AHP-模糊算法在卷烟制丝过程质量评价中的应用

目的 实现曲轴轴承盖在包装生产线上的自动分选,提高生产效率,降低企业生产成本。方法 提出一种基于机器视觉的曲轴轴承盖外形轮廓分类方法,首先等间隔提取预处理曲轴轴承盖图像的行和列,计算每行和每列所含目标像素数量,将关于图像中心对称的2列目标像素数量求和,将提取的特征依序组成对轴承盖正反摆放具有不变性的特征向量;然后采用主成分分析法,对归一化处理的特征向量进行降维;最后采用支持向量机分类。结果 实验结果表明,对样本集的特征向量提取前5个主成分,零件外形轮廓分类准确率达到99.8%。结论 文中所述方法可实现轴承盖零件的准确分类。     

2—2.833/150型氧压机的一点小改进

我厂有一台江苏省苏州地区机械厂出产的2-2．833/150型氧压机。该机曲轴两端轴承同中间两主轴承一样,由两半上下瓦组成,两端外加轴承盖。其中靠飞轮一端为了防止曲轴箱内的机油往外渗漏,配了一个挡油瓦(铸铁件)另在轴承盖上加了一道挡油毛毡(图1)。     

2-2.833/150型氧压机的一点小改进

<正>我车间有两台苏州地区机械厂产的2- 2．833/150型氧压机。该机曲轴两端轴承同中间两主轴承一样,由两半上下瓦组成,两端外加轴承盖。其中靠飞轮一端为防止曲轴箱内机油往外渗漏,加了一个挡油瓦(铸铁件),另在轴承盖上加了一道挡油毛毡。我们在试车过程中,发现靠飞轮一端漏油很严重,直接影响设备的正常运行。     

计入轴瓦变形的曲轴轴承系统动力学摩擦学耦合分析

以一四缸柴油机曲轴-轴承系统为研究对象,建立了计入轴瓦弹性变形时弹性曲轴-轴承系统的动力学摩擦学耦合分析模型;采用ADAMS和Matlab联合仿真,在额定工况下进行了弹性曲轴动力学和主轴承摩擦学耦合分析;着重分析了计入轴瓦弹性变形时,主轴承摩擦学行为和曲轴动力学响应之间的相互影响.计算结果表明:计入轴瓦弹性变形,主轴承最小油膜厚度大幅度下降,最大油膜压力大幅度上升或小幅度下降,曲轴轴承系统动力学特性及响应也发生变化.     

浅析MC11系列发动机缸体激光涨断技术的应用

中国重汽集团MC11系列发动机是中国重汽集团与德国MAN公司合作生产的目前世界上最先进的重卡发动机，该系列发动机缸体生产线上采用的是德国ALFING公司生产目前世界上最先进的激光涨断设备，缸体的材料为蠕墨铸铁GJV450，采用激光涨断工艺替代传统的铣、磨等分体加工方法，使曲轴孔主轴承盖定位精度、装配质量大幅提高，对提高主轴承盖承载、抗剪切能力及发动机整机性能具有重要作用。     

Easylaser激光对中仪在测量机体同轴度中的应用

机体是柴油机的主要部件之一,曲轴的主轴颈、凸轮轴的凸轮轴颈分别安装在机体的主轴承、凸轮轴承中,因此主轴承、凸轮轴承具有支承曲轴、凸轮轴,保证曲轴、凸轮轴的正确轴线,使曲轴、凸轮轴在其中能轻快平稳地转动的作用。主轴承与主轴颈要有合适的间隙,允许进入适量的润滑油,形成油膜。保证运动部件与气缸、主轴承的正确位置关系,减少摩擦并带走摩擦而产生的热量。     

基于时频相干分析的曲轴主轴承磨损故障诊断研究

为了早期发现曲轴轴承磨损故障,提出一种基于时频相干分析的曲轴轴承磨损故障诊断方法。对曲轴主轴承座和机体振动信号进行分析,搞清曲轴轴承磨损故障振动信号产生机理;对故障源与机体信号进行时频相干估计,建立故障源振动传播模型;根据传播模型对机体振动信号进行故障特征提取与诊断识别。研究结果表明:该方法可以揭示曲轴磨损故障产生机理,建立故障源与机体振动之间的映射关系,为曲轴轴承磨损故障的不解体诊断提供理论依据。     

六缸发动机活塞动力学建模与数值仿真研究

本文在考虑活塞二阶运动与曲轴在主轴承中的径向运动的基础上,对新型发动机的曲轴连杆活塞系统进行动力学建模,建立了活塞缸套间的流体动压模型、曲轴主轴承间的流体动压模型,然后对整体模型进行进行综合求解,在确定计算流程之后,由此算法编制Fortran语言进行求解,得到活塞二阶运动的变化规律以及曲轴在主轴承中的径向运动规律。     

皇冠盖的发展综述

分析了皇冠盖的国内现状,指出了国内皇冠盖在材料、模具以及生产设备上与国外的差距.对皇冠盖的市场需求作了预测,奠定了皇冠盖研究的必要性,并探讨了皇冠盖的发展趋势,指明了研究方向.提出了皇冠盖的研究内容、关键技术、研究方法和创新点,最后预测了皇冠盖结构和模具研究的经济意义.     

