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关键词： 硅油风扇离合器   柴油发动机   风扇转速   维护   冷却液温度   散热能力   冷却系统   可调节  

摘要： 风扇的风量是随着转速的增加而增大的，所以，改变风扇的转速可调节冷却系统的散热能力。目前，改变风扇转速的办法是采用风扇离合器，在冷却液温度较高时，离合器使风扇保持较高的转速。

关键词： 闭式双点压力机   高速   切片   同向传动   齿轮结构  

摘要： 以我厂交付客户使用的压力机设计参数为依据,从台板尺寸和滑块行程次数切入,剖析了一台闭式双点800t高速热切片压力机传动结构分析设计过程。

关键词： 斜齿轮   遗传算法   ABAQUS   优化设计  

摘要： 选取一对外啮合渐开线斜齿圆柱齿轮,以其分度圆圆柱体积最小为优化目标函数,建立数学模型。为满足斜齿轮齿根弯曲强度和齿面接触疲劳强度,运用改进的遗传算法将求解过程简化,得到最优解。并利用ABAQUS有限元软件,对齿轮啮合进行有限元强度分析,最后将分析结果进行模拟显示。结果表明,利用遗传算法求解斜齿轮问题便捷可靠。

关键词： 湿式离合器   输入轴   托板   刀杆   立铣刀   螺旋角   刀头   轴器   开关电源   螺纹孔  

摘要： 介绍一种用于压力机湿式离合器的拆卸和安装装置,可以实现快速、方便的拆卸和安装,在实际应用中取得了较好的效果。

关键词： 自适应控制   AMT   发动机扭矩   商用车   离合器接合   协调控制策略   接合点   传递扭矩   压盘   油门开度  

摘要： 为了提高商用车AMT(Automated Mechanical Transmission)起步的舒适性和鲁棒性,本文就某商用客车AMT的起步过程进行了理论分析和试验研究。针对AMT起步过程由于离合器磨损、离合器表面温度变化、路况条件变化以及车辆载荷变化等造成的离合器接合控制鲁棒性差的问题,本文提出了离合器的自适应控制策略。该策略不仅能随着离合器磨损对离合器半接合点进行自动修正,也能根据每次起步过程离合器主从动部分速差和发动机转速的变化,实时自动调节离合器目标接合速率。同时,本文还提出了AMT起步过程发动机扭矩协调控制策略。试验结果表明,AMT起步过程离合器自适应控制策略和发动机扭矩协调控制策略改善了起步过程的鲁棒性和舒适性,减小了起步过程离合器滑磨功。

关键词： 压铸铝合金   侧浇口   中心浇口   模拟  

摘要： 以两种结构相似的压铸铝合金离合器壳体为例,根据现场实际生产,对两种不同浇注系统(中心浇口、侧浇口)铸件进行了分析对比。结果表明,中心浇口铸件品质优于侧浇口铸件。后期利用MAGMA软件对两种浇注系统的充型过程进行模拟,分析验证了两种浇注系统产生缺陷的位置及原因。为提高压铸铝合金离合器壳体品质,采用中心浇口方式,并对中心浇口存在的问题,给出了解决方案。

关键词： Pin on disc tribometer   Design   Control   Friction   Wear   Dry clutch   FRICTION   WEAR   SYSTEM   JUDDER   SIMULATION   VIBRATIONS   FIBER  

摘要： The paper presents the design of a pin-on-disc type tribometer intended for experimental characterization of static and dynamic friction behaviors for various sliding sample pairs. The normal force, slip speed, and temperature, as the main influencing parameters, are precisely controlled during experiments, by applying vertical and rotational servo-axes and an electric heater built in the rotating disc. A compact three-axial piezoelectric force sensor, placed between the vertical-axis screw drive and the friction sample, provides direct measurement of normal and tangential forces used to calculate the sample coefficient of friction. The slip speed is measured directly using an incremental encoder mounted at the rotational table. The disc temperature is measured by a built-in Pt probe, whose wires, together with the heater wires, are connected to the temperature control unit by means of slip rings. The tribometer performances are demonstrated through a study of coefficient of friction, shudder sensitivity, and wear rate characterization for a dry clutch friction material. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Bacterial endosymbionts   Harmonia   Male-killer   Maternal investment   Spiroplasma   INHERITED MICROORGANISMS   MATERNAL INVESTMENT   AXYRIDIS COLEOPTERA   HARMONIA-YEDOENSIS   MALE-KILLER   SEX-RATIO   WOLBACHIA   COCCINELLIDAE   OVIPOSITION   PERFORMANCE  

