Design Of Air-floating Weft Insertion Guide For Heavy-duty Wide-width Rigid Rapier Loom

In recent years,with the rapid development of the economy,China has not only become a major import and export of textiles,but also has an increasingly strong ability in the design and manufacture of textile machinery.According to relevant surveys,China's textile machinery industry has developed rapidly since 2000,but there are also problems such as:domestic textile machinery products tend to assimilate,automation level is not high,vehicle speed is low,and cost is high.Moreover,domestic textile machines mostly stay at the middle and low level,the added value of products is low,and the ability to compete with the world's advanced textile machines is weak.Especially in the rigid rapier looms,almost no domestic manufacturers can develop and produce them themselves.One of the major difficulties is the design and manufacture of the weft insertion guides.In the past,most of them were supported by rollers,and the roller bearings were rotated about1.344?10~7once a day,requiring frequent parking to replace bearings and rapiers.Because of air has low viscosity,low friction coefficient and environmental friendliness,this paper designs a static pressure air-floating guide to replace the conventional roller guide,which can effectively reduce the wear of the rapier and reduce the number of machine stops.In this paper,the air-floating weft guide rail of heavy-duty wide-width rigid rapier loom is taken as the research object.In order to develop the air-floating guide rail which can be practically applied,the following work is mainly done.(1)The basic principles of gas lubrication are expounded and their mathematical models are derived,including Navier-Stokes equations,continuity equations,state equations,Reynolds equations and gas dynamic lubrication equations.According to the air-floating guide rail structure of this paper,the calculation formula of bearing capacity,the calculation formula of gas film stiffness and the calculation formula of gas mass flow are derived.(2)The throttle selection and structural design were carried out for the use environment of the air-floating guide rail designed in this paper.After comparing different throttling modes,the small throttle is selected as the throttling device of the air floating guide.A gas-lubricated guide rail with a semi-closed structure is designed for the load state of the rapier,which can reliably provide positioning and support for the rapier.Considering the corrosion resistance,stability,thermal expansion and processing technology of the air-floating guide rail,1Cr18Ni9 stainless steel was selected as the base material,and ZCuZn38 brass was used as the material of air plug.(3)The running state of the rapier and the air-floating guide rail was analyzed.The air-floating guide rail and the fluid area were modeled in three dimensions by UG,and the computational fluid area was meshed using the Fluent Mesh module.(4)Using Fluent,the bearing capacity and air consumption of air-floating guide rails under different film thicknesses and air supply pressures were studied.The effects of different throttle arrangement methods on the bearing capacity and air consumption of air-floating guides were studied.The influence of the diameter of the small hole on the bearing capacity and gas consumption of the air-floating guide rail was studied.The influence of the aspect ratio of the small-diameter throttle on the bearing capacity and gas consumption was studied.The effects of different rapier tilt rates and rapier speed on bearing capacity and mass flow were studied.(5)The static test platform of air-floating guide rail was built,and the air-floating guide rail was tested under different loads and air supply pressure.The test results show that the air-floating guide rail designed in this paper has sufficient carrying capacity to support the rapier,and the air consumption of the guide rail is also Within a reasonable range.