中英文文獻翻譯-機構(gòu)和機器原理

1、 英文原文MECHANISMS AND MACHINE THEORY1.Introduction to Mechanism：The function of a mechanism is to transmit or transform motion from one rigidbody to another as part of the action of a machine. There are three types of commonmechanical devices that can be used as basic elements of a mechanism.1、Gear sy

2、stem, in which toothed members in contact transmit motion betweenrotating shafts.2、Cam system, where a uniform motion of an input member is converted into anonuniform motion of the output member.3、Plane and spatial linkages are also useful in creating mechanical motions for apoint or rigid body.A ki

3、nematic chain is a system of links, that is, rigid bodies , which are eitherjointed together or are in contact with one another in a manner that permits them tomove relative to one another. If one of the links is fixed and the movement of anyother link to a new position will cause each of the other

4、links to move to definitepredictable position, the system is a constrained kinematic chain. If one of the links isheld fixed and the movement of any other link to a new position will not cause each ofthe other links to move to a definite predictable position then the system is anunconstrained kinema

5、tic chain,A mechanism or linkage is a constrained kinematic chain, and is a mechanicaldevice that has the purpose of transferring motion and/or force from a source to anoutput. A linkage consists of links (or bars), generally considered rigid, which areconnected by joints, such as pin Cor revolute)

6、or prismatic joints, to form open orclosed chains (or loops). Such kinematic chains, with at least one link fixed, becomemechanisms if at least two other links remain mobility, or structures if no mobilityremains. In other words, a mechanism permits relative motion between its rigidlinks; a structur

7、e does not. Since linkages make simple mechanisms and can bedesigned to perform complex tasks, such as nonlinear motion and force transmissionthey will receive much attention in mechanism study.Mechanisms are used in a great variety of machines and devices. The simplestclosed-loop linkage is the fou

8、r-bar linkage, which has three moving links (plus one fixed link) and four pin joints. The link that is connected to the power source or primemover and has one moving pivot and one ground pivot is called the input link. Theoutput link connects another moving pivot to another ground pivot. The couple

9、r orfloating link connected the two moving pivots, thereby coupling the input to theoutput link.The four-bar linkage has some special configurations created by making one ormore links infinite in length. The slider-crank (or crank and slider) mechanism is afour-bar chain with a slider replacing an i

10、nfinitely long output link. The internalcombustion engine is built based on this mechanism. Other forms of four-linkmechanisms exist in which a slider is guided on a moving link rather than on a fixedlink. These are called inversions of the slider-crank, produced when another link (thecrank, coupler

11、, or slider) is fixed link.Although the four-bar linkage and slider-crank mechanism are very useful andfound in thousands of applications, we can see that these linkages have limitedperformance level. Linkages with more members are often used in more demandingcircumstances. However it is often diffi

12、cult to visualize the movement of a multilooplinkage, especially when other components appear in the same diagram. The first stepin the motion analyses of more complicated mechanisms is to sketch the equivalentkinematic or skeleton diagram. The skeleton diagram serves a purpose similar to thatof the

13、 electrical schematic or circuit diagram .Organization movement analysis second step: Draws a graphic chart, is mustdetermine the organization the number of degrees of freedom. Based on degree offreedom, but Italy refers needs certain independent inputs the movement number, bydetermined organization

14、 all components are opposite in the ground position. Thepeople have thousands of different types conceivably the link motion gear. You mayimagine a bag containing massive link motion gear the component: Two pole groups,three pole groups, four pole groups and so on, as well as components, rotation, m

15、otion,cam follower, gear, tooth chain, chain wheel, leather belt, belt pulley and so on.(Sphere movement, screw vice-as well as the permission three dimensional relativemotion other connections not yet includes, here, discusses in parallel planes merelyplane motion). Moreover you conceivable put the

16、se components various types linkmotion gear possibility which forms in the same place. How exists helps the people tocontrol forms these organizations the rule? In fact, the majority organization duty isrequests a sole input to transmit to a sole output. Therefore the single degree offreedom organiz

17、ation uses most one kind of organization type. For example, namelymay see by the intuition: Four pole organizations are a single degree of freedom linkmotion gear. The picture motion diagram and the determination organization degree offreedom process, is the movement analysis and the synthesis proce