摘要： Maternally inherited bacterial endosymbionts can kill male embryos of their arthropod hosts to enhance the transmission efficiency of the endosymbionts. The resources from killed male eggs can be reallocated to infected female hatchlings as additional maternal investment. As a result, the number of offspring per patch and the maternal investment per offspring are expected to differ from the original optimal values for the host mother. Thus, in response to infection, these trait values should be adjusted to maximize the lifetime reproductive success of host females and the fitness of inherited endosymbionts as well. Here, we examined clutch size, egg size, and the proportion of trophic eggs (i.e., production of unhatched eggs, a maternal phenotype) per clutch of host mothers infected with male-killing bacteria. First, we developed a mathematical model to predict the optimal clutch size and trophic egg proportion in uninfected and infected females. Next, we experimentally compared these life-history traits in a ladybird, Harmonia yedoensis, between females infected or uninfected with male-killing Spiroplasma bacteria. Consistent with our predictions, clutch size was larger, egg size was smaller, and trophic egg proportion was lower in infected H. yedoensis females, compared with uninfected females. To our knowledge, this is the first empirical demonstration of variation in these life-history traits depending on infection with bacterial endosymbionts.

关键词： CHAMAELEO-CHAMELEON   NORTHERN MADAGASCAR   COMMON CHAMELEONS   BIOLOGY   INVASION   CAMEROON   REPTILES   ECOLOGY   FOREST   EGG  

摘要： We studied an established population of Furcifer oustaleti (Oustalet's Chameleon) in southeastern Florida to understand aspects of reproductive biology in this nonnative species. Reproduction of Oustalet's Chameleon had not been documented in the field in Florida, and limited information is available about its reproduction in its native range. We conducted surveys from July 2011 to October 2012 in the Persea americana (Avocado) grove where this species was introduced in Miami-Dade County, FL. During these surveys, we removed more than 430 chameleons. We encountered 23 gravid females from June to October. Mean clutch size was 42.3 eggs, and we recorded a new maximum clutch size of 72 eggs. Utilizing radio-telemetry, we were able to track a gravid female to a nest cavity, and herein describe the first Oustalet's Chameleon nest in Florida. Our findings suggest that management for eradication of the species should include ongoing surveys, with removal efforts intensified from June to October, when females are known to be gravid.

关键词： OBLIGATE BROOD PARASITES   BILL-SIZE CONSTRAINTS   GREAT REED WARBLERS   CUCULUS-CANORUS   EUROPEAN PASSERINES   CUCKOO PARASITISM   COMMON CUCKOO   HOST DEFENSES   COWBIRD EGGS   BIRD EGGS  

摘要： Avian hosts of brood parasites can evolve anti-parasitic defenses to recognize and reject foreign eggs from their nests. Theory predicts that higher inter-clutch and lower intra-clutch variation in egg appearance facilitates hosts to detect parasitic eggs as egg-rejection mainly depends on the appearance of the egg. Therefore, we predict that egg patterns and rejection rates will differ when hosts face different intensity of cuckoo parasitism. We tested this prediction in two populations of the plain prinia Prinia inornata: Guangxi in mainland China with high diversity and density of cuckoo species, and Taiwan where there is only one breeding cuckoo species, the oriental cuckoo Cuculus optatus. As expected, egg patterns were similar within clutches but different among clutches (polymorphic eggs) in the mainland population, while the island population produced more uniform egg morphs. Furthermore, the mainland population showed a high rate of egg rejection, while the island population exhibited dramatically reduced egg grasp-rejection ability in the absence of parasitism by the common cuckoo Cuculus canorus. Our study suggests that prinias show lower intra-clutch consistency in egg colour and lose egg-rejecting ability under relaxed selection pressure from brood parasitism.