This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/s...This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.展开更多
The goal of net zero carbon emissions is of a great concern to energy conservation and emission reduction.In aerospace and other industrial fields,one of main energy consumption forms is friction between motion pairs,...The goal of net zero carbon emissions is of a great concern to energy conservation and emission reduction.In aerospace and other industrial fields,one of main energy consumption forms is friction between motion pairs,although the energy consumption caused by equipment mass cannot be ignored.Therefore,ultra-low density self-lubricating composites with an interpenetrating polymer network(IPN)structure-liquid lubricant coupling mechanism are designed and prepared in this work to meet the pressing requirements of energy saving and emission reduction.The liquid lubricant is locked in situ into polyurethane acrylate(PUA)with IPN structures(IPN-PUA structures).The thermodynamic,mechanical,and tribological properties,as well as the comprehensive density-friction properties of the material with IPN-PUA structures were studied.After the liquid lubricant is locked into the IPN-PUA structure,the material possesses not only excellent self-lubricating properties but also good micro-mechanical properties,with a coefficient of friction(COF)of 0.0938,wear rate of 6.58×10^(−15) m^(3)/(N·m)and nanoindentation modulus of 4.5 GPa.Compared with other polymeric materials,such composite materials also possess an ultra-low density of 1.107 g/cm3,which contributes to their excellent versatile self-lubrication and low-density characteristics.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51620105010,51675019 and 51575019)the National Basic Research Program of China(No.2014CB046402)+1 种基金the ‘‘111" Projectthe Excellence Foundation of BUAA for PhD Students
文摘This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.
基金financially supported by the Natural Science Foundation of Hebei Province of China(No.E2021203092)the Opening Foundation of State Key Laboratory of Tribology in Advanced Equipment(SKLT)at Tsinghua University(No.SKLTKF21B13)+1 种基金the National Natural Science Foundation of China(No.51905297)the Aviation Scientific Fund Project(No.20200045099001).
文摘The goal of net zero carbon emissions is of a great concern to energy conservation and emission reduction.In aerospace and other industrial fields,one of main energy consumption forms is friction between motion pairs,although the energy consumption caused by equipment mass cannot be ignored.Therefore,ultra-low density self-lubricating composites with an interpenetrating polymer network(IPN)structure-liquid lubricant coupling mechanism are designed and prepared in this work to meet the pressing requirements of energy saving and emission reduction.The liquid lubricant is locked in situ into polyurethane acrylate(PUA)with IPN structures(IPN-PUA structures).The thermodynamic,mechanical,and tribological properties,as well as the comprehensive density-friction properties of the material with IPN-PUA structures were studied.After the liquid lubricant is locked into the IPN-PUA structure,the material possesses not only excellent self-lubricating properties but also good micro-mechanical properties,with a coefficient of friction(COF)of 0.0938,wear rate of 6.58×10^(−15) m^(3)/(N·m)and nanoindentation modulus of 4.5 GPa.Compared with other polymeric materials,such composite materials also possess an ultra-low density of 1.107 g/cm3,which contributes to their excellent versatile self-lubrication and low-density characteristics.
