Wear mechanism of disc-brake block material for new type of drilling rig

To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Feabundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Feabundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.     

钻机开槽滚筒加工新方法

针对钻机圆弧型不完全开槽滚筒的结构特点,通过工艺分析及数控编程,根据数控车削中心的加工特点,给出加工此类不规则线型的一种新方法,有效提高了生产效率和加工质量。     

石油钻机井架起升的动力学仿真

石油钻机井架的起升是井架的危险工况之一,而利用准静态的计算分析方法忽略了绞车转速对此动态过程的影响.采用虚拟样机技术对JJ45Q/45-K型井架的安装起升过程进行了动力学仿真分析,论述了绞车转速对起升过程的影响.结果表明井架的起升速度与绞车转速之间存在非线性关系.绞车转速越高,起升时的振动越大.     

安装角度对旋挖钻机变幅机构的力学影响

为研究和改善旋挖钻机变幅机构的力学性能,基于牛顿-欧拉方法建立变幅机构的动力学模型,在MATLAB的Simulink工具箱中建立仿真模型,进而比较分析安装角度对旋挖钻机变幅机构力学性能的影响。仿真结果表明:安装角度位于41°～45°范围内时,旋挖钻机变幅机构的力学性能最佳。     

Wear mechanism maps of uncoated HSS tools drilling die-cast aluminum alloy

A map describing the flank wear characteristics of uncoated high-speed steel (HSS) tools is constructed under the condition of drilling die-cast aluminum alloy. Several wear mechanisms are revealed which describe different wear modes observed by SEM in uncoated HSS tools, including adhesive wear, adhesive and abrasive wear, abrasive wear, severely plastic flow, and thermal wear. In the map, there exists a minor wear region, which is called “safety cutting zone” to the HSS tools. This map will be a good reference for choosing suitable drilling parameters of uncoated HSS cutting tools.     

一种新型复合材料布带缠绕压力施力导向机构优化设计

为了提高复合材料布带缠绕压力传导精度和稳定性,提出了采用直线滚动导轨作为传导元件的压力导向机构。利用ANSYS参数化建模平台,以直线滚动导轨副结合面动力学性能实验数据为依据,建立了压力导向机构参数化模型。通过对压力导向机构进行模态和谐响应分析,提出了相应的改进措施。经进行压力传导性能实验,表明直线滚动导轨压力施力导向机构传导压力精度高、稳定性好。     

旋挖钻机动臂结构强度分析

动臂是旋挖钻机的一个主要构件,在动臂变幅、钻进和提钻等工况下均是主要承力构件.文中分别对动臂变幅、钻进和提钻工况下,旋挖钻机以最不利的姿势作业,且承受最大载荷时动臂的结构强度进行分析,为动臂的结构设计及优化设计等提供了理论基础.     

用于自动钻铆系统滑块式送钉模块设计与研究

针对工业机器人平台自动钻铆系统中自动送钉难的问题,介绍了一种能够为自动钻铆机自动逐个输送铆钉的滑块式送钉模块。铆钉在从供钉管道到吹钉管道的输送过程中存在着铆钉容易掉落、输送成功率低以及难以逐个送钉的问题,为此通过运用空间分析和受力分析等方法,结合合理的结构设计,提出了利用双顶针气缸控制铆钉的逐一释放、采用带有输钉孔的滑块将铆钉从储钉管道输送至吹钉管道,继而通过气流经吹钉管道将铆钉输送至自动钻铆机的目标位置的送钉方案,并计算得出了满足铆钉逐个输送的顶针气缸伸出长度、最小气缸供气气压等必要条件。研究结果表明,全程封闭的送钉模式提高了输送过程的可靠性和成功率,计算结果和实验结果验证了该送钉模块在自动钻铆系统的可行性。     

海洋平台钻机集成监控系统的可靠性多目标优化

为了提高海洋平台钻机集成监控系统的可靠性,以满足海洋钻井作业高可靠性、高可用性和高安全性的要求,通过对海洋平台钻机集成监控系统进行分析,建立了一种适用于海洋平台钻机集成监控系统的可靠性冗余优化模型;针对传统算法求解多目标资源优化分配收敛慢、易早熟的问题,提出一种1阶邻域解的启发式算法与改进的自适应顺序选择遗传算法相结合的算法。对遗传算子进行改进,保证了种群多样性,防止早熟现象发生;通过与1阶邻域解的启发式算法、自适应遗传算法、1阶邻域解的启发式算法与自适应遗传算法相结合的算法进行比较,验证了所提方法的有效性及合理性,表明该方法可为海洋平台钻机集成监控系统的可靠性优化设计提供理论依据。     

旋挖钻机三角形连接架的有限元分析

在详细分析旋挖钻工况下受力情况的基础上,建立了旋挖钻机的数学模型,并且确定了旋挖状况下的典型工况。利用ANSYS软件对旋挖钻机工作装置支撑机构中的三角形连接架进行了静力学有限元分析,揭示三角形连接架在各种典型位置工况下的最大变形值、最大应力值、危险截面区域以及变形和应力的分布规律,分析结果显示,三角形连接架变形和应力分布规律与实际计算相符,且该结构在强度和刚度设计上都存在一定裕量,为改进支撑机构结构形式和减轻自重提供一定的参考。     

