玉米剝皮機設(shè)計【含CAD圖紙、說明書】
本科畢業(yè)論文(設(shè)計)題 目: 玉米剝皮機設(shè)計 . 學 院專 業(yè)班 級學 生學 號 指導(dǎo)老師 -60 -目錄摘要4Abstract5第 1 章緒論61.1 研究背景及研究意義61.1.1 研究背景61.1.2 研究意義61.2 國內(nèi)外發(fā)展概況71.2.1 國內(nèi)發(fā)展狀況71.2.2 國外發(fā)展狀況81.3 市場上對玉米剝皮機的基本要求81.4 題目來源及技術(shù)要求91.4.1 題目來源91.4.2 技術(shù)要求:91.5 果穗脫皮機理:101.6 設(shè)計思路及其原理:11第 2 章 總體方案設(shè)計122.1 剝皮過程工藝分析122.2 總體配置的選擇122.3 主要工作部件型式的選擇132.4 總體配置參數(shù)確定132.4.1 傳動系統(tǒng)配置132.4.2 機架的配置152.4.3 剝皮裝置的確定162.4.4 料斗的設(shè)計:192.4.5 機架、連接架的設(shè)計:19第 3 章傳動部分設(shè)計203.1 果穗與剝皮輥接觸時的受力分析203.2 皮帶傳動的設(shè)計計算及校核:213.3 齒輪的設(shè)計計算233.3.1 d=60mm 的齒輪計算和校核233.3.2 對于 d = 74mm 齒輪的計算及校核273.3.3 對于 d = 80mm d = 140mm 齒輪的計算及校核:303.4 軸的強度校核與設(shè)計計算:343.5 鍵的選擇及校核363.6 電動機的選擇36第 4 章玉米剝皮機的使用、保養(yǎng)、調(diào)整及修復(fù)384.1 每日技術(shù)保養(yǎng)384.2 使用注意事項384.3 傳動裝置的使用和調(diào)整394.4 機器的保管40總結(jié)41參 考 文 獻42外文文獻譯文和原文43摘要常言道:“民以食為天”,玉米作為世界三大谷物之一,在全球人民的生活中占有非常重要的地位。玉米是我國第二大糧食作物,在我國養(yǎng)殖業(yè)蓬勃發(fā)展的今天,促進了玉米加工工業(yè)的進一步發(fā)展。因此我國國內(nèi)對玉米的需求量極大,種植的面積也由此不斷擴大。但是,在收獲的季節(jié),由于種植面積廣,很多生產(chǎn)地區(qū)還是以人工收獲為主,這就導(dǎo)致了一系列的問題,比如說有勞動強度大,生產(chǎn)效率低,勞動力的利用率很低等等問題。我國機械工業(yè)發(fā)展比較晚,農(nóng)業(yè)機械發(fā)展也比較落后,盡管某些地方已經(jīng)出現(xiàn)了使用剝皮機的情況,但現(xiàn)有的裝置存在很多問題,不太適合廣大的農(nóng)戶使用,為此,本文對現(xiàn)已經(jīng)應(yīng)運的剝皮機的不足進行了分析,對該裝置進行了原理分析結(jié)構(gòu)設(shè)計的改進,從而提高剝皮效率,提高剝凈率。本文主要是通過對剝皮輥的螺旋外形的采用從而提高了剝凈率,通過對喂入裝置的分入槽設(shè)計,降低了玉米容易被卡死的問題,還增加了壓送裝置,能夠有效的防止剝不凈籽粒易破損的現(xiàn)象而且能提高剝皮效率。關(guān)鍵詞:玉米剝皮機,剝皮輥AbstractAs the saying goes saying claims, as one of the worlds three big grain, corn in the world occupies very important position in peoples lives. Corn is the second food crops in China, in the vigorous development of aquaculture in China today, promote the further development of corn processing industry. So our domestic demand for corn, planting area of the continuously expanding.However, in the season of harvest, because the planting area is wide, many production is mainly artificial harvesting, this leads to a series of problems, such as labor intensity, low production efficiency, labor utilization rate is very low and so on.Late machinery industry development in our country, the agricultural machinery development is relatively backward, although some places have appeared the use of peeling machine, but the existing device has a lot of problems, not very suitable for the general farmers to use, therefore, in this paper, now times peeling machine was analyzed, and the deficiency of the principle analysis of the structure design of the device is improved, thereby improving the efficiency of stripping, stripping the net rate.This article mainly is through to the stripping roller spiral shape was adopted to improve the net rate, based on the points into the groove design of the feeding device, reduces the corn problems are easy to be jammed, also increased the pressure feed device, can effectively prevent the strip dont net grain easy breakage phenomenonand can improve the efficiency of peeling.Keywords: Corn peeling machine, Peeling roller第 1 章緒論1.1 研究背景及研究意義1.1.1 研究背景玉米是極為重要的糧食作物,在我國種植面積約占總作物種植面積30%,總產(chǎn)量達1127 億噸左右,我國有三大玉米生產(chǎn)區(qū),一是北方玉米區(qū),二是黃淮平的玉米區(qū),三是西南丘陵玉米區(qū)。從總體來看,我國對剝皮機的需求量很大, 但是,現(xiàn)實數(shù)據(jù)顯示我國剝皮機普及程度僅僅為5%,遠遠低于小麥70和水稻20的機收水平。所以,玉米剝皮機的市場潛力很大,需要加大力度開發(fā)。在我國玉米生產(chǎn)過程中, 耕、耙、播、管已普遍實現(xiàn)了機械化或半機械化作業(yè), 有較完善的多種型號的機具, 但機械化收獲問題至今尚未解決。而歐美等發(fā)達國家早已實現(xiàn)機械化的全過程。除少數(shù)大型農(nóng)場部分外。我國玉米的種植多一半是通過農(nóng)戶種植管理的, 結(jié)果導(dǎo)致土地生產(chǎn)管理不集中, 農(nóng)戶不能夠購買大型聯(lián)合收割機,所以生產(chǎn)效率很低。通過人工玉米收割,其結(jié)果就是勞動強度大, 效率很低, 勞動力嚴重浪費, 其中最嚴重的一個問題是由于收獲時玉米果穗水分較大, 玉米苞葉吸濕性很強, 玉米籽粒不能及時通風而干燥, 這就會引起籽粒發(fā)霉,發(fā)芽等嚴重問題。由于人工剝皮效率及其低,每人每天最多能完成兩畝或者三畝地的工作, 且勞動強度大, 對人傷害很大, 每到收獲季節(jié), 由于果穗不能及時剝皮而造成的損失相當大。