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关键词： 齿片   从动盘   压盘   防松   外齿   传动效率   传动系统   摩擦片   密封环   离合器接合  

摘要： 转向离合器作为推土机传动系统中的关键部件,其操纵灵活性、传动效率、装配方法直接影响推土机的安全性能及使用成本。为此我们针对推土机转向离台器结构和存在问题进行分析,并对其结构进行了改进。1.改进前的结构及存在问题（1）结构推土机转向离合器主要由长螺栓1、防松垫2、压盘3、定位套4、小弹簧5、大弹簧6、主动盘7、从动盘8、外齿摩擦片9、内齿片10、密封环11、活塞12等组成。其结构如图1所示。

关键词： Larval dispersal   Life-history traits   Phylogenetic least squares   Reproductive strategies   Size-number trade-off   OPTIMAL OFFSPRING SIZE   PARENTAL CARE   LIFE-HISTORIES   PROPAGULE SIZE   MARINE INVERTEBRATE   LIKELIHOOD APPROACH   EVOLUTION   DISPERSAL   PATTERNS   PRODUCE  

摘要： Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm(3), scattered eggs = 0.18 mm(3), pelagic eggs = 0.52 mm(3)) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.

关键词： vehicle   automated dry clutch   position control   modified predictive functional control   sliding mode observer   TORQUE  

摘要： Dry clutch control is a typical nonlinear problem due to the nonlinear characteristics of diaphragm springs. For precise position control of the automated dry clutch, a modified predictive functional control (mPFC) method is proposed. First, a novel mechanical actuator is designed and models of the automated dry clutch system are built based on theoretical analysis and experimental data. Then, in order to compensate for the position error of direct current (DC) motor caused by load torque, modifications are introduced to a regular predictive functional control (PFC), including a sliding mode observer (SMO) to estimate the load torque and a predictive model concerning the load torque. Next, simulations show that the SMO could estimate the load torque accurately and the mPFC performs well with the nonlinear load torque. Finally, experiments are carried out on a test bench and the results are in accordance with the simulations. Due to the little online computing burden and the simple structure of the mPFC, it could be used in other industrial control systems which need fast response.

关键词： Design optimization   High pressure die casting   Solidification   Computational fluid dynamics (CFD)   MODEL  

摘要： Aluminum die casting is so complex where flow momentum is critical matter in the mould filling process due the high velocity of the liquid metal. Actually, in complex parts the exact calculation of mould filling performance with using experimental knowledge is almost impossible. Aluminum die castings play a definitive role in the manufacturing of lightweight automobile bodies. Hence it is more essential today that these castings be produced with the high quality methods. In this condition the simulation is becoming more important in the designing procedure. This saves time and reduces the cost of the casting system design, which is an advantage of using simulation programs. Also, economical utilization of materials can be obtained when the quantity of test castings is decreased. This paper describes the advantages of the clutch housing die casting mold simulations to achieve better casting system design in High pressure die castings (HPDC). Filling analysis is used to determine the size and location of the gate as well as proper runner system design for ensuring a complete and balanced filling of the clutch housing part.

关键词： Fructose dehydrogenase   Direct electron transfer   Electron transfer pathway   Overpotential   Axial ligand   Heme c   BILIRUBIN OXIDASE   BIOFUEL CELLS   FUEL-CELLS   ENZYMES  

摘要： D-Fructose dehydrogenase (FDH), a flavoprotein-cytochrome c complex, exhibits high activity in direct electron transfer (DET)-type bioelectrocatalysis. One of the three types of heme c in FDH is the electron-donating site to the electrodes, and another heme c is presumed to not be involved in the catalytic cycle. In order to confirm the electron transfer pathway, we constructed three mutants in which the sixth axial methionine ligand (M301, M450, or M578) of one of the hemes was replaced with glutamine, which was selected with the expectation that it would shift the formal potential of the hemes in the negative direction. An M450Q mutant successfully reduced the overpotential by approximately 02 V, giving a limiting current close to that of the native FDH. In contrast, an M301Q mutant remained almost unchanged and an M578Q mutant drastically decreased DET-type catalytic activity. The results indicate that the electron transfer in the native FDH occurs in sequence from the flavin, through the heme c with M578, to the heme c with M450 (as the electron-donating site to the electrodes), without going through the heme c with M301. The M450Q mutant will be useful for biofuel cells because of the decreased overpotential. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Clutch   Response surface method   Shape optimization   Topology optimization   SHAPE OPTIMIZATION   TOPOLOGY  

摘要： This paper presents a methodology for re-designing a failed tractor transmission component subjected to cyclic loading. Unlike other vehicles, tractors cope with tough working conditions. Thus, it is necessary to re-design components by using modern optimization techniques. To extend their service life, we present a design methodology for a failed tractor clutch power take-off finger. The finger was completely re-designed using topology and shape optimization approach. Stress-life based fatigue analyses were performed. Shape optimization and response surface methodology were conducted to obtain optimum dimensions of the finger. Two design parameters were selected for the design of experiment method and 15 cases were analyzed. By using design of the experiment method, three responses were obtained: Maximum stresses, mass, and displacement depending on the selected the design parameters. After solving the optimization problem, we achieved a maximum stress and mass reduction of 14% and 6%, respectively. The stiffness was improved up to 31.6% compared to the initial design.

关键词： 拖拉机   离合器   使用   调整  

摘要： 拖拉机离合器常因使用维护不当而发生故障,因此,本文以拖拉机离合器使用维护中常出现的问题为重点,有针对性地阐述了离合器使用、保养、调整技术要点。

关键词： 自动变速器   锁止离合器  

摘要： 锁止离合器控制是广泛应用于自动变速器控制中的技术,对于降低油耗有着重要意义,滑差控制是锁止离合器控制中的关键技术,文章针对滑差控制,展示了一种控制算法。

关键词： 汽车离合器   故障   检测  

摘要： 在汽车行驶过程中,由于频繁使用离合器,会导致离合器的磨损甚至故障。本文讨论了汽车离合器分类,以及汽车离合器的常见故障及检测,希望能够降低汽车故障的发生率和提高诊断故障的效率,也使广大汽车用户从中获益。