共查询到20条相似文献,搜索用时 421 毫秒
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通过对汽车传动系统传动机理的分析,建立了12自由度多间隙非线性动力传动系统扭振模型,研究了各工况下的瞬态冲击响应特性。以主减速器齿轮角加速度作为瞬态冲击的评价指标,对比分析了离合器快速分离工况与急松驱动踏板工况的传动系统瞬态冲击响应特性。结果表明:发动机与传动系统的动力解耦会导致传动系统产生"震荡"现象。采用控制变量法研究了急松驱动踏板工况下扭转减振器扭转特性与传动系瞬态冲击强弱的对应关系,结果表明:离合器一级扭转刚度比二级扭转刚度对瞬态冲击强度的影响更大,通过调整一级扭转刚度降低传动系统瞬态冲击效果更加明显。 相似文献
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利用载荷标定方法制作轴箱弹簧力传感器和一系减振器力传感器,线路测试得到动车转向架构架的垂向载荷时间历程。结合车载GPS信号和陀螺仪信号,分析列车起动加速、高低速直线运行、线路曲线通过、电机扭矩波动、制动停车等典型工况下构架载荷的变化特征。采用有限元仿真分析的方法确定构架端部的疲劳危险区域及载荷与应力的传递关系,进而编制构架在轴箱弹簧载荷、一系减振器载荷和耦合载荷作用时的应力幅值谱,最后依据疲劳损伤线性累计准则计算得到构架的疲劳损伤分布。研究结果表明,与构架非动力侧相比,构架动力侧轴箱弹簧载荷受电机输出扭矩的影响较大,尤其在列车起动、制动、电机扭矩波动等工况载荷变化明显。在轴箱弹簧载荷和一系减振器载荷单独作用时,构架端部的应力较大位置分布基本一致,最大载荷-应力传递系数为6.56 MPa/kN。在耦合载荷作用下,构架端部各测点处的疲劳损伤值均高于轴箱弹簧载荷、一系减振器载荷的单独作用。列车由速度200km/h增大至350km/h时,构架一位侧疲劳危险点的累计损伤值由0.078增大至0.435,增大了约4.6倍。在同一速度级下,一系减振器载荷产生的疲劳损伤影响参数大于轴箱弹簧载荷。研究结果可为焊接构架的优化设计及仿真分析提供一定理论参考。 相似文献
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《机械工程学报》2017,(4)
建立汽车怠速状态下传动系统的四自由度集总参数模型,给出怠速工况下系统动态响应的计算方法。定义齿轮敲击指数作为怠速敲齿的评价指标,分析离合器从动盘扭转减振器的多级扭转非线性特性、齿轮间啮合力时变特性对齿轮敲击指数的影响。针对一汽车怠速时敲齿的问题,利用建立的模型,对扭转减振器的一级扭转刚度和一级扭转角进行改进,分析离合器改进前后变速器的齿轮敲击指数、齿轮啮合力以及啮合齿轮间相对位移随时间的变化。在怠速工况下,测试分析离合器改进前后对发动机舱变速器侧的噪声、变速箱壳体振动加速度的影响。测试结果和计算结果表明:齿轮敲击指数与变速器侧的噪声、变速箱壳体振动加速度有一定的关联性;基于本文的建模分析方法,可调整离合器的扭转减振器一级扭转刚度和一级扭转角,降低汽车怠速时变速器的敲齿现象。 相似文献
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以某纯电动城市客车车架为研究对象,建立客车整车虚拟样机模型,选择满载弯曲工况与扭转工况对客车进行整车仿真分析,提取各工况各载荷动态峰值力,对客车车架进行参数化优化设计,并对优化前后车架进行对比分析。结果表明,优化后的车架减重12.73%,在扭转工况下最大应力为200 MPa,最大变形为7.45 mm,车架强度与刚度满足安全要求。 相似文献
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齿轮传动中啮合冲击的计算分析 总被引:1,自引:0,他引:1
在文献[1]所建立的齿轮传动啮合冲击动力学模型的基础上,通过理论分析并编制相应的分析程序,计算了渐开线直齿轮传动中啮入冲击力、冲击速度的变化情况,分析了传动比、模数、载荷等对齿轮传动中冲击力的影响情况。结果表明:(1)随着传动比的增大,齿轮传动中的冲击力随之降低;(2)模数增大,使得轮齿之间的冲击力增大;(3)在其他条件不变时,载荷增大将导致冲击力增大;(4)载荷和速度相比,速度对冲击力的影响较大。 相似文献
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从下运带式输送机整体受力分析入手,分析输送机在下运工况滚筒所受圆周力的大小,结合满载工况下电机的工作状态,在此基础上,确定下运输送机所需功率的大小。 相似文献
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Brian P. Borovsky Christopher Bouxsein Cullen O’Neill Lucas R. Sletten 《Tribology Letters》2017,65(4):148
We have developed a technique for measuring frictional forces and contact areas, over a wide range of applied loads, at microscopic contacts reaching high sliding speeds near 1 m/s. Our approach is based on integrating two stand-alone methods: nanoindentation and quartz crystal microbalance (QCM). Energy dissipation and lateral contact stiffness are monitored by a transverse shear quartz resonator, while a spherical indenter probe is loaded onto its surface. Variations in these two quantities as functions of shear amplitude, with the normal load held fixed, reveal a transition from partial to full slip at a critical amplitude. Average values of both the threshold force for full slip and the kinetic friction during sliding are determined from these trends, and the contact area is inferred from the lateral stiffness at low shear amplitudes. Measurements are performed at loads ranging from 5 µN to 8 mN using an electrostatically actuated indenter probe. For the materials chosen in this study, we find that the full slip threshold force is about a factor of two larger than kinetic friction. The forces increase sublinearly with load in close correspondence with the contact area, and the shear strengths are found to be relatively insensitive to pressure. The threshold shear amplitude scales in proportion to the contact radius. These results demonstrate that the probe–QCM technique is a versatile and full-featured platform for microtribology in the speed range relevant to practical applications. 相似文献
