共查询到19条相似文献，搜索用时 171 毫秒
1.
本文论述了液压传动技术在工程机械行走驱动系统中的应用,并通过对液压传动技术与传统纯机械传动和液力传动的对比,探讨了液压传动技术的优势和未来发展趋势. 相似文献
2.
森林多功能单轨车的结构分析 总被引：1，自引：1，他引：0
阐述了森林多功能单轨运输车各部件的结构特点和性能,介绍了森林多功能单轨运输车各装置的主要参数。通过研究各部件的性能,为设计高质量森林多功能单轨运输车提供基础数据。 相似文献
3.
介绍了森林多功能单轨运输车的安装要求,阐述了森林多功能单轨运输车各部件安装的注意事项;通过深入研究各部件的安装要求,为安装高质量的森林多功能单轨运输车做好技术保证。 相似文献
4.
介绍了森林多功能单轨运输车的使用现状,阐述了其在我国应用的意义,提出了安全使用单轨运输车的几点建议。 相似文献
5.
针对林地货物运输困难等问题,设计制造了区别于传统运输方式的林用单轨运输车。利用ADAMS与ANSYS数据接口实现虚拟设计,通过对简化模型的仿真研究得到单轨车部分构件的运动学与动力学性能参数,仿真结果表明这些性能参数达到了机构及功能的设计要求。 相似文献
6.
7.
8.
介绍了森林多功能单轨运输车的技术指标及生产应用试验,并对试验结果进行了分析. 相似文献
9.
在汽车传动系中机械传动系的运用最广泛,而机械传动系广泛选用摩擦式离合器。正确选择和优化离合器主要参数对传动系工作质量和使用寿命是至关重要的。 相似文献
10.
我场在学习江西省赣州贮木场ZP—771型机械传动原水扎排机的基础上,于1979年试制成功LZ—1型液压传动电控原木扎排机。经一年投产运转,工作可靠。现简介如下: 一、主要结构1、浮船(图1):用以支承扎排机,并使其在设计吃水深度条件下工作。采用三网一筋结构的钢丝网水泥船。单船规格(长 相似文献
11.
二次调节静液储能拖拉机传动系统 总被引：1，自引：0，他引：1
二次调节静液储能拖拉机传动系统是由柴油机，液压蓄能器，液压泵/马达（二次元件），差动变速器和驱动轴等组成，该系统充分利用了液压蓄能功率密度大，二次元件具有较高的控制质量，可实现四象限工作等特点；实现了柴油机和拖拉机行驶载荷的分离，工作过程中当外负载扭矩发生变化时，将引起二次元件的转速变化，从而引起二次元件排量的变化，通过调节液压马达的变量机构使其与工作负载所需转速相适应。 相似文献
12.
在水力碎浆机的设计中传动系统的设计非常重要,其决定了整台机器的性能和效率。传动系统的转矩由电动机通过带轮、主轴传动至转子,转子的回转形成浆流的循环和物料的摩擦,从而达到把物料碎解成浆的目的。Abstract： The design of the transmission system of hydraulic pulpers is very crucial,because it determines the performance and efficiency of the whole machine.The transmission system transfers torque from the motor through a pulley and from the main shaft to its ro 相似文献
13.
人造板多层热压机低能耗液压系统设计 总被引：1，自引：0，他引：1
结合人造板生产工艺过程，分析了人造板多层热压机液压系统工作循环中能量转换的特点。提出了降低能耗的新思路，设计了复合快速缸-蓄能器液压系统。经分析、对比，该系统作为人造板多层热压机动力传递装置，明显降低了能耗，节约了能源，并改善了热压机的工作性能。 相似文献
14.
