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关键词： 有限元分析   离合器盖   强度设计   优化  

摘要： 汽车离合器最为主要的功能在于保障汽车的平稳起步,这对于实现换挡平顺以及避免传动装置过载具有重要的作用。而离合器盖是其中的一个关键部件,对于离合器以及变档机构起着密封封闭的作用。因此,文章结合有限元分析方法,对离合器盖强度的优化设计进行研究,旨在更好的指导企业的实际生产。

关键词： 自动变速器   行星齿轮传动机构   换挡执行机构  

摘要： 本文以拉维娜式四挡自动变速器为例,完成该自动变速器的传动机构设计,包括各个挡位传动路线及其传动方案设计,最终通过给定具体参数,完成整个行星齿轮传动部分的结构设计。

关键词： 离合器   离合操纵   校核  

摘要： 在整车开发前期,因为离合器系统关系到整车操控的舒适性,所以其匹配开发工作显得尤为重要。文章针对上汽通用五菱汽车股份有限公司某新开发轿车车型的离合器及离合操纵系统进行设计校核,校核离合器摩擦功、后备系数、起步温升、离合踏板力及离合踏板行程等相关设计参数。

关键词： 大型养路机械   钢轨打磨车   减速箱脱齿   现场试验   离合器   脱齿工装  

摘要： GMC96B钢轨打磨车在作业时要对A车减速箱进行合齿实现低速液压传动,作业结束后减速箱脱齿实现高速液力走行。在现场使用中出现了由各种因素导致的作业结束后减速箱无法脱齿的故障,受现场封锁时间限制,若故障无法及时查找并处理时将严重影响正常行车,导致列车晚点。本文分析了减速箱无法脱齿的原因,针对各故障提出了相应的解决方案,并研制了可快速完成减速箱脱齿的工装,通过现场实际应用,有效地解决了减速箱故障处理难题,确保了打磨车的运行安全。

关键词： 中重卡   离合器   离合器操纵机构  

摘要： 某中重卡车型匹配的离合器存在批量早期烧蚀故障,文章对离合器与离合器操纵机构匹配情况进行了理论计算及结构分析,通过改进离合器操纵机构,解决了离合器市场故障。

关键词： 双离合器自动变速器   换挡控制   模糊控制   换挡品质   仿真  

摘要： 为提高双离合器式自动变速器的换挡质量,研究换挡过程中双离合器的协调控制方法。分析了双离合器自动变速器的结构和动力传递路线,并建立传动系统的数学模型。综合考虑整车动力性、经济性和换挡平顺性等因素,采用模糊控制理论设计了综合智能型的换挡策略。以MATLAB/Simulink/Stateflow为软件平台,开发动力传动系统的仿真模型并对换挡过程进行仿真试验。结果表明,该策略可以较好地减少换挡时间和缓和冲击度,优化了换挡品质。

关键词： Conspecific superparasitism   Host discrimination   Multiple-egg clutches   Quasi-gregarious   Self-superparasitism  

摘要： In the quasi-gregarious parasitoid wasp Anastatus disparis, a mother may lay more than one egg in a host during a single host encounter. This is conventionally known as self-superparasitism and, since only one adult offspring can complete development on the host, it may represent a waste of eggs and time. However, this behavior may be better described as "multiple-egg clutches," which differs fundamentally from self-superparasitism and has seldom been addressed. The potential benefits of laying multiple-egg clutches are currently unclear, and we therefore aimed to investigate them in A. disparis. First, our results showed that production of multiple-egg clutches by A. disparis is not due to a lack of discrimination between unparasitized and parasitized hosts, as females preferred to lay eggs in unparasitized hosts. It was also unrelated to the age of the female or her mating status, or to the presence of conspecific females. However, compared to the temperatures of 26 and 32 degrees C, we observed that the frequency of multiple-egg clutches increased at the temperature of 20 degrees C. In addition, low developmental temperatures significantly decreased the rate of successful wasp eclosion from hosts in which a single egg was deposited, and this rate was increased by laying multiple-egg clutches. These results suggest that female A. disparis adults produce multiple-egg clutches to increase the probability of obtaining offspring from the host, and may have the ability to regulate oviposition and reproduction strategy based on environmental temperature. Significance statement Anastatus disparis exhibited an oviposition behavior of facultative production of multiple-egg clutches, which is not due to a lack of host discrimination, or due to the age of the female or her mating status nor the presence of conspecific females. However, our results suggest that A. disparis adults produce multiple-egg clutches when it increased the probability of obtaining offspring from the h

