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手臂
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手臂伸缩、升降用液压缓冲器设计,手臂,伸缩,升降,液压,缓冲器,设计
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Mechanical handmechanical hand, is also called from begins, auto hand can imitate the manpower and arms certain holding function, with by presses the fixed routine to capture, the transporting thing OR operation tools automatic operation installment. It may replace persons strenuous labor to realize the production mechanization and the automation, can operate under the hostile environment protects the personal safety, thus widely applies in departments and so on machine manufacture, metallurgy, electron, light industry and atomic energy. the manipulator is mainly composed of the hand and the motion. The hand is uses for to grasp holds the work piece (or tool) the part, according to is grasped holds the thing shape, the size, the weight, the material and the work request has many kinds of structural styles, like the clamp, the request hold and the adsorption and so on. The motion, causes the hand to complete each kind of rotation (swinging), the migration or the compound motion realizes the stipulation movement, changes is grasped holds the thing position and the posture. Motions fluctuation, the expansion, revolving and so on independence movement way, is called manipulators degree-of-freedom. In order to capture in the space the optional position and the position object, must have 6 degrees-of-freedom. The degree-of-freedom is the key parameter which the manipulator designs. The degree-of-freedom are more, manipulators flexibility is bigger, the versatility is broader, its structure is also more complex. Generally the special-purpose manipulator has 23 degrees-of-freedom. the manipulators type, may divide into the hydraulic pressure type, the air operated according to the drive type, electromotive type, the mechanical manipulator; May divide into the special-purpose manipulator and the general-purpose manipulator two kinds according to the applicable scope; May divide into the position control and the continuous path according to the path control mode controls the manipulator and so on. the manipulator usually serves as the engine bed or other machines add-on component, like on the automatic machine or the automatic production line loading and unloading and the transmission work piece, replaces the cutting tool in the machining center and so on, generally does not have the independent control device. Some operating equipment needs by the person direct control, if uses in the host who the atomic energy department manages the dangerous goods from the type operator also often being called the manipulator. Modern industrial robots are true marvels of engineering. A robot the size of a person can easily carry a load over one hundred pounds and move it very quickly with a repeatability of +/-0.006 inches. Furthermore these robots can do that 24 hours a day for years on end with no failures whatsoever. Though they are reprogrammable, in many applications (particularly those in the auto industry) they are programmed once and then repeat that exact same task for years. A six-axis robot like the yellow one below costs about $60,000. What I find interesting is that deploying the robot costs another $200,000. Thus, the cost of the robot itself is just a fraction of the cost of the total system. The tools the robot uses combined with the cost of programming the robot form the major percentage of the cost. Thats why robots in the auto industry are rarely reprogrammed. If they are going to go to the expense of deploying a robot for another task, then they may as well use a new robot. This is pretty much the typical machine people think of when they think of industrial robots. Fanuc makes this particular robot. Fanuc is the largest maker of these type of robots in the world and they are almost always yellow. This robot has six independent joints, also called six degrees of freedom. The reason for this is that arbitrarily placing a solid body in space requires six