Franks PJ 《Tree physiology》2004,24(8):865-878
A better understanding of the mechanistic basis of stomatal control is necessary to understand why modes of stomatal response differ among individual trees, and to improve the theoretical foundation for predictive models and manipulative experiments. Current understanding of the mechanistic basis of stomatal control is reviewed here and discussed in relation to the plant hydraulic system. Analysis focused on: (1) the relative role of hydraulic conductance in the vicinity of the stomatal apparatus versus whole-plant hydraulic conductance; (2) the influence of guard cell inflation characteristics and the mechanical interaction between guard cells and epidermal cells; and (3) the system requirements for moderate versus dramatic reductions in stomatal conductance with increasing evaporation potential. Special consideration was given to the potential effect of changes in hydraulic properties as trees grow taller. Stomatal control of leaf gas exchange is coupled to the entire plant hydraulic system and the basis of this coupling is the interdependence of guard cell water potential and transpiration rate. This hydraulic feedback loop is always present, but its dynamic properties may be altered by growth or cavitation-induced changes in hydraulic conductance, and may vary with genetically related differences in hydraulic conductances. Mechanistic models should include this feedback loop. Plants vary in their ability to control transpiration rate sufficiently to maintain constant leaf water potential. Limited control may be achieved through the hydraulic feedback loop alone, but for tighter control, an additional element linking transpiration rate to guard cell osmotic pressure may be needed. 相似文献
15.
We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in hydraulic safety. 相似文献
16.
Maximum plant height and the biophysical factors that limit it 总被引：1，自引：0，他引：1
Niklas KJ 《Tree physiology》2007,27(3):433-440
Basic engineering theory and empirically determined allometric relationships for the biomass partitioning patterns of extant tree-sized plants show that the mechanical requirements for vertical growth do not impose intrinsic limits on the maximum heights that can be reached by species with woody, self-supporting stems. This implies that maximum tree height is constrained by other factors, among which hydraulic constraints are plausible. A review of the available information on scaling relationships observed for large tree-sized plants, nevertheless, indicates that mechanical and hydraulic requirements impose dual restraints on plant height and thus, may play equally (but differentially) important roles during the growth of arborescent, large-sized species. It may be the case that adaptations to mechanical and hydraulic phenomena have optimized growth, survival and reproductive success rather than longevity and mature size. 相似文献
17.
MYD型木片压缩打包机电气系统的设计 总被引：2，自引：0，他引：2
介绍了采用机、电、液一体化来实现木片压实、包装工艺打包机的重要组成部分电气系统的设计内容。根据压缩打包机的功能要求，考虑到打包为已实际工作时的动作要求、性能价格比、现场工作环境及工人的素质等因素，选用了常规的控制方式，设计出了一套功能较完善、自动化程度较高的电控系统。 相似文献
18.
本文根据多年的实践经验.提出了筑路机械在低温条件下的使用与保养措施.文中对发动机、传动系统、操纵系统、液压系统的使用与保养提出了较为有效的措施,从而保证筑路机械在低温条件下的正常使用. 相似文献
19.
We do not know why trees exhibit changes in wood characteristics as a function of cambial age. In part, the answer may lie in the existence of a tradeoff between hydraulic properties and mechanical support. In conifers, longitudinal tracheids represent 92% of the cells comprising the wood and are involved in both water transport and mechanical support. We used three hydraulic parameters to estimate hydraulic safety factors at several vertical and radial locations in the trunk and branches: vulnerability to cavitation; variation in xylem water potential (psi); and xylem relative water content. The hydraulic safety factors for 12 and 88 percent loss of conductivity (S(H12) and S(H88), representing the hydraulic safety factors for the air entry point and full embolism point, respectively) were determined. We also estimated the mechanical safety factor for maximum tree height and for buckling. We estimated the dimensionless hydraulic and mechanical safety factors for six seedlings (4 years old), six saplings (10 years old) and six mature trees (> 110 years old) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Over the natural range of psi, S(H12) decreased linearly from treetop to a minimum of 0.95 at the tree base. Young and mature trees had S(H12) values 1.4 and 1.3 times higher, respectively, at their tips (juvenile wood) than at their bases (mature wood). Modeling analyses indicated that if trees were made entirely of mature wood, S(H12) at the stem base would be only 0.7. The mechanical safety factor was 1.2 times higher for the base of the tree than for the rest of the tree. The minimum mechanical safety factor-1.6 for the critical buckling height and 2.2 for the critical buckling load-occurred at the base of the live crown. Modeling analysis indicated that if trees were made only of mature wood, these values would increase to 1.7 and 2.3, respectively. Hydraulic safety factors had values that were less than half those for mechanical safety factors, suggesting that wood structure in Douglas-fir has evolved primarily as a result of selection for hydraulic safety rather than mechanical safety. The results suggest that forest managers must consider the role of juvenile wood in tree physiology to avoid producing plantations vulnerable to drought. 相似文献