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关键词： Vertical axis wind turbine   Building integration   Resistance type wind turbine   Sistan wind mill  

摘要： The Persian or Sistan wind mill is possibly the oldest wind energy device. It consists of a vertical axis with six blades, and an outer shroud which encases half the rotor against the wind. The wind only acts on one half of the runner, providing the driving force. The efficiency of this machine was assumed to be between 5 and 14%, too low for practical application today. The concept however is interesting since it has the potential for integration into buildings. Recently, the Sistan wind mill was re-visited to assess whether the performance could be improved. Initial exploratory tests reported in the literature indicated potential. At Southampton University, a series of tests was conducted with a model of 0.6 m diameter and 0.5 m high runner employing an improved measurement and data acquisition system. Two geometries were investigated. Qualitative tests indicated that a gap between blade and axis is essential for functionality. Performance tests with an improved geometry resulted in efficiencies of 0.4-0.5, similar to e.g. Darrieus-type VAWTs, for blade to wind speed ratios of 0.82-1.8. The modified resistance-type vertical axis wind turbine appears to have potential for further development. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： VAWT   Aerodynamic stability   Airfoil   Steady flow simulation   Deviation and fluctuation   ENERGY-PRODUCTION   DYNAMIC STALL   PERFORMANCE   PREDICTION   DESIGN   SIMULATION   SOLIDITY   SYSTEM   MODEL  

摘要： This paper presents a method examining static forces and moment of airfoil in steady solver. Aerodynamic stability is one subject that many scholars have begun to realize very crucial for design and daily operation. Fundamentals of aerodynamics were firstly scrutinized concerned about lift, drag and moment. Then steady simulation solver is set up instead of transient solver because we would like to examine airfoil without the effect of vortex motion, temporarily focus on static forces on airfoil. Dependent variable include cl, cd and cm of three airfoils, FLAT PLATE, NACA0012 and NACA23012 at TSR = 0, 2, 5 and 7. Stability is characterized by deviation and fluctuation at 360 degrees of azimuth position. We found that FLAT PLATE showed most deviation and fluctuation as an example of airfoil for VAWT. NACA0012 representing symmetric airfoil has more stable cm at whole time and cd just at TSR of 2 and 5. NACA23012 representing cambered airfoil has more stable cl all phases of running. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Clutch   Non-back-drivability   Design   Prosthetic   Robotics   PROSTHESIS  

摘要： A non-back drivable mechanism (transmission or clutches) is a device able to transmit torques from its input to the output axis and vice-versa to lock torques applied to its output. These devices are widely used in robotic, mechatronic systems and prosthetics in order to lock joints or to physically engage/disengage transmission axes. An efficient way to implement non-back drivability is to exploit the wedge phenomenon that occurs to rolling elements when they are compressed between circular and cam surfaces. The current literature describing such mechanisms and underlying equations is rather scattered and incomplete. In this paper, a relevant set of equations is presented to optimize their design, which is of particular interest in prosthetics to minimize weight of limbs. The conceptual framework and the general design are described. The relationship between the locking torque and the properties of the components are then derived. Moreover, the sources and effects of tolerance and of operational conditions are introduced. The contact pressures, the input torque required to unlock the clutch, the critical torque and the input backlash are finally analyzed. The final part of the paper is devoted to a step-by-step procedure useful in the design of non-back drivable roller clutches. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： 液压操纵式离合器   诊断   问诊   故障成因  

摘要： 本文介绍了汽车液压操纵式离合器常见故障产生的原因和故障诊断的常用方法,通过引用两起汽车离合器故障案例重点突出问诊和经验诊断等方法,汽车维修技术人员应在工作中不断的学习和总结分析,才能将文中重点介绍的问诊法和直观诊断法使用的得心应手。

关键词： 双离合器自动变速器   侧隙   预挂挡策略   挂挡策略   啮合阶段  

摘要： 某款双离合器自动变速器在开发过程中,经过整车变速器试验,在滑行降挡过程中存在clonk噪声问题。通过INCA软件连接ETAS设备采集数据,进行clonk噪声试验,分析clonk噪声来源于扭矩变换在传动侧隙上产生敲击变速器噪声。双离合器自动变速器的控制策略决定了换挡时机、预换挡时机及换挡机构的运行动作,对变速器clonk噪声的贡献度很大。结果表明,通过优化换挡及预挂挡策略,降低扭矩变化的幅度,可以避免clonk噪声的出现。

关键词： 技术通报   捷豹   路虎   压力过低   Range   高压系统   低压系统   离合器  

摘要： 捷豹空调性能不良涉及车辆：捷豹XK、XJ、XF、XE、F-TYPE、XK Range及F-PACE 故障通报：以上部分车型空调（A/C）性能不良。高压系统上记录的压力过低,低压系统上记录的压力过高。压缩机离合器工作正常。

关键词： 超越离合器   赫兹接触   接触应力   接触特性  

摘要： 以滚柱式超越离合器为研究对象,采用赫兹接触理论,对其关键传动部件间的接触应力进行分析研究。通过超越离合器常见两种力学分析模型获得了对应接触副间的正压力P,求得了所对应的赫兹应力值,结合赫兹接触优化理论研究成果,提出了两种力学方法的适用条件。并结合有限元仿真分析得到了反映接触副接触特性的部分参数,如接触压力、滑动距离等,同时验证了两种力学方法的适应性条件。结果表明,考虑摩擦因数的力学分析方法更加适合于理论计算,而理想化的线接触分析模型适合于实际工况计算。从而为进一步了解超越离合器的工作特性及后续的优化设计提供了坚实的理论依据。

关键词： 浇注系统   中心浇口   侧浇口   出品率  

摘要： 文章以公司JS180-1601015-5-Y压铸产品为例,分析了模具不同浇注系统对模具设计、及生产经济性造成的不同的影响。结果表明,中心浇注系统相对侧浇注系统不仅节约模具成本达到6.69万,也提高了生产出品率18.8%,节约辅料成本相比可达36%,大大体现了其自身优势,为公司离合器壳体类似压铸产品的浇注系统设计提供了借鉴。

关键词： NVH性能   发动机   离合器  

摘要： 研究了整车开发后期四种性能零件对车辆NVH的影响,通过对这四种性能零件的优缺点分析,提出三项改善离合器性能的重要指标,最后通过多年、多车型的整车性能对比测试方法,证明改善离合器的三项重要指标对发动机端的NVH性能改善效果明显。