文獻翻譯文獻翻譯 英文原文：英文原文： NOVEL METHOD OF REALIZING THE OPTIMAL TRANSMISSION OF THE CRANK-AND-ROCKER MECHANISM DESIGN Abstract: A novel method of realizing the optimal transmission of the crank-and-rocker mechanism is presented. The optimal combination design is made by finding the related optimal transmission parameters. The 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 possesses the main characteristic. 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. Especially, the method is simple and convenient in practical use. Keywords：Crank-and-rocker mechanism, Optimal transmission angle, Coefficient of travel speed variation INTRODUCTION By conventional method of the crank-and-rocker design, it is very difficult to realize the optimal combination between the various 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 mechanism. 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. 1. ESTABLISHMENT OF DIAGRAM FOR OPTIMAL TRANSMISSION DESIGN It is always one of the most important indexes that designers pursue to improve 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 rocker 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 is how to find the maximum 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 following steps are taken in the usual design method. Firstly, the initial values of the length of rocker 3l and the oscillating angle of rocker are given. Then the value of the coefficient of travel speed variation K is chosen in the permitted range. Meanwhile, the coordinate of the fixed hinge of crank Apossibly realized is calculated corresponding to value K. 1.1 Length of bars of crank and rocker mechanism As shown in Fig.1, left arc GC2 is the permitted field of point A. The coordinates of point A are chosen by small step from point 2C to point G. The coordinates of point A are 02hyycA (1) 22 A AyRx (2) where 0 h, the step, is increased by small increment within range(0,H). If the smaller the chosen step is, the higher the computational precision will be. R is the radius of the design circle. d is the distance from 2 C to G. 2 c o s) 2 c o s (2 2 c o s 33 lRld (3) Calculating the length of arc 1 AC and 2 AC, the length of the bars of the mechanism corresponding to point A is obtained1,2. 1.2 Minimum transmission angle min Minimum transmission angle min (see Fig.2) is determined by the equations3 32 2 14 2 3 2 2 m i n 2 )( c o s ll llll (4) 32 2 14 2 3 2 2 m a x 2 )( c o s ll llll (5) m a xm i n 180 (6) where 1 lLength of crank(mm) 2 lLength of connecting bar(mm) 3 lLength of rocker(mm) 4 lLength of machine frame(mm) Firstly, we choose minimum comparing min with min . And then we record all values of min greater than or equal to 40 and choose the maximum of them. Secondly, we find the maximum of min corresponding to any oscillating angle which is chosen by small step in the permitted range (maximum of min is different oscillating angle and the coefficient of travel speed variation K). Finally, we change the length of rocker 3 l by small step similarly. Thus we may obtain the maximum of min corresponding to the different length of bars, different oscillating angle and the coefficient of travel speed variation K. Fig.3 is accomplished from Table for the purpose of diagram design. It is worth pointing out that whatever the length of rocker 3 l is evaluated, the location that the maximum of min arises is only related to the ratio of the length of rocker and the length of machine frame 3 l/ 4 l, while independent of 3 l. 2. DESIGN METHOD 2.1 Realizing the optimal transmission design given the coefficient of travel speed variation and the maximum oscillating angle of the rocker The design procedure is as follows. (1) According to given K and , taken account to the formula the extreme included angle is found. The corresponding ratio of the length of bars 3 l/ 4 l is obtained consulting Fig.3. 