數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計
數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計,數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計,數(shù)控車床,縱向,進給,導軌,潤滑,機構(gòu),設計
一、設計(論文)內(nèi)容任務:數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計 本道工序內(nèi)容:1.在進行縱向進給系統(tǒng)設計時,電機和絲杠的接合處須采用柔性結(jié)構(gòu),須對電機大小選擇進行校驗計算,對滾珠絲杠直徑進行強度和剛度校和。2.導軌潤滑系統(tǒng)設計需做到潤滑充分,且各潤滑點充分潤滑。二、設計(論文)依據(jù)床身上最大回轉(zhuǎn)直徑 400mm;加工最大長度1000 mm;快移速度 Z軸8 m/ min;X軸4 m/ min;螺距范圍 0.01-12.00 mm;定位精度 Z軸0.04 mm;X軸0.035 mm;重復定位精度 Z軸0.01 mm;X軸0.0075 mm;三、技術(shù)要求本數(shù)控車床設計要求為經(jīng)濟型中檔精度機床,縱向進給傳動要求用伺服電機帶動滾珠絲杠螺母副實現(xiàn)設計精度。絲杠要有安全防護罩。導軌潤滑采用電控自動間隙潤滑,潤滑點包含縱橫向?qū)к壖翱v橫向滾珠絲杠處。四.畢業(yè)設計(論文)物化成果的具體內(nèi)容及要求(具體內(nèi)容參照機械工程系畢業(yè)設計大綱及實施細則的有關(guān)要求填寫)1設計說明書 1份 (不少于1萬字以上)2總裝圖 1份 A03縱向進給系統(tǒng)裝配圖 1張 A04導軌潤滑系統(tǒng)裝配圖 1張 A05床鞍零件圖 1份 A06電機支座零件圖 1張 A17螺母座零件圖 1張 A28滾珠絲杠副零件圖 1張 A39零件圖 19張 A4A2五. 畢業(yè)設計(論文)進度計劃起訖日期工作內(nèi)容備 注33145畢業(yè)實習,收集資料,完成實習報告46420資料整理,擬定設計方案,編寫草稿421430繪制結(jié)構(gòu)草圖并初審 5263繪制工程圖64615編寫設計說明書616620審圖,改圖 621622準備答辯資料623627參加答辯六. 主要參考文獻:1 余良英. 機床數(shù)控技術(shù)改造設計與實例.第1版.北京:機械工業(yè)出版社,19822 李峻勤 ,費仁元. 數(shù)控機床及其使用與維修.北京:機械工業(yè)出版社,19853 楊學桐 ,李冬茹. 我國數(shù)控產(chǎn)業(yè)的現(xiàn)狀與發(fā)展舉措. 中國機械工程,1999(10)108110834陳秀義,施高義.機械設計課程設計.浙江:浙江大學出版社,1995(1)5徐錦康.機械設計.北京:機械工業(yè)出版社,2001(2)6袁國定,朱洪海.機械制造基礎.南京:東南大學出版社,2000(2)7鄭文緯,吳克堅.機械原理.南京:高等教育出版社,19958王辰寶.機械加工工藝基礎. 南京:東南大學出版社,19969 龐懷玉.機械制造工程學. 北京:機械工業(yè)出版社,199810 徐亞明.大型數(shù)控車床的進給系統(tǒng)設計與分析.甘肅:機械制造,1998(6) 七、其他鹽城工學院機械工程系畢業(yè)設計(論文)任務書機械設計制造及其自動化 專業(yè)設計(論文)題目數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計 學生姓名 沈 燕 班 級 材機99(5)班 學 號 B9912003 起訖日期2003.03.27.2003.06.27 指導教師 沙 愛 民 教研室主任 姜 煜 林 系 主 任 徐 文 寬 發(fā)任務書日期 2003 年 3 月 31 日鹽城工學院機械工程系畢業(yè)設計說明書摘要本文主要研究了CA6140經(jīng)濟型中檔精度數(shù)控車床的縱向進給及導軌潤滑機構(gòu)的設計及其改造。本文對數(shù)控車床縱向進給系統(tǒng)的設計與改造方案進行了重點論述,對該機構(gòu)的主要組成部件:滾珠絲杠副、交流伺服電機、聯(lián)軸器等進行了設計計算與選型。其中對滾珠絲杠副、交流伺服電機的設計計算及選型作了詳細論述。