| The joint bearing is widely used in high-speed train because of its high efficiency in heavy load,high torque and other working conditions.Multiple factors that use such demanding conditions,easy to cause high iron bearing failure,for example,fabric liner layer and bearing inner ring wear soared,leading to stuck on the surface of the workpiece with low surface precision in transmission distortion,the fabric liner layer and outer bonding strength is not enough,etc.,and as a result,the high-speed rail bearing manufacturing put forward higher request,needs to solve the following problem:(1)high efficiency and high precision manufacturing technology of bearing parts;(2)high strength interface bonding technology of bearing self-lubricating liner layer and key parts mating surface.In view of the above problems,this paper has carried out a new polishing method of high-speed train bearing parts and the research on the interface characteristics of micro structure fabric of friction pairs.The specific research work is as follows:A new method of shear thickening chemical compound polishing for key bearing parts is put forward to solve the problems of insufficient manufacturing accuracy of joint bearing parts,low surface accuracy of workpiece mating surface,resulting in transmission distortion,etc.The basic principle and material removal mechanism of shear thickening and chemical compound polishing are expounded,and the material removal model is established.The test platform and processing system are built,the speed range of the driving polishing tool is 0?10.8 m/s,and the polishing pressure is 30?150 k Pa.The main influencing factors of the polishing process are analyzed,and the material removal model is verified.A new type of polishing fluid was developed,which is suitable for the efficient machining of high train bearing steel.The components of polishing solution are Ce O2,H2O2,PEG600,Na OH,dilute sulfuric acid,EDTA,p-chloro-m-dimethylphenol and deionized water.Through the test and inspection,the performances of the new polishing fluid are stable and can be used for the high-efficiency polishing of high-speed train bearing steel materials.The high efficiency and high-quality polishing process of high train bearing parts was optimized.Through the polishing test of 9Cr18 material,the influence of controllable process factors such as temperature,p H,polishing minimum clearance and polishing speed on the polishing surface quality was analyzed.The results show that,with the increase of temperature,the removal rate of polishing decreases and the surface quality decreases;under acid condition,when p H=4,the removal rate of polishing is high and the precision of surface roughness and shape is high;in the shear thickening elastic layer(about 0.4mm),the smaller the polishing gap is,the higher the polishing quality is,when the polishing minimum gap is greater than 0.4 When mm,it is difficult to obtain high efficiency polishing quality;with the increase of polishing speed,the material removal rate is relatively improved.When the polishing speed is 1250 rpm,the material removal rate is the largest and the surface quality is high;the surface roughness of the polished mating surface of the part reaches Ra 0.068?m(superior to the value Ra 0.800?m specified in the national standard GB/T 304.9-2008),and the surface accuracy is very high.The inner ring of the bearing corresponds to the sliding friction pair of the bearing.A new technology of interfacial bonding between the inner surface of the bearing outer ring and the fabric liner is proposed.Orthogonal experiments were carried out on the main factors affecting the bond strength,such as the surface microstructure,the amount of adhesive,and the loading and curing time,etc.,and the results showed that the influence degree of peel strength was successively>loading and curing time>microstructure morphology of the amount of adhesive.The optimal processing parameters were obtained as follows:the morphology of the micro structure was regular hexagon countersunk hole(0.5mm side length×0.5mm hole depth),the amount of glue(the whole outer ring)was 11.60g,and the loading and curing time was 6h.This new process makes the interface bonding strength of the micro structure fabric liner layer on the surface of the part high,the average peel strength is 0.59 N/mm,which is 1.67 times of national military standards(0.35 N/mm,GJB5502-2005),and meets the actual use requirements. |
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