解決玉米果穗剝皮問題已成為提高玉米產(chǎn)品質(zhì)量、降低損失、解放農(nóng)村勞動力的關(guān)鍵問題。1.1.2 研究意義根據(jù)目前我國玉米剝皮機發(fā)展的現(xiàn)狀以及市場上現(xiàn)有玉米剝皮機所存在的一系列問題,從而改進設(shè)計了目前在用的家用小型玉米剝皮機。采用兩組帶有牙齒狀突起的橡膠輥作為剝皮輥代替以往的鐵輥。從而降低了玉米籽粒的破損率,并且提高了玉米剝皮機的工作效率和剝凈率,使農(nóng)民的勞動強度大大的降低了,很好地解決了由于玉米種植面積大,無法使用大型機械的地區(qū),使那些種植面積小且零散的地區(qū)玉米機械化生產(chǎn)的一實現(xiàn)。是一款非常經(jīng)濟實用的家庭版的玉米剝皮機。1.2 國內(nèi)外發(fā)展概況1.2.1 國內(nèi)發(fā)展狀況我國在20世紀60年代開始對剝皮裝置進行自主研究。在六七十年代主要 是對國外產(chǎn)品的仿制,到了8O年代則主要針對關(guān)鍵零部件學習,9O年代以后我 國對剝皮機的研究已經(jīng)有了長足的發(fā)展。目前市場上玉米剝皮機主要有兩大類 型:一是單獨小型玉米剝皮機。二是和玉米聯(lián)合收割機相組裝的玉米剝皮裝置。在6O年代,中國農(nóng)機院首先研制出型號為6YBS一2型玉米剝皮機。其所用 的動力為3kW三相電機,生產(chǎn)率3t/h,剝凈率80,籽粒落粒率2,籽粒破碎 率1。在7O年代,山東淄博農(nóng)機所研制了6TPJ一4型玉米剝皮機,動力為3kW三 相電機,生產(chǎn)率15 2t/h,剝凈率90,籽粒落粒率5,籽穗破碎率1。這兩種機型剝凈率都較低,玉米籽粒破碎率比較高,所以最終只生產(chǎn)了很少量, 并沒有得到大范圍的推廣。在8O年代,我國開始的對農(nóng)村地區(qū)經(jīng)濟體制進行一系列改革,國內(nèi)各農(nóng)機研究所開始研制適合廣大農(nóng)戶使用的中、小型玉米剝皮機。大約在9O年代,我國對玉米剝皮機的研制有了較大發(fā)展,逐步實現(xiàn)了系列化。目前固定式玉米剝皮機有下列幾種:(1)白城市農(nóng)機所根據(jù)意大利種子玉米剝皮機的實現(xiàn)原理, 研制出全橡膠花瓣型輥玉米剝皮機。但是該機型由于剝皮效果較差還未能投入市場使用。(2)在1993年,吉林農(nóng)機研究所研制了玉米剝皮機,1994年設(shè)計出6YBJ一2型系列玉米剝皮機,投入小批生產(chǎn)。該系列共有六種機型:6YBJ一2型、6YBJ一2A型、6YBJ一2B型、6YBJ 4型、6YBJ一4A、6YBJ一4B型。6YBJ第列玉米剝皮機采用螺旋凸棱全橡膠剝皮輥,生產(chǎn)率為4t/h。剝凈率98,籽粒落粒率15,籽粒破損率85,破碎率、損失率低端傳動比,初定高端傳動比:i高 = 2.42i總 = i高 i低i低 = 1.83.、傳動系統(tǒng)簡圖圖 2-1傳動系統(tǒng)簡圖皮帶和齒輪的傳動比: i= D2 = 242 = 2.42(2-2)帶D1100i= 144 =1.8總降速比:齒80(2-3)i=2.42 1.8=4.36(2-4)直軸的轉(zhuǎn)速為:n電動機in=總1440()= 4.32 =330n/min2-5由于依實驗數(shù)據(jù)得出結(jié)論,剝皮輥最佳轉(zhuǎn)速范圍為 n=300350n/min 所以這一轉(zhuǎn)數(shù)符合要求。這二級減速及傳動系統(tǒng)各部件的尺寸如下:主動帶輪基準直徑:D1 = 100mm從動帶輪基準直徑:D2 = 242mm齒輪 1 的分度圓直徑:d1 = 80mm齒輪 2 的分度圓直徑:d2=140mm 齒輪 3、4 的分度圓直徑 :d3=d4=74mm齒輪 5、6、7、8 的分度圓直徑:d5 = d6 = d7 = d8 = 60mm動力由電動機傳到完成一級減速,再由皮帶傳到1軸上,1軸上有一與皮帶輪同轉(zhuǎn)速的齒輪1,齒輪1與齒輪2嚙合完成二級減速。2軸為主動軸,在其上有三個齒輪。齒輪2與齒輪1嚙合完成降速;齒輪3與齒輪4嚙合實現(xiàn)傳動比為1的傳動;4軸的齒輪7與5軸的齒輪8嚙合實現(xiàn)同速傳動來實現(xiàn)最終的剝皮過程;2軸上的齒輪6 與3 軸上的齒輪5 嚙合實現(xiàn)同速傳動。2 、3 、4 、5 軸的最終轉(zhuǎn)速為330r/min.2.4.2 機架的配置本設(shè)計的機架采用角鋼焊接而成,如圖 2-2 所示:圖 2-2機架為了便于作業(yè)后的移動,在機架底部安裝有四個行走輪,這樣使整機的移動更加方便,更便于生產(chǎn)中的使用。2.4.3 剝皮裝置的確定剝皮裝置是由一對相向轉(zhuǎn)動的剝皮輥抓取和剝除玉米穗的苞葉。剝皮輥與苞葉間的摩擦力必須大于苞葉與穗輥間的鏈接力,為了使苞葉剝凈,在玉米穗沿剝皮輥下滑的同時,自身應(yīng)能轉(zhuǎn)動。在剝皮輥的上方設(shè)有壓送器,使果穗對剝皮輥穩(wěn)定地接觸而避免跳動。壓送器示意圖如圖 2-3:圖 2-3壓送器的示意圖1、剝皮輥長度確定:傳統(tǒng)式玉米剝皮輥長度為 1700 美國甜玉米剝皮機滾長為 1500mm,玉米在剝皮輥上的剝凈率在開始 400mm 內(nèi)剝凈率為 85%,在 600mm 內(nèi)剝凈率為 93%,因此輥長定為 1000mm 可使苞葉的剝凈率在 93%以上。剝皮輥的長度是影響剝凈率的主要參數(shù),為保證剝凈苞葉,剝皮輥應(yīng)有足夠的長度,但過長會引起籽粒脫落和破碎,剝皮輥的直徑應(yīng)不使最小直徑的果穗收擠壓和被抓取為準。2 剝皮輥生產(chǎn)能力的確定:單對剝皮輥生產(chǎn)能力:Q剝=3600quL + Dl g(2-6)ug =s n f600000(2-7)其中:q剝凈率果穗質(zhì)量平均為 0.5KgL果穗長度最大為 250mmug果穗沿剝皮輥移動速度 m/sS剝皮輥螺距 s=900mmN剝皮輥轉(zhuǎn)速 330r/minf滑動綜合系數(shù)試驗得 f=0.05l50mm(3-7)帶入(3-6)有:Q剝=3600qL + Dl s n f600000= 6s n f q100 L + Dl= 6 900 330 0.05 0.5 100250 + 50=1680Kg/h所以兩對輥計算生產(chǎn)率為 3360Kg/h ; 設(shè)計要求為 1500kg/h, 由于1680kg/h1500kg/h 符合設(shè)計要求。由于此機是由人手式喂入, 故實際生產(chǎn)能力大約在每對輥的生產(chǎn)率1500Kg/h 左右,這是經(jīng)過實驗后得出結(jié)論。3.剝皮輥的配置剝皮輥的配置可以從剝皮輥的排列形式、剝皮輥配置度和剝皮輥表面與壓送器頂端配置間隙考慮。1) 兩對或兩對以上的剝皮輥裝置,采用V 型排列和槽型排列兩種方案( 如圖2- 4,2-5所示) 。本機采用槽型排列結(jié)構(gòu)。當采用鑄鐵輥橡膠輥組合時,一般橡膠輥在上,鑄鐵輥在下。圖2-4槽型排列方式圖2-5V型排列方式2) 為使玉米果穗在剝皮機構(gòu)上更利于繞自身軸線回轉(zhuǎn)將苞葉全部剝凈,兩剝皮輥的配置度應(yīng)有一高度差H( 如圖3-5 所示) 。如果H 值過大,則果穗易從輥上滑掉,減少與上剝皮輥的接觸面積; 如果H 過小,則會增大果穗脫粒、破粒的可能性。其極限位置為果穗的中心與下剝皮輥的中心在同一垂直面上,此時最大高度差為Hmax。圖2-6為剝皮輥排列圖,圖2-7為剝皮輥實物圖:H H圖 2-6剝皮輥排列圖= (D )2 / (D + D )其中:maxggsDg 剝皮輥直徑(mm) ;Ds 帶皮玉米穗直徑(mm)圖2-7剝皮輥實物圖3) 剝皮輥表面與壓送器頂端配置間隙應(yīng)略小于玉米果穗直徑,并可調(diào)節(jié)。2.4.4 料斗的設(shè)計:果穗料斗不但有暫存果穗的能力,而且也夠使果穗沿剝皮輥的軸向方向上 進入兩輥所形成的槽型中,在配置上與剝皮輥的傾角相同,均與水平面成11 角, 在長度上按展開 1000mm 設(shè)計,因為考慮到玉米進入到剝皮輥時的方向性,所以將出口處的滑板設(shè)計成與剝皮輥組數(shù)相等的槽型,可能保證每次只能通過一穗 玉米。進料斗是送入玉米的裝置,由于本機采用兩對剝皮輥工作,所以進料斗必 須設(shè)計成雙出口的結(jié)構(gòu)。玉米需自動滑到剝皮輥的方向上進入兩輥形成的槽型 中進行剝皮,這就要求料斗具有一定得傾斜度,經(jīng)參考實驗數(shù)據(jù)選傾斜度為11 。為保證玉米滑向剝皮輥時每次只能通過一穗玉米,可將出口設(shè)計成與剝皮輥組 數(shù)相同的槽型。