parameters; three to specify the location (x, y, z for example) and three to specify the orientation (roll, yaw, pitch for example).If you look closely you will see two cylindrical pistons on the side of the robot. These cylinders contain anti-gravity springs that are a big part of the reason robots like these can carry such heavy loads. These springs counter-balance against gravity similar to the way the springs on the garage door make it much easier for a person to lift.You will see robots like these welding, painting and handling materials. The robot shown at right is made by an American company, Adept Technology. Adept is Americas largest robot company and the worlds leading producer of SCARA robots. This is actually the most common industrial robot. SCARA stands for Selective Compliance Articulated (though some folks use Assembly here) Robot Arm. The robot has three joints in the horizontal plane that give it x-y positioning and orientation parallel to the plane. There is one linear joint that supplies the z positioning. This is the typical pick and place robot. When combined with a vision system it can move product from conveyor belt to package at a very high rate of speed (think Lucy and the candies but way faster).The robots joint structure allows it to be compliant (or soft) to forces in the horizontal plane. This is important for peg in hole type applications where the robot will actually flex to make up for inaccuracies and allow very tight part fits. The machine at left can be called a Cartesian robot, though calling this machine a robot is really stretching the definition of a robot. It is Cartesian because it allows x-y-z positioning. Three linear joints provide the three axes of motion and define the x, y and z planes. This robot is suited for pick and place applications where either there are no orientation requirements or the parts can be pre-oriented before the robot picks them up (such as surface mounted circuit board assembly).simple one of most useful organizations is four pole organizations. In on following elaboration majority of content centralism discussion link motion gear, but this procedure is also suitable for the more complex link motion gear. We already knew four pole organizations have a degree of freedom. About four pole organizations, has the useful more contents which must know? Indeed is some! These pull the Xiao husband criterion including the standard, the transformation concept, the blind spot position (divergence point), branch office, transmission angle, with theirs movement characteristic, including position, speed and acceleration. Four pole organizations may have one kind of being called as crank rocker organization form, one kind of double rocking lever organization, one kind of double crank (tension bar) does the organization, which one form send in is called as the organization, is decided in two pole movement scopes which (fixed component) connects with the rack. The crank rocker organization input component, the crank may revolve through 360 and the continuous rotation, but outputs the component to make the undulation merely (i.e. swing member). As an exceptional case, in the parallel four pole organization, inputs the pole the length to be equal to outputs the pole the length, the go-between length and the fixed link (rack) length, also is equal. Its input and the output all may make the complete alternation rotation or transform the being called as antiparallel quadrangle organization the overlapping structure. The standard pulls the Xiao husband criterion (theorem) to indicate that,If in four pole organizations, between two poles can do willfully relatively rotates continuously, that, its longest pole length is smaller than sum of with the shortest pole length or is equal to sum of the other two pole length.Should pay attention: The same four pole organization, may have the different form, which pole is this decided in was stipulated (i.e. makes fixed link) as the rack. The movement transformation process is in the fixed organization transmission chain different member has the different organization