齿轮-前条传动横向型芯旋转脱螺纹注塑模

论述了齿轮-齿条传动横向型芯旋转脱螺纹注望模结构特点和工作原理。该模具一模两腔，潜伏式浇口。利用开模力，通过齿轮-齿条传动，使横向型芯旋转脱螺纹。齿条设置在注射机型板之外，因此齿条长度不受模具厚度的限制，简化了模具结构，减小了模具体积。模具结构紧凑，工作可靠，操作方便。生产效率高，生产的塑件精度高。     

Numerical analysis of jacking operations for a self-elevated jack-up unit

Localized failure and collapse of a jack-up unit may take place during installation on site, especially under severe sea state conditions. To minimize the loss, structural behavior is predicted before construction. When the hull of a unit is elevated from sea water level, the structure system varies with time. This means that normal structural analysis is difficult to satisfy the relevant requirements. To capture the system status at different times, an innovative method is proposed and incorporated into Finite Element Analysis (FEA). With a full model of a jack-up unit having been built and with the techniques developed, behavior such as Rack phase difference (RPD), vertical reaction forces of the pinions and footing reactions, etc., under different loads and boundary conditions can be determined by FEA in the time domain. These valuable data would be helpful in re-designing the unit, and also provide guidance for site installation. To determine the general characteristics of a jack-up unit, casestudies on a practical design have been done, with some important findings concluded.     

齿条表面化学镀Ni-P-SiC镀层耐磨性的研究

对齿条表面化学镀Ni-P-SiC镀层的耐磨性进行了研究.结果表明:Ni-P-SiC镀层具有弥散强化、沉淀强化和固溶强化三重强化机制,齿条表面Ni-P-SiC镀层可以大幅度提高齿条的耐磨性,并有利于纤维梳理.     

大齿轮齿形在机测量原理与技术

在机测量大齿轮齿形误差具有广阔的发展前景。本文分析了大齿轮齿形误差在机测量的关键问题，提出了运用齿条刃边测头与被测齿轮横截面进行啮合的测量方法，既能测量齿轮的端截面齿形误差，又使仪器结构紧凑。在分析影响大齿轮形在机测量的诸误差因素的基础上，得出了在仪器的制造及安装精度要求不很高的情况下仍能实现齿轮的高精度测量的可喜结论。     

神经网络自适应PID控制在柴油机齿条位置控制中的应用

提出了基于BP神经网络的PID控制算法在柴油机齿条位置控制系统中的应用，把传统的PID控制和BP(误差反向传播)神经网络控制相结合，采用“先离线学习，后在线控制”的思想实现了齿条位置闭环的自适应控制。初步实验结果表明，该控制算法能满足齿条位移控制的性能指标，且其稳态特性较好，克服静摩擦的效果令人满意。     

自动化伺服电机选型

本文介绍了提升用的伺服电机驱动机构的计算方法和步骤,详细计算了滚珠丝杆机构和齿轮齿条机构的提升受力情况,在不同的传动结构下,伺服电机的选型,通过滚珠丝杠的负载计算和齿轮齿条的负载计算的对比,可以得出负载相同的情况下,电机功率和型号可以相互借鉴.     

电动助力转向系统内齿条加工工艺的研究

主要介绍了乘用车内3种电动助力转向系统的应用范围,不同转向机内关键件齿条的结构及主要加工工艺。研究了齿条关键工序的工艺过程、关键点及关键设备,并说明了以上工艺的适用生产条件及注意点。介绍了变节距齿条的工艺,简述部分转向机厂家技术领先的皮带轮驱动助力转向系统的滚珠丝杆齿条的主流工艺,提出了结合现代化制造实现智能自动化生产的方法。     

Influence of the elimination and addition of seeds on the colour,phenolic composition and astringency of red wine

Several winemaking techniques have been developed to eliminate seeds to prevent the release of high amounts of very astringent proanthocyanidins, especially when the grapes are unripe. However, there is no scientific information on the effects of this practice. The aim of this paper is to study how the elimination and addition of seeds influence the colour, phenolic composition and astringency of red wine. The elimination of around 80% of the seeds led to a significant decrease of colour intensity and anthocyanin concentration. The addition of seeds originated wines with a greater concentration of total anthocyanin, but did not significantly affect the wine colour. These wines also presented significantly higher levels of proanthocyanidins, a greater proportion of epicatechin-3-gallate, a lower mean degree of polymerization, and, in particular, a drastic increase in astringency. Wines obtained with the elimination of seeds, on the other hand, had exactly the opposite characteristics.     

自升式钻井平台悬臂梁齿轮齿条驱动系统设计

以某自升式钻井平台为例,采用"电机+变速箱+小传动轮+齿条"方式驱动悬臂梁移动。通过悬臂梁的结构及悬臂梁上的设备质心确定移动悬臂梁所需的推力。计算悬臂梁齿轮齿条几何参数,并设计悬臂梁与齿轮齿条的连接结构及悬臂梁驱动控制系统,合理配置驱动系统电机功率和减速器传动比。通过采用闭环交流变频控制方式,对悬臂梁速度进行反馈和控制,实现左右两侧悬臂梁的同步移动。     

Adaptive preloading for rack-and-pinion drive systems

In the field of machine tools, rack-and-pinion drive systems are one of the commonly used feed drive systems. In order to achieve the high accuracy specifications of modern production facilities, these drives are electrically preloaded to reduce backlash in the drive train. In most cases, the preload is fixed, even though the method of electrical preloading allows adjustment during operation.This paper describes a novel approach – called adaptive preloading – to adjust preload during operation. The objective is to increase the drive system’s energy efficiency by continuously adapting the preload, which is minimally required for maintaining the drive system’s accuracy.