A mixed method of solution for contact stresses on rollers was suggested by the combina- tion of similitude principle.photoelastic method,Hertz's contact theory and numerical calculation.Thus,not only the distribu...A mixed method of solution for contact stresses on rollers was suggested by the combina- tion of similitude principle.photoelastic method,Hertz's contact theory and numerical calculation.Thus,not only the distribution regularity of axial contact pressure on roller of limited length,but also the three-dimensional solution of stresses in the contact po- sitions may be obtained.An actual example is presented in the paper.It shows that the practical damaged phenomenon in real roller is in agreement with the result of the analysis展开更多
An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(EHL)of a logarithmic profile roller,which is rolling over a flat plane,is given The analysis takes account of sideways fl...An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(EHL)of a logarithmic profile roller,which is rolling over a flat plane,is given The analysis takes account of sideways flow of lubricant in the inlet region of the contact When the results are presented in suitable non dimensional groups,it is shown that more uniformly pressure and shape of the film distributing in axial direction is taken place under light loading As the increase of the load,the end closure is displayed and the oil pressure rises sharply at the ends The seal action formed by the end closure makes the film thickness a little And the minimum film thickness is transferred from the central to the ends and the value is reduced rapidly As the increase of the speed,the end closure becomes much serious The optimum crowning value obtained in EHL state is larger than the design value obtained in elastostatic contact state for the same working conditions In order to verify the correctness of theory,optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling conditions It is found the agreement between numerical solutions and experiments is very good.展开更多
According to elastic contact theory, contact model between roller and race is established. Compared with the Hertz results, the results are proved, based on which contact stress distribution of different crowning and ...According to elastic contact theory, contact model between roller and race is established. Compared with the Hertz results, the results are proved, based on which contact stress distribution of different crowning and initial contact length is given, then the appropriate value is derived. On the basis, inertia force and different radial force is given into consideration. Via analysis, it con- cludes that under balanced pure radial load condition the largest contact stress between roller and race increases along with crowning value increasing. With the same crowning value, the largest contact stress between roller and race decreases in the first and increases at the end along with initial contact length increasing. Contact stress between roller and outer race increases along with revolution speed increasing.展开更多
According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roll...According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roller shell under the condition of periodic thermal shock.The temperature variation law inside the roller shell is studied during the process of continuousroll casting, and the steady temperature distributions of the roller shell at different castingvelocities have been obtained when the thermal contact conductance between the roller shell and thecasting strip is considered.展开更多
In this paper, the effect of the grinding undercut of the raceways on the longitudinal pressure distribution of the profiled rollers, which are the most popular axial profile employed by the bearing manufacturers, was...In this paper, the effect of the grinding undercut of the raceways on the longitudinal pressure distribution of the profiled rollers, which are the most popular axial profile employed by the bearing manufacturers, was discussed. Based on the profiled roller geometrical equations and numerical calculation of three dimensional elastic contact problems of finite length, a new numerical method for calculating the crown drop evaluation considering the effect of grinding undercut was used. The analyses of two structure case, that roller length is greater or less than raceway width, were carried out and compared with each other. The Results show that the width of grinding undercut must be considered in determining the crown drop of rollers.展开更多
文摘A mixed method of solution for contact stresses on rollers was suggested by the combina- tion of similitude principle.photoelastic method,Hertz's contact theory and numerical calculation.Thus,not only the distribution regularity of axial contact pressure on roller of limited length,but also the three-dimensional solution of stresses in the contact po- sitions may be obtained.An actual example is presented in the paper.It shows that the practical damaged phenomenon in real roller is in agreement with the result of the analysis
基金This project is supported by National Natural Science Foundation of China (No.59475037).
文摘An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(EHL)of a logarithmic profile roller,which is rolling over a flat plane,is given The analysis takes account of sideways flow of lubricant in the inlet region of the contact When the results are presented in suitable non dimensional groups,it is shown that more uniformly pressure and shape of the film distributing in axial direction is taken place under light loading As the increase of the load,the end closure is displayed and the oil pressure rises sharply at the ends The seal action formed by the end closure makes the film thickness a little And the minimum film thickness is transferred from the central to the ends and the value is reduced rapidly As the increase of the speed,the end closure becomes much serious The optimum crowning value obtained in EHL state is larger than the design value obtained in elastostatic contact state for the same working conditions In order to verify the correctness of theory,optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling conditions It is found the agreement between numerical solutions and experiments is very good.
基金Nation Key Technology R&D Program of China (2011BAF09B01)National Science and Technology Major Project of China(2009ZX04010-021)
文摘According to elastic contact theory, contact model between roller and race is established. Compared with the Hertz results, the results are proved, based on which contact stress distribution of different crowning and initial contact length is given, then the appropriate value is derived. On the basis, inertia force and different radial force is given into consideration. Via analysis, it con- cludes that under balanced pure radial load condition the largest contact stress between roller and race increases along with crowning value increasing. With the same crowning value, the largest contact stress between roller and race decreases in the first and increases at the end along with initial contact length increasing. Contact stress between roller and outer race increases along with revolution speed increasing.
基金This work was supported by the State Key Project of Fundamental Research(No.199906496).
文摘According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roller shell under the condition of periodic thermal shock.The temperature variation law inside the roller shell is studied during the process of continuousroll casting, and the steady temperature distributions of the roller shell at different castingvelocities have been obtained when the thermal contact conductance between the roller shell and thecasting strip is considered.
文摘In this paper, the effect of the grinding undercut of the raceways on the longitudinal pressure distribution of the profiled rollers, which are the most popular axial profile employed by the bearing manufacturers, was discussed. Based on the profiled roller geometrical equations and numerical calculation of three dimensional elastic contact problems of finite length, a new numerical method for calculating the crown drop evaluation considering the effect of grinding undercut was used. The analyses of two structure case, that roller length is greater or less than raceway width, were carried out and compared with each other. The Results show that the width of grinding undercut must be considered in determining the crown drop of rollers.