rate process. Besides has about the component rotation scope knowledge, but also must have how causes the organization before the manufacture on energy “the revolution” the good measure, that will be very useful. Hardenbergh (Hartenberg) speaks of: “The revolution” is terminology, its significance passes to outputs the component the movement validity. It meant the revolution is steady, in which can in output in the component to have a strength or the torque biggest force component is effective. Not only although the final output strength or the torque are the connecting rod geometric figure functions, moreover also is generally the power or the force of inertia result, that is frequently big to like static strength several times. In order to analyze the idling or in order to easy to obtain how can cause any organization “the revolution” the index, the transmission angle concept is extremely useful. In organization movement period, the transmission angle value is changing. The transmission angle 0 may occur in the special position. Will output the pole but in this special position the movement with not to exert inputs on the pole the strength many to have nothing to do with greatly. In fact, as a result of the movement vice-friction influence, the general basis practical experience, with the transmission angle planning board which is bigger than the rating. The weight link motion gear transmission movement ability matrix foundation definition already studied. A determining factor value (it includes regarding some assigns organization graph, position output movement variable to input variable derivative) is a this link motion gear in concrete position mobility criterion. If the organization has a degree of freedom (e.g. four pole organizations), then stipulated a location parameter, if the input angle, completely determined this organization stops position (neglect branch offices possibility). We may study one about four pole organization component absolute angular position analysis expression. When analyzes certain positions and (or) certain different organization time, this will be must be much more useful than the geometric figure analysis program, because this expression will cause the automated computation easy to program. The realization organization speed analysis relative velocity law is the speed polygon is one of several effective methods. This end (goes against) the spot to represent on the organization all spots, has the zero speed. From this the line which stipples respectively to the speed polygon in is representing the absolute speed which this organization photograph well should select respectively. In a line connection speed polygon random two points represents is taking on this organization two corresponding spot relative velocity. Other method is the instantaneous center law, namely the instantaneous center law, this method is extremely useful moreover is frequently when the complex link motion gear analysis quick method. The instantaneous center is a spot, this spot in that flash, on between the organization two components does not have the relative motion. In order to discover known organization certain instantaneous centers the position, Kennedy the (Kennedy) three center theories extremely are useful. It is said that,Each other relative motion three object three instantaneous centers are surely in a straight line. The organization various components acceleration is makes one be interested, because it affects the force of inertia, subsequently affects the machine part the stress, the bearing load, the vibration and the noise. Because the final goal is the machine and the organization force of inertia analysis, the all acceleration various components all should the disposable picture - - in the organization fixed component inertial coordinate system express in the identical coordinate system. Should pay attention: Is opposite in rotates on the vice-rotation rigid body an acceleration component usually to have two fixedly. A force component direction cuts in this path, its direction is same with this object angle acceleration