18、ss first stage. In themovement analysis, adds on its characteristic according to the organization geometryshape which possibly knew (for example input angle, speed, angle acceleration and soon) studies the determination concrete organization. On the other hand, the movementsynthesis is designs an or

19、ganization to complete the duty process which an instituterequests. In this, chooses the new organization the type and the size is a movementsynthesis part. Conceives the relative motion ability, can guess the reason that designsan organization the reason and makes the improvement to a concrete desi

20、gn ability islike this a successful organization scientists symbol. Although these abilities comefrom the congenital creativity, however more is because has grasped the technologywhich enhances from the practice.1.1The movement analysi：ssimple one of most useful organizations is four pole organizati

21、ons. In onfollowing elaboration majority of content centralism discussion link motion gear, butthis procedure is also suitable for the more complex link motion gear.We already knew four pole organizations have a degree of freedom. About fourpole organizations, has the useful more contents which must

22、 know? Indeed is some!These pull the Xiao husband criterion including the standard, the transformationconcept, the blind spot position (divergence point), branch office, transmission angle,with theirs movement characteristic, including position, speed and acceleration.Four pole organizations may hav

23、e one kind of being called as crank rockerorganization form, one kind of double rocking lever organization, one kind of doublecrank (tension bar) does the organization, which one form send in is called as theorganization, is decided in two pole movement scopes which (fixed component)connects with th

24、e rack. The crank rocker organization input component, the crankmay revolve through 360 and the continuous rotation, but outputs the component tomake the undulation merely (i.e. swing member). As an exceptional case, in theparallel four pole organization, inputs the pole the length to be equal to ou

25、tputs thepole 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 transformthe being called as antiparallel quadrangle organization the overlapping structure. Thestandard pulls the Xiao husband c

26、riterion (theorem) to indicate that,If in four poleorganizations, 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 equalto sum of the other two pole length. Should pay attention: The same four

27、pole organization, may have the differentform, 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 chaindifferent member has the different organization rate process. Besides has about thecompon

28、ent rotation scope knowledge, but also must have how causes the organizationbefore the manufacture on energy “the revolution” the good measure, that will be veryuseful. Hardenbergh (Hartenberg) speaks of: “The revolution” is terminology, itssignificance passes to outputs the component the movement v

29、alidity. It meant therevolution is steady, in which can in output in the component to have a strength or thetorque biggest force component is effective. Not only although the final outputstrength or the torque are the connecting rod geometric figure functions, moreoveralso is generally the power or

30、the force of inertia result, that is frequently big to likestatic strength several times. In order to analyze the idling or in order to easy to obtainhow can cause any organization “the revolution” the index, the transmission angleconcept is extremely useful. In organization movement period, the tra

31、nsmission anglevalue is changing. The transmission angle 0 may occur in the special position. Willoutput the pole but in this special position the movement with not to exert inputs onthe pole the strength many to have nothing to do with greatly. In fact, as a result of themovement vice-friction infl

32、uence, the general basis practical experience, with thetransmission angle planning board which is bigger than the rating. The weight linkmotion gear transmission movement ability matrix foundation definition alreadystudied. A determining factor value (it includes regarding some assigns organizationg

33、raph, position output movement variable to input variable derivative) is a this linkmotion gear in concrete position mobility criterion.If the organization has a degree of freedom (e.g. four pole organizations), thenstipulated a location parameter, if the input angle, completely determined thisorgan

34、ization stops position (neglect branch offices possibility). We may study oneabout four pole organization component absolute angular position analysis expression.When analyzes certain positions and (or) certain different organization time, this willbe must be much more useful than the geometric figu

35、re analysis program, because thisexpression will cause the automated computation easy to program. The realizationorganization speed analysis relative velocity law is the speed polygon is one of severaleffective methods. This end (goes against) the spot to represent on the organization allspots, has

36、the zero speed. From this the line which stipples respectively to the speedpolygon in is representing the absolute speed which this organization photograph wellshould select respectively. In a line connection speed polygon random two pointsrepresents is taking on this organization two corresponding

37、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 linkmotion gear analysis quick method. The instantaneous center is a spot, this spot in thatflash, on between the organiza

38、tion 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,Eachother relative motion three object three instantaneous centers are surely in

39、a straightline.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 andthe organization force of inert

40、ia analysis, the all acceleration various components allshould the disposable picture - - in the organization fixed component inertialcoordinate system express in the identical coordinate system.Should pay attention: Is opposite in rotates on the vice-rotation rigid body anacceleration component usu