進行這一設計主要是為了進一步地提高數(shù)控車床縱向進給機構(gòu)的定位精度,重復定位精度以及改造手動進給裝置,以使其能夠可靠地運行,且能滿足各項性能指標的要求,達到預期的結(jié)果,即滿足設計任務書的要求。最后, 本文還對各個零部件進行了設計,并繪制了全部零件圖以及該數(shù)控車床縱向進給機構(gòu)的裝配圖。此結(jié)構(gòu)簡單可靠,可應用于相似的各類數(shù)控車床上。關(guān)鍵詞: 數(shù)控車床 進給系統(tǒng) 潤滑機構(gòu) AbstractThis article mainly told the research, the designing and transformation on the longitudinal motion system and track lubrication mechanism of CA6140 economic medium precision NC machine. The article made a brilliant exposition on the designing and transformation scheme of the longitudinal motion system and track lubrication mechanism of NC machine. The article also exposed brilliantly the mechanisms mail parts: the ball-race bearing, the servo-electric machine, the coupling and so on. Doing the design is for the sake of improving the site precision, duplicate site precision and transformating the Longitudinal motion system .So it can work credibility, meet the request of every property norm, come to the expected consequence, and fulfill the require of design assignment list. Besides, the author has designed and drawed all of mechanism parts, and also drawed the assemble chart. This mechanism is simple and reliable, it can apply to every similar NC machine. Key words: NC machine Longitudinal motion system Track lubrication mechanism 目 錄摘要Abstract0 前言11總體設計方案.31 1總體設計方案論證311 1驅(qū)動元件12 2傳動機構(gòu)11 3聯(lián)軸器11 4潤滑方式1 2總體設計方案的確定612 1縱向進給系統(tǒng)的改造2縱向進給機構(gòu)的設計與計算721已知條件.722滾珠絲桿副主要參數(shù)的確定.7221設計步驟222設計計算簡況23伺服電機的選擇10231選用螺桿驅(qū)動方式的伺服電機232求換算到電機軸上的負荷力矩234求換算到電機軸上的慣性力矩235加減速力矩的計算236實際力矩的計算小結(jié).12致謝.13參考文獻.14附件清單.15鹽城工學院機械工程系畢業(yè)設計說明書0前言一我國數(shù)控產(chǎn)業(yè)的現(xiàn)狀 當前,我國的數(shù)控系統(tǒng)正處在由研究開發(fā)階段向推廣應用階段過渡的關(guān)鍵時期。也是由封閉型系統(tǒng)向開放型系統(tǒng)過渡的時期。我國數(shù)控系統(tǒng)在技術(shù)上已趨于成熟,在重大關(guān)鍵技術(shù)上(包括核心技術(shù)),已達到國外先進水平。目前,已新開發(fā)出數(shù)控系統(tǒng)80種。自“七五”以來,國家一直把數(shù)控系統(tǒng)的發(fā)展作為重中之重來支持,現(xiàn)已開發(fā)出具有中國版權(quán)的數(shù)控系統(tǒng),掌握了國外一直對我國封鎖的一些關(guān)鍵技術(shù)。