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关键词： 干式离合器   温度模型   线性  

摘要： 影响离合器使用寿命最重要的因素就是离合器工作时的表面温度。通过分析干式离合器压盘热力学环境,研究热量传导过程,提出轴向分层线性计算方法,并建立了温度估算模型,进而设计台架试验方案,通过台架试验获取转速,扭矩和表面温度等测量数据,利用Simulink模型离线仿真的方法对温度模型进行参数标定和估算温度校验,仿真结果表明该方法可较准确估算离合器压盘表面温度。

关键词： Black Brent   Branta bernicla nigricans   Fitness   Lack clutch   Life history   BRANTA-BERNICLA-NIGRICANS   LIFE-HISTORY   ADAPTIVE SIGNIFICANCE   BARNACLE GEESE   CANADA GEESE   SNOW GEESE   SURVIVAL   COSTS   REPRODUCTION   GOSLINGS  

摘要： Lack 18:125-128 (1967) proposed that clutch size in precocial species was regulated by nutrients available to females during breeding. Drent and Daan 68:225-252 (1980) proposed the individual optimization hypothesis, whereby individual state determines the optimal combination of breeding date and clutch size. Neither hypothesis accounts for variation in nutrients among females at the end of egg laying, strong right truncations in clutch size distributions, or the fact that many species with precocial young are determinate layers. One solution is that there is a maximum clutch size, above which the number of fledged young declines. We manipulated brood size in Black Brent geese to decouple brood size from maternal quality and produce broods larger than the natural maximum. We recaptured marked goslings to assess variation in prefledging survival as a function of brood size and we estimated relative prefledging survival of goslings using a Bayesian hierarchical approach. We considered effects of natural clutch size, brood size and their interaction on probability that we captured goslings at about 4 weeks of age. Prefledging survival declined with increasing brood size ( = -0.53; 95% CI -0.91 to -0.16), while laid clutch size had little influence on prefledging survival ( = -0.04; 95% CI -0.42 to 0.32). Despite declining per capita survival with increasing brood size, the most productive brood size was six goslings, which is greater than the typical maximum clutch size of five. Thus, reduced survival in large broods, by itself, is not the sole mechanism that limits maximum clutch size. We suggest elsewhere that incubation limitation and lower residual reproductive value for females tending larger broods may be other mechanisms limiting maximal clutch size in brent.

关键词： Hybrid electric vehicle   Engine clutch   Torque observer   Estimation   DESIGN  

摘要： This paper mainly focuses on the accurate estimation of the torque transferred through the engine clutch installed between the engine and the drive motor in parallel-type hybrid electric vehicles. The estimation of the engine clutch torque primarily relies on the forward-direction observer which uses the nominal engine net torque information. To overcome the limitation of using the nominal engine torque information that it may not be accurate during the transient states or due to the influence of external disturbance such as the road condition and wind, the forward-direction observer is supplemented by the use of reverse-direction observer which uses the driveline model and wheel speed measurements. In addition, the drive motor torque information is used to calibrate the nominal engine torque during the idle charging state, so that the driveline characteristic unique to parallel-type hybrid electric vehicle can be utilized to increase the estimation accuracy. Finally, the estimation performance of the designed observer is tested via simulation and experiments based on a real vehicle.

关键词： Wind tunnel testing   Blade element momentum theory   Horizontal axis wind turbine   Power coefficient   Thrust coefficient   PERFORMANCE   DESIGN  

摘要： The umbrella-type rotor concept for horizontal axis wind turbine is proposed. The rotor allows blades to fold along the hinge which is fixed at the hub. The blade pitching and rotor coning are coupled as the hinge is inclined. This rotor is designed as a new approach to realize power control in high wind speed. The model-scale umbrella-type rotor with three blades was made and a rotor mechanical power testing platform was set up. Wind tunnel testing was conducted to supply data to estimate the rotor power performance. In the field of wind turbine aerodynamics theory, the blade element momentum model was improved for the umbrella type rotor aerodynamics calculation. Comparison between wind tunnel testing data and simulation result has been made. Experiment result showed that umbrella-type rotor was effective in adjusting power output by folding blades. The highest power coefficient was 0.259 in current study. Nevertheless it dropped down to 0.06 when the blades were folded at 20. In wind speed from 5 m/s to 9.54 m/s, a constant power output of 8.87 W was achieved. The calculated rotor power coefficient was found to be in good agreement with the experiment data. The highest average deviation was 11.81%. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： 齿轮   失效形式   预防措施  