180 1 1 K K (7) (2) Choose the length of rocker 3 l according to the work requirement, the length of the machine frame is obtained from the ratio 3 l/ 4 l. (3) Choose the centre of fixed hinge D as the vertex arbitrarily, and plot an isosceles triangle, the side of which is equal to the length of rocker 3 l(see Fig.4), and 21DC C. Then plot 212 CCMC, draw NC1, and make angle 90 12 NCC. Thus the point of intersection of MC2 and NC1 is gained. Finally, draw the circumcircle of triangle 21C PC. (4) Plot an arc with point D as the centre of the circle, 4 l as the radius. The arc intersections arc GC2 at point A. Point A is just the centre of the fixed hinge of the crank. Therefore, from the length of the crank 2/ )( 211 ACACl (8) and the length of the connecting bar 112 lACl (9) we will obtain the crank and rocker mechanism consisted of 1 l, 2 l, 3 l, and 4 l.Thus the optimal transmission property is realized under given conditions. 2.2 Realizing the optimal transmission design given the length of the rocker (or the length of the machine frame) and the coefficient of travel speed variation We take the following steps. (1) The appropriate ratio of the bars 3 l/ 4 l can be chosen according to given K. Furthermore, we find the length of machine frame 4 l(the length of rocker 3 l). (2) The corresponding oscillating angle of the rocker can be obtained consulting Fig.3. And we calculate the extreme included angle . Then repeat (3) and (4) in section 2.1 3. DESIGN EXAMPLE The known conditions are that the coefficient of travel speed variation 1818. 1K and maximum oscillating angle 40. The crankandrocker mechanism realizing the optimal transmission is designed by the diagram solution method presented above. First, with Eq.(7), we can calculate the extreme included angle 15. Then, we find 93. 0/ 43 ll consulting Fig.3 according to the values of and . If evaluate 50 3 l mm, then we will obtain 76.5393. 0/50 4 l mm. Next, draw sketch(omitted). As result, the length of bars is 16 1 l mm,46 2 l mm,50 3 l mm,76.53 4 l mm. The minimum transmission angle is 3698.46 2 )( arccos 32 2 14 2 3 2 2 min ll llll The results obtained by computer are 2227.16 1 l mm, 5093.44 2 l mm, 0000.50 3 l mm, 8986.53 4 l mm. Provided that the figure design is carried under the condition of the Auto CAD circumstances, very precise design results can be achieved. 4. CONCLUSIONS A novel approach of diagram solution can realize the optimal transmission of the crank-and-rocker mechanism. The method is simple and convenient in the practical use. In conventional design of mechanism, taking 0.1 mm as the value of effective the precision of the component sizes will be enough. 譯文：譯文： 認識曲柄搖臂機構設計的最優傳動方法認識曲柄搖臂機構設計的最優傳動方法 摘要：摘要：一種曲柄搖臂機構設計的最優傳動的方法被提出。這種優化組合設計被用 來找出最優的傳遞參數。得出最優傳遞圖。在圖中，在極小的傳動角度之間, 滑 移速度變化系數，搖臂的擺動角度和桿的長度被直觀地顯示。 這是這種方法擁 有的主要特征。根據指定的要求，它將傳動角度之下的最優傳動參數直接地表達 在圖上。 通過這種方法， 機械傳動的特性能用以獲取最優傳動效果。 特別是， 這 種方法是簡單和實用的。 關鍵字：關鍵字：曲柄搖臂機構 最優傳動角度 滑移速度變化系數 0 介紹介紹 由曲柄搖臂機構設計的常規方法, 在各種各樣的參量之間很難找出優化組合 的最優傳動。通過本文介紹的圖面設計方法可以幫助達到這個目的。在指定的情 況下，通過觀查設計圖面, 我們就能得到每個參量和另外一個曲柄搖臂機構設計 之間的聯系。由因認識最優傳動。 具體的設計的理論和方法， 以及它們各自的應用事例將在以下介紹。 1 優化傳動設計的建立優化傳動設計的建立 優化傳動的設計一直是設計師改進傳輸效率和追求產量的最重要的索引的 當中一個。曲柄搖臂機構被廣泛應用在機械傳動中。如何改進工作效率和減少多 余的功率損失直接地與滑移速度變化系數， 搖臂的擺動角度和曲柄搖臂的比率有 關系。這些參數的合理組合采用對機械效率和產量有重要作用, 這些主要體現在 極小的傳輸角度上。 認識機械優化傳動目的是找到極小的傳輸角度的最大值。設計參數是適度地 減少限制而且分開的合理優化方法的結合。因此，完全限制領域的優化傳動建立 了。 以下步驟被采用在通常的設計方法。 首先，測量出搖臂的長度3l和搖臂的 擺動角度的初始值。 然后滑移速度變化系數K的值被定在允許的范圍內。 同 時，曲柄固定的鉸接座標A可能被認為是任意值K。 1.1 曲柄搖臂機構桿的長度曲柄搖臂機構桿的長度 由圖 Fig.1，左弧GC2是點A被允許的領域。點A的座標的選擇從點2C到點 G。 點A的座標是 02hyycA (1) 22 A AyRx (2) 當 0 h，高度，在 range(0 ，H) 被逐漸增加。如果選的越小,計算精度將越高。R 是設計圓的半徑。d是從 2 C到G的距離。 2 c o s) 2 c o s (2 2 c o s 33 lRld (3) 計算弧 1 AC和 2 AC的長度，機械桿對應于點A的長度是 obtained1,2 。 1.2 極小的傳動角度極小的傳動角度 min 極小的傳動角度 min (參見 Fig.2) 由 equations3確定 32 2 14 2 3 2 2 m i n 2 )( c o s ll llll (4) 32 2 14 2 3 2 2 m a x 2 )( c o s ll llll (5) m a xm i n 180 (6) 由于 1 l曲柄的長度(毫米) 2 l連桿的長度（毫米） 3 l搖臂的長度（毫米） 4 l 機器的長度（毫米） 首先, 我們比較極小值 min 和 min 。 并且我們記錄所有 min 的值大于或等于 40，然后選擇他們之間的最大值。 第二, 我們發現最大值 min 對應于一個逐漸變小的范圍的任一個擺動的角度 (最大值 min 是不同于擺動的角度和滑移速度變化系數K) 。 最后, 我們相似地慢慢縮小搖臂 3 l的長度。 因而我們能獲得最大值 min 對應 于桿的不同長度, 另外擺動的角度和滑移速度變化系數K。 Fig.3 成功的表達設計的目的。 它確定了無論是搖臂的長度 3 l,最大值 min 出現的地點，只與搖臂的長度和機 械的長度的比率 3 l/ 4 l有關, 當確定 3 l時。 2 設計方法設計方法 2.1 認識最優傳動設計下滑移速度變化系數和搖臂的最大擺動的角度認識最優傳動設計下滑移速度變化系數和搖臂的最大擺動的角度 設計步驟如下。 (1) 根據所給的K和， 通常采取對發現極限角度的解釋。 桿的長度的