Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly...Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly from 1.7×10^(-7) to 9.8× 10^(-7) mm^3/mm under the load lower than 300 N, and then increased dramatically to the climax of 216×10^(-7) mm^3/mm under the load over 300 N, which indicated the transition of wear mechanism with the increase of applied load. The wear mechanism mainly was plastic deformation and abrasive wear under the load less than 300 N. As the applied load was more than 300 N, the wear mechanism of Cu-15Ni-8Sn alloy primarily was delamination wear. Besides, the transition can also be confirmed from the different morphologies of worn surface, subsurface and wear debris. It is distinctly indicated that the appearance of flaky debris at the applied load over 300 N may be a critical point for the change of wear mechanism.展开更多
Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated bas...Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated based on the theory of hydrodynamic lubrication.N-S equation,energy equation,viscosity-temperature equation and vapor transport equation were solved with the finite volume method by using Fluent software,which was performed to analyze the influence of the viscosity-temperature and cavitation effect on hydrodynamic lubrication failure of the film.The research demonstrates that it will lead to the significant difference of the temperature field by considering the coupling of temperature and viscosity.When the film thickness decreases and the rotating speed rises,cavitation regions and viscous friction heat increases,the opening force of the film is also enhanced.However,the growth rate is restricted to the cavitation regions and viscous friction heat,and the opening force begins to decline to a certain extent,and thereby being insufficient to open the surfaces of the seals and leading to the failure of automatic adjustment function and severe wear,lubrication failure occurrs.Through comprehensive research on the influences of viscosity-temperature and cavitation effect on hydrodynamic lubrication performance,the theories of failure and design of upstream pumping mechanical seal are further developed.展开更多
External return mechanism is a mechanical structure applied to axial piston pumps.To study its lubrication characteristics,the Reynolds equation applied to an external return spherical hinge pair was deduced based on ...External return mechanism is a mechanical structure applied to axial piston pumps.To study its lubrication characteristics,the Reynolds equation applied to an external return spherical hinge pair was deduced based on the vector equation of relative-motion velocity of the external return spherical hinge pair under the influence of external swash plate inclination and offset distance.The results show that the total friction,axial leakage flow,and maximum value of the maximum oil-film pressure increase with increasing pump-shaft speed and decrease with increasing offset distance in one working cycle when the external-swash-plate inclination is constant.However,the varying offset distance has little effect on the axial leakage flow.The maximum value of the maximum oil-film pressure decreases with increasing external-swash-plate inclination and the total leakage flow increases with increasing external-swash-plate inclination in one working cycle when the offset distance is constant.It can be seen that the abovementioned parameters are important factors that affect the lubrication characteristics of external return spherical hinge pairs.Therefore,the complex effects of different coupling parameters should be comprehensively considered in the design of the external return mechanism.展开更多
The sliding-rolling mixed motion behavior degrades the ball screw’s precision at different levels.Based on the sliding-rolling mixed motion between ball and screw/nut raceway,the ball screw’s precision loss consider...The sliding-rolling mixed motion behavior degrades the ball screw’s precision at different levels.Based on the sliding-rolling mixed motion between ball and screw/nut raceway,the ball screw’s precision loss considering different given axial loading and rotational speed working conditions was investigated.Since creep and lubrication relate to sliding and rolling motion wear,the creep and lubrication characteristics are analyzed under different working conditions.Besides,the precision loss was calculated considering the sole influence of sliding behavior between ball and screw and compared with the results from other current models.Finally,research on precision loss owing to the sliding-rolling mixed motion behavior was realized under given working conditions,and suitable wear tests were carried out.The analytical results of precision loss are in good agreement with the experimental test conclusions,which is conducive to better predicting the law of precision loss in stable wear period.展开更多
本文中以美国食品药品监督管理局(Food and Drug Administration,FDA)批准的食品添加剂月桂酰肌氨酸钠和氨基酸为原料,采用简单的质子交换反应合成了2种氨基酸基离子液体Lys-LS和Arg-LS,并将其用作水基润滑添加剂.利用SRV-V微动摩擦磨...本文中以美国食品药品监督管理局(Food and Drug Administration,FDA)批准的食品添加剂月桂酰肌氨酸钠和氨基酸为原料,采用简单的质子交换反应合成了2种氨基酸基离子液体Lys-LS和Arg-LS,并将其用作水基润滑添加剂.利用SRV-V微动摩擦磨损试验机和全自动真彩共聚焦显微镜考察了2种离子液体添加剂的摩擦学性能,并采用扫描电镜(SEM)、石英晶体微天平(QCM)和X射线光电子能谱仪(XPS)深入探究了其润滑机理.研究结果表明:2种氨基酸基离子液体添加剂具有良好的热稳定性且可以显著抑制铸铁在水中的腐蚀.与去离子水相比,当Lys-LS和Arg-LS的添加质量分数为0.5%时,水基润滑液的摩擦系数和磨损体积分别降低了约70%和85%,具有显著的减摩抗磨效果.机理分析结果表明,离子液体在界面处形成的摩擦化学反应膜与物理/化学吸附膜协同作用,有效地阻止了滑动摩擦副之间的直接接触,进而赋予水基润滑液优异的摩擦学性能.2种润滑添加剂制备简单,安全无毒且绿色环保,有望作为水基金属加工液和难燃液压液的关键润滑添加剂使用.展开更多
基金Project(2016YFB0301402)supported by the National Key Research and Development Program of ChinaProject(CSU20151024)supported by the Innovation-driven Plan in Central South University,China
文摘Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly from 1.7×10^(-7) to 9.8× 10^(-7) mm^3/mm under the load lower than 300 N, and then increased dramatically to the climax of 216×10^(-7) mm^3/mm under the load over 300 N, which indicated the transition of wear mechanism with the increase of applied load. The wear mechanism mainly was plastic deformation and abrasive wear under the load less than 300 N. As the applied load was more than 300 N, the wear mechanism of Cu-15Ni-8Sn alloy primarily was delamination wear. Besides, the transition can also be confirmed from the different morphologies of worn surface, subsurface and wear debris. It is distinctly indicated that the appearance of flaky debris at the applied load over 300 N may be a critical point for the change of wear mechanism.