同時為保證玉米在剝皮過程中受切向力的擠壓導(dǎo)致彈出,在剝 皮輥上方增加壓送裝置,以防止果穗彈出。下料斗是在玉米剝皮結(jié)束后,果穗 畫出的裝置,它可以設(shè)計成任何方便的形狀。圖 2-8 為進料斗的模擬圖:圖 2-8 進料斗2.4.5 機架、連接架的設(shè)計:機架和連接架均由角鋼焊接而成,兩種機型結(jié)構(gòu)相同,僅寬度不同。在滿足要求的前提下具有一定得抗壓能力既可,主要目的是便于組織生產(chǎn),提高通用程度,因此無特別要求。第 3 章傳動部分設(shè)計3.1 果穗與剝皮輥接觸時的受力分析玉米果穗在剝皮輥間的受力,如圖7所示。玉米在兩輥間由于受到兩輥磨擦力Fa,F(xiàn)b而使玉米可以發(fā)生自轉(zhuǎn),在自轉(zhuǎn)的過程中使苞葉進入兩輥互相嚙合的凹槽中,使得苞葉被撕開。玉米果穗的受力分析如圖3-1:圖 3-1玉米果穗受力分析兩輥對玉米產(chǎn)生的兩個摩擦力Fa Fb分別為: Fa = Na fX =0 Nb sin b +Fb cos b -Fa sinq -Fa cosq =0Fb = Nb fY =0Nb cos b +Fb cosq -Fa sin b -Fa sinq =0(3-1)H = 2 R = 22.53cosg = 0.943g = 19.59。 cosj = 0.545j = 56.94。q = 90。- g -j=13.59d = 180。-q - b =113.88b = 180。- 2j -q =52.53Na = Q sin bsin d= 0.868QNb = Q sinqsin d= 0.257Q所以: Fa = Na f= 4.55NFb = Nb f= 1.69N撕破苞葉的抓取力 Fa 大約為F1 = 20同時在自轉(zhuǎn)過程中撕扯力 F 2 = F1 f 2 = 7N而扯斷苞葉所需力 F3 = 100N故 F = F1 + F2 + F3 = 27N ,此時每個軸所承受的力不僅有 F,而且還要有 Fa 與 Fb總P = 21.58=3.16kw 每對剝皮輥消耗的功率: P = F V =1.58kw因此兩對輥消耗的總功率:T = 9.55106=0.46105 N mm(3-2)與皮帶輪同軸的齒輪所需扭矩為(d = 140mm)T = 9.55106=1.85105 N mm(3-3)3.2 皮帶傳動的設(shè)計計算及校核:已知:電動機轉(zhuǎn)速 n=1440r/mini高 =2.42P=3kw1、確定計算功率 pca :工作情況系數(shù) KA = 1.1,所以:pca = KAP = 1.13kw = 3.3kw(3-4)2、選取窄 V 帶帶型:根據(jù) pcan電 由參考文獻10確定選用 SPA 型帶。3、確定帶輪的基準直徑:1試取主動輪直徑 dd= 100mm高由i= n1= dd21n2dd則從動輪的直徑為:dd 2 = i高 dd1 = 2.42100 = 242mm4、驗算帶的速度:V = dn電 1000= p 100 1440 1000 = 7.54 35m/sd1 6060所以:帶的速度符合要求。5、確定窄 V 帶的基準長度 Ld 和傳動中心距 a :0.7(dd1 + dd2 ) a0 120主動輪上的包角符合設(shè)計要求。7、計算窄 V 帶的根數(shù) z:z =pca( p0 + Dp0 ) kakl(3-8)根據(jù)條件n電=1440r / min , dd= 100 mm, i高=2.42查表得:1P0 =1.6kwDP0 = 0.23kw查參考文獻3取 ka = 0.96kl = 0.89z =pca( p0 + Dp0 ) kakl3.3=(1.6 + 0.23) 0.96 0.892(3-9)所以取 v 帶根數(shù) z=28、計算預(yù)緊力 F0 :P 2.5 -1ca kF = qV 2 + 500 a0z(3-10)查表知q=0.07 kg / m0F = 0.07 7.532 + 5003.3 2.5 = 225.25N9、計算作用在軸上的壓軸力 Fp :2 0.96 -1(3-11)F = 2z sin a = 2 2sinp2159.522= 302N(3-12)10、帶輪結(jié)構(gòu)設(shè)計(1) 帶輪的材料選為鑄鐵選 HT250(2)結(jié)構(gòu)選擇:大小帶輪都選用腹板式的帶輪。11、皮帶采用自動張緊或定期張緊。3.3 齒輪的設(shè)計計算3.3.1 d=60mm 的齒輪計算和校核d=60mm 的齒輪模數(shù)的選?。簃 其中: T = 0.462105 N mmKt = 1.3jd = 0.4YFa = 2.3(3-13)YSa = 1.1Fs = KFN dS= 0.9 680 = 437.14Mpa1.4由上式對齒數(shù)進行試選:選取 Z=24m = 2.2mm由m 2.2mm圓整后可取 m=2.5幾何尺寸:因為分度圓直徑 d=60mm,模數(shù) m=2.5h* = 1c* = 0.25a = 20d = d= mz= 60mma中心距:a = 1 (d22 + d2121) = 1 (60 + 60) = 60mm 2ma齒頂圓直徑: d= d + 2mh* = 65mmda = da = 65mm12d= d= d - 2m(h* + c* ) = 53.75mmf1f21a對于d = 60mm 的齒輪進行校核:a. 按要求選該齒輪材料、齒輪精度、齒輪類型、及齒數(shù)(1) 材料選擇??紤]此齒輪振動沖擊較大,選大小齒輪材料為 45 鋼(調(diào)質(zhì))硬度為 240HBS,表面淬火,齒形變形不大,不需磨削。(2) 由于剝皮機為一般性工作,轉(zhuǎn)動速度不高,所以對精度要求不高,故選用8 級精度傳動(GB10095-8)(3) 按傳動方案,選用直齒輪傳動。(4)選齒數(shù) z1 = z2 = 24b. 按接觸強度設(shè)計和校核:(1)根據(jù)公式:2kT u +1 zdt 2.323 t 1 E (3-14)jdu s H 選取公式內(nèi)數(shù)值:載荷系數(shù): Kt = 1.3計算扭矩:T1 = 95.5 105P N = 0.462 105 N mm由參考文獻13選取齒輪寬系數(shù)jd =0.5由參考文獻9選取材料的彈性影響系數(shù): zE = 190MPa由參考文獻 13 按齒面硬度中間值 52HRC 查得齒輪接觸疲勞極限1s H lim= 1210MPa1由參考文獻13查得疲勞壽命系數(shù) KHN = 0.88計算應(yīng)力循環(huán)次數(shù): N = 60n jL= 609601(2830015) = 4.1510911h計算接觸疲勞強度需用應(yīng)力 取失效概率 1%,安全系數(shù) S=1Hs 1= KHN s H lim11s= 1064MPa(2) 計算試計算齒輪分度圓直徑dt1 :2kT u +1 z1.3 0.462105 1+1 190 2d 2.323 t 1 E = 2.323 = 59.32mmtjdu s H 0.51 1064 計算圓周速度 v: v = p dn60v = p 60330 = 1.04m / s 601000計算齒寬 b :b = jd dt1 = 0.559.32 = 29.66mm 取 b=30mm計算齒寬與齒高之比 b/h:模 數(shù) mt = 2.5kv = 1.12 齒高h = 2.25mt = 2.25 2.5 = 5.625齒寬齒高之比 b = 29.66 = 5.27h5.625計算載荷系數(shù):由參考文獻13查得系數(shù): kv = 1.12直齒輪kA Ft b 100N m由參考文獻13查得 kHa= kFa= 1.1由參考文獻13查得使用系數(shù) kA = 1由參考文獻13查得 kH b = 1.43由參考文獻13查得 kF b = 1.37k = kAkvka kH b= 11.121.11.13 = 1.72(3-15)按實際載荷系數(shù)校正算得分度圓直徑:kkd1 = dt1 3t= 59.32= 60mm(3-16)計算模數(shù) m:m = d1z1= 60 = 2.5mm 24c. 