摘要： 齿轮作为机械传动中的普遍而重要的零件,由于齿轮传动的工作条件和应用范围各不相同,常常会因为某种原因在使用工程当中被损坏,降低或失去使用性能,因而影响失效的原因很多。本文具体阐述了齿轮传动不同的失效形式及预防措施。

关键词： 微粒群算法   离合器设计   优化  

摘要： 离合器是汽车最重要的部件之一,汽车离合器的设计对于汽车的性能具有重要的影响。文章在离合器优化设计中引入微粒群算法,运用微粒群算法对离合器中的主要构建进行优化设计,并对部件的特性进行了分析,得出运用微粒群算法进行离合器的主要构建设计能够满足构建特性的结论。

关键词： 漏油   拖拉机   密封胶圈   减压轴   油箱开关   离合器   变速杆   起动机  

摘要： （1）轴漏油。回转轴包括起动机变速杆轴和离合器手柄轴以及发动机减压轴。若因轴与孔相互磨损,可将起动机变速杆轴和离合器手柄轴在车床上车出密封环槽,此时只要装上相应尺寸的密封胶圈即可。若因减压轴胶圈老化失效,则应更换新胶圈。（2）开关漏油。包括水阀、油箱开关和汽油开关等。若因球阀磨损或锈蚀漏油,应清除球阀与座孔之间的锈物,

关键词： 磁阻   新型电磁离合器   数值模型   转差角   电磁性能   转矩特性  

摘要： 基于磁阻原理设计了一种新型电磁离合器并阐述了其基本结构和工作原理。针对新型电磁离合器在一定的负载力矩下外齿发生跳齿失位的情况,对离合器进行了转矩理论分析计算,并利用Maxwell软件建立了新型电磁离合器的数值模型,分析了内外齿转差角的变化对新型电磁离合器电磁性能以及转矩特性的影响,研究了励磁线圈安匝数的变化对新型电磁离合器最大转矩的影响。研究结果表明:此新型电磁离合器的的设计方案可行,具有良好的应用前景。

关键词： 齿轮传动系统   故障模拟   综合实验台  

摘要： 由于齿轮传动有着传动精度高、承载能力强、传动功率稳定的特点,所以在各个机械行业中都获得了广泛地运用。但是,因为齿轮传动系统的内部结构比较复杂,而且齿轮传动运行的环境也不好,经常会使得齿轮传动系统在运行过程中出现故障。这些故障问题给其生产效率带来了非常大的影响,故障问题严重的话还会引起极大地安全事故。所以,大程度地降低齿轮传动系统运行中的故障问题是非常有必要的。本文主要对齿轮传动系统故障的原因和改进对策以及实验台的设计方案进行了简单的分析和研究,从而保障齿轮传动系统能够更加顺利地进行。

关键词： 膜片弹簧离合器   零件应力   机器视觉   结构形状   有限元分析  

摘要： 论文根据桂林福达股份有限公司对膜片弹簧离合器关键零件的应力分析与外观检测的需要。基于有限元分析方法和机器视觉在线检测系统，对膜片弹簧离合器关键零件进行应力分析与外观检测的研究。主要内容包括使用有限元分析软件ANSYS对膜片弹簧离合器的几个关键零件（盖零件、膜片弹簧、减振盘和波形片等），进行受力情况分析、再应用机器视觉的检测方法对成品零件的表面加工质量进行检测。本论文主要研究内容如下：\n 1、有限元应力分析部分主要包括：对盖零件进行变形分析，以及如何对其进行改进设计；对膜片弹簧、减振盘和波形片各点应力情况进行分析，确定应力最大点及其应力峰值；模拟零件的工作状态，找出零件在工作过程中的危险点，判断其在正常工作状态是否会出现断裂。\n 2、机器视觉检测部分主要是针对零件的结构形状和相关特性，设计一套合适的在线机器视觉检测系统。对各个零件制定不同的检测方法。这些关键零件大小不一，形状各异，对检测设备要求有一定的景深。本文采用双远心镜头对膜片弹簧、压盘和从动盘等零件的工作表面和关键尺寸进行检测。检测其机械加工情况，以及各安装孔的位置度情况。最后根据有限元分析与外观检测情况判定零件是否合格。\n 论文的分析成果可用于指导生产实际，具有一定的应用价值。通过有限元分析和结构优化设计，本文中涉及到关键零件的强度最终都可以满足设计使用要求；在线机器视觉检测系统的结构设计也已经完成，并申请了相关的专利。