The Mixed Lubrication Friction Characteristics Analysis Of Rolling Piston Compressor's Sliding Vane-Chute

AS to the improvement of mechanical efficiency of compressor,the friction characteristics research of compressor has important practical significance.Based on the rolling piston compressor sliding vane-chute motion as the research object,through numerical simulation analysis and experimental research,the paper has explore the sliding vane-chute friction characteristics behavior,especially the influence law of lubrication condition and second-order motion on it.In the paper,it has built the dynamic model which based on the second-order motion and the lubrication model which based on the mixed lubrication.And it has solved its coupled model.And the paper has analyzed the effect on second-order motion,lubrication condition and the friction characteristics of the motion pair which from factors such as the different clearance,piston speed,surface roughness,exhaust pressure,oil temperature and viscosity.Through the second-order motion observation experiment and the friction on both sides of siding vane measuring experiment based on floating chute method,it has proved the high correctness of the model.Through experiments,it has found that there is an optimal range on the low speed motion range of sliding vane,low speed may also make the friction power increases.Specific achievements have the following content:(1)Based the analysis of the sliding vane motion behavior and the force regularity,it has found that the gas pressure in suction cavity,compression cavity and the back pressure cavity of the rolling piston compressor is very unequal.There must be clearance and lubrication between the sliding vane and chute due to the need of installation and motion.So,the second-order motion must be exist and its influence on friction characteristics cannot be ignored.It has built the dynamic model of the sliding vane-chute which based on the second-order motion of the sliding vane,then it analysis the dynamic model and the friction on both sides of the sliding vane.(2)Due to the existence of the second-order motion of the sliding vane and oil lubrication on the both sides of the sliding vane,it has pointed out that the clearance between sliding vane and chute would periodically dynamic change.And the lubrication condition has been completely changed between boundary lubrication,mixed lubrication and fluid lubrication.And it has influence on the performance of the sliding vane-chute lubrication characteristics and friction characteristics.Considering the above factors,it has built the lubrication model which based on the mixed lubrication between the sliding vane-chute,and this model is based on the average Reynolds equation and micro convex body contact model between two rough surface.And it has described the effect on the friction characteristics which from the bearing capacity,thickness of oil film and its change.(3)The paper has used the finite difference method and Broyden iterative method to solve Coupled numerical simulation that based on dynamic model of second-order motion and mixed lubrication model.It has analyzed the changing rule of the sliding vane-chute second-order motion,lubrication condition and the friction characteristics.And the paper has analyzed the effect on the friction characteristics,lubrication condition and second-order motion of the motion pair which from factors such as the different clearance,piston speed,surface roughness,exhaust pressure,oil temperature and viscosity.(4)The author has independently designed and machined a set of experimental device for measuring friction of sliding vane-chute simulated rolling piston compressor based on floating slide chute method.And the paper has introduced its measuring principle.Using high-speed photography,the author has observed the process of the clearance dynamic change between the sliding vane-chute in periodic operation.The experimentation has proved that the second-order motion of the slider vane is real existence and the experimental results are consistent with the simulation results.Through dynamic measurement of friction on both sides of sliding vane,it has obtained the curves of friction on both sides in the whole cycle and it has the same trend and amplitude of simulation curve in the same working condition.This result has proved the Correctness and Validity of the dynamic model which based on the second-order motion and the lubrication model which based on the mixed lubrication.At the same time,it has pointed out that the friction suddenly increase is due to insufficient lubrication at the corner that sliding vane back to the slide chute,which easy to cause the friction loss and abrasion.Also,it has analyzed the effect of sliding speed on friction characteristics of low speed range and has found that there exists an optimal range in the low frequency of the variable frequency rolling piston compressor.Low speed may also make the friction power increases.