环锭细纱机动态捻度的试验研究

本试验工作是在棉纺环锭细纱机运转情况下,用高速闪光摄影的方法,对纱段(纺纱段、气圈段、卷绕段)捻度及其分布进行了比较系统细仔的实验研究。实验结果得出了各纱段在一落纱中捻度变化及其分布的规律、捻度传递的关系等作了分析,并通过锭速与钢丝圈对捻度影响的实验,予以论证。实验进一步证实:气圈段捻度大于卷绕段捻度,纺纱段捻度最小;在一落纱中,满纱时捻度最大,管底完成时大直径位置最小;在改变各工艺参数使捻度分布发生变化时,气圈形态对捻度的影响较张力的影响为大,因而应注意控制气圈形态偏小掌握。     

环锭细纱机加捻卷绕运动所引起的纱线捻度不匀

环锭细纱机的加捻是用钢领、钢丝圈将须条加捻成纱。由于钢领板上下运动、卷绕直径的变化及气圈形态的波动,使加捻卷绕运动速度不断改变。这种速度的改变实际上又反映了管纱捻度的起伏,从而将使卷绕效果和成品质量受到相应的影响。本文从理论上分析了各主要运动学参数同捻度不匀度之闻的关系。     

环锭纺纱线气圈的研究

用圆柱坐标系建立纱线微段的微分方程,用数值方法求解可获得气圈形态及其纱线受力的精确解。用解析方法建立气圈形态及其纱线受力的近似解析表达式,可反映气圈各参数对形态或受力的影响,其分析过程清晰、简捷的特点显著。两种计算结果的相对误差甚微。     

考虑空气阻力及哥氏惯性力影响后的气圈底端张力分析

环锭纺纱过程中的纱线断头主要取决于纱线张力与纱线强力之间的矛盾，而纺纱张力是气圈底端纱线张力经由气圈、导纱钩向上传递而产生的．以往关于气圈底端张力的推算大都是在忽略空气阻力和哥氏惯性力的情况下进行的．针对考虑空气阻力和哥氏惯性力影响的情况，对钢丝圈受力及气圈底端张力进行分析计算，并指出随着纺纱的高速化及对纱线质量要求的提高，在研究纱线张力时，应考虑空气阻力及哥氏惯性力．     

纱线绕在圆环面上的曲线状态及其滑动时的张力变化

本文主要分析圆环面上纱线卷绕时或滑动时的稳定曲线状态(短程线)以及纱线在圆环面上的实际包围角,根据这一包围角可以计算纱线在圆环面上滑动时的张力变化。     

气圈纱线的几个动力学问题的研究

从气圈纱线的非稳定运动出发，研究了气圈纱线的准稳定运动、稳定运动、气圈纱线的固有振动、强迫振动，重点研究了气圈纱线的共振问题，对环锭纺纱中气圈的形态和张力、气圈纱线的固有频率、临界参数与工作参数的计算进行了探讨，并在俄罗斯IIM—76—SM环锭细纱机上作了实验验证。     

防止纱线重叠的卷绕比确定方法

纱线卷绕中,不当的卷绕参数会导致纱线间距过小以致重叠,造成容纱量低、卷绕振动、退绕断头及混纱等问题。采用几何及数学方法,分析了纱线排布规律及其与卷绕比的关系,发现适宜的卷绕比可以实现纱线规律性的错开排布,进而有效防止纱线间距过小而产生重叠。提出了适应不同工艺要求的卷绕比确定方法,分析了卷绕过程中纱线夹角及最小纱线间距的细微变化及其对卷绕比选取的影响,给出了优化卷绕比防止纱线重叠的完整方法并进行了示例说明。     

环锭纺捻陷现象的研究及捻度损失的计算

本文研究环锭纺动态捻度传递过程，对导纱钩的捻陷作用及捻度损失的计算进行了分析探讨。同时，对用欧拉张力公式计算在摩擦表面上运动纱线的张力的方法进行了补充修正。     

环锭纺气圈环形成的双段气圈形态和张力分析

环锭细纱机安装气圈环后将形成上下两段气圈。本文采用修正波长后的正弦曲线近似解来代替椭圆积分精确解,两者所得结果非常接近;此外再考虑了空气阻力及气圈环对纱线滞后作用的影响,就此两段气圈形态和张力进行了分析计算,既能使计算得到简化,又能保持较高的计算精度。     

赛洛纺纱捻度的研究

研究了赛洛纺纱的加捻过程．认为汇聚点的存在及其在纺纱过程中的不断波动,是形成纱条捻度及单纱上正、反交替变化捻度的重要原因,也是导致赛洛纱线在结构和性能上不同于其他纱线的根本原因．     