隔膜泵曲轴轴承半套装配体接触非线性有限元分析

隔膜泵曲轴部装包括:曲轴、连杆、轴承等零件。曲轴部装作为隔膜泵动力端的关键部件,在隔膜泵动力系统中发挥着重要作用。曲轴曲柄、半套和连杆轴承组成的系统是将曲轴的旋转运动转化为十字头直线往复运动的关键部件,半套的不同设计结构尺寸会导致其在运动过程中产生不同的受力状态和变形结果。本文利用ANSYS软件对曲轴曲柄、半套和轴承内圈组成的装配体进行接触非线性有限元分析。针对两种不同尺寸的半套结构分别进行分析,获得了计算结果,分析了半套和曲轴曲柄接触宽度对半套机械强度影响。分析结果对半套的设计有一定的指导意义。     

现代轨道交通刹车材料的发展与应用

分析了轨道交通车辆用盘形制动装置中闸片/制动盘组成的摩擦副的工作条件及其对材料的要求,介绍了铸铁闸片、树脂基闸片、铁基和铜基粉末冶金闸片的性能特点及适用领域,重点分析了粉末冶金闸片各组元的功能及摩擦磨损性能调控机制.基于制动盘热斑形成机理,阐明了闸片形状与排布对制动盘热源分布的影响规律.阐述了铸铁、铸钢、锻钢、金属基复合材料和C/C复合材料制动盘的研究进展,并指出了现代轨道交通刹车材料设计与制造的研究热点及研究方向.     

合金铸铁玻璃模具的研究现状

概述了合金铸铁玻璃模具的研究,对多种合金铸铁玻璃模具材料进行了分析。铸铁作为玻璃模具材料在未来仍将占据重要地位,应采取新工艺、新技术,加强控制组织和化学成分,优化铸铁性能。对模具的生产提出了一些看法及建议。     

Optimized cast components in the drive train of wind turbines and inner ring creep in the main bearing seat

Using large components made of nodular cast iron (GJS) in wind turbines enables the application of lightweight construction through the high degree of design freedom. Besides the sand-casting process, casting into a permanent metal mould, i.e. chill casting, leads to a finer microstructure and higher quasi-static mechanical properties as well as higher fatigue strength. Unfortunately, in present design methodologies specific fatigue data is only available for sand cast and not for chilled cast GJS. Thus, lightweight design strategies for large, chilled cast components are not achievable, which led to the publicly funded project “Gusswelle”. Based on material investigations of EN-GJS-400-18-LT chill cast, an optimized hollow rotor shaft is developed. The design process and the resulting shaft design are presented. The optimized hollow rotor shaft prototype will be tested on a full-scale test bench to validate the design methodology. The intended validation plan as well as the test bench setup is shown in this paper. Furthermore, the decreasing wall thickness influences the interference fit between main bearing and hollow rotor shaft. Thus, through the applied bending moment, inner ring creep is more probable to occur in the main bearing seat. The creeping behaviour is investigated with finite element simulations and a measuring method is presented.

     

影响球墨铸铁曲轴质量的因素

通过对失效的球墨铸铁曲轴的分析和统计,认为造成球铁曲轴断裂失效的主要因素有铸态下存在孔洞类缺陷、等温淬火态时组织脆性较大和正火态时圆角不强化,而曲轴磨损失效的主要因素是润滑不足。提高等温淬火组织的韧性和强化曲轴圆角是防止曲轴断裂失效的主要措施。     

Failure investigation of lime coated grey cast iron moulds at TEMCO ferroalloy smelter

This case study outlines an investigation to identify the root cause for the failure of casting machine moulds, manufactured from grey cast iron, at the TEMCO Ferroalloy smelter in Bell Bay, Tasmania. A preliminary stress analysis shows that the thermal stresses developed in the moulds during operation are insufficient to cause failure in a non-defective mould. The failure can instead be attributed to high temperature oxidation that results from a combination of high mould surface temperature, decomposition of the hydrated lime release coating and the grey cast iron structure. Preventing the oxidation reaction would eliminate this material damage and increase the service life of the moulds. The formation of the high temperature oxide can be prevented by reducing the maximum surface temperature of the mould, using a coating that does not release water at operating temperatures or using moulds manufactured from a different type of cast iron.     