direction, and is called the tangential acceleration. Its existence is completely because the angular speed rate of change causes. Another component, always aims at the object the center of rotation, is called the standard the centripetal acceleration, because this component the velocity vector direction has the change to exist. The movement comprehensiveGanization is forms many mechanisms the basic geometry structural units, these mechanisms including automatic packaging, printer, mechanical toy, textile machinery and other machineries and so on. The typical organization must design causes the movement which the rigid component relative datum component produces hoped. The organization movement design is the movement synthesis, first step frequently designs the entire machine first. When consideration stress, must ask dynamics aspect question, the bearing load, the stress, the lubrication and so on the similar question, but the major problem is the machine structure question. The movement scientist defines the kinematics as “the development facility movement and the foundation organization method”. This definition first part involves the kinematic analysis. The known organization, its constitution state of motion determined by the kinematic analysis. The narration movement analysis duty contains the organization between the main dimension, the component links mutually with the input movement technical characteristic or the actuation method. The goal is must discover the displacement, the speed, the acceleration, the impact or the beat (two step accelerations), with various components higher order acceleration which possibly occurs as well as describes the diameter mark and the movement which realizes by certain components. The definition second part of available following two aspect explained ：1. research produces with the aid of the organization assigns the movement the method. 2. research construction to be able to produce assigns the motion the method, but in two plans, the movement is assigns the organization is the foundation. This is the movement synthesis essence. Such movement synthesis involves to for assigns the performance the organization system design. The movement synthesis aspect may sum up as following two kinds: 1. types are comprehensive. The stipulation requests the performance, how is one kind of type organization appropriate? (Tooth gear train, link motion gear? Cam gear?)How many components but should the organization have? How many degrees of freedom needs? How outline structure is hoped? . About the member number and the degree of freedom consideration was usually considered is in the type synthesis is been called as for a quantity synthesis branch domain. 2. sizes are comprehensive. The movement synthesis second predominant type is the best method which determined through the goal law. The size synthesis attempts to determine the organization the important size and the starting position, this organization is conceives beforehand for the realization stipulation duty and the anticipated performance. Of the so-called important size meanings are refer about two poles, three poles and so on between the length or the pole are away from, angle between number of articles and spool thread, cam contour size, cam follower diameter, eccentricity, gear quota and so on. Expected the organization type possibly is the crank slide organization, four pole organizations, the tape reel from the moving parts cam gear, but or is non-has some kind of structure shape more complex link motion gear because by the analysis situs method which the inferior analytic method determined. Is comprehensive regarding the movement, in the convention has three duties: Function production, path production and movement production. Inputs and outputs the component in the function production organization the rotation or the migration must be the interdependence. Regarding arbitrary function y=f(x), a movement synthesis duty possibly is designs a link motion gear to cause the input and the output establishes the relations in order to cause in the xoxxn-1 scope to input