机构

Finally, experiments and analyses in valve gear vibration and noise are conducted by means of the advanced measuring and processing instruments. Especially, the noise caused by valve setting is separated and analysed from the total noise, such work has never been done before. The conclusions are significant for reducing vibration and noise of valve gear.

本文使用目前国际上先进的测试、分析仪器对配气机构的振动、噪声进行了实验和分析，特别是在噪声分析上设法将气门的落座噪声分离出来，专门地进行了分析，这在配气机构的噪声分析上还是第一次，得到了一些有意义的结论，为配气机构的减振、降噪提供了依据。

Actuation of a valve requires both a mounting device for attaching the actuator to the valve, and a coupling device to interface actuator input/output with the valve stem.

阀门的执行机构需要安装装置，用于将执行机构附加在阀门上；和连接装置，用作执行机构输入/输出与阀门阀杆的交互界面。

Research has been done on the coupling form between the two-row planetary gear train and the shift restriction based on the matrix, and then the method of establishing mathematics model has been presented to analyze the planetary gear transmission using MATLAB. The coupling-matrix, restriction-matrix and transmission matrix form the model. All coupling-matrices corresponding two kinds of the coupling form determine the planetary gear transmission model.

基于矩阵理论对双排行星齿轮变速机构的行星排之间联结、换挡约束进行研究，提出用联结矩阵、约束矩阵和传动矩阵构建数学模型并使用MATLAB进行传动分析的方法。2种方式的联结形式所对应的联结矩阵可以确定机构所有可能的结构型式，据此得到双排行星齿轮变速机构全部型式谱图。

Initially, assuming that the contact between cam and tappet is"dry contart", a dynamics model of Hertzin contact stiffness and impact damping is established. Next, with dynamic load on cam—tappet pair from the model, an analysis is made both to unsteady EHD oil film in cam—tappet pair under condition of full and partial lubrtication and to wear characteristics of cam profile. then, according to the fact that the lubrication in cam—tappet contact surface is EHD lubrication, taking the interaction between stiffness and damping of unsteady EHD oil film and rigidity of solid object contact into account, a dynamics equation of valve train relating to the dynamic effect of EHD oil film is built up and solved. Consequently, a further study is made on the dynamic characteristics of valve train under interaction of EHD oil film dynamic behavior and the problem of EHD lubrication in cam—tappet pair. Finally, the dynamic effect of full and partial EHD oil film is studied accordingly.

首先，通过对凸轮—挺杆接触为&干接触&的假设，建立了考虑赫兹&接触刚度&和冲击&阻尼&的配气机构动力学模型，用由此求得的凸轮—挺杆表面动载荷对凸轮—挺杆进行了全膜状态和部分膜状态非稳态弹流润滑分析，并研究了凸轮轮廓的磨损规律；然后，是在凸轮挺杆表面存在弹流动压油膜这一事实的基础上，相当于在动力学方程中考虑非稳态弹流油膜的&刚度&、&阻尼&和固体接触&刚度&的耦合作用，建立并求解了考虑弹流润滑行为动力学效应的配气机构的动力学方程，从而深入地研究了弹流润滑行为与动力学行为耦合作用下的配气机构动力学特征以及凸轮挺杆弹流润滑问题；作为前面工作的对应部分，考虑弹流油膜动力学效应的研究工作也同样分为全膜状态和部分膜状态进行。

In the 1980s, investment banks, encouraged by regulators, began a transformation from stodgy, tradition-bound institutions to restless, relentless seekers of profit.

上世纪80年代，在监管机构的鼓励下，投资银行开始从受传统束缚的平庸机构，向着不安分的逐利机构转变。

This paper takes a kind of parallel robot with 2-DOF actuation redundancy as the object of study and according to the spatial model of the parallel robot mechanism and the reverse solution of dynamics,the relationship between the function target of output speed of the tip of this parallel robot mechanism and the dimensions of bar components was probed.

以一种平面2自由度驱动冗余并联机器人为研究对象，根据该并联机器人机构的空间模型和运动学反解，探讨了该并联机器人机构的末端输出速度性能指标与杆件尺寸之间的关系，并绘制了相应的性能图谱，这些图谱是该并联机器人机构设计的重要参考依据。

Taking QY80 auto-crane's rocker mechanism of four一axle steering system asexample,this paper presents a new method which applies multibedy system Kinematics theory toanalyse mechanism's spatial motion, builds up mathematical model of optirnization for the rochermechanism of steering System, and chooses minimization adoptive random search method to developan optimization design microcomputer program,Using aboving method and program , this paper fi-nally optimlzes each design Variable, and obtains better resul...

以QY80汽车起重机四轴转向摇臂机构为例，利用多刚体系统运动学理论对机构作了空间运动分析，建立了转向摇臂机构优化设计的数学模型，并用改进了的约束随机方向搜索法编写了优化设计的微机软件，并已应用于生产实践。

Hebei University of Technology, Tianjin, 300132Abstract: Calculations of kinematic movement are carried out with the R-W method in the dynamics of multi-rigid-body systems. A general program for the double arm suspension and steering mechanism is formulated.

由于双横臂悬架和转向机构组成的系统是复杂的空间杆机构，悬架和转向机构的运动相互关联，其设计很难获得较好的转向性能。

This loading structure is more simple and reliability,which uses to low speed and big torque motor to drive the star wheel,reduces cost and extend using life.

根据掘进机装载机构在使用过程中暴露出的一些问题，对装载机构进行改进设计，采用低速大扭矩马达直接驱动星轮的装载形式，使掘进机装载机构结构更简单，工作更可靠，降低了成本，延长了使用寿命。

They are divided into two main classes: one class with handwheels but no gearing, and the other class with cranking actuators and worm gearing or worm and spur gearing combined.

这些地轴架分为两大类：一类配置手轮，没有齿轮执行机构；另一类配置转动曲轴执行机构和蜗轮或蜗轮和凸轮组合执行机构。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。