【正文】 e of andy cam is to produce a displacement of its follower。these provide some unusual follower motions,but also make follower design camshaft in the automotive engine illustrates a simple but important application of a late cam assemblies in automatic record players illustrate a somewhat more plex application.Cam profiles are accurately constructed by either praphical or mathematical transition from development drawings to working (shop) drawing can be made in several ways: a fullscale is desirable from the manufacturing standpoint,but it will not guarantee accurate cam profiles. radial is fairly accurate,but sometimes produces layout problems in the shop. coordinate procedure will ensure accuracy.In selecring one of these methods,one should consider the function of the cam in terms of desired preciseness.Because the cam work outline already determined, therefore the cam structural design mainly was determines the curve outline axial thickness and the cam and the drive shaft connection way. When the work load pares the hour, curve outline axial thickness generally takes for the outline curve biggest radius of vector 1,/10 ～/5。 2) translation cam. (2) space cam gear according to from movement vice element shape classification (1) apex from。 Far stops the angle: With from far rests the cam corner which the regulation corresponds。 Nearly stops the angle: With from nearly rests the cam corner which the regulation corresponds。 From raveling schedule: In pushes in the regulation or the return trip from the biggest displacement, indicated with h。the groove in the periphery of the cam should be shaped to acmodate the type of cam is expensive to cylindrical cam has two outstanding is the fact that the cam is positive outside forces (such as gravity or spring action ) are needed to hold the follower against the working surface of the second feature is the fact that the follower can move through a plete cycle in the course of several revolutions of the example,it is possible to design the cam so the follower could move from a starting position at the left end to the extreme right position in three revolutions( or more),then the starting position in two variations are possible.A translation cam is the figure shown the cam reciprocates horizontally and the follower moves up and pivoted follower can be used with this type .The translation cam can be made positive by providing a guided plate with an inclined slot for the cam。harmonic motion is produced by this type of arrangement.Types of FollowersIn neneral,the follower is considered to be the part that es in contact with the cam profile .However,when a secondly follower is used, the motion of the secondary follower is dictated by that of the primary example ,a roller follower can be reciprocated by acting against the edge of a pivoted follower.The simplest type of follower is the reciprocation type that merely moves up and down (or in and out ) with the rotation of the cam。some of these are in the form of rounded points or thin meta threeway valves in air circuits have similar cams are used to operate mechanical ponents directly,a roller is much more effective.Cam rollers are mercially available in roller sizes ranging from1/2 in .to 6 in Basic dynamic capacities range from 620 to 60000 ,based on rpm and 500hr of minimum life .Correction factors must be used for any other speed or life should be noted that the cam can be lubricated through and oil hole in the end of the contact with the cam surface minimizes wear mounting arrangements are possible with this type of follower .shows the roller follower mounted on a pivoted arm .A pivoted flatfaced follower is shown .As with any flatfaced follower,friction between the follower face and the cam profile must be lubrication can reduce the effects of friction.