Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump wa...Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.展开更多
Several key problems in the research and development of continuously variable transmission for automobile, such as those connected to the transmitting frictional pair and the related automatic tight pressing actuator...Several key problems in the research and development of continuously variable transmission for automobile, such as those connected to the transmitting frictional pair and the related automatic tight pressing actuator, the transmission ratio control logic and the related automatic control system, are discussed. The strategies taken for solving these key problems are described.展开更多
In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased th...In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased the coefficient of friction and wear scar depth under low loads,but these slightly increased under high loads.The steel/steel friction pair showed excellent tribological properties even under high loads.Severe plastic deformation on the copper surface reduced the stability of the graphene tribofilm because of a rough copper transfer film on the steel during the running-in period.The results provide a better understanding of the mechanism of graphene as a lubricant additive.展开更多
The corrosion and tribocorrosion behaviors of AISI 304 austenitic stainless steel and Cr26Mo1 ultrapure high chromium ferrite stainless steel in 3.5 wt.%NaCl and 0.5 mol/L H2SO4 solutions were investigated.Microelectr...The corrosion and tribocorrosion behaviors of AISI 304 austenitic stainless steel and Cr26Mo1 ultrapure high chromium ferrite stainless steel in 3.5 wt.%NaCl and 0.5 mol/L H2SO4 solutions were investigated.Microelectrode electrochemical measurement technology was applied to identify electrochemistry behaviors during tribocorrosion tests in situ.The surface morphologies and compositions of the wear tracks were analyzed by scanning electron microscopy and Raman spectrum.The results showed that compositions of stainless steels,corrosive mediums and applied loads have great influence on tribocorrosion behaviors of stainless steels.Firstly,the corrosion resistance in static state of stainless steels primarily dominates its tribocorrosion behavior;meanwhile,better mechanical properties are in favor of tribocorrosion resistance.Secondly,the corrosion rate is promoted significantly in 3.5%NaCl solution by friction,while the tendency is inconspicuous in 0.5 mol/L H2SO4 solution.Last but not least,passive films on stainless steels can be wiped off by small friction force.With the increase in applied load,the effect of friction converts to forming friction oxide film from removing passivation film,so that a critical load exists below which the friction force can promote the corrosion process extremely.展开更多
基金Projects(51475332,51275356)supported by the National Natural Science Foundation of China
文摘Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.
文摘Several key problems in the research and development of continuously variable transmission for automobile, such as those connected to the transmitting frictional pair and the related automatic tight pressing actuator, the transmission ratio control logic and the related automatic control system, are discussed. The strategies taken for solving these key problems are described.
基金This work was supported by National Natural Science Foundation of China(Nos.51527901 and 51335005)the National Key Basic Research Program of China(973 Program,No.2014CB046404)Tribology Science Fund of State Key Laboratory of Tribology(No.SKLTKF18A02).
文摘In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased the coefficient of friction and wear scar depth under low loads,but these slightly increased under high loads.The steel/steel friction pair showed excellent tribological properties even under high loads.Severe plastic deformation on the copper surface reduced the stability of the graphene tribofilm because of a rough copper transfer film on the steel during the running-in period.The results provide a better understanding of the mechanism of graphene as a lubricant additive.
基金supported by PetroChina Key Core Technology Project(21ZG10)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDC04040400).
文摘The corrosion and tribocorrosion behaviors of AISI 304 austenitic stainless steel and Cr26Mo1 ultrapure high chromium ferrite stainless steel in 3.5 wt.%NaCl and 0.5 mol/L H2SO4 solutions were investigated.Microelectrode electrochemical measurement technology was applied to identify electrochemistry behaviors during tribocorrosion tests in situ.The surface morphologies and compositions of the wear tracks were analyzed by scanning electron microscopy and Raman spectrum.The results showed that compositions of stainless steels,corrosive mediums and applied loads have great influence on tribocorrosion behaviors of stainless steels.Firstly,the corrosion resistance in static state of stainless steels primarily dominates its tribocorrosion behavior;meanwhile,better mechanical properties are in favor of tribocorrosion resistance.Secondly,the corrosion rate is promoted significantly in 3.5%NaCl solution by friction,while the tendency is inconspicuous in 0.5 mol/L H2SO4 solution.Last but not least,passive films on stainless steels can be wiped off by small friction force.With the increase in applied load,the effect of friction converts to forming friction oxide film from removing passivation film,so that a critical load exists below which the friction force can promote the corrosion process extremely.