according to x movement, but outputs according to the y=f(x) movement. In the input and in the output gyroscopic motion situation, the corner phi and phi respectively is x and the y linear simulation. When inputs rotates to an independence x value, in one “black box” in the organization, causes to output which the component to change to corresponds in the value which by function y=f(x) decided. This may consider is the mechanical analogy computer simple situation. Each kind of different organization all may contain in this “the black box” in, however produces regarding the arbitrary function non-error, four pole organizations are helpless, possibly matches merely in the limited precision with it. It widely uses in the industry, because four pole organizations in the construction and the service all are simple. In the path production organization, in “floats the walking beam” on a spot to have to draw one to be opposite in a fixed coordinate system determination path. If this path spot is both must and have to be related with the time correlation with the position, this duty is called it the predetermined cyclical path production. A path production organization example is the design throws the baseball or the tennis four pole organization. In this case, will select P the path will be this: Picks a ball in the predetermined position, and transmits in the predetermined time cycle along the predetermined diameter mark the ball, can achieve the appropriate speed and the direction. In the mechanism design has many situations, both must guide the rigid body in these situations through a series of stipulations, the independent position which limits, and must limit in the reduction when independent position number, to the vehicle speed and (or) the acceleration restrains, that is necessary. Movement production or rigid body guiding organization request: A complete object must guide passes a predetermined movement sequence. Took the object which guides usually is “the fluctuation component” not only a part, that is the target point P path, also is and inserts in this object through this spot the line rotation. For example, this possibly represents in the automated machinery a carrier, but that has a predetermined path in a carrier on spot this carrier also to have a predetermined angle position. The predetermined way charger cableway bucket movement is the movement production organization another example. The cableway bucket end path has the limit. Because its port must realize the excavation path, is following close on the path which must realize promotes and falls in torrents. The cableway bucket angle position to guaranteed fights the material to fall in torrents from the correct position similarly is (but actually) important.The cam and the gearcam gear is changes one kind of movement Cheng Ling one kind of movement the convenience installment. This kind of machine part has the curved surface or the trough surface, this curved surface or the trough surface with passes to from the moving parts appropriate match merge the movement from the moving parts. The cam movement (usually is rotation) is transmitted for does from the moving parts the undulation or the migration, or both have. Because various geometric solid and the massive cams with unify from the moving parts, therefore the cam is one kind of extremely numerous function multi-purpose machine parts. Although the cam and from the moving parts may for the movement, the path and the function production designs, but it mainly is uses in using the cam and takes the function production component from the moving parts. According to the cam shape, the most universal cam type is: Disc transmission cam (two dimensional, namely plane) and cylindrical cam (three dimensional, namely space) organization. May use several methods from the moving parts to classify: According to from the moving parts movement, for example the migration or the undulation classifies, according to the translation type (straight line) from the moving parts movement is along the radial direction from the cam shaft center bias and the basis