汽车方向盘骨架轻量化设计

首先,以某车型方向盘轻量化设计为目标,建立方向盘骨架梁体混合分析模型,依国家及企业标准规定的试验方法和评价指标,对其进行静强度和模态分析,并对分析结果进行试验验证。其次,将骨架截面参数化,以标准规定的方向盘性能评价指标为响应,对不同截面形状参数进行灵敏度分析。最后,以灵敏度分析找出的非敏感参数作为设计变量,以性能评价指标为约束条件,进行方向盘骨架轻量化设计。研究结果表明:文中所提的三步轻量化法高效可行,在满足方向盘法规要求的前提下,能提高方向盘骨架轻量化设计的效率和精准性,该方法对同类机械结构轻量化设计具有一定的工程指导意义。     

汽车方向盘骨架强度计算与结构改进

汽车正面碰撞时,驾驶员会与方向盘发生直接或间接碰撞接触,因此方向盘的强度极为重要.针对三辐结构方向盘骨架进行了轴向力和冲击的数值计算,并与实物试验进行了对比,得出方向盘骨架轮辐上有较多的圆弧过渡处容易出现应力集中,破坏由此处开始,且此三幅结构的方向盘骨架不能满足试验要求.针对此原因,提出改进为四辐结构,从数值计算结果和实物试验都可以看出其强度有一定程度的提升,能够满足试验要求.此外,数值计算结果也为实际的设计提供了指导方向.     

一种方向盘助力装置的设计

机动车方向盘转向较为费力,现有用于机动车方向盘助力的装置有很多种,其中电子式、液压式助力装置价格较高,不适合应用在机动三轮车上.研究机动车方向盘助力问题,在分析了现有方向盘助力装置的基础上,设计出了一种机动车的方向盘助力装置,主要解决以往机动车转向费力的问题.该方向盘助力装置的关键就是通过两个齿轮的内啮合,将作用在前轮...     

Effect of steering wheel heating system on hand thermal sensation

A numerical study is conducted to verify the effect of the steering wheel heating system for enhancing the thermal sensation of the hand. First, a numerical study was conducted to quantify the sensory index called thermal sensation. A five-layer skin model was developed, and the reliability of the model was confirmed by comparing it to previous research results. The temperature and its rate of changes for skin layers were predicted by the numerical study, while the relationship between the numerical results and the hand thermal sensation data from ISO/TS 13732-2:2001 were quantitatively analyzed. A one-dimensional unsteady heat transfer model dealing with a steering wheel was designed and developed and it was determined whether the wheel heating system is effective as an auxiliary personal heating system for electric vehicles in the cold winter. Consequentially, even a small amount of electrical energy could provide a meaningful effect to hand thermal sensation.

     

功能危险分析在飞机刹车系统中的应用研究

功能危险分析(Functional Hazard Analysis,即FHA)是一个分析和评估过程,主要是以分析评估系统内或设备中潜在的故障及所发生故障的影响。它通过分析来确定系统操作中可能发生的故障,并判断故障对人员的危害。FHA是系统安全评估中的重要内容,是其他安全性分析项目的基础,更是民用飞机满足适航审定要求必须完成的分析项目。通过对功能危险分析方法在飞机刹车系统应用过程的分析,总结了该方法应用时遇到的难点以及应对办法,并简要说明了分析结果。     

六轮车辆滑移转向动力学建模和运动特性分析

轮式滑移转向车辆由于其机动灵活和结构简单可靠而具有广泛的应用价值。针对一种六轮车辆,车轮触地点的速度分析、轮轴转动副摩擦分析和车辆力平衡关系,建立了稳态滑移转向时的动力学模型,分析了车辆主要结构参数和左右侧车轮转速的不同对滑移转向的瞬心位置、转向角速度和车轮所需力矩的影响规律。研究结果可为六轮车辆的合理设计和实现滑移转向时的轮速控制与驱动提供理论依据。     

主动前轮转向横摆稳定性模糊控制系统设计

提出了一种基于主动前轮转向横摆稳定性控制方法,以横摆角速度和质心侧偏角为控制目标。采用鲁棒性较强的模糊控制方法对汽车稳定性进行控制。建立了整车线性二自由度模型,以反馈系统中的误差信号及其变化率作为模糊系统的输入设计了模糊控制器,通过控制横摆力矩来实现车辆稳定性的控制。对转向盘阶跃输入信号和正弦输入信号两种工况分别进行了仿真研究。通过分析仿真结果,该控制方法能有效地控制车辆横摆角速度和质心侧偏角,提高车辆转向时的稳定性,同时能有效的降低驾驶员的操纵负担。     

砂轮磨削的超声修整效果

论述了超声振动修整砂轮的机理，分析了超声振动修整和普通修整的不同，以及采用不同砂轮磨削不锈钢时的工件表面粗糙度的变化情况。     

Modeling and simulation of grinding surface topography considering wheel vibration

Grinding is an important means of realizing precision and ultra-precision machining. Vibration caused by an unbalanced grinding wheel in grinding process has a significant impact on the quality of workpiece surface. However, the effect of wheel surface topography and/or the relative vibration between grinding wheel and workpiece are not considered in most researches. Taking the relative vibration between grinding wheel and workpiece into account, alongside the abrasive grain trajectory equation, a new analysis and simulation model for surface topography of the grinding process is established. The model for the topography of the grinding wheel surface is first studied, and subsequently, a new simulation model for surface topography of the grinding process is proposed. Case studies are performed at the end, and the influence of grinding wheel vibration amplitude, wheel grit number, as well as grinding parameters on the surface waviness and roughness is discussed. The simulation results could be used to optimize the actual grinding process to improve the ground surface quality or predict the surface topography by given grinding parameters.     