按齒根彎曲疲勞強度設(shè)計:m 彎曲強度的設(shè)計公式為:(3-17)(1) 確定公式內(nèi)的各計算數(shù)值:彎曲疲勞強度極限:由參考文獻11查得齒輪的彎曲疲勞強度極限s FE = 450MPa彎曲疲勞壽命系數(shù)YFa = 2.3計算彎曲疲勞許用應(yīng)力取彎曲疲勞安全系數(shù) S=1.4計算載荷系數(shù) K:o= kFN sFS= 0.9 680 = 437.14MPa 1.4k = kAkvka kFb= 11.121.1 2.3 = 2.83查取應(yīng)力校正系數(shù)由參考文獻11可查得YSa = 1.1 ja = 0.4T = 0.462 105 N mmja = 0.4z = 24(2) 設(shè)計計算m = 2.38(3-18)對此計算結(jié)果,由齒面接觸疲勞強度計算的模數(shù),由于齒輪模數(shù) 的大小主要取決于彎曲強度所決定的承載能力,而齒面接觸疲勞強度所決定承載能力,僅與齒輪直徑有關(guān),可取由彎曲強度算得模數(shù) 2.38,就近圓整 m=2.5,計算分度圓直徑為d1 = 603.3.2 對于d = 74mm 齒輪的計算及校核a. 選定齒輪類型、精度等級、材料及齒數(shù)(1) 按傳動方案選用直齒輪傳動。(2) 考慮齒輪較大,故大小齒輪都選用硬齒面。由參考文獻3選得大小齒輪材料均為 45 鋼(調(diào)質(zhì)),并經(jīng)調(diào)質(zhì)表面淬火,齒面硬度 240HBS。(3) 選取精度等級,因采用表面淬火,輪齒變形不大,不需磨削,故初選 8 級精度。(4)選齒數(shù) z1 = 31 z2 = 31b. 按齒面接觸強度設(shè)計:由設(shè)計計算公式進行計算,即:2kT u +1 zdt 2.323 t 1 E jdu s H (3-19)(1) 確定公式內(nèi)的各計算數(shù)值:載荷系數(shù): Kt = 1.3 T1= 9.55106= 9.55106 0.161330= 0.9105 N mm由參考文獻13選取齒輪寬系數(shù)jd =0.5由參考文獻13選取材料的彈性影響系數(shù): zE = 190MPa 由參考文獻 13 按齒面硬度中間值 52HRC 查得齒輪接觸疲勞極限1s H lim= 1210MPa計算應(yīng)力循環(huán)次數(shù): N = 60n jL= 609601(2830015) = 4.1510911h由參考文獻13查得接觸疲勞強度壽命系數(shù):kHN= kHN 2 = 0.91計算接觸疲勞許用應(yīng)力: 取失效概率 1%,安全系數(shù) S=1Hs 1= KHN s H lim11s= 1064MPa(2) 計算計算齒輪分度圓直徑dt1 :2kT u +1 z1.3 0.9105 1+1 190 2d 2.323 t 1 E = 2.323 = 69.45mmtjdu s H 0.51 1064 計算圓周速度 V: v = p dn60v = p 69.45 330 = 1.199m / s 601000計算齒寬 b:b = jd dt1 = 0.5 69.45 = 34.725mm計算齒寬與齒高之比 b/h:模數(shù)mt1= dt1z1= 2.24kv = 1.12齒高h = 2.25mt = 2.25 2.24 = 5.04mm齒寬齒高之比 b = 34.725 = 6.89h5.04計算載荷系數(shù):根據(jù) V=3.44m/s,8 級精度由參考文獻13查得系數(shù): kv = 1.12直齒輪kA Ft b 100N m由參考文獻13查得 kHa= kFa= 1.1由參考文獻13查得使用系數(shù) kA = 1由參考文獻13查得 kH b = 1.43由參考文獻13查得 kF b = 1.37k = kAkvka kH b= 11.121.11.13 = 1.72按實際載荷系數(shù)校正所行分度圓直徑:=kkd1dt1 3t= 69.45 31.721.3= 74mm(3-20)計算模數(shù): m = d1z1= 74 = 2.5mm 31c.按齒根彎曲疲勞強度設(shè)計:彎曲強度的設(shè)計公式為:m (3-21) 由參考文獻6查得齒輪的彎曲疲勞強度極限:s FE= 680MPa 由參考文獻6查得彎曲疲勞壽命系數(shù):kFN1 = kFN 2 = 0.88計算彎曲疲勞許用應(yīng)力:F1取彎曲疲勞安全系數(shù)S = 1.4s = kFN1 s FES= 0.88 680 = 427.41MPa 1.4計算載荷系數(shù): k = kAkvka kFb= 11.121.11.37 = 1.69 查取齒形系數(shù):參考文獻7查得:YSa1 = YSa2 = 1.55 查應(yīng)力校正系數(shù):由機械設(shè)計P197 表 105 查得:YFa1 = YFa2 = 2.63計算: m = 2.38對比計算結(jié)果,由于齒輪模數(shù) m 的大小主要取決于彎曲強度所決定的承載能力,而齒面接觸疲勞強度所決定的承載能力僅與直徑有關(guān),由齒面接觸疲勞強度計算的模數(shù) m 略小齒根彎曲疲勞強度計算的模數(shù),可取由彎曲強度算得模數(shù) 2.38mm,就近圓整為 2.5mm,按接觸強度算得分度圓直徑: d1 = d2 = 74mm1z = d1 m= 742.5= 313.3.3 對于d = 80mm d = 140mm 齒輪的計算及校核:第二級降速機構(gòu)兩齒輪的設(shè)計:降速比: i = 1.8大齒輪轉(zhuǎn)速為: n1 = 594r / min小齒輪轉(zhuǎn)速為:n = 594 = 330r/min21.8傳動功率:p = 665wa. 選定齒輪類型、精度等級、材料及齒數(shù)(1) 選用直齒輪傳動。(2) 考慮減速機構(gòu)振動較大,在設(shè)計強度滿足的前提下,盡量選較大一些模數(shù), 齒面材料也選取硬度稍微大一些。大小齒輪均為 45 鋼,并調(diào)質(zhì)及表面淬火,齒面硬度 4855HRC。(3) 選取精度等級:因采用表面淬火,輪齒的變形不大,故選 8 級精度。(4) 試選小齒輪齒數(shù) z1 = 29z2 = ib. 按齒面接觸強度設(shè)計:2kT u +1 zdt 2.323 t 1 E jdu s H (3-22)(1)確定公式內(nèi)的各計算數(shù)值 : 試選載荷系數(shù) Kt = 1.3計算扭矩: T = 9.55106 P n = 9.55106 0.665300 = 2.1105 N mm由參考文獻7選取齒輪寬系數(shù)jd =0.5由參考文獻7選取材料的彈性影響系數(shù): zE = 190MPa 由參考文獻 7 按齒面硬度中間值 52HRC 查得齒輪接觸疲勞極限1s H lim= 1210MPa應(yīng)力循環(huán)次數(shù): N = 60n jL = 609601(2830015) = 4.1510911hN4.151099N2 = 1 = 2.3110i1.8參考文獻7查得接觸疲勞壽命系數(shù):1KHN = 0.88KHN 2 = 0.89計算接觸疲勞需用應(yīng)力: 取失效概率為 1% ,安全系數(shù) S=1Hs 1= KHN s H lim11s外文文獻譯文和原文譯文:圖 2.4.9 三個轉(zhuǎn)子觀察接近傳感器:兩個轉(zhuǎn)子橫向振動測量傳感器正交的方向和一鍵相位傳感器。示波器屏幕顯示橫向振動波形數(shù)據(jù)從兩個側(cè)面以時間為基礎(chǔ)的傳感器。鍵相位點的是波形上疊加。每個轉(zhuǎn)子旋轉(zhuǎn)的的鍵相位傳感器提供了序列空白/亮點。識別的方向繞在示波器屏幕上: 由于信號 X 的振幅峰值的發(fā)生較早比峰值的振幅 Y(在時間上),所述轉(zhuǎn)子的軌道是在從 X 到 Y 的方向上,獨立于轉(zhuǎn)子的旋轉(zhuǎn)方向。還提供了顯示的信號的絕對相位,以及垂直與水平運動的相對相位,相對垂直頻率與水平,并與旋轉(zhuǎn)速度。-19 -圖 2.4.10示波器的屏幕顯示與轉(zhuǎn)子的軌道運動。未經(jīng)濾波的軌道是一個 放大的轉(zhuǎn)子的中心線的橫向運動路徑。它的形狀是一個反映會發(fā)生什么的轉(zhuǎn)子。需要注意的是,如果將示波器設(shè)置在直流(dc),則軌道中心表示所述轉(zhuǎn)子的中 心線位置(例如軸承間隙內(nèi),在示波器上可以打上屏)。如果示波器上設(shè)置交流(交流電),那么軌道中心將總是會出現(xiàn)在屏幕中間。從序列中的空白亮點,創(chuàng)建疊加鍵相位信號,轉(zhuǎn)子的旋轉(zhuǎn)方向與軌道方向可以被確定。