B4C包覆ZTA颗粒增强铁基复合材料制备与性能

ZTA (ZrO₂增韧Al₂O₃)陶瓷颗粒表面包覆B₄C微粉,将其制备成蜂窝状结构陶瓷预制体。采用传统重力浇注工艺将陶瓷预制体与熔融的高铬铸铁(HCCI)金属溶液进行复合,获得ZTA陶瓷颗粒增强高铬铸铁基复合材料。对复合材料中ZTA陶瓷颗粒增强相与高铬铸铁基体之间的界面及复合材料的耐磨料磨损性能进行了研究。结果表明,ZTA陶瓷颗粒与高铬铸铁界面结合处形成了明显的过渡区域,界面过渡区域的存在提高了陶瓷颗粒与金属基体的结合,从而提升了复合材料的整体稳定性能。同时,三体磨料磨损试验表明该复合材料的耐磨料磨损性能是高铬铸铁的3.5倍左右。     

Sintering of grey cast iron powder recycled via jet milling

Porous grey cast iron powder metallurgy parts were made from grey cast iron powder manufactured via target jet milling of machining scraps. The powders were used in the as-milled state without any further physical or heat treatment.Sintering was conducted at 1025, 1100 and 1175 °C in an argon atmosphere and the effect of sintering temperature on microstructure, sintered density and apparent hardness of the grey cast iron specimens pressed to 5.8 g/cm³ was investigated.Although diffusion processes were partially activated at 1025 °C, it was determined that a temperature of 1175 °C proved to be the ideal temperature for solid state sintering of grey cast iron parts. The hardness value and sintered density for the specimens sintered at 1175 °C were found to be 96 BHN and 6.1 g/cm³ (around 15% porosity) respectively, all of which lends itself to promising properties for making self-lubricating bearings and parts with sliding properties.     

Dual metal crankshaft for heavy‐duty engines by cast‐joining of DCI and forged steel

An alternative design of a crankshaft applicable for heavy‐duty diesel engines up to 5000 horsepower has been introduced to achieve cost effectiveness and manufacturing efficiency simultaneously not sacrificing its reliability. Because it is expensive and time consuming to make full‐scale prototype and run a test, analytical feasibility study has been made in this paper. From the point of material, cast‐joined dual metal for a crankshaft is totally unprecedented and will be realized by virtue of the latest dual metal cast joining of ductile cast iron (DCI) and forged steel, which consequently reduces the manufacturing lead time dramatically. The strength of the dual metal interface is experimentally investigated to make sure its possibility and soundness. The key features of the new crankshaft include crankpins and journals made of forged steel and crankwebs of DCI. Prior to actual manufacturing of the new conceptual crankshaft, the design is analytically examined to verify its reliability in an existing heavy‐duty engine. Both conventional and the new dual metal crankshafts are investigated and compared to each other in terms of the stress and fatigue using comprehensive multi‐body dynamic analysis. The results demonstrate that the new dual metal approach is likely to provide higher reliability than the conventional monometallic crankshafts. In addition, it is shown that the inferior mechanical properties of DCI for a crankweb are effectively countered by the superior characteristics of forged steel for a crankpin and journal in the dual metal crankshaft.     

Study in the variation of mechanical properties of nodular cast iron depending upon section thickness

Cast iron has become a popular cast metal material which is widely used in modern industry and today's technology because of its low cost and desirable properties such as good castability, convenient machining properties, better wear resistance, etc. This paper is concerned with the variation of mechanical properties depending on section thickness of nodular cast iron. Firstly manufacturing process of GGG40 (EN‐GJS‐400‐15/DIN 1693 or 60‐40‐18/ASTM A536) nodular (ductile) cast iron was performed. Sand mould casting was only used as a molding process. Following, convenient moulds were prepared and the casting process was carried out in moulds that have different diameters (≤30 mm) to examine the cooling rate effects to the mechanical properties. Finally, tensile, hardness, metallography and fatigue tests were applied to cast materials test specimens. The results show that the cooling rate which is related to the section thickness affects the mechanical properties clearly.     

玻璃模具用球墨/蠕墨复合铸铁的研究

介绍了用稀土和Ｋ－Ｎａ复合变质处理而形成的球墨／蠕墨复合铸铁玻璃模具材质的组织,力学性能及热特性,探讨了影响这些性能的因素,试用表明,这种材和于玻璃具有着良好的使用性能和较高的经济价值。