全自动称重式液体灌装机设计

介绍了一种全自动称重式液体灌装机的工作原理、结构设计以及控制系统硬件的组成,此设计思路亦可为制药机械相关灌装设计所借鉴。     

磨床成组心轴的设计

在机械加工中,以工件内孔定位磨削外圆柱面时,通常采用心轴作为定心磨削夹具。当工件外圆面相对基准孔有较高的圆跳动(或同轴度)要求时,就需要将定心心轴的基准直径进行分组,设计成组心轴,以提高定心精度,保证工件的加工精度。下文介绍成组心轴的设计计算方法: 1.心轴分组公差△K′的初步估算     

成组夹具有设计及应用

本文介绍了成组夹具的结构特点、设计过程和技术经济效果。     

成组夹具的设计与应用

成组技术是近年来国内外机械制造领域内得到迅速发展的一种作业方式。而成组夹具则是按成组技术原理，在零件分组的基础上，针对一组（或几组）相似零件的一道（或几道）工序设计的夹具。它具有专用夹具的若干特点，又具有对工件特征在一定范围内变化的适应性。这在目前争夺国际市场，使产品不断升级换代，特别是能使产品多品种、中小批量生产得到大批量生产的效果上，有着不可比拟的优势。零件的分析与分组如某厂生产的交、直流电动机、发电机机壳，由于结构简单，采用１０号无缝钢管加工而成。此道工序为半精车内孔，其品种有１２种之多。…     

液压油缸产品的成组化设计与制造

文中将液压油缸产品设计成组化,以减少产品结构类型,使产品生产制造成组化、装配成组化,建立成组流水线,可提升生产的专业化程度,提高生产效率,是提高多品种、中小批量液压油缸产品生产经济效益的一种有效方法.     

计算机辅助成组夹具设计探讨

结合生产需要开发了圆柱齿轮类零件齿形加工用成组夹具ＣＡＤ系统。该系统采用功能模块的设计方法对零件进行特征编码，特征图引导和莱单输入，并建立零件和夹具的成组编码系统，简要介绍了图形库的建立和程序设计方法。     

专机生产线成组配套管理信息系统的设计

专机生产线成组配套管理信息系统实时跟踪生产线装配进程,统计并分析专机生产线在生产各个阶段中零件的计划产量、计划生产时间、实际产量、计划生产时间以及零件库存等有关数据,以改进与确定零件在生产线的工艺流程、确保生产线装配过程中的问题能够得到及时的处理,从而确保在生产线装配过程中,装配零件无论是在产量还是在时间节点上计划与实际相匹配的目的。系统已投入商业生产,显示了系统的有效性。     

成组不等径丝锥设计的新方法

介绍成组不等径丝锥的设计方法,指出应用“等差数列求和”的方法确定各支丝锥的大径、中径和小径名义尺寸比应用传统的经验公式具有更高的准确性     

Development of Al-base lubricating grease thickeners

In this paper are presented the results of work on the development of poly-oxo–aluminium acylates that are dissolved in synthetic lubricants, polyalphaolefins (PAOs) andpolyisobutenes (PIBs), and one pharmaceutical mineral oil in order to produce a range of greases that can be food-grade, and have chemical stability. The method of synthesis is described, together with the results using different base oils (two different PAOs, four different polybutenes, and a pharmaceutical grade IS0 VG 46 white mineral oil. These greases are characterised here in terms of their mechanical stability and physical properties. As well as being of food grade, these greases are also shown to be chemically stable.     

Thermorheological behaviour of a lithium lubricating grease

Thermal-induced changes in the viscous and viscoelastic responses of lubricating greases have been investigated through different rheological techniques in a temperature range of 0–175 °C. Small-amplitude oscillatory shear and viscous flow measurements were carried out on a model conventional lithium lubricating grease prepared by inducing the in situ saponification reaction between 12-hydroxystearic acid and hydrated lithium hydroxide. The linear viscoelasticity functions dramatically decrease above 110 °C, but not below this critical temperature, which determines the maximum recommended operating temperature in relation to its durability and resistance under working conditions. Two different regions, below and above this critical temperature, in the plateau modulus versus temperature plot have been detected. From this thermal dependence, a much larger thermal susceptibility of the lubricating grease at temperatures above 110 °C is apparent. The thermo-mechanical reversibility of this material has been studied by applying different combined stress–temperature protocols. Regarding the viscous flow, a minimum in the shear stress versus shear rate plots appeared at temperatures above 60 °C, more pronounced as temperature increases, resulting from material instabilities. The experimental results obtained have been explained on the basis of the thermo-mechanical degradation of the lubricating grease microstructure.     

A rheological model for lithium lubricating grease

The rheological properties of a lithium lubricating grease were examined under various settings of shear rate, time and temperature with an emphasis on the thixotropy of grease. A HAAKE RV 20 rheometer was employed in the experiments, utilizing a cone and plate configuration. Precautions were taken when scheming and carrying out the test in order to eliminate the effects of slip at the wall, fracture and other forms of disturbance. Flow curves and thixotropic hysteresis loops were obtained. Based on the measurement results, a new rheological model involving a structural parameter has been proposed. The characteristics of the proposed model and its implication for lubrication analysis were discussed.     