41、ally to have two fixedly. A force component direction cutsin this path, its direction is same with this object angle acceleration direction, and iscalled the tangential acceleration. Its existence is completely because the angularspeed rate of change causes.Another component, always aims at the obje

42、ct the center of rotation, is called thestandard the centripetal acceleration, because this component the velocity vectordirection has the change to exist. The movement comprehensiveGanization is forms many mechanisms the basic geometry structural units, thesemechanisms including automatic packaging

43、, printer, mechanical toy, textilemachinery and other machineries and so on. The typical organization must designcauses the movement which the rigid component relative datum component produceshoped. The organization movement design is the movement synthesis, first stepfrequently designs the entire m

44、achine first. When consideration stress, must askdynamics aspect question, the bearing load, the stress, the lubrication and so on thesimilar question, but the major problem is the machine structure question.The movement scientist defines the kinematics as “the development facilitymovement and the f

45、oundation organization method”. This definition first part involvesthe kinematic analysis. The known organization, its constitution state of motiondetermined by the kinematic analysis. The narration movement analysis duty containsthe organization between the main dimension, the component links mutua

46、lly with theinput movement technical characteristic or the actuation method. The goal is mustdiscover the displacement, the speed, the acceleration, the impact or the beat (two step accelerations), with various components higher order acceleration which possiblyoccurs as well as describes the diamet

47、er mark and the movement which realizes bycertain components. The definition second part of available following two aspectexplained ：1. research produces with the aid of the organization assigns the movement themethod.2. research construction to be able to produce assigns the motion the method,but i

48、n two plans, the movement is assigns the organization is the foundation. This isthe movement synthesis essence. Such movement synthesis involves to for assigns theperformance the organization system design. The movement synthesis aspect maysum up as following two kinds:1. types are comprehensive. Th

49、e stipulation requests the performance, how is onekind of type organization appropriate? (Tooth gear train, link motion gear? Camgear?)How many components but should the organization have? How many degreesof freedom needs? How outline structure is hoped? . About the member number andthe degree of fr

50、eedom consideration was usually considered is in the type synthesis isbeen called as for a quantity synthesis branch domain.2. sizes are comprehensive. The movement synthesis second predominant type isthe best method which determined through the goal law. The size synthesis attemptsto determine the

51、organization the important size and the starting position, thisorganization is conceives beforehand for the realization stipulation duty and theanticipated performance.Of the so-called important size meanings are refer about two poles, three polesand so on between the length or the pole are away fro

52、m, angle between number ofarticles and spool thread, cam contour size, cam follower diameter, eccentricity, gearquota and so on. Expected the organization type possibly is the crank slideorganization, four pole organizations, the tape reel from the moving parts cam gear,but or is non-has some kind o

53、f structure shape more complex link motion gearbecause 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

54、in the function production organization therotation or the migration must be the interdependence. Regarding arbitrary functiony=f(x), a movement synthesis duty possibly is designs a link motion gear to cause theinput and the output establishes the relations in order to cause in the xoxxn-1 scopeto i

55、nput 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 phirespectively is x and the y linear simulation. When inputs rotates to an independence xvalue, in one “black box” in the organization, causes t

56、o output which the componentto change to corresponds in the value which by function y=f(x) decided. This mayconsider is the mechanical analogy computer simple situation. Each kind of differentorganization all may contain in this “the black box” in, however produces regardingthe arbitrary function no

57、n-error, four pole organizations are helpless, possibly matchesmerely in the limited precision with it. It widely uses in the industry, because fourpole organizations in the construction and the service all are simple.In the path production organization, in “floats the walking beam” on a spot tohave

58、 to draw one to be opposite in a fixed coordinate system determination path. Ifthis path spot is both must and have to be related with the time correlation with theposition, this duty is called it the predetermined cyclical path production. A pathproduction organization example is the design throws

59、the baseball or the tennis fourpole organization. In this case, will select P the path will be this: Picks a ball in thepredetermined position, and transmits in the predetermined time cycle along thepredetermined diameter mark the ball, can achieve the appropriate speed and thedirection.In the mecha

60、nism design has many situations, both must guide the rigid body inthese situations through a series of stipulations, the independent position which limits,and must limit in the reduction when independent position number, to the vehiclespeed and (or) the acceleration restrains, that is necessary. Mov