請注意,沒有關(guān) 于這個序列建立公約; 在每一個特定的情況下,它有相應(yīng)的時基波(線索轉(zhuǎn)子鍵相位缺口與投影有關(guān)示波器約定)單獨進行調(diào)查。多頻振動分量,已過濾的時基信號的絕對相位,提供接近換能器的轉(zhuǎn)子觀察,“滯后”(常規(guī)正號),一個 空白(或亮)的鍵相器的點從一開始作為相位測量第一正峰值的信號。過濾組 件的轉(zhuǎn)子的橫向振動的相位表示旋轉(zhuǎn)機械中的最重要的診斷工具。鍵相傳感器 的轉(zhuǎn)子橫向振動數(shù)據(jù)聯(lián)系到其旋轉(zhuǎn)運動:監(jiān)測旋轉(zhuǎn)機械振動圖 2.4.11使用鍵相位標記,以確定轉(zhuǎn)子軌道軌道旋轉(zhuǎn)頻率比,需要注意的是兩個連續(xù)的鍵相位標記之間有一個旋轉(zhuǎn)的轉(zhuǎn)子。 旋轉(zhuǎn)振動頻率比的評價(圖 2.4.11)。鍵相傳感器所提供的信息是極其寶貴的轉(zhuǎn)子動平衡程序,在診斷其他各種機器故障,如轉(zhuǎn)子固定部分摩擦或轉(zhuǎn)子開裂是無價的。2.4.2 傳感器的選擇傳感器安裝在一臺機器上,是當今先進的心臟計算機監(jiān)控系統(tǒng)。機器監(jiān)控系統(tǒng)傳感器的選擇取決于機器上的建設(shè),估計類型的振動故障和參數(shù),評估故障,機器的內(nèi)部和外部環(huán)境,轉(zhuǎn)速范圍廣,預(yù)期機動態(tài)/振動行為。機器結(jié)構(gòu)強加限制在傳感器安裝。環(huán)境參數(shù),如溫度、工作流體壓力、腐蝕性和/或輻射表示傳感器操作條件。預(yù)期的機器的動態(tài)行為,其可能的故障類型,回答問題什么參數(shù)來衡量,什么是振動信號電平,信號噪聲比和頻率范圍。它必須被很好地理解,旋轉(zhuǎn)機械的轉(zhuǎn)子的任何表示源振動。通過測量轉(zhuǎn)子的振動,得到的直接信息。當測量外殼振動速度傳感器或加速度傳感器,振動的信息是間接的,扭曲的外殼傳遞。這也是不完整的,不能得到轉(zhuǎn)子的軌道和內(nèi)間隙的中心線位置,在低頻率范圍內(nèi)的信號的分辨率差。一個選擇的傳感器和進一步的數(shù)據(jù)管理系統(tǒng)可以在一個廣泛的基礎(chǔ),通常, 除以旋轉(zhuǎn)機械分類,比如“關(guān)鍵的“基本”和“平衡的植物”(通用機器) 。不能幸免,大型和昂貴的機器,以及那些機器將創(chuàng)建一個重大危險源或生產(chǎn)損失, 如果他們突然變得不起作用,被列為關(guān)鍵設(shè)備。因此,主要的因素是,一個危險 的生產(chǎn)失敗的一個給定的機器。關(guān)鍵設(shè)備必須要小心使用最好的上線系統(tǒng)。另 一方面,很容易更換的通用的機器可以被周期性地監(jiān)視與可接受的結(jié)果,使用 便攜式儀器。后者可能代表接近傳感器集成到機器的振動數(shù)據(jù)的簡單收藏家, 或者他們可能會周期性地安裝在機器外殼上的速度傳感器或加速度計。2.4.3 機床操作模式的數(shù)據(jù)采集與數(shù)據(jù)處理格式安裝在旋轉(zhuǎn)的機器的上的的在線監(jiān)測系統(tǒng)包括換能器和的數(shù)據(jù)采集和處理 硬件和軟件。這種監(jiān)測系統(tǒng)的最終產(chǎn)品應(yīng)該是人性化,充分格式化,便于在機 器健康方面的解釋。存在內(nèi)容詳實的介紹了各種格式的機器的震動和處理數(shù)據(jù), 而應(yīng)收集在五個不同的機器運行狀態(tài)如下:1. 在靜止: 這被稱為為靜態(tài)數(shù)據(jù),提供了在軸承內(nèi)部的轉(zhuǎn)子靜止位置,并可能也揭示了任何外部振動源的存在下。靜止時,各種機器元素和毗鄰的建筑,如管道,結(jié)構(gòu)共振可以進行測試,采用模態(tài)分析方法。2. 在慢速輥,即,在低轉(zhuǎn)速(通常小于 10的第一余額共振速度)在該狀態(tài)下, 轉(zhuǎn)子的動態(tài)響應(yīng)主要是由于在轉(zhuǎn)子的弓和/或電氣和機械的跳動。慢搖數(shù)據(jù)提供 為轉(zhuǎn)子的直線度檢查,和振子/轉(zhuǎn)子表面調(diào)節(jié)檢查。3. 在啟動時:在這段短暫的狀態(tài)振動捕獲的數(shù)據(jù)是非常重要的。它有助于確定慢輥的速度范圍內(nèi),共振速度,振動模式,自激振動的存在下,并提供了對模態(tài)的有效阻尼和同步的放大系數(shù)的信息。獲得最佳的數(shù)據(jù),如果啟動的角加速度為良好的分辨率的數(shù)據(jù)與由瞬態(tài)過程的轉(zhuǎn)動速度和低的污染是足夠小的。然而,請注意,如果機器顯示出高的振動加速度緩慢更可能危及其健康,振動源要被淘汰。瞬態(tài)過程的數(shù)據(jù)顯示格式是整體橫向振動的振幅,極性和過濾的 1 波特圖并過濾其他頻率成分(圖 2.4.13 到 2.4.16),與轉(zhuǎn)速轉(zhuǎn)子中心線位置(圖2.4.17), 頻譜級聯(lián)( 圖 2.4.18 和 2.4.19 ),轉(zhuǎn)子橫向振動頻譜瀑布(圖2.4.20 見 2.4.5 段)。全方位改善了簡單的獨立光譜波形完整顯示(圖 2.4.21 和 2.4.22),.在慢速輥,即,在低轉(zhuǎn)速(通常小于 10的第一余額共振速度) 在該狀態(tài)下,轉(zhuǎn)子的動態(tài)響應(yīng)主要是由于在轉(zhuǎn)子的弓和/或電氣和機械的跳動。 慢搖數(shù)據(jù)提供為轉(zhuǎn)子的直線度檢查,和振子/轉(zhuǎn)子表面調(diào)節(jié)檢查。兩個 XY 傳感器(參見 2.4.5 節(jié))。此信息有助于確定故障的根本原因,產(chǎn)生特定的反應(yīng)模式。全頻譜圖可伴有轉(zhuǎn)子軌道和/或時基波形序列完整的顯示(圖 2.4.21 和 2.4.22) 監(jiān)測旋轉(zhuǎn)機械振動圖2.4.12 極地塊轉(zhuǎn)子無補償(a)和(b)補償同步(1)振動數(shù)據(jù)在啟動一個橫向距離提供位移傳感器。在補償情節(jié),慢滾向量已經(jīng)矢量地減去。開始的情節(jié)已被移動到零點。該地塊上的數(shù)字代表以轉(zhuǎn)的轉(zhuǎn)速。圖2.4.13典型波德圖(1)過濾無償振動轉(zhuǎn)子的同步,4.在操作的速度,即,在機器的動態(tài)平衡:振動信息簡稱為穩(wěn)態(tài)數(shù)據(jù)是最有意義的處理時,使用時間趨勢的格式的,以評估任何惡化的動態(tài)行為。靜態(tài)數(shù)據(jù),提供了在軸承內(nèi)部的轉(zhuǎn)子靜止位置,并可能也揭示了任何外部振動源的存在下。靜止時,各種機器元素和毗鄰的建筑,安裝在旋轉(zhuǎn)的機器的上的的在線監(jiān)測系統(tǒng)包括換能器和的數(shù)據(jù)采集和處理硬件和軟件。一個選擇的傳感器和進一步的數(shù)據(jù)管理系統(tǒng)可以在一個廣泛的基礎(chǔ),通常,除以旋轉(zhuǎn)機械分類,比如“關(guān)鍵的“基本”和“平衡的植物”(通用機器) 。不能幸免,大型和昂貴的機器,以及那些機器將創(chuàng)建一個重大危險源或生產(chǎn)損失,如果他們突然變得不起作用,被列為關(guān)鍵設(shè)備。這種監(jiān)測系統(tǒng)的最終產(chǎn)品應(yīng)該是人性化,充分格式化,便于在機器健康方面的解釋如管道,結(jié)構(gòu)共振可以進行測試上面的運行速度的監(jiān)測數(shù)據(jù)可以顯示在時基的波形,軌道(圖2.4.23),整體最大和最小振幅(圖2.4.24),瀑布圖(圖2.4.25),在趨勢格式的趨勢,格式包括轉(zhuǎn)子中心線位置(圖2.4.26),轉(zhuǎn)子振幅和相位.圖2.4.14典型的波特圖轉(zhuǎn)子同步(1)過濾補償和無償?shù)恼駝訄D2.4.15轉(zhuǎn)子的垂直和水平同步1x響應(yīng)波特圖表示支持各向異性(分裂共振),在低轉(zhuǎn)速的結(jié)構(gòu)共振。圖2.4.16極地地塊的轉(zhuǎn)子1x振動,測量內(nèi)側(cè)和外側(cè)的位置,覆蓋兩種模式: 平移和樞轉(zhuǎn)的轉(zhuǎn)子。