from the moving parts contact face shape (for instance plane, rollarounds, spot - - knife point type, spherical surface, plane curve or space-like surface). Regarding one to the heart translation roller from the moving parts disk cam, may draw and cam surface contacting also with the wheel axle concentric most small circle is the base circle. The follower spot produces the pitch line rollarounds center spot. The angle of pressure is the roller center path course line and passes the rollarounds center between the pitch line normal included angle moreover is the transmission angle coangle. The neglect frictional influence, this normal direction with the cam with from the moving parts the contact force direction is the superposition consistent. In a link motion gear, the angle of pressure the change is precisely likely the cam transmits in the circulation generating process the movement action one kind of measurement which goes from the moving parts. The big angle of pressure will produce exerts from the moving parts pole side force, because of the friction force existence, that inevitably will limit from the moving parts in the guide channel. Need the intermittent motion in automated machinery many applications. As soon as a typical example will request one to include the rise to stand still a returns and the possible another idle time cycle, each stage will pass through the angle which will assign, will follow an institute to request from the moving parts displacement, this displacement or will measure by the centimeter. Designers work designs this cam correspondingly. First must do the decision-making is must choose the cam from the moving parts type. The stipulation application possible to request the cam and unifies from the moving parts. Transforms includes for policy-making certain factors: Geometry shape condition, dynamic condition, environmental condition and economic agent. Once the cam with was designated from the moving parts movement vice-type, then surely designated from the moving parts movement. Therefore, the speed, the acceleration and in certain situations, really are the extreme from the moving parts displacement further plan to be important. The gear is draws support in gear teeth success meshing transmits the movement the machine part. Gear from a gyro-axle to another gyro-axle transmission movement or transmission movement to a transmission rack. In the most applications all (or often decides torque by the constant angle transmission ratio to compare) exists. In the constant angle transmission ratio application is surely the axial transmission. In various useful gear type foundation, the input axis and the output shaft need or need parallel mutually in a straight line all not any limit. Because uses the non-round gear, the non-linear angle transmission ratio also is very useful. In order to maintain the constant angular speed, each gear tooth profile must obey the gear meshing the basic rule: In order to a pair of tooth can transmit the constant angle transmission ratio, they contact the tooth profile the shape to have to be must like this: The common normal passes in two gear center segment the fixed point. Satisfies the meshing basic rule two meshing tooth profile to be called the conjugate tooth profile. Although has many satisfies meshes the tooth possible tooth profile to be able to design, satisfies the basic meshing rule, but only has two kinds to use generally: Cycloid tooth profile and involute tooth profile. Has certain important merits involute: But it easy to process between the manufacture and a pair of involute gear center distance may change does not change the transmission ratio, when uses the involute tooth profile, but does not request between the precise axis the common difference.Some several kind of standard gears may supply to select. In order to applies under the parallel axis condition, usually uses the straight tooth cylindrical gears, parallel axle tilt gear or herringbone tooth gear. Uses the straight bevel gear or the helical gear in the intersection axis situation. Regarding the non-intersection