关键词： Alternative reproductive tactics   Bi-parental care   Conditional strategy   Costs of reproduction   Individual quality  

摘要： Multiple breeding within the same season is a typical reproductive strategy among short-lived species. Despite the apparent increase in the number of offspring, not all individuals become multiple breeders in most species or populations, known as facultative multiple breeding (FMB). Elucidating the mechanisms producing FMB would be a significant contribution to a better understanding of the complex life histories in wild populations. In the present study, we regarded FMB as a female alternative reproductive tactic (ART) and examined the factors affecting reproductive decisions. ARTs have been investigated mostly in males and male conditions. However, in many bird species both parents raise their offspring and, therefore, a partner's condition may also affect ARTs. We analyzed 6 years of data on multiple breeding in Japanese tits (Parus minor) in northern Japan, where nearly half of breeding pairs reproduce multiple times within breeding seasons. We found that females started breeding early were more likely to breed again in that season. Also, females paired with older males start breeding earlier, suggesting that factors associated with male age, such as territory quality, influence whether a female has multiple broods or not. We found no trade-off between multiple breeding and female apparent survival. Rather, multiple breeders exhibited a higher apparent survival than single breeders. These results suggested that late-started females may take an alternative tactic by avoiding the cost of second breeding and concentrating on post-fledging care of the first broods. We also demonstrated the partner's roles in the decision of conditional strategy.

关键词： Dual clutch transmission   Control-oriented model   Clutch torque estimation   Drive shaft torque estimation   Gear shift control  

摘要： Over the years, dual-clutch transmission (DCT) has demonstrated its higher efficiency and superior shift performances over other types of transmissions, and has been increasingly used in modern mass-produced vehicles. However, due to the absence of the smoothing effects of torque converters, vehicles with DCT are easily exposed to driveline oscillations that lead to poor driving quality, especially during gear shifts. Therefore, torque transfer through the driveline should be controlled with great care by two clutches and engine to achieve the DCT's outstanding performance. The main obstacle to the accurate torque control is its lack of adequate sensors in production vehicles. Thus, the objectives of this paper are two-fold. First, a control-oriented model with practical concerns is implemented for DCT drivelines, aiming to accurately describe the powertrain oscillations that should be suppressed by the torque control. Secondly, a real-time torque monitoring strategy based on the proposed model is suggested to deal with the absence of torque sensors. The primary task of the torque estimator is to concurrently estimate the torque transmitted through both clutches and drive shaft by using only readily available data from production cars. The developed torque estimator is verified through multiple experiments under various driving conditions. (c) 2017 Elsevier Ltd. All rights reserved.

关键词： elevational gradient   evolutionary constraints   offspring mortality   life-history evolution   phenotypic plasticity   predation risk manipulation   reproductive investment   resource availability  

摘要： The risk that an animal's offspring are eaten by predators is thought to strongly influence an animal's decisions regarding reproductive effort. We found that birds breeding in locations with a high risk of nest predation laid fewer eggs than their conspecifics nesting in areas with a lower risk of nest predation. Montane birds nesting at higher elevations lay fewer eggs than at lower elevations because of the higher risk of nest predation at higher *** about the ecological drivers of, and mechanistic constraints on, productivity have driven research on life-history evolution for decades. Resource availability and offspring mortality are considered among the 2 most important influences on the number of offspring per reproductive attempt. We used a factorial experimental design to manipulate food abundance and perceived offspring predation risk in a wild avian population (red-faced warblers;Cardellina rubrifrons) to identify the mechanistic cause of variation in avian clutch size. Additionally, we tested whether female quality helped explain the extant variation in clutch size. We found no support for the Food Limitation or Female Quality Hypotheses, but we did find support for both predictions of the Nest Predation Risk Hypothesis. Females that experienced an experimentally heightened perception of offspring predation risk responded by laying a smaller clutch than females in the control group. Additionally, predation rates at artificial nests were highest where red-faced warbler clutch size was smallest (at high elevations). Life-history theory predicts that an individual should invest less in reproduction when high nest predation risk reduces the likely benefit from that nesting attempt and, indeed, we found that birds exhibit phenotypic plasticity in clutch size by laying fewer eggs in response to increasing nest predation risk.