圖2.4.17 兩個接近傳感器配置在XY測量,并繪制隨時間變化,標志著轉(zhuǎn)子轉(zhuǎn)速和機器負荷轉(zhuǎn)子中心線位置。本特利內(nèi)華達公司診斷服務(wù)的禮貌。圖2.4.18振動時基信號從一個傳感器獲得的頻譜分析圖2.4.19頻譜級聯(lián)情節(jié)轉(zhuǎn)子振動參展1x和流體鞭振動。奇數(shù)高次諧波,諧波和/差也出現(xiàn)在頻譜中。圖 2.4.20(一)全光譜級聯(lián)包括流體旋轉(zhuǎn)(參見第 4 章第 4.2 節(jié)),(二)全光譜級聯(lián)輕輕摩擦轉(zhuǎn)子在滑行過程中伴隨著一些轉(zhuǎn)子軌道(見第 5.6 章的轉(zhuǎn)子振動 5 原文:Figure 2.4.9 Three rotor-observing proximity transducers: two rotor lateral vibration-measuring transducers in orthogonal orientation and one Keyphasor transducer. Oscilloscope screen showing lateral vibration time-base waveform data from two lateral transducers. Keyphasor dots are super-imposed on the waveforms. The Keyphasor transducer provides the sequence of blank/bright dots at each rotor rotation. Identification of the direction of orbiting on the oscilloscope screen: Since the amplitude peak of the signal X occurs earlier (in time) than the peakof amplitude Y, the rotor orbiting is in direction from X to Y, independently of the direction of rotor rotation. The displayed signal provides also absolute phases, as well as relative phases of vertical versus horizontal motion, relative vertical frequency versus horizontal and versus rotational speed. the rotor orbiting is in direction from X to Y, independently of the direction of rotation. The signal provides also absolute phases, as well as relative phases of vertical versus horizontal motion, relative vertical frequency versus horizontal and versus rotational speed.Figure 2.4.10 Oscilloscope screen with the rotor orbital motion display. The unfiltered orbit is a magnified path of the rotor centerline lateral motion. Its shape is a reflection of what happens to the rotor. Note that if the oscilloscope is set on direct current (dc) then the orbit center indicates the rotor centerline position (for instance within the bearing clearance, which can be marked on the oscilloscope screen). If the oscilloscope is set on ac (alternating current) then the orbit center will always occur in the middle of the screen. From the sequence of blank bright spots, created by superposed Keyphasor signals, the direction of rotor orbiting versus the direction of rotation can be determined. Note that there is no established convention about this sequence; in each particular case it has to be investigated individually on the corresponding time base waves (the clues are related to rotor Keyphasor notchversus projection and to oscilloscope convention).frequency-multiple vibration components. The absolute phase on a filtered time- base signal, provided by a rotor-observing proximity transducer, is measured as a phase lag (conventionally with positive sign) from the start of a blank (or bright) Keyphasor dot to the first positive peak of the signal. The phases of filtered components of rotor lateral vibration represent one of the most important diagnostic tools in rotating machinery. The Keyphasor transducer ties the rotor lateral vibration data to its rotational motion: it servesFigure 2.4.11 Using rotor orbits with Keyphasor marks to determine orbiting-to- rotation frequency ratios. Note that between two consecutive Keyphasor marks there is one rotation of the rotor. for the evaluation of vibration-to-rotation frequency ratio (Figure 2.4.11). The informa-tion provided by the Keyphasor transducer is extremely valuable for rotor balancing procedures (see Section 6.1of Chapter 6),and is priceless in diagnosing various other machine malfunctions, such as rotor-to- stationary part rubs or rotor cracking.2.4.2 Transducer SelectionThe set of transducers installed on a machine is the heart of todays sophisticated computerized monitoring systems. A selection of transducers for the machine monitoring system