Research On The Cam Assembly Of High-speed Computerized Flat Knitting Machine

Currently,computerized flat knitting machines are mainly to be used in sweater manufacturing industry.They are electromechanical products with higher degree of intellectualization and automation.They are full automatic knitting machines with more advanced mechanical and electrical integration technology.Computerized flat knitting machines have higher productivity and higher degree of automation than common flat knitting machines.So they are more suitable for knitting fabrics with high-speed and volume-produce.Computerized flat knitting machine is the main development direction of the knitting machine industry which combine software engineering with computer digital control technique and gather computer hardware and software,knitting process and mechanical design in integral whole.It is very important for computerized flat knitting machine to improve its production efficiency in the field of knitting.Compared with foreign computerized flat knitting machine,domestic computerized flat knitting machine started late and the technology was relatively backward.Some researches on key technology and intellectualization are also not ideal.So high-end computerized flat knitting machines market must rely on imports.The high-end market of computerized flat knitting machine still has been occupied by foreign,and the price is relatively high.In order to change this situation,it is particularly important to study the key technology and improve the competitiveness of domestic computerized flat knitting machine.Firstly,this paper described the present development situation of computerized flat knitting machines home and abroad,and the purpose and significance of high-speed computerized flat knitting machine cam assembly were studied.This subject introduced the name and role of each cam assembly,and analyzed the work principle and knitting cycle of computerized flat knitting machine and the knitting principle of knitting system.Then the knitting process principle and needle system running tracks of non-knitting,tucking,looping,stitch reception and loop transfer were deeply analyzed,hoping to provide a theoretical basis for the research and development of high-speed computerized flat knitting machine cam assembly.The kinetic theoretical analysis between cam assembly and needle system of computerized flat knitting machine were analyzed.It mainly includes the force analysis when needles run smoothly and impulsive force analysis between cam assembly and needle system.Larger collision and impulsive force easily lead to the displacement curves of needle system departure with the theoretical trajectory.Even occurred endurance cracksituation and reduced the efficiency and stability of the knitting system.From the analysis can be drawn the factors that affect pressure R between cam assembly and needle system when needles run smoothly and factors that affect the size of impulsive force in a state of shock.In addition,the situation on needles are out of control,needles channeling jump phenomenon,needles self-jamming phenomenon and the situation on master jacks are out of control,these phenomenons were all analyzed avoiding they occurring again when designing the cam assembly of high-speed computerized flat knitting machine.The characteristics of several common curve was analyzed,mainly including polynomial curve,simple harmonic curves,cycloidal curve and double harmonic curves.Design of cam assembly curve is a crucial factor to affect the high-speed development of computerized flat knitting machine.It can make sure the acceleration of needle system is continuous and smooth when needles along the curved cam assembly face running.So it can make the breakage of needles and the abrasion of cam assembly reduced.Then according to the characteristics of several common curves to select a suitable curve for high-speed computerized flat knitting machine cam assembly.Polynomial curve cam assembly was analyzed and designed.Taking 7 needles per inch computerized flat knitting machines for example,analyzing and designing their needle raising cam,sinking cam and needle selection guide reset cam.According to the boundary conditions of latch needle running along each cam assembly and their vertical and horizontal travel values,drawing the polynomial curve graphs of each cam assembly.Finally obtained the optimized cam assembly curve graphs and analyzed.40 figures,1tables and 122 references.