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1.
针对高压注入井油管在服役环境下长期承受交变拉伸载荷作用存在泄漏风险的问题,通过搭建交变拉伸载荷下油管丝扣密封性能测试试验平台、优选试验设备及制定合理的试验步骤,对平扣、BGT扣、FOX扣油管试样在10~50 t拉伸交变载荷下的密封性能进行了模拟。模拟结果显示:对3种扣型油管试样施加同等拉伸载荷,其密封性能随交变次数增加而降低,降低幅度为平扣>BGT扣>FOX扣;50 t拉伸载荷施加5次后,3种扣型油管试样的密封性能分别为5.67 MPa、32.69 MPa、73.67 MPa。研究表明,平扣无法满足注入井的密封要求,BGT扣及FOX扣具有较好的适用性。研究结果为注入井油管扣型选择提供了依据。 相似文献
2.
Ball screws are crucial for improving the reliability and interchangeability of transmission mechanical systems; however, existing contact measurement methods that utilise stylus contact are not efficient, which precludes their use for rapid in-situ geometry evaluation. This paper presents a vision-based two-stage method for rapid measurement of key parameters (raceway arc radii and centre distance) of ball screws. The edge contour information is extracted from the acquired image using the dual-tree complex wavelet transform and non-maximal suppression. In the matching stage, a shape-matching algorithm is used for detecting approximate geometrical centres of raceway arcs. The refinement stage, on the other hand, is implemented for acquiring precise dimensional results. Furthermore, the method of averaging multiple measurements is performed to suppress random noise. A comparative experiment is presented to validate the robustness of the proposed method. Based on experimental results, the calculated mean absolute errors in the measurement of the two raceway arc radii and the centre distance are found to be 0.0082 mm, 0.0079 mm and 0.0055 mm, respectively. This study therefore paves the way for key parameter measurement without removing ball screws. 相似文献
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M. R. Thompson 《Drug development and industrial pharmacy》2015,41(8):1223-1231
Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique. 相似文献
6.
In order to protect bolts from corrosion, electroplating such as zinc plating is widely used. However, hydrogen can easily penetrate or diffuse into the vacancies and dislocations between the lattices of bolt steel during electroplating. As the diffused hydrogen defects inside the lattice are in gaseous form, small cracks can easily be produced due to high pressure from the hydrogen gas. In this research, in order to determine the root cause of the fracture in pole fastening screws resulting from hydrogen embrittlement in typical electric motors, additional factors that accelerate hydrogen embrittlement fracture were selectively applied, including a small fillet in the head–shank transition and excessive hardness, and parametric study was performed experimentally. 相似文献
7.
Kaidi Nie Felix von Drigalski Joshua C. Triyonoputro Chisato Nakashima Yoshiya Shibata Yoshinori Konishi 《Advanced Robotics》2020,34(7-8):477-498
ABSTRACTIn this paper, we describe the approach of Team O2AS to complete the task-board task of the World Robot Challenge 2018, held in Tokyo. We use a custom gripper and graspable tools with in-built compliance to work with various kinds of parts, increase robustness against uncertainties, and to avoid complicated control strategies. The robots are able to finish all the sub-tasks without the need to exchange grippers. The main idea is to use mechanical compliance and self-centering mechanisms to deal with uncertainty. This is achieved by aligning the objects using either the gripper and tools, or by the design of the robot motions. 相似文献
8.
根据顶板高位定向钻孔快速钻进成孔与工作面卸压瓦斯高效抽采治理需要,针对现有螺杆马达定向钻进技术与分级扩孔方法存在的问题,开展了顶板硬岩定向钻进与大直径扩孔钻进关键技术研究,开发了冲击回转定向钻进技术、扭冲回转定向钻进技术、扭冲旋转扩孔技术以及双级双速扩孔技术等钻孔提速新技术,研制了冲击螺杆马达、矿用小直径扭力冲击器、双级双速螺杆马达、组合式扩孔钻头等配套钻具。综合试验结果表明,硬岩定向钻孔平均机械钻进效率达到8.34 m/h,最高达到13.6 m/h,较常规螺杆马达定向钻进技术提升20%~30%;硬岩大直径扩孔终孔直径达到200 mm,机械钻进效率平均达到5.6 m/h以上,最高达到10.5 m/h。该技术提升了顶板硬岩定向钻进效率与大直径扩孔钻进效率,缩短了顶板高位定向钻孔的综合施工周期,为大直径高位定向长钻孔快速成孔与高效抽采治理回采工作面卸压瓦斯提供了可靠的技术手段。 相似文献
9.
SCM440钢冲床球头螺杆使用了约1年就发生断裂。采用断口检验、金相分析、化学成分分析和力学性能测试等方法分析了球头螺杆断裂的原因。结果表明:球铁螺杆的显微组织为网状铁素体,晶粒粗大,并存在夹杂物、孔洞及锻造裂纹等缺陷,螺杆热处理过程中裂纹从这些缺陷处产生,并在使用中在应力的作用下扩展,最终导致螺杆断裂。 相似文献
10.
为解决塔式光热的核心构筑物吸热塔"方变圆"变径超高筒体结构施工难题,选用一套可变形的滑模平台系统,通过操作系统上可调千斤顶支座、门架横向液压千斤顶装置、多处可调节模板角度和收缩模板的丝杆等,使得滑模根据施工需求可在一定的范围内调节模板倾角、间距,并逐步完成收缩变形,其理论滑模允许偏角20°,最终高效完成异形结构施工。该滑模系统刚度大、承载及堆料能力强、空间大、机械化程度高,施工操作简单,安全性高,适应沙漠极端环境。全过程仅需使用一套滑模体系,就能完成方形段、方变圆的变形段及圆形段施工,大大提高了施工效率,为类似环境下相似结构的施工提供了一定的参考。 相似文献