axis and the non-parallel gear shaft transmission, will interlock the axis helical gear, the worm bearing adjuster worm gear, the end surface gear, the skewed tooth bevel gear or the accurate hyperboloid gear is selected. Regarding the straight tooth cylindrical gears, the counter gear festival circle is each other contacting. They roll mutually do not have the glide. The gear addendum is the gear teeth stretches out surpasses the festival circle (also is highly between festival circle and addendum circle in radial direction distance). Goes against the crack is assigns the tooth the dedendum (in the festival circle following tooth depth) to be bigger than the gear gear addendum quantity which meshes with it (interpolation). The tooth thick is along the festival round circular arc in the cross tooth distance, but the tooth spacing (socket S) is along the festival round circular arc in the neighboring two space between teeth space length. But the tooth side clearance is bigger than its counter gear in festival circle tooth thick interpolation in the festival circle socket width. fasten with the joint components typical method including the use such as bolt, the cap nut, the cap screw, the set screw, the rivet, the locking installment and the key. The components also may use the melt to weld, the braze and the clamp connection. And the metal working craft research includes frequently in the engineering plat study about each kind of connection method explanation, very much is interested regarding this in the project, intellectual curiosity strong anybody can obtain naturally about fastens in the method the good elementary knowledge. .机械手能模仿人手和臂的某些动作功能，用以按固定程序抓取、搬运物件或操作工具的自动操作装置。它可代替人的繁重劳动以实现生产的机械化和自动化，能在有害环境下操作以保护人身安全，因而广泛应用于机械制造、冶金、电子、轻工和原子能等部门。机械手主要由手部和运动机构组成。手部是用来抓持工件（或工具）的部件，根据被抓持物件的形状、尺寸、重量、材料和作业要求而有多种结构形式，如夹持型、托持型和吸附型等。运动机构，使手部完成各种转动（摆动）、移动或复合运动来实现规定的动作，改变被抓持物件的位置和姿势。运动机构的升降、伸缩、旋转等独立运动方式，称为机械手的自由度 。为了抓取空间中任意位置和方位的物体，需有6个自由度。自由度是机 械手设计的关 键参数。自由 度越多，机械手的灵活性越大，通用性越广，其结构也越复杂。一般专用机械手有23个自由度。机械手的种类，按驱动方式可分为液压式、气动式、电动式、机械式机械手；按适用范围可分为专用机械手和通用机械手两种；按运动轨迹控制方式可分为点位控制和连续轨迹控制机械手等。机械手通常用作机床或其他机器的附加装置，如在自动机床或自动生产线上装卸和传递工件，在加工中心中更换刀具等，一般没有独立的控制装置。有些操作装置需要由人直接操纵，如用于原子能部门操持危险物品的主从式操作手也常称为机械手。现代工业机器人是真正的奇迹工程。一个像人一样大小的机器人可以轻松地随身携带负载百磅，并很快地重复性移动+ / -0.006英寸。此外这些机器人可以做到没有失败的一天24小时的连续工作几年。尽管它们是可以改编的，在许多应用中（特别是在汽车行业） ，他们是一次编程，然后多年重复相同的任务。六轴机器人像Fanuc的黄一个低于成本约为六万美元。我认为有趣的是，部署机器人的费用为另外的20万美元 。因此，机器人本身的成本只是整个系统费用总额的一小部分。这些机器人使用的工具与设计机器人的结构的成本一起构成了在成本的主要百分比。这就是为什么机器人在汽车业很少改编。如果他们将要去为部署机器人的另一项任务而花钱，那么他们可能会使用新的机器人。当他们想到工业机器人时，人们认为这是非常典型的机械。Fanuc发明了这个特殊的机器人。Fanuc是全球最大的这些类型的机器人制造商，他们几乎都是黄色的。这种机器人有6个独立的节点，也称为六自由度。这样做的理由是，任意放置一个立体都需要6个参数;三个指定地点（例如x ， y，z坐标）和3个指定的方向（例如转动，偏移，掷） 。如果你仔细观察你会看到有两个圆柱形活塞分别在机器人的两侧。这些圆柱含有“反重力”弹簧这是机器人可以携带这样重物的一大部分原因。这些弹簧平衡重力的方式类似于车库门上的弹簧能够更容易使一个人进入。你会看到这样的机器人焊接，涂装和处理材料。在右侧显示的机器人是由一家美国公司，Adept Technology ，制造的。Adept Technology是美国最大的机器人公司和全球领先的SCARA机器人制造商。这实际上是最常见的工业机器人。 SCARA主张选择地遵守铰接式（尽管有些人在这里利用组装）机械臂。该机器人在水平面有三个接合处，这给它x-y的定位和平行与水平面的方向。有一个线性的联合供应的Z定位。这是典型的“采摘和放置”的机器人。加上一个视觉系统它就可以在一个非常高的速度下将产品从传送带上进行封装。这个机器人的联合结构允许它兼容（或软的）来使机器人放置在水平面。对于“用孔固定在水平面”型应用机器人这是非常重要的，这个机器人将会很灵活，容易弯曲，可能会导致误差，而且它晕眩部件紧密配合。在左侧的机器可以被称为笛卡尔机器人。然而叫这台机器为机器人实际上是伸展了机器人的定义。这是笛卡尔的因为它可以让x-y-z坐标系定位。三个线性接合处提供了3个轴的运动，并确定了X ， Y和Z位面。这种机器人适合对场合和地点都没有方向的要求或部分可预先方向的拾起和放置应用（如表面裱好的电路板的装配） 最简单最有用的机构之一是四杆机构。以下论述中的大部分内容集中讨论连杆机构上，而该程序也适用于更复杂的连杆机构。我们已经知道四杆机构具有一个自由度。关于四杆机构，有没有要知道的有用的更多内容呢？的确是有的！这些包括格拉肖夫准则，变换的概念，死点的位置（分歧点），分支机构，传动角，和他们的运动特征，包括位置，速度和加速度。四杆机构可具有一种称作曲柄摇杆机构的形式，一种双摇杆机构，一种双曲柄（拉杆）机构，致于称作哪一种形式的机构，取决于跟机架（固定构件）相连接的两杆的运动范围。曲柄摇杆机构的输入构件，曲柄可旋转通过360并连续转动，而输出构件仅仅作摇动（即摇摆的杆件）。作为一个特例，在平行四杆机构中，输入杆的长度等于输出杆的长度，连接杆的长度和固定杆（机架）的长度，也是相等的。其输入和输出都可以作整周转动或者转换成称作反平行四边形机构的交叉结构。格拉肖夫准则（定理）表明：如果四杆机构中，任意两杆之间能作连续相对转动，那么，其最长杆长度与最短杆长度之和就小于或等于其余两杆长度之和。应该注意：相同的四杆机构，可有不同的形式，这取决于哪一根杆被规定作为机架（即作固定杆）。运动变换的过程就是固定机构传动链中的不同的杆件以产生不同的机构运动过程。除了具备关于构件回转范围的知识之外，还要具备如何使机构在制造之前就能“运转”的良好措施，那将是很有用的。哈登伯格（Hartenberg）说到：“运转”是一个术语，其意义是传给输出构件的运动的有效性。它意味着运转平稳，其中能在输出构件中产生一个力或扭矩的最大分力是有效的。虽然最终的输出力或扭矩不仅是连杆几何图形的函数，而且一般也是动力或惯性力的结果，那常常是大到如静态力的几倍。为了分析低速运转或为了易于获得如何能使任一机构“运转”的指数，传动角的概念是非常有用的。在机构运动期间，传动角的值在改变。传动角0可发生在特殊位置上。在此特殊位置上输出杆将不运动而与施加到输入杆上的力多大无关。