and 30%,the weave diameters of 100μm,200μm,and 300μm,and the depth of 100μm were selected for the friction test study.To ensure the accuracy of the test,the load of the pin disc test as well as the rotational speed were determined equivalently by the PV value.Firstly,the wear characteristics of centerless grinding were studied.Under dry friction conditions,the graphs of the wear morphology of the three test discs were intercepted,and the comparison showed that the friction marks and wear depths of the three places were more uniform,which indicated that this friction test and the operation condition were good and stable,and could be used for the subsequent test study.Under the oil lubrication condition,the wear amount and friction coefficient are reduced due to the presence of oil film.In the study of the wear characteristics of the weaving,it is shown that the friction coefficient is the smallest for a surface density of 30%and a weave diameter of 200μm under dry friction conditions,and the smallest for a surface density of 20%and a weave diameter of 300μm under oil lubrication conditions by analyzing the average friction coefficient.It provides a theoretical basis for the design of weaving and wear reduction for the floating oil seal of sprocket assembly.The research in this paper provides theoretical support for the analysis of the rubber seal of the floating oil seal and proposes a surface weaving treatment for the contact surface of the floating seal ring in the floating oil seal,which provides a theoretical basis for practical engineering applications.