譯文凸輪 通過(guò)凸輪和從動(dòng)件的作用，可得到不同的運(yùn)動(dòng)。使用凸輪的目的是使其從動(dòng)件產(chǎn)生位移，次級(jí)從動(dòng)件常用來(lái)在另一位置產(chǎn)生附加位移。圓柱凸輪用來(lái)將其旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)變?yōu)閺膭?dòng)件的直線運(yùn)動(dòng)。圓柱凸輪 用來(lái)將其放置運(yùn)動(dòng)轉(zhuǎn)變?yōu)閺膭?dòng)件的直線運(yùn)動(dòng)。汽車發(fā)動(dòng)機(jī)上的凸輪軸顯示了盤(pán)形凸輪的簡(jiǎn)單和重要的應(yīng)用場(chǎng)合，錄音機(jī)上的凸輪組件是更復(fù)雜的應(yīng)用實(shí)例。這是制造需要，但不能保證精確的凸輪輪廓。這相當(dāng)精確，但在生產(chǎn)時(shí)有時(shí)會(huì)產(chǎn)生排布問(wèn)題。這種方法能保證精度。凸輪的結(jié)構(gòu)設(shè)計(jì)：因凸輪的工作輪廓已經(jīng)確定，所以凸輪的結(jié)構(gòu)設(shè)計(jì)主要是確定曲線輪廓的軸向厚度和凸輪與傳動(dòng)軸的連接方式。在確定凸輪與傳動(dòng)軸的聯(lián)接方式時(shí)，應(yīng)綜合考慮凸輪的裝拆、調(diào)整和固定等問(wèn)題。為此，在結(jié)構(gòu)設(shè)計(jì)上要求凸輪能相對(duì)于傳動(dòng)軸沿圓周方向進(jìn)行轉(zhuǎn)動(dòng)，并可靠地加以固定。從動(dòng)件的結(jié)構(gòu)設(shè)計(jì)：直動(dòng)從動(dòng)件的結(jié)構(gòu)：設(shè)計(jì)時(shí)要考慮從動(dòng)件的導(dǎo)向和防止旋轉(zhuǎn)。1)vmax愈大，則動(dòng)量mv愈大。因此，當(dāng)從動(dòng)件質(zhì)量較大時(shí)，為了減小動(dòng)量，應(yīng)選擇vmax值較小的運(yùn)動(dòng)規(guī)律。作用在高副接觸處的應(yīng)力愈大，機(jī)構(gòu)的強(qiáng)度和耐磨性要求也就愈高。前述幾種運(yùn)動(dòng)規(guī)律的vmax、amax、沖擊特性及適用場(chǎng)合如下表對(duì)于擺動(dòng)從動(dòng)件凸輪機(jī)構(gòu)，其運(yùn)動(dòng)線圖的橫坐標(biāo)表示凸輪轉(zhuǎn)角，縱坐標(biāo)則分別表示從動(dòng)件的角位移、角速度和角加速度。凸輪機(jī)構(gòu)設(shè)計(jì)的基本問(wèn)題1) 凸輪機(jī)構(gòu)類型選擇，確定凸輪形狀、從動(dòng)件形狀與運(yùn)動(dòng)形式及凸輪與從動(dòng)件維持高副接觸的方式2) 從動(dòng)件運(yùn)動(dòng)規(guī)律設(shè)計(jì)，根據(jù)應(yīng)用場(chǎng)合對(duì)從動(dòng)件行程和運(yùn)動(dòng)特性的要求，確定從動(dòng)件運(yùn)動(dòng)規(guī)律。4) 凸輪輪廓曲線設(shè)計(jì)。6) 凸輪機(jī)構(gòu)結(jié)構(gòu)設(shè)計(jì)，繪制機(jī)構(gòu)裝配圖和各零件的工作圖。凸輪機(jī)構(gòu)的分類按兩活動(dòng)構(gòu)件間的相對(duì)運(yùn)動(dòng)特性分類1)平面凸輪機(jī)構(gòu)(1)盤(pán)形凸輪；(2)移動(dòng)凸輪。注：在介紹凸輪機(jī)構(gòu)分類這部分內(nèi)容時(shí)，應(yīng)指出各種凸輪機(jī)構(gòu)的優(yōu)缺點(diǎn)及其適應(yīng)場(chǎng)合，說(shuō)明各種凸輪機(jī)構(gòu)的內(nèi)在聯(lián)系，為以后的移動(dòng)凸輪及圓柱凸輪輪廓的設(shè)計(jì)打下基礎(chǔ)。凸輪的類型有以下幾種：盤(pán)形凸輪設(shè)計(jì)簡(jiǎn)單，制造容易。從動(dòng)件可按不同升降比實(shí)現(xiàn)不同形式的運(yùn)動(dòng)，應(yīng)控制運(yùn)動(dòng)以避免凸輪傳到從動(dòng)件的力發(fā)生突變。極限情況出現(xiàn)在A、B點(diǎn)必須計(jì)算這兩點(diǎn)的作用力值。B點(diǎn)應(yīng)量靠近凸輪，以減少滾子從動(dòng)件支承彎曲。需用分析受力，選擇尺寸，以避免零件尺寸過(guò)大。這種凸輪制造成本高。比如，可設(shè)計(jì)這樣的凸輪，當(dāng)凸輪轉(zhuǎn)3轉(zhuǎn)（或更多轉(zhuǎn)）時(shí)，從動(dòng)件從左端起始點(diǎn)運(yùn)動(dòng)到右端極限位置，然后凸輪再轉(zhuǎn)2轉(zhuǎn)使從動(dòng)件回到起點(diǎn)。凸輪水平往復(fù)運(yùn)動(dòng)，從動(dòng)作一下運(yùn)動(dòng)。通過(guò)帶有斜槽的導(dǎo)板，可使移動(dòng)凸輪與從動(dòng)件實(shí)現(xiàn)幾何鎖合，斜槽與作垂直往復(fù)運(yùn)動(dòng)的從動(dòng)件上的銷或滾子配合。在這種形式中，凸輪旋轉(zhuǎn)，從動(dòng)件實(shí)現(xiàn)（通常是滾子或銷）通過(guò)凸輪端面上的槽來(lái)引導(dǎo)。這種類型 的機(jī)構(gòu)也是幾何鎖合，它的制造費(fèi)用比簡(jiǎn)單的盤(pán)形凸輪高很多。這種裝置有時(shí)稱為蘇格半約克機(jī)構(gòu)?？赏ㄟ^(guò)這種裝置得到諧和的運(yùn)動(dòng)。然而，當(dāng)用次數(shù)從動(dòng)件時(shí)，次級(jí)從動(dòng)件的運(yùn)動(dòng)就需通過(guò)主要從動(dòng)件來(lái)實(shí)現(xiàn)。最簡(jiǎn)單的從動(dòng)件是隨著凸輪的轉(zhuǎn)動(dòng)而僅作上下（或進(jìn)出）往復(fù)運(yùn)動(dòng)的從動(dòng)件，其中心線可與凸輪中心線共線，也可與之偏離。如果用點(diǎn)或表面接觸，很高的正應(yīng)力會(huì)導(dǎo)致擦傷和過(guò)量的磨損。比如，操縱一個(gè)小的速動(dòng)開(kāi)關(guān)不會(huì)產(chǎn)生凸輪表面磨損。氣動(dòng)回路中的微型三通閥中有類似的啟動(dòng)器。這就是一個(gè)往復(fù)運(yùn)動(dòng)的滾子從動(dòng)件。在其他轉(zhuǎn)速或壽命值下，須對(duì)基本受力值加以修正。與表面的滾動(dòng)接觸減少了磨損問(wèn)題。當(dāng)用平面從動(dòng)件時(shí)須控制從動(dòng)件表面和凸輪輪廓之間的摩控。 附錄 開(kāi)合螺母加工工藝過(guò)程卡附錄 開(kāi)合螺母加工工序卡