depends on the machine construction, estimated types of vibrational malfunctions and parameters, which assess the malfunction, machine internal and external environ-ment, rotational speed range, and the expected machine dynamic/vibrational behavior. The machine structure imposes limitations parameters, such as temperature, working fluid pressure, corrosiveness, and/or radiation indicate the transducer operational conditions. The expected machine dynamic behavior and its possible malfunction types answer the questions regarding what parameters to measure, and what are vibration signal levels, signal-to-noise ratioand frequency range. It has to be well understood that the rotor of any rotating machine represents a source of vibration. By measuring the rotor vibrations, direct informatio is obtained. When measuring casing vibrations using velocity transducers or accelerometers, the vibrational information is indirect, distorted by casing transmissibility. It is also incomplete, as rotor orbits and centerline positions within clearances cannot be obtained, and the signal resolution in the low frequency range is poor.A selection of transducers and further data management systems can be made on a broad basis, generally, by dividing rotating machinery into categories, such as critical, essential, and balance-of-plant (general purpose machines). Large and expensive machines, which cannot be spared, as well as those machines which would create a major hazard or production loss if they suddenly became inoperative, are classified as critical machines. The main factor is, therefore,a vulnerability of production to failure of a given machine. The critical machines have to be carefully instrumented with the best on-line systems. On the other hand, the easily replaceable general-purpose machines may be periodically monitored with acceptable results, using portable instruments. The latter may represent simple collectors of vibrational data from proximity transducers incorporated into the machine, or they may be velocity transducers or accelerometers periodically installed on the machine housings.2.4.3 Machine Operating Modes for Data Acquisition and Data Processing FormatsThe online monitoring systems installed on rotating machines include transducers and data acquisition and processing hardware and software. The end product of such monitoring systems should be user-friendly, and adequately formatted for easy interpretation in terms of the machine health. There exist avariety of informative presentation formats of the machine vibration and process data, which should be collected during five different machine operational states as follows:1. At rest: The data, which is referred to as static data, provides the rotor static position within the bearings, and may also reveal the presence of any external source of vibration. At rest, the structural resonances of various machine elements and adjoining constructions, such as pipelines, can be tested, using modal analysis methods.2. At slow roll, i.e., at low speed (typically less than 10% of the first balance resonance speed). In this condition, the rotor dynamic response is mainly due to rotor bow and/or electric and mechanical runout. The slow roll data serves for the rotor straightness check, and for the transducer/rotor surface conditioning check-up. The slow roll data are vital in rotor crack diagnosis and in the machine balancing process (see Sections 6.1 and 6.5 of Chapter 6). At the slow roll speed, the 1 slow roll vector can be identified and then used to compensate Bode and polar plots obtained during startup or shutdown of the machine (Figure 2.4.12).3. At start-up: Vibrational data captured