【正文】 桿組 .三桿組 .四桿組以及連桿 .回轉(zhuǎn)副 .滑動(dòng)副 .凸輪隨動(dòng)件 .齒輪 .鏈條 .鏈輪 .皮帶 .皮帶輪等。然而，想象多回環(huán)的連桿機(jī)構(gòu)的運(yùn)動(dòng)常常非常困難。連桿即浮動(dòng)桿將兩個(gè)移動(dòng)鉸鏈接起來，把輸入傳送到 輸出桿。連桿機(jī)構(gòu)通常由被認(rèn)為是剛體的構(gòu)件或桿組成，它們之間用銷軸鉸接，例如用柱銷（圓形的）或棱柱體的銷軸鉸接，形成開式或閉式 （回環(huán)式）的運(yùn)動(dòng)鏈。 If a mechanism has one degree of freedom (. a fourbar linkage), then prescribing one position parameter, such as the angle of the input link, will pletely specify the position of the rest of the mechanism (discounting the branching possibility). We can develop an analytical expression relating the absolute angular positions of the links of a fourbar linkage. This will be much more useful than a graphical analysis procedure when analyzing a number of positions and /or a number of different mechanisms, because the expressions will be easily programmed for automatic putation. The relative velocity or velocity polygon method of performing a velocity analysis of a mechanism is one of several methods available. The pole represents all points on the mechanism having zero velocity. Lines drawn from the pole to points on the velocity polygon represent the absolute velocities of the corresponding points on the mechanism. A line connecting any two points on the velocity polygon represents the relative velocity for the two corresponding points on the mechanism. Another method is the instantaneous center or instant center method, which is a very useful and often quicker in plex linkage analysis. An instantaneous center or instant center is a point at which there is no relative velocity between two links of a mechanism at that instant. In order to locate the locations of some instant centers of a given mechanism, the Kennedy’s theorem of three centers is very useful. It states that the three instantaneous centers of three bodies moving relative to one another must lie along a straight line. The acceleration of links of a mechanism is of interest because of its effect on inertia force, which in turn influences the stress in the parts of a machine, bearing loads, vibration, and noise. 黃石理工學(xué)院 畢業(yè)設(shè)計(jì) (論文 ) 外文文獻(xiàn)翻譯 Since the ultimate objective is inertiaforce analysis of mechanisms and machines, all acceleration ponents should be expressed in one and the same coordinate system : the inertia frame of reference of the fixed link of the mechanism. . Notice that in general there are two ponents of acceleration of a point on a rigid body rotating about a ground pivot. One ponent has the direction tangent to the path of this point, pointed in the same sense of the angular acceleration of this body, and is called the tangential acceleration .Its presence is due solely to the rate of change of the angular velocity. The other ponent, which always points toward the center of rotation of the body, is called the normal or centripetal acceleration. This ponent is present due to the changing direction of the velocity vector. 譯文： 機(jī)構(gòu)介紹 機(jī)構(gòu)是機(jī)械運(yùn)動(dòng)的一個(gè)部分，他的功能是把運(yùn)動(dòng)從一個(gè)剛體傳遞或轉(zhuǎn)換到另一個(gè)剛體。 Hartenberg mentions that“ run”is a term that means effectiveness with which motion is imparted to the output link ； it implies smooth operation， in which a maximum force ponent is available to produce a force or torque