基金National Natural Science Foundation of China(Grant No.51279067)
文摘Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated based on the theory of hydrodynamic lubrication.N-S equation,energy equation,viscosity-temperature equation and vapor transport equation were solved with the finite volume method by using Fluent software,which was performed to analyze the influence of the viscosity-temperature and cavitation effect on hydrodynamic lubrication failure of the film.The research demonstrates that it will lead to the significant difference of the temperature field by considering the coupling of temperature and viscosity.When the film thickness decreases and the rotating speed rises,cavitation regions and viscous friction heat increases,the opening force of the film is also enhanced.However,the growth rate is restricted to the cavitation regions and viscous friction heat,and the opening force begins to decline to a certain extent,and thereby being insufficient to open the surfaces of the seals and leading to the failure of automatic adjustment function and severe wear,lubrication failure occurrs.Through comprehensive research on the influences of viscosity-temperature and cavitation effect on hydrodynamic lubrication performance,the theories of failure and design of upstream pumping mechanical seal are further developed.
基金Project(GXXT-2019-048)supported by the University Synergy Innovation Program of Anhui Province,ChinaProject(51575002)supported by the National Natural Science Foundation of ChinaProject(gxbj ZD11)supported by the Top-Notch Talent Program of University(Profession)in Anhui Province,China。
文摘External return mechanism is a mechanical structure applied to axial piston pumps.To study its lubrication characteristics,the Reynolds equation applied to an external return spherical hinge pair was deduced based on the vector equation of relative-motion velocity of the external return spherical hinge pair under the influence of external swash plate inclination and offset distance.The results show that the total friction,axial leakage flow,and maximum value of the maximum oil-film pressure increase with increasing pump-shaft speed and decrease with increasing offset distance in one working cycle when the external-swash-plate inclination is constant.However,the varying offset distance has little effect on the axial leakage flow.The maximum value of the maximum oil-film pressure decreases with increasing external-swash-plate inclination and the total leakage flow increases with increasing external-swash-plate inclination in one working cycle when the offset distance is constant.It can be seen that the abovementioned parameters are important factors that affect the lubrication characteristics of external return spherical hinge pairs.Therefore,the complex effects of different coupling parameters should be comprehensively considered in the design of the external return mechanism.
基金Project(51975012)supported by the National Natural Science Foundation of ChinaProject(Z1511000003150138)supported by the Beijing Nova Program,China+1 种基金Project(Z191100001119010)supported by the Shanghai Sailing Program,ChinaProject(2018ZX04033001-003)supported by the National Science and Technology Major Project,China。
文摘The sliding-rolling mixed motion behavior degrades the ball screw’s precision at different levels.Based on the sliding-rolling mixed motion between ball and screw/nut raceway,the ball screw’s precision loss considering different given axial loading and rotational speed working conditions was investigated.Since creep and lubrication relate to sliding and rolling motion wear,the creep and lubrication characteristics are analyzed under different working conditions.Besides,the precision loss was calculated considering the sole influence of sliding behavior between ball and screw and compared with the results from other current models.Finally,research on precision loss owing to the sliding-rolling mixed motion behavior was realized under given working conditions,and suitable wear tests were carried out.The analytical results of precision loss are in good agreement with the experimental test conclusions,which is conducive to better predicting the law of precision loss in stable wear period.
文摘本文中以美国食品药品监督管理局(Food and Drug Administration,FDA)批准的食品添加剂月桂酰肌氨酸钠和氨基酸为原料,采用简单的质子交换反应合成了2种氨基酸基离子液体Lys-LS和Arg-LS,并将其用作水基润滑添加剂.利用SRV-V微动摩擦磨损试验机和全自动真彩共聚焦显微镜考察了2种离子液体添加剂的摩擦学性能,并采用扫描电镜(SEM)、石英晶体微天平(QCM)和X射线光电子能谱仪(XPS)深入探究了其润滑机理.研究结果表明:2种氨基酸基离子液体添加剂具有良好的热稳定性且可以显著抑制铸铁在水中的腐蚀.与去离子水相比,当Lys-LS和Arg-LS的添加质量分数为0.5%时,水基润滑液的摩擦系数和磨损体积分别降低了约70%和85%,具有显著的减摩抗磨效果.机理分析结果表明,离子液体在界面处形成的摩擦化学反应膜与物理/化学吸附膜协同作用,有效地阻止了滑动摩擦副之间的直接接触,进而赋予水基润滑液优异的摩擦学性能.2种润滑添加剂制备简单,安全无毒且绿色环保,有望作为水基金属加工液和难燃液压液的关键润滑添加剂使用.