润滑脂在轴承中的应用及选型

轴承润滑脂的应用使摩擦副表面形成一层薄薄的油膜,防止滚动体与滚道两者间直接接触,从而减少轴承内部摩擦、磨损及发热,防止烧粘,同时还具有密封及防止轴承被锈蚀腐蚀的作用。因此,轴承润滑脂选型至关重要,不仅要考虑轴承的工作温度、转速、载荷等要求,还要考虑润滑脂的初始填充量和使用寿命等因素。本文主要对润滑脂的作用及机理、润滑脂选择要点、使用寿命等方面进行总结分析,且列举两个型号轴承进行计算验证,期望为轴承行业润滑脂的应用与选型提供参考与借鉴。     

扣除壁滑移的润滑脂流变特性检测研究

为了检测扣除壁滑移的润滑脂流变特性及去除粘弹性、触变性等对流变特性测试的影响，研究开发了适宜壁滑移研究的高精度管流流变检测系统，并制定了合理的测试步骤和方法。文中阐述了系统的测试原理、系统组成和测试方法，研究了测试过程中除壁滑移外的影响测试的因素。通过在不同管径中的试验，验证了壁滑移速度和扣除壁滑移后真实流变模型不随管径变化的流变特性。该测试系统既可以测得润滑脂含壁滑移的流变参数，也能为润滑脂集中润滑泵送系统的设计提供测试依据。     

An assessment of beeswax as a thickener for environmentally friendly lubricating grease production

Environmentally friendly lubricants are preferred in many applications where groundwater or soil pollution is possible. The main purpose of the current study was to evaluate the possibility of beeswax use as a thickener for lubricating greases. European beeswax was used as a thickening material for the preparation of lubricating greases. Rapeseed oil and two mineral oils were used as base oils. The consistency, dropping point temperature, and tribological properties of the prepared lubricating greases were investigated and compared with conventional soap‐thickened greases. The prepared greases exhibited good tribological properties, especially the rapeseed‐oil‐based grease. However, tribological properties of conventional lubricating grease were superior to prepared ones. The weakness of the prepared lubricating greases is their narrow working temperature range. However, the beeswax together with rapeseed oil has great potential in the production of environmentally friendly, completely renewable lubricating greases. Copyright © 2014 John Wiley & Sons, Ltd.     

Reducing the effect of three-body abrasive wear by adding polymeric powder to lubricating grease

The present paper reports on work aimed at improving the abrasive wear resistance of surfaces lubricated with contaminated greases. The intended improvement can be achieved by reducing the effect of wear occurring between the abrasive particles and the rubbing surfaces. Different polymeric thickeners in powder form, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyvinylchloride (PVC), polyamide (PA6) and polymethylmethacrylate (PMMA), were added to lithiumbased grease. The wear resistance and the coefficient of friction of cylindrical steel specimens were examined using a cross-pin test machine. The test machine provides concentrated contact under mixed lubrication conditions. Wear was measured on the stationary test specimen by the wear scar diameter, using an optical microscope, with an accuracy of ±1 μm. The frictional torque generated between the rubbing surfaces was measured using a full bridge strain gauge measuring cell attached to the stationary test specimen holder. The experiments were performed using clean and contaminated lubricating greases to which Air Cleaner Fine Test Dust (SCFTD) was added to the greases at a concentration of 10 wt.%. The results show that the effect of the abrasive contaminants can be reduced by the addition of polymeric powders. However, the addition of polymer to lubricating grease at relatively high concentration (more than 35 wt.%) has no effect on the antiwear action of the lithium grease. Further, the addition of polymeric powder with a particle size relatively greater than that of the contaminant can be considered as a useful method of eliminating the cutting process of the three-body abrasive mechanism introduced by the presence of the hard contaminant particles.     

微小卫星用陶瓷轴承脂润滑姿控飞轮的性能试验

为解决微小卫星姿态控制执行元件—姿控飞轮的轻量化、高效支撑及润滑问题,提出了应用脂润滑陶瓷轴承为微小卫星姿控飞轮提供支撑和润滑的方法。试验研究了陶瓷轴承脂润滑姿控飞轮的启动、摩擦功耗、温度特性、抗振动性能及寿命特性,试验结果显示:与同型号钢制球轴承相比,陶瓷球轴承在静态摩擦力矩及功耗方面性能更优良,可以有效减小姿控飞轮的启动电流和摩擦功耗。陶瓷轴承脂润滑姿控飞轮在-30～50℃具有良好的启动性能,低于卫星最低工作温度20℃时仍能保持良好的启动特性,无冷焊问题,完全满足卫星发射时抵抗振动的要求。振动试验后的姿控飞轮在4年的地面真空试验中功耗电流变化率在有真空度和温度变化的影响下小于1%,验证了陶瓷轴承脂润滑姿控飞轮使用寿命优于4年,满足国内微小卫星对姿控飞轮轻量化和使用寿命的要求。     

轴承元件陶瓷化——简述陶瓷金属耦合材料润滑油脂在轴承上的应用

陶瓷金属耦合材料在轴承工业的应用使轴承陶瓷化,实现了陶瓷金属航天材料在轴承工业中的普及化和民用化。在不更换设备、不改变技术、工艺和材料的基础上,冲破材料本身的极限,使轴承的寿命、精度、档次产生一个质的飞跃。