| Modern equipment manufacturing technology is increasingly developing towards ultra-precision machining.The key technical bottleneck of ultra-precision machining is how to achieve micro-nano-scale displacement.Most of the current micro-nano-scale displacement is driven based on the performance of functional materials,but this type of micro-nano drive method generally achieves high precision while the stroke is generally small.The macro-micro composite mechanism is one of the driving technologies that can meet high precision and large stroke at the same time,but it also has the disadvantages of non-linearity inherent in smart materials.This topic proposes a micro-nano feed system based on a fully static pressure structure and simultaneously driven by screw and nut.Based on the high bearing capacity and high transmission accuracy of the hydrostatic screw nut pair,The micro-nano feed motion is synthesized under the two-drive "differential".This article takes the full static pressure double drive screw transmission system as the research object,based on the theoretical calculation model derivation,combined with MATLAB,SOLIDWORKS,FLUENT and other analytical calculation software,the performance of the micro-nano feed system has been studied in many aspects,the main research content include:(1)Based on the expected functions of the screw drive system,the overall design scheme of the micro-nano feed system is described,and the working principle of the double drive type full static pressure screw nut pair is analyzed.The platform control strategy of the screw drive system and the design plan of the hydraulic station are proposed.(2)Based on the thin plate bending theory,the principle of the PM flow controller supplying oil to the hydrostatic nut pair is analyzed.The detailed design parameters of the oil film groove of the hydrostatic screw nut pair are explained,and the calculation model of the flow and bearing capacity of the hydrostatic screw nut pair is established.Furthermore,the performance analysis of the static pressure screw nut pair based on the PM flow controller is realized.(3)Based on the working principle of the tapered bearing,the bearing capacity of the nut bearing in the double drive type full static pressure screw nut pair is deduced and analyzed.Establish a geometric model of the hydrostatic nut bearing fluid,mesh it and import it into FLUENT fluid simulation software to analyze the effect of bearing oil supply pressure and speed on its performance.(4)The dynamic model of the full static pressure double drive screw transmission system in each driving mode is established.Combined with the servo motor model and friction analysis,the simulation model of the screw drive system is established in MATLAB.The theoretical feasibility of the system to realize large stroke and high-precision motion is verified through simulation. |
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