二數(shù)控產(chǎn)業(yè)發(fā)展面臨的問題當前,我國數(shù)控機床產(chǎn)業(yè)面臨的挑戰(zhàn)是國內(nèi)市場占有率偏低。據(jù)有關(guān)資料表明,1999年國產(chǎn)數(shù)控機床的市場占有率僅為38.88%。造成這種嚴峻的形勢,除客觀原因外,主要是產(chǎn)品的質(zhì)量、可靠性不過硬?!笆濉逼陂g,我國機械制造工業(yè)正朝著精密化、柔性化、集成化、自動化、智能化方面迅速發(fā)展,國內(nèi)數(shù)控機床需求強勁,我國數(shù)控機床產(chǎn)業(yè)適逢極好的發(fā)展機遇。然而,我國加入后,國外生產(chǎn)的數(shù)控機床將會更多的進入我國市場,市場競爭更為激烈。提高國產(chǎn)數(shù)控機床市場占有率,關(guān)鍵在于提高質(zhì)量和可靠性。幾年來,經(jīng)過對國內(nèi)外數(shù)控機床的機械結(jié)構(gòu)剖析和使用性能的調(diào)研,探索和總結(jié)了數(shù)控機床機械結(jié)構(gòu)設計和制造的新技術(shù)?,F(xiàn)時主要存在有以下幾個問題: 1缺乏產(chǎn)業(yè)規(guī)模 2缺乏發(fā)展數(shù)控產(chǎn)業(yè)的政策和技術(shù)配套體系 3缺乏技術(shù)創(chuàng)新,產(chǎn)品更新和產(chǎn)業(yè)調(diào)整的內(nèi)在動力 4面臨國外強手競爭的巨大壓力三數(shù)控機床簡介數(shù)控機床是一種高科技的機電一體化產(chǎn)品,是綜合應用計算機技術(shù)、精密測量及現(xiàn)在機械制造技術(shù)等各種先進技術(shù)相結(jié)合的產(chǎn)物。數(shù)控機床作為實現(xiàn)柔性制造系統(tǒng)、計算機集成制造系統(tǒng)和未來工廠自動化的基礎已成為現(xiàn)在制造技術(shù)中不可缺少的生產(chǎn)手段,是機電一體化技術(shù)的重要組成部分。隨著科學技術(shù)的迅速發(fā)展,數(shù)控技術(shù)的應用范圍日益擴大。數(shù)控機床已成為現(xiàn)在機械制造業(yè)中的主要技術(shù)裝備。四經(jīng)濟型數(shù)控車床的改造 縱橫向進給系統(tǒng)原機床掛輪機構(gòu)、進給箱、溜板箱、滑動絲杠,光杠等全部拆除,縱、橫向以伺服電機作為驅(qū)動元件,經(jīng)一級齒輪減速轉(zhuǎn)矩增大后,由滾珠絲杠傳動??v向進給機構(gòu):縱向伺服電機為P20B200DxS,2.0的交流伺服電機,滾珠絲杠仍利用原絲杠位置,其螺母副通過托架安裝在床鞍底部,滾珠絲杠兩端加裝接套、接桿及支承,與床身尾部步進電機相聯(lián)接。伺服電機經(jīng)減速后,減速器輸出軸用套筒聯(lián)軸器與絲杠直接聯(lián)接,這種結(jié)構(gòu)簡單,徑向尺寸小,可防止被聯(lián)接軸的位移和偏斜所帶來裝配困難和附加應力。 改造后的數(shù)控機床應有以下發(fā)展方向:單一的數(shù)字控制應向數(shù)控中心發(fā)展,數(shù)控機床總體布局更加合理,機床控制系統(tǒng)的控制和運算功能更進一步加強,機床的伺服系統(tǒng)采用交流數(shù)字伺服系統(tǒng)代替直流伺服系統(tǒng),編程更趨合理化,加工工藝更趨簡單化90%機床的檢測和監(jiān)控系統(tǒng)要能實現(xiàn)自動化。隨著科學技術(shù)水平和人類生活水平的提高,對機械產(chǎn)品的質(zhì)量要求越來越高,產(chǎn)品品種越來越多,中大批量的產(chǎn)品需求越來越少,而單件小批量生產(chǎn)模式迅速增加。作為實現(xiàn)單件小批量加工自動化的數(shù)控機床,由于其突出的優(yōu)點而得到廣泛應用。目前,國外數(shù)控機床的性能正朝著高精度、高效率、高柔性、高自動化方向迅速發(fā)展,這將對數(shù)控機床機械結(jié)構(gòu)設計和制造的質(zhì)量和可靠性提出更高的要求?!笆濉逼陂g,我國機械制造行業(yè)必須瞄準國際數(shù)控機床發(fā)展的科學前沿,開拓創(chuàng)新,消化吸收國外先進技術(shù),開創(chuàng)我國數(shù)控機床