during this transient state is extremely important. It helps to identify slow-roll speed range, resonance speeds, vibration modes, presence of self-excited vibrations, and provides information on modal effective damping and synchronous amplification factors. The best data is obtained if the start-up angular acceleration is small enough for good resolution of data versus rotational speed and low contamination by transient processes. Note, however, that if the machine exhibits high vibrations the slow acceleration may even more jeopardize its health; the source of vibrations have to be eliminated.The data display formats for transient processes are overall lateral vibrationamplitudes, polar and Bode plots of filtered1 and filtered other frequency components(Figures2.4.13 to2.4.16), rotor centerline position versus rotational speed (Figure 2.4.17), spectrum cascade (Figures 2.4.18 and 2.4.19), and rotor lateral vibration full spectrum cascades (Figure 2.4.20; see subsection 2.4.5). The full spectrum is an improvement over simple independent spectra from two XY transducers (see Section 2.4.5). It provides better insight into the rotor orbital path and orbiting direction of vibration frequency components. Thisinformation helps in identification of the root cause of a malfunction generating a specific response pattern. The fullspectrumplotsmaybe accompanied by a sequence of rotor orbits and/or time-base waveforms for complete display (Figures 2.4.21 and 2.4.22).Figure 2.4.12 Polar plots of rotor uncompensated (a) and compensated (b) synchronous (1) vibration data during start-up provided by one lateral proximity displacement transducer. In the compensated plot, the slow roll vector has been vectorially subtracted. The beginning of the plot has been moved to zero point. The numbers on the plots represent rotating speed measured in rpm.Figure 2.4.13 Typical Bode plot rotor of synchronous (1) filtered uncompensated vibrations.4. At operating speed, i.e., at dynamic equilibrium of the machine: The vibration information referred to as steady-state data is most meaningful when processed using time-trend formats in order to assess any deterioration in the dynamic behavior. The data monitored at the operating speed can be displayed in the time-base waveform, orbit (Figure 2.4.23), overall maximum and minimum amplitude (Figure 2.4.24), waterfall spectrum (Figure 2.4.25), and in trend formats. The trend formats include rotor centerline position (Figure 2.4.26), rotor amplitude and phase .Figure 2.4.14 Typical Bode plot of rotor synchronous (1) filtered compensated and uncompensated vibrations.Figure 2.4.15 Rotor vertical and horizontal synchronous 1 response plots indicating support anisotropy (split resonance) and structural resonances at low rotational speed.Figure 2.4.16 Polar plots of rotor 1 vibrations, measured at inboard and outboard locations, covering two modes of the rotor: translational and pivotal.Figure 2.4.17 Rotor centerline position measured by two proximity transducers in XY configuration and plotted versus time, marking rotor rotational speed and machine load. Courtesy of Bently Nevada Corporation Diagnostic Services.Figure 2.4.18 Spectrum analysis of vibration time-base signal obtained from one transducer.Figure 2.4.19 Spectrum cascade plot of rotor vibrations exhibiting 1 and fluid whip vibrations. Odd higher harmonics and sum/difference harmonics are also present in the spectrum.Figure 2.4.20 (a) Full spectrum cascade of a rotor vibrations including fluid whirl (see Section 4.2 of Chapter 4). (b) Full spectrum cascade of a lightly rubbing rotor during coast down accompanied by some rotor orbits (see Section 5.6 of Chapter 5).
收藏