凿岩台车推进器有限元分析及优化设计

凿岩台车井下作业工作环境苛刻,推进器部件易出现疲劳损坏,有必要对台车推进器受载情况进行分析研究。首先以某一型号凿岩台车为例,利用有限元软件ANSYS Workbench 对正常工作状况下凿岩台车推进器进行有限元分析,得出推进器鞍架处存在显著应力集中现象的结论。然后对推进器存在显著应力集中的部件进行了相应的优化设计,优化后推进器鞍架显著应力集中现象得到改善。最后对推进器系统进行了振动模态分析,得到了系统的各阶固有频率,为整个台车系统力学性能的改善与优化提供了理论依据。     

基于SolidWorks和ANSYS的旋挖钻机钻桅结构强度分析

介绍旋挖钻机钻桅主流结构形式及其工作原理,通过SolidWorks建模和ANSYS分析的有效结合,对钻桅进行三种极限工况下的仿真,给出各工况下的Mises应力云图和位移云图,并分析仿真结果。结果表明:在三种极限工况下,钻桅变幅油缸支座位置都属于应力集中区域,鹅头变形最大,在进行钻桅结构的改进时,应当对这些位置予以重视。     

夹片钻孔传送机构设计

针对锥形零件(夹片)设计出夹片专用提升斗,通过提升机的工作原理将供料箱中的夹片顺序提升到合适的工作位置.通过计算确定夹片的重心位置,确定两三角皮带之间的间隙及皮带项面到轮缘的高度,利用夹片外锥的特征进行有效的整列确保钻孔时定位夹紧的合理性.整个装置基于立式钻床本体,结合控制技术进行传送机构设计.解决了夹片钻孔工序自动上下料问题.提高了生产效率,降低了劳动强度,保证了交货期.     

钻井泵阀的设计研究

在分析泵阀失效的基础上,提出了一套合理的泵阀设计方法,并以此为基础设计制造了新型泵阀。该阀具有密封好,冲击小及耐磨损等特点。     

新型振荡减振机构的研究

为了改善机械行业传统的偏心轮振荡机构的不足,设计了新型振荡减振机构,此机构中增设了平衡偏心轴,其体积小、结构紧凑、操作方便。     

石油钻机立根自动连接系统中钻杆水平运移装置的设计

基于顶部驱动钻机的需要设计了一套立根自动连接系统,详细地介绍了单根钻杆水平运移装置.针对石油钻杆移运的工作状况,设计了水平移运机构中的关键部件钻杆运移小车和钻杆定位机构,并对小车关键零部件进行了静力学分析和计算.     

Analytical models of composite material drilling

Drilling of composite material structures is widely used for aeronautical assemblies. When drilling, damage to the composite laminate is directly related to the cutter geometry and the cutting conditions. Delamination of the composite materials at the hole exit as directly related to the axial force (F _Z) of the cutter is considered to be the major such defect. To address this issue, an orthotropic analytical model is developed in order to calculate the critical force of delamination during drilling and a number of hypotheses for loading are proposed. This critical axial load is related to the delamination conditions (propagation of cracks in the last layers) and the mechanical characteristics of the composite material machined. A numerical model is also drawn up to allow for numerical validation of the analytical approach. A comparison between these analytical and numerical modellings and experimental results from quasi-static punch tests led to the choice of the loading hypothesis closest to the experimental conditions. The selection of corresponding load permits to model the drilling critical thrust force on delamination and then to optimise the cutting conditions. The dimensions and geometrical shape of the cutter are of considerable importance when it comes to choosing this load. The present article focuses on the case of the twist drill, which is commonly used to drill thick plates. However, this work can be adapted to different cutter geometries.     

一种新型冶金起重机起升机构

JB／T7688．1-1995《冶金起重机技术条件通用要求》中规定冶金起重机的范围为：适用于金属冶炼、轧制和热加工的专用起重机。而征询意见稿的JB／T 7688．5《冶金起重机技术条件铸造起重机》中“2．1更改原标准的适用范围,扩大到凡搬运液态金属的都属铸造起重机”。根据上述要求,冶金企业中吊运液态金属的起重机都属于冶金起重机。     

一种新型抱紧辅助支承机构

介绍了一种精加工用新型辅助支承机构,该机构一个动力油缸可带动两个辅助支承点支承工件,并且夹紧套靠液压油抱紧导杆,从而加工过程中支承点不会有任何动作,保证了加工精度.     

Wear mechanism of ceramic tools

Cutting tests were performed using ceramic cutting tools under continuous cutting conditions. The tests were carried out on AISI 1040 steel, with cutting speeds ranging from 5 to 11 m s⁻¹. The wear mechanism was investigated for both crater and flank. Alumina-toughened zirconia of submicron grain size showed the best wear resistance. Alumina with TiC, TiN and ZrO₂ inclusions exhibited a wear resistance a little lower than the above-mentioned materials. Low chemical stability seems to be the reason for the poor performances of the silicon carbide whiskers-reinforced alumina, silicon nitride and the tungsten carbide inserts.