事实上，由于运动副摩擦的影响，一般根据实际经验，用比规定值大的传动角去设计机构。衡量连杆机构传递运动能力的矩阵基础的定义已经研究出来。一个决定性因素的值（它含有对于某个给定机构图形，位置的输出运动变量对输入变量的导数）是该连杆机构在具体位置中的可动性的一个尺度。如果机构具有一个自由度（例如四杆机构），则规定的一个位置参数，如输入角，就将完全确定该机构休止的位置（忽视分支机构的可能性）。我们可研究一个关于四杆机构构件绝对角位置的分析表达式。当分析若干位置和（或）若干不同机构时候，这将是比几何图形分析程序要有用得多，因为该表达式将使自动化计算易于编程。实现机构速度分析的相对速度法即速度多边形是几种有效的方法之一。这端（顶）点代表着机构上所有的点，具有零速度。从该点到速度多边形上的各点画的线代表着该机构上相应各点的绝对速度。一根线连接速度多边形上的任意两点就代表着作为该机构上两个对应的点的相对速度。另外的方法就是瞬时中心法，即瞬心法，该方法是非常有用的而且常常是在复杂连杆机构分析时较快的方法。瞬心是一个点，该点在那一瞬间，机构上的两构件之间不存在相对运动。为了找出已知机构某些瞬心的位置，肯尼迪（Kennedy）三中心理论就非常有用。它是说：彼此相对运动的三个物体的三个瞬心必定是在一直线上。机构各构件的加速度是令人感兴趣的，因为它影响惯性力，继而影响机器零件的应力、轴承载荷、振动和噪音。由于最终的目的是机器和机构惯性力的分析，所有加速度的各分量都应一次性地画在同一坐标系中机构的固定构件的惯性坐标系中表示出来。应注意的是：相对于固定回转副的回转刚体上的一点加速度分量通常有两个。一个分力方向切于该点的轨迹，其指向与该物体的角加速度方向相同，并被称为切向加速度。它的存在完全是由于角速度的变化率引起的。另一个分量，总是指向物体的回转中心，被称为标准的向心加速度，这个分量由于速度矢量的方向发生改变而存在。. 机构是形成许多机械装置的基本几何结构单元，这些机械装置包括自动包装机、打印机、机械玩具、纺织机械和其他机械等。典型的机构要设计成使刚性构件相对基准构件产生所希望的运动。机构的运动设计即运动的综合，第一步常常是先设计整部机器。当考虑受力时，要提出动力学方面的问题，轴承的荷载、应力、润滑等类似的问题，而较大的问题是机器结构问题。运动学家把运动学定义为“研究机构的运动和创建机构的方法”。这个定义的第一部分就涉及运动学分析。已知一个机构，其构成的运动特性将由运动学分析来确定。叙述运动分析的任务包含机构的主要尺寸、构件间的相互连结和输入运动的技术特性或驱动方法。目的是要找出位移、速度、加速度、冲击或跳动（二阶加速度），和可能发生的各构件的高阶加速度以及所描述径迹和由某些构件来实现的运动。定义的第二部分可用以下两方面来解释：1研究借助机构来产生给定运动的方法2研究建造能产生给定运动机构的方法，在两个方案中，运动是给定的而机构是创建的。这就是运动综合的本质。这样运动综合涉及到为给定性能的机构的系统设计。运动综合方面又可归结为以下两类：1类型综合。规定所要求的性能，怎样一种类型的机构才是合适的？（齿轮系，连杆机构？还是凸轮机构？）而机构应具有多少构件？需要多少个自由度？怎样的轮廓结构才是所希望的？等等。关于杆件数目和自由度的考虑通常被认为是类型综合中被称作为数量综合的一个分支领域。2尺寸综合。运动综合的第二个主要类型是通过目标法来确定的最佳方法。尺寸综合试图确定机构的重要尺寸和起动位置，该机构是为着实现规定的任务和预期的性能而事先设想的。所谓重要的尺寸意思是指关于两杆、三杆等的长度或杆间距离，构件数和轴线间的角度，凸轮轮廓尺寸，凸轮随动件的直径，偏心距，齿轮配额等等。预想机构类型可能是曲柄滑块机构、四杆机构，带盘型从动件的凸轮机构，或者是以拓扑学方法而非因次分析法所确定的具有某种结构形状更为复杂的连杆机构。对于运动综合，惯例上有三个任务：函数生成，轨迹生成和运动生成。在函数生成机构中输入和输出构件的转动或移动必须是相互关联的。对于一个任意函数yf（x），一个运动综合的任务可能是设计一个连杆机构使输入和输出建立起关系以便使得在xoxxn-1的范围内输入按x运动，而输出按yf（x）运动。在输入和输出件回转运动情况下，转角和分别是x和y的线性模拟。当输入件回转到一个独立x值时，在一个“黑箱”的机构中，使输出构件转到相对应的由函数yf（x）决定的数值上。这可被认为是机械模拟计算机的最简单的情形。各种不同的机构都可以包含在这个“黑箱”内，然而对于任意函数的无误差生成，四杆机构是无能为力的，仅仅可能在有限精确度内与之相匹配。它广泛用于工业上，因为四杆机构在构建和维修上都是简单的。在轨迹生成机构中，在“浮动杆”上一个点要描画一条相对于一个固定坐标系确定的轨迹。如果该轨迹点是既要与时间相关又要与位置相关，该任务被称之为预定周期的轨迹生成。轨迹生成机构的一个例子就是设计来投掷棒球或网球的四杆机构。在这种情况下，点P的轨迹将是这样：在预定的位置捡起一个球，并在预定的时间周期内沿着预定的径迹把球传送出去，能达到合适的速度和方向。机械装置设计中有着许多情形，在这些情形中既要导引刚体通过一系列规定的、受限制的独立位置，又要在减少受限制而且独立的位置的数目时，对运动体的速度和（或）加速度加以约束，那是必要的。运动生成或刚体导引机构要求：一个完整的物体要被导引通过一预定的运动序列。作为被导引的物体通常是“浮动构件”的一部分，那不仅是预定点P的轨迹，也是通过该点并嵌入该物体内的线的转动。例如，该线可能代表自动化机械中的一个载体件，那是在载体件上的一个点具有一个预定的轨迹而该载体件又具有一个预定的角度方位。预定方式装料机的吊斗的运动是运动生成机构的另一个例子。吊斗端的轨迹是有极限的。因为其端口必须实现挖掘的运动轨迹，紧跟着要实现提升和倾泻的轨迹。吊斗的角度方位对保证斗中物料从正确的位置倾泻（倒）同样是重要的。凸轮和齿轮：凸轮装置是把一种运动改变成另一种运动的方便装置。这种机器零件具有曲面或槽面，该曲面或槽面与从动件相配合并将运动传给从动件。凸轮的运动（通常是转动）被传递给从动件作摇动或移动，或两者均有。由于各种各样的几何体和大量的凸轮与从动件相结合，因此凸轮是一种极多功能的万用的机械零件。虽然凸轮和从动件可以为运动、轨迹和功能生成而设计，但其主要是用于利用凸轮和从动件作为功能生成构件。根据凸轮形状，最普遍的凸轮种类是：盘形传动凸轮（两维的，即平面的）和圆柱形凸轮（三维的，即空间的）机构。从动件可以用几个方法分类：根据从动件的运动，例如移动或摇动来分类，根据平移式（直线）从动件运动是沿径向的还是从凸轮轴中心偏心的和根据从动件接触面的形状（比如平面、辊子、点刀尖式，球面，平面曲线或空间曲面）。对于一个对心直动滚子从动件盘形凸轮，可画出的与凸轮表面相切且与轮轴同心的最小圆是基圆。随动件的点就是产生节线的辊子中心的点。压力角就是辊中心轨迹方向线和通过辊子中心的节线的法线之间的夹角而且是传动角的余角。忽略摩擦影响，这法线方向跟凸轮与从动件之间接触力方向是重合一致的。像在一连杆机构中，压力角在循环运转过程中变化且是凸轮把运动作用力传递到从动件去的一种量度。大压力角将产生施加到从动件杆上的侧向力，因摩擦力存在，那将势必把从动件限制在导槽中。在自动化机械中的许多应用需要间歇运动。一个典型的例子将要求一个含有上升一停歇一返回和可能另一个停歇的周期，每阶段经过一个指定的角度，伴随着一个所要求的从动件的位移，这个位移以厘米或度来度量。设计者的工作就是相应地设计出该凸轮。首先要做的决策就是要选择凸轮从动件的类型。规定的应用可能要求凸轮和从动件相结合。转化为决策的某些因素有：几何形状条件，动力条件，环境条件和经济因素。一旦凸轮与从动件运动副类型被选定，则从动件运动就必定选定。因此，速度、加速度和在某些情况下，从动件位移的进一步的方案实属极端重要。齿轮是借助于轮齿成功啮合来传递运动的机器零件。齿轮从一根回转轴到另一回转轴传递运动或传递运动到一传动齿条。多数应用中都以恒定角速比（或常定扭矩比）而存在。恒定角速比应用中必定是轴向传动。在各种各样有用的齿轮类型基础上，输入轴和输出轴需要在一直线上或需要互相平行都不受什么限制。由于使用非圆齿轮，非线性角速比也是很有用的。为了保持恒定的角速度，各个齿轮齿廓必须服从齿轮啮合的基本规律：为了一对齿能传递恒定角速比，他们接触齿廓的形状必须是要这样：公法线通过两齿轮中心连线上的固定点。满足啮合基本规律的两啮合齿廓被称为共轭齿廓。尽管有着许多满足相啮合齿的可能齿形能被设计出来，以满足基本啮合规律，但一般仅有两种在使用：摆线齿廓和渐开线齿廓。渐开线具有若干重要的优点：它易于加工制造和一对渐开线齿轮之间的中心距可以变化而不改变速比，当使用渐开线齿廓时，可不要求精密的轴间公差。有几种标准齿轮可供选用。为了在平行轴条件下应用，通常使用直齿圆柱齿轮，平行轴斜齿轮或人字齿齿轮。在相交轴的情况下使用直齿锥齿轮或螺旋齿轮。对于非相交轴和非平行轴齿轮传动，交错轴螺旋齿轮，蜗杆蜗轮，端面齿轮、斜齿圆锥齿轮或准双曲面齿轮将被选用。对于直齿圆柱齿轮，相啮合齿轮的节圆是彼此相切的。他们互相滚动而无滑动。齿顶高是轮齿伸出超过节圆的高度（也是节圆和齿顶圆之间在径向的距离）。顶隙是一个给定齿的齿根高（在节圆以下的齿高）大于与它相啮合的齿轮的齿顶高的量（差值）。齿厚是沿着节圆圆弧上跨齿的距离，而齿间距（齿槽S）是沿着节圆圆弧上相邻两齿间的空间距离。而齿侧间隙是在节圆上的齿槽宽度大于其相啮合齿轮在节圆上的齿厚的差值。螺纹件、紧固件和联接件：固紧和联接零件的典型方法包括利用诸如螺栓、螺帽、有头螺钉、定位螺钉、铆钉、锁紧装置和键。零件也可以用熔焊、铜焊和夹紧连接。在工程图学和金属加工工艺研究中常常包括关于各种连接方法的
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