可拆卸性评价

分析了拆卸性的评价指标,给出了一个系统的指标体系、各指标的评分标准和可拆卸评价方法,并用模糊层次分析法来确定指标的权重,避免了层次分析法中较难解决的一致性判断问题。通过一个实例说明产品或零部件可拆卸性评价方法的具体应用,比较系统全面地实现了对可拆卸性的评价,而且可以指导设计者对结构等进行修改。     

包边注塑的浇口位置对黏合撕裂强度的影响

针对汽车玻璃塑料包边成型生产中易出现黏合撕裂强度不足的问题,文章研究了浇口位置的设定方法,根据生产中玻璃的形态和塑料包边断面的变化情况,建立包边注塑通用简化模型;根据玻璃嵌件的物理特性,设定熔体与玻璃、模具之间的边界条件,建立传递方程;分别运用数值计算和试验方法得到沿流道方向和包边横截面上的温度和压力分布,分析不同浇口位置对黏合撕裂强度的影响。结果表明,在综合考虑玻璃几何形状的前提下,在位于曲率变化较大的位置附近设定浇口,有利于保障压力平衡且减少注射和保压阶段温度的波动,对包边注塑的浇口设计和工艺、模具设计有指导作用。     

越野路面不平度与车轮跳离路面量间的关系

为提高越野汽车的平顺性,研究了典型越野路面不平度与车轮跳离路面量间的关系.以采石场路面高程样本为研究对象,估算得到路面功率谱密度.把路面不平度作为输入,在设定悬架质量、车轮质量、阻尼和悬架弹簧刚度等条件下,建立了车轮突然失去支承时车轮向下加速度方程.利用仿真技术考察了不同尺寸凹坑作用下车轮的跳跃.结果表明,如果凹深较小时,有无减振器影响不大.当凹深达到一定值时,对没有阻尼作用的汽车,车轮不会从路面跳离.有阻尼作用时车轮开始跳离路面.该结果可以用来指导典型越野路面上行驶的汽车悬架设计.     

Novel Plastic Encapsulation Holding Method for Automobile Glass Using Injection Molding Process

Glass positioning and holding is difficult in the process of injection molding encapsulation of automobile glass. A suction cup or soft resin is always introduced in this process. However, these materials cannot hold glass tightly, thus resulting in the unsteady quality of toughened glass and encapsulated plastic. To solve this problem, a novel holding method called magnetic high-pressure holding with twin bags is proposed to address the features of toughened glass and the encapsulation injection process. Firstly, a pair of permanent magnets is introduced as energy source, followed by the magnetization of a couple of magnetic particle bags. Contact between the single bag and the glass surface will enable the couple of magnetic particle bags to hold glass tightly and to self-adapt the freeform of the glass. Secondly, an experimental system with mechanical and control systems is designed. This system is controlled by the opening and closing force of the mold, which turns the magnetic field on or off to hold or loosen the glass. The magnetic field distributions are measured at important positions of the permanent magnets and in the magnetized particles in the experiments to determine the holding performance. Finally, the process of determining the parameters of the magnet and its attenuation is analyzed, including the minimum friction force between the glass and the particle bag during injection molding, the magnetic energy product and the magnetized filed distributions, and the re-checklng method for these parameters. The theoretical analysis and the experimental result show that this flexible holding system may produce sufficient holding force, which not only protects glass but serf-adapts the glass freeform as well. The production practice meets the technical requirements of injection molding with a defect-free surface, with no scratches and cracks on the glass and no slight glass movements in the mold cavity.     

曲面冲压件的拼焊内压快速成形法研究

提出曲面冲压件的薄板微元拼焊内高压法快速成形方法.阐述离散化曲面片方法和利用高压介质成形的原理;建立拼焊平板之间的几何关系模型和单个拼焊板变形前后之间的关系模型,运用应力平衡方程、屈服准则计算成形力;利用自行设计的拼焊毛坯内高压成形试验系统,对不同厚度、不同拼焊方式的毛坯以及不同压力介质进行成形试验.结果表明,利用该方法能够得到与理想冲压制件基本一致的原型件,制造成本比较低,基本达到金属板料快速原型件的质量和成本要求.     

双刀架数控车削仿真系统关键技术研究

研究了双刀架数控车削仿真系统中的NC代码反读技术，将数控代码翻译为刀具加工信息、运动信息及其它指令，作为仿真系统的输入信息。研究了车削仿真中的关键技术，推导出其计算公式，并以火车车轮轮箍的车削加工为例，阐述了干涉校验、工步规划评估和中断评估的方法，实现了车削加工一次试切成功。     

用切触线法加工曲线轮廓

用切触线近似表示满足正则条件的曲线,将切触线沿法向偏移刀具半径大小位置,以计算得到曲线轮廓数控铣削的刀位轨迹,简化了常用的隐式方程或参数方程形式计算刀位数据的过程。分析了误差影响的因素并提出了控制方法;以摆线的轮廓加工为例,阐述了该算法的正确性与高效性。该方法可移植到运算能力较强的数控系统中,并可作为乘积型曲面刀位点数据计算的基础。