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1、文献翻译英文原文：NOVEL METHOD OF REALIZING THE OPTIMAL TRANSMISSIONOF THE CRANK-AND-ROCKER MECHANISM DESIGNAbstract: Anovelmethod ofrealizingtheoptimaltransmission ofthecrank-and-rocker mechanism is presented. The optimal combination design is made by finding the related optimal transmission parameters. The
2、 diagram of the optimal transmission is drawn. In the diagram, the relation among minimum transmission angle, the coefficient of travel speed variation, the oscillating angle of the rocker and the length of the bars is shown, concisely, conveniently and directly. The method possessesthe main charact
3、eristic. That it is to achieve the optimal transmission parameters under the transmission angle by directly choosing in the diagram, according to the given requirements. The characteristics of the mechanical transmission can be improved to gain the optimal transmission effect by the method. Especial
4、ly, the method is simple and convenient in practical use.Keywords：Crank-and-rocker mechanism, Optimal transmission angle, Coefficientof travel speed variationINTRODUCTIONBy conventional method of the crank-and-rocker design, it is very difficult to realize the optimal combination between the various
5、 parameters for optimal transmission. The figure-table design method introduced in this paper can help achieve this goal. With given conditions, we can, by only consulting the designing figures and tables, get the relations between every parameter and another of the designed crank-and-rocker mechani
6、sm. Thus the optimal transmission can be realized.The concerned designing theory and method, as well as the real cases of its application will be introduced later respectively.1ESTABLISHMENT OF DIAGRAM FOR OPTIMAL TRANSMISSION DESIGNIt is always one of the most important indexes that designers pursu
7、e toimprove the efficiency and property of the transmission. The crank-and-rocker mechanism is widely used in the mechanical transmission. How to improve work ability and reduce unnecessary power losses is directly related to the coefficient of travel speed variation, the oscillating angle of the ro
8、cker and the ratio of the crank and rocker. The reasonable combination of these parameters takes an important effect on the efficiency and property of the mechanism, which mainly indicates in the evaluation of the minimum transmission angle.The aim realizing the optimal transmission of the mechanism
9、 is how to find themaximum of the minimum transmission angle. The design parameters are reasonably combined by the method of lessening constraints gradually and optimizing separately. Consequently, the complete constraint field realizing the optimal transmission is established.The followingsteps are
10、 taken in the usual design method. Firstly, the initialvalues of the length of rocker l 3 and the oscillating angle of rockerare given.Then the value of the coefficientof travel speed variation Kischosen in thepermitted range. Meanwhile, the coordinate of the fixed hinge of crank A porealized is cal
11、culated corresponding to value K .1.1 Length of bars of crank and rocker mechanism. TheAs shown in Fig.1, left arc C2Gis the permitted field of pointAcoordinates of point Aare chosen by small step from point C 2 to point G .The coordinates of point Aarey Ayc 2 h 0(1)x A22(2)Ry Awhere h0 , the step,
12、is increased by small increment within range(0,H ). If thesmaller the chosen step is, the higher the computational precision will be.Ris theradius of the design circle. dis the distance from C 2to G .dl 3 c o s2 R c o s () l 3 c o s(3)222Calculating the length of arc AC 1and AC 2 , the length of the
13、 bars of themechanism corresponding to point Ais obtained1,2 .1.2 Minimum transmission angleminMinimum transmission angle3min (see Fig.2) is determined by the equationsc o sc o s22(l 42l 2l 3l 1 )mi n2l 2 l 3l 22l 32( l 4l1 ) 2ma x2l 2 l 3(4)(5)mi n1 8 0ma x(6)wherel 1 Length of crank(mm)l 2 Length
14、of connecting bar(mm)l 3 Length of rocker(mm)l 4 Length of machine frame(mm)Firstly, we choose minimum comparingminwithmin. And then we recordall values ofmingreater than or equal to 40and choose the maximum of them.Secondly, we find the maximum ofmincorresponding to any oscillating anglewhich is chosen by small step in the permitted range (maximum of minisdifferent oscillating angleand the coeffici