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In general, slew bearings are less firmly supported by their mounting structures than small bearings. Hence, the load distribution around the bearing may be vastly different than that predicted by classic bearing formulas. The finite element method has been employed to determine load distribution in a three-row roller slew bearing mounted between two flexible, ring shaped supporting structures composed of beam elements. A special bar element modeling the system of two opposite rollers in contact with its raceways has been elaborated. The influence of the nonlinear force displacement characteristics of each of the rollers, as well as the influence of gaps between the rollers and its raceways have been taken into account. The nonlinear contact problem has been solved utilizing the Newton-Raphson method with continually updated stiffness matrix due to both element nonlinearity and contact status. The effect of a number of design parameters on the load distribution has been investigated. 相似文献
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In this paper we present the exploitation of Fused Filament Fabrication (FFF) to manufacture a load cell using double extrusion of conductive and non-conductive commercial materials in a single-step printing cycle. A load cell with four embedded strain gauges, manufactured with tailored process parameters and strategies, was used to deposit the conductive filament to obtain near equal electrical resistance values among the four strain gauges, aiming to connect them in a full Wheatstone bridge configuration. Subsequently, several tests were performed, firstly to understand the behavior of each strain gauge and then to characterize the load cell. The tests showed that the strain gauges are sensible to compressive and tensile deformation and that the load cell's voltage, obtained by connecting the four strain gauges in a full Wheatstone bridge, decreases as the force applied increases. This work demonstrates the potential of FFF technology in the sensor manufacturing field and that it is possible to integrate sensitive elements into non-sensitive elements without an additional assembly process by using low-cost commercial filaments and 3D printers. 相似文献
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称重传感器在大多数称量实践中,总是伴随出现横向力(力矩)的干扰,而产生横向灵敏度。本文分析了引起横向灵敏度的诸因素及其对称量结果的影响。指出横向灵敏度的大小取决于弹性元件的结构形状,压头、底垫、安装平台等附件的性能,若有5%的横向力存在,会在高准确度称重传感器中出现满量程±0.1%的偏差;在普通准确度称重传感器中出现±0.6%的偏差。并以圆柱式称重传感器为例,介绍了利用单层或双层环形膜片与弹性元件和外壳焊接,补偿横向力和弯曲力矩的原理和工艺方法,给出了圆形膜片的挠度和应力计算公式。 相似文献
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叶片是风力机最为关键的部件之一,叶片、轮毂组成的风轮是能量捕获机构,将风能转变为机械能,与此同时,叶片又是风力机力源,主要承载部件,对整个风力机安全运行起着关键作用。在对大型风力机及其叶片产业发展现状分析基础上,从气动外形与结构设计现状、运行监测与控制技术现状、发展趋势与有待研究的问题等几个角度进行较为全面的梳理总结,从而从总体上把握现代大型风力机叶片研究现状及发展趋势。指出今后将在针对抗台风叶片、低风速叶片、仿生叶片和低噪音叶片等的个性化设计,具有外部载荷环境和自身结构状态变化感知功能的智能风力机叶片设计等方面进一步发展;已经形成的风力机叶片设计、制造及运行监控理论等还要随着大批量风力机全生命周期服役实践,进一步完善和发展。 相似文献