Establishment Of False Twist Model And Function Analysis Of Navel In Rotor Spinning

The navel is an important component in rotor spinning, and it has an irreplaceable effect on motion process and stress process of yarn in the rotor. The studies of predecessors are not perfect, and the false twist process of the navel has not got a good explanation, meanwhile, there are disagreements about the processes of twist deterrent and twist fault. In addition, most studies stay in the research stage, and they were not proved by experiment. The article focus on the perfect study of the theory of the false twist、twist fault and twist deterrent of the navel. Then, it proved the theory by related experiment to establish a relatively complete theoretical system of the effect of navel. This theory is a good reference for production practice.It has carried on the research work from the following aspects:Firstly, it described the concepts of revolution motion and spinning motion of yarn, and it defined that the true twist can only generate due to the revolution motion as the false twist can only generate due to the rotation motion.Secondly, it differentiates the false twisting process form the common false twisting, and make the false twisting process be assigned to line false twisting process. Then, it deduced related formula about the false twisting effect of static yarn by the navel through the theoretical analysis, the formula is it shows that the ratio of twists is not only related to the lengths of the two yarns(S and L), but also related to the radius of the navel(ro). In addition, it calculated that the ratio was2.85. Meanwhile, the experimental facility was made and use black-white yarn replace the rotor spinning yarn to tested the ratio of yarn twists under different rotate speeds of navel. The experiment proved effectively the difference of the navel false twisting process and the common false twisting process, and the experiment data is consistent with the theoretical formula.Thirdly, it deduced the tension-twist formula about the false twisting effect of dynamic yarn by the navel through the theoretical analysis, and carried out relevant experiments. The formula is and it shows that the false twist is related to tension difference of the yarn, the radius of navel, the ratio of circular and axial rubbing speeds(tanβ) and the properties of yarn(GI). It use the strobe photography to overcome the difficulty that getting the twist of the fast moving yarn, and got the twist online. The test results shows that the false twist added from5.1twist/100cm to21.3twist/10cm, and the calculation results shows that the false twist added from3.6twist/10cm to18.6twist/10cm when the speeds of navel added from200r/min to1600r/min. The formula was confirmed and provide a way to get the yarn twist by testing the yarn tension at the same time. So, we also get a new approach to test the rotor spinning yarn, and it has great significance to regulate and control the yarn twist and yarn tension in rotor spinning production.Lastly, it analyzed the process of twist deterrent and twist fault of yarn, and rejected the twist deterrent process of yarn, and conclude that the twist can’t pass the inner of the rotor to outer. Then, it analysis the twist fault process of the static yarn, and observed the twist transmission process when the twist deterrent happened. The test shows that the twist deterrent happened when the orbit laps reached27under the5(g) mass counter weight and the twist deterrent happened when the orbit laps reached36under the10(g) and15(g) mass counter weights.