【正文】 ） 3. The fourbar linkage may take form of a socalled crankrocker or a doublerocker or a doublecrank (draglink) linkage, depending on the range of motion of the two links connected to the ground link. The input crank of a crankrocker type can rotate continuously through 360, while the output link just rocks (or oscillates). As a particular case, in a parallelogram linkage, where the length of the input link equals that of the output link and the lengths of the coupler and the ground link are also the same, both the input and output link may rotate entirely around or switch into a crossed configuration called an antiparallelogram linkage. [1] Grashof39。曲柄搖桿機構(gòu)的輸入構(gòu)件，曲柄可旋轉(zhuǎn)通過 360176。作為一個特例，在平行四桿機構(gòu)中，輸入桿的長度等于輸出桿的長度，連接桿的長度和固定桿（機架）的長度，也是相等的。格拉肖夫準則（定理）表明：如果四桿機構(gòu)中，任意兩桿之間能作連續(xù)相對轉(zhuǎn)動，那么，其最長桿長 度與最短桿長度之和就小于或等于其余兩桿長度之和。 it implies smooth operation, in which a maximum force ponent is available to produce a force or torque in an output member. Although the resulting output force or torque is not only a function of the geometry of the linkage, but is generally the result of dynamic or inertia force, which are often several times as large as the static force. For the analysis of lowspeed operations or for an easily obtainable index of how any mechanism might run, the concept of the transmission angle is extremely useful. During the motion of a mechanism, the transmission angle changes in value. A transmission angle of 0 degree may occur at a specific position, on which the output link will not move regardless of how large a force is applied to the input link. In fact, due to friction in the joints, the general rule of thumb, is to design mechanisms with transmission angle of larger than a specified value. Matrixbased definitions have been developed which measure the ability of a linkage to transmit motion. The value of a determinant (which contains derivatives of output motion variables with respect to an input motion variable for a given linkage geometry[2] ) is a measure of the movability of the linkage in a particular position. （ 除了具備關(guān)于構(gòu)件回轉(zhuǎn)范圍的知識之外，還要具備如何使機構(gòu)在制造之前就能 “ 運轉(zhuǎn) ”的良好措施，那將是很有用的。它意味著運轉(zhuǎn)平穩(wěn)，其中能在輸出構(gòu)件中產(chǎn)生一個力或扭矩的最大分力是有效的。為了分析低速運轉(zhuǎn)或為了易于獲得如何能使任一機構(gòu) “ 運轉(zhuǎn) ” 的指數(shù)，傳動角的概念是非常有用的。傳動角 0176。在此特殊位置上輸出桿將不運動而與施加到輸入桿上的力多大無關(guān)。衡量連桿機構(gòu)傳遞運動能力的矩陣基礎(chǔ)的定義已經(jīng)研究出來。 ） 5. Mechanisms form the basic geometrical elements of many mechanical devices including automatic packaging machinery, typewriters, mechanical toys, textile machinery, and others. A mechanism typically is designed to create a desired motion of a rigid body relative to a reference member. Kinematic design, or kinematic syntheses, of mechanisms often is the first step in the design of a plete machine. When forces are considered, the additional problems of dynamics, bearing loads, stresses, lubrication, and the like are introduced, and the larger problem bees one of machine design. （ 機構(gòu)是形成許多機械裝置的基本幾何結(jié)構(gòu)單元，這些機械裝置包括自動包裝機、打印機、機械玩具、紡織機械和其他機械等。機構(gòu)的運動設(shè)計即運動的綜合，第一步常常是先設(shè)計整部機器。 ） 6. A kinematician defined kinematics as the study of the motion of mechanisms and methods of creating them. The first part of this definition deals with kinematic analysis. Given a certain mechanism, the motion characteristics of its ponents will be determined by kinematic analysis. The statement of the tasks of analysis contains all principal dimensions of the mechanism, the interconnections of its links, and the specification of the input motion or method of actuation. The objective is to find the displacements, velocities, accelerations, shock or jerk (second acceleration), and perhaps higher accelerations of the various members, as well as the paths described and motions performed by certain elements. In short, in kinematic analysis we determine the performance of a given mechanism. The second part of definition may be paraphrased in two ways: （ 運動學家把運動學定義為 “研究機構(gòu)的運動和創(chuàng)建機構(gòu)的方法 ”。已知一個機構(gòu)，其構(gòu)成的運動特性將由運動學分析來確定。目的是要找出位移、速度、加速度、沖擊或跳動（二 次 加速度），和可能發(fā)生的各構(gòu)件的高階加速度以及所描述徑跡和由某些構(gòu)件來實現(xiàn)的運動。這就是運動綜合的本質(zhì)。運動綜合方面又可歸結(jié)為以下兩類 (1) Type synthesis. Given the required performance, what type of mechanism will be suitable? (Gear trains? Linkages? Cam mechanisms?) Also, how many links should the mechanism have? How many degrees of freedom are required? What configuration is desirable? And so on. Deliberations involving the number of links and degrees of freedom are often referred to as the province of a subcategory of type synthesis called number synthesis. (2) Dimensional synthesis. The second major category of kinematic synthesis is best defined by way of its objective : Dimensional synthesis seeks to determine the significant dimensions and the starting position of a mechanism of preconceived type for a specified task and prescribed performance. 1．類型綜合。關(guān)于桿件數(shù)目和自由度的考慮通常被認為是類型綜合中被稱作為數(shù)量綜合的一個分支領(lǐng)域。運動綜合的第二個主要類型是通過目標法來確定的最佳方法。 of their contacting profiles must be such that the mon normal passes through a fixed point on the line of the centers. 齒輪是借助于輪齒成功嚙合來傳遞運動的機器零件。多數(shù)應(yīng)用中都以恒定角速比（或常定扭矩比）而存在。在各種各樣有用的齒輪類型基礎(chǔ)上，輸入軸和輸出軸需要在一直線上或需要互相平行都不受什么限制。為了保持恒定的角速度，各個齒輪齒廓必須服從齒輪嚙合的基本規(guī)律：為了一對齒能傳遞恒定角速比，他們接觸齒廓的形狀必須是要這樣：公法線通過兩齒輪中心連線 上的固定點。 rule around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party anizations and Party members do not touch the bottom line . Here, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process。 the third part introduces two party regulations modified the main changes and needs to grasp several key problems。 follow the correct direction, grasp the limited goals, adhere to the party39。s 18 and the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the party3