Mechanism analysis of pressure fluctuation in wheel loader articulated steering hydraulic system

Journal of Mechanical Science and Technology - This paper studies the influence of hinge point positioning of a steering cylinder on the pressure fluctuation of the steering system of a wheel...     

轿车前轮角输入的随动转向分析与仿真

根据简化的2自由度随动转向力学模型,建立了动力学微分方程.分析了车速、整车质量、转动惯量和轮胎侧偏刚度对车辆随动转向稳定性的影响.通过对某轿车后桥随动转向的仿真计算与分析,验证了所得方法的正确性,为改善车辆的操纵稳定性提供了理论依据.     

图像去雾算法的改进和主客观性能评价

本文主要研究了图像去雾技术以提高由于雾霾影响而导致的失真图像的主客观质量。对基于暗通道先验和大气散射模型的去雾算法进行了改进,设计了新的天空区域计算和透射率阈值确定方法,通过增强结果图的对比度和调整亮度,进一步降低了算法的失真。还通过对图像加雾,分别从主观质量评价和以结构相似度作为客观标准的客观评价两方面,用数理统计方法比较了各个相关算法的性能。实验表明,所提算法有效地降低了图像的失真(评价分最高),使去雾图像有较高的主观质量(总体评价分并列最高)。     

基于ProCAST的汽车方向盘零件模流分析与压铸模具优化设计

以ProCAST压铸模流分析软件为平台,汽车方向盘零件为载体,针对汽车方向盘压铸件的结构特点进行分析,模拟材料的充型凝固过程,分析了过程中可能产生的缺陷,优化了浇注系统与排气系统的结构设计,辅助设计人员进行模具结构的优化设计,实现了汽车方向盘零件精密压铸模具的生产.     

Model-based Type B uncertainty evaluations of measurement towards more objective evaluation strategies

This article proposes a more objective Type B evaluation. This can be achieved when Type B uncertainty evaluations are model-based. This implies, however, grey-box modelling and validation instead of white-box modelling and validation which are appropriate for Type A evaluation.     

轮式装载机行驶中振动对物料完整性的影响

以轮式装载机为研究对象,对其行驶中铲斗振动对物料完整性的影响进行了研究.首先通过简化分析建立了铲斗振动的数学模型和动态方程,求出其振动响应;然后通过分析铲斗振动的最大加速度,找出了影响物料完整性的各因素;最后基于MATLAB对ZL45型轮式装载机的物料完整性进行了仿真分析.结果表明,绕质心的转动惯量小,且较小弹性系数的低压比宽式专用轮胎等因素,有利于保持物料的完整性.     

声振动修整砂轮系统的阻抗分析

通过合理划分超声振动修整系统,计算出超声振动修整砂轮系统的各个子系统机械阻抗,运用机械阻抗综合法求出系统的共振频率,为实验中寻求系统的谐振点提供了理论依据.并且提出修整瓦的尺寸对系统的谐振频率影响不大,从而简化修整瓦的设计.     

Time-dependent vibration frequency reliability analysis of blade vibration of compressor wheel of turbocharger for vehicle application

Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.     

商用车方向盘怠速抖动优化与验证

针对某商用车在发动机怠速时方向盘抖动的问题,利用LMS测试与分析系统对其进行了测试分析,发现转向系统的固有频率和发动机二阶激励频率耦合是其抖动的原因。为抑制方向盘的抖动,对方向盘进行了轻量化设计,同时对仪表台横梁局部增厚,以提高转向系统固有频率使其与发动机怠速激励频率错开来避免共振。最后使用非线性有限元方法对优化后的结构进行了强度校核,并通过试验验证了优化方案的有效性。     

砂轮失衡引起振动的成因分析与防范措施

详细分析了砂轮失衡引起磨削系统振动的原因,指出提高磨削系统的特性,尽可能地降低稳态振动响应,配合其他防范措施,可使系统振动降至最低。     

The state sensitivity analysis of the front wheel steering vehicle: In the time domain

In this paper, a sensitivity analysis of a front wheel steering vehicle in the time domain is considered. For this study, a two degree-of-freedom bicycle model is used. This model displays the simplest lateral dynamic effect and is useful for understanding of the dynamic characteristics and control aspects of the target system. The side slip angle and yaw rate are selected as the system state variables. Vehicle mass, inertia, cornering stiffness, and wheel base are taken as design variables. Sensitivity analyses are performed by the direct differentiation method, which is an efficient tool for error control in numerical integration. This research proposes a basis for re-design and new-design of a vehicle by checking variations in the state variable with respect to changes in the design variable. Finally, dominant design variables are suggested through simulations.