纱线动态加捻的理论研究 第一部分:动态加捻基本方程的建立

动态加捻过程的描速是成纱原理研究的基础,它能够帮助我们理解纱线结构和特性的形成过程并揭示一些提高生产效率、改善纱线质量的途径。在本文第一部分,我们从捻度流概念和纱线微元分析入手,推导动态加捻所遵从的运动学和动力学方程。运动学方程描述了纱线回转运动与捻度分布之间的关系,而动力学方程则给出了加捻力矩与纱线捻度以及运动学参数之间的联系。将这两个方程结合起来可以描述捻度波在运动纱线中的传播过程。     

Analysis on the Characterization of the Twist Insertion Level and Its Effect of the Compact and Ring Spun Yarns

In this paper,the difference of the twist insertion levels of the compact and ring span yarns of the same count is analyzed based on the relationship of the yarn twist factor to the twist angle and the bulk density.It is proposed that the relationship of the twist angle,twist level,and the yarn diameter should be synthetically considered when evaluating the twist insertion level of the compact yarn.The twist angle of the compact yarn is smaller than that of the ring yarn with the same twist insertion level.This results from the ordered fiber arrangement and compact structure of the compact yarn.Experiment was conducted to verify the conclusions.It is also discovered that the selection of the twist factor of the compact yarn,which can be usually lower than that of the ring yarn by 10％-15％,can be determined based on the yarn tensile strength.     

转杯纺假捻盘作用现状研究

介绍了转杯纺假捻盘对纱线加捻过程影响作用的研究现状,分析和评价了几项比较具有代表性的研究,说明了假捻盘在转杯纺纱加捻过程中具有假捻、阻捻或捻陷作用的不同观点及其相应的分析方法,并对今后分析假捻盘在转杯纺加捻过程中作用的研究思路提出了建议。     

Study of the Twist Distribution inside Rotor

In this paper, the kinematics and dynamics of the yarn on the navel were studied. A series of twist distribution curves were obtained by numerical calculation. The results show that the navel is essential to the false twist development on the yarn arm. The fiber surface properties, yarn linear density, rotor speed and diameter, navel design are all the parameters having remarkable effects on the false twist level inside rotor.     

转杯纺捻度传递长度的解析研究

通过转杯凝聚槽内须条的运动和受力分析,对转杯纺捻度传递长度进行解析研究,建立了数学模型.并分别以棉和涤纶为纺纱原料对捻度传递长度进行了数值计算,分析了影响捻度传递长度的各种因素.     

Theoretical Study of the Peripheral Twist Extent Length in Rotor Spinning

The mathematical model of peripheral twist extent(PTE) length was set up by studying the kinematics anddynamics of the yarn in rotor groove. The value of PTElength was calculated by using numerical method, andthe factors affecting the PTE length were also discussed.The results show that the theoretical predicted value ofPTE length seems to be consistent with the measured val-ue. The yarn linear density and rotor speed have re-markable effects on PTE length. The parameters includ-     

Effect of Static False Twist on Rotor Spinning

Many practices of the rotor spinning show that the false twist effect of the navel is much more complicated than that of the one point based friction model. Both ends of the yarn＇s twist and torque changes were analyzed under the static effect of the navel, and then established yarn twist ratio on both ends. It verified its correctness through simulation experiment by designing the experimental device, and analyzed the effect of navers radius on twist ratio.     

Experimental Investigation of Yarn Twist Blockage

In twisting a yarn running over a guide surface, the twist inserted into the part in front of the guide is impeded to transmit freely to the part behind the contact zone. A new device has been set up for investigating twist blockage and yarn torque - twist simultaneously. Measurements of twist blockage in relationship to different parameters have been carried out by using a monofilament yarn and a multifilament yarn. The factors under consideration include the wrap angle, yarn tension and input twist.     

STRUCTURAL VARIATIONS OF HOLLOW SPINDLE WRAP SPUN YARNS

The structure of a hollow spindle wrap spun yarn depends greatly on the steadiness of bindertension and of balloon rotation.The two commonly used binder bobbin forms,the cop type andthe flanged type,both as sources of spinning condition fluctuation,are examined in order to revealtheir effects on the wrap spun yarn structure.False twist is introduced on hollow spindle spinningmachines in order to avoid strand breaks before it is tightly wrapped up.However,an investigationof the false twisti g-wrapping process shows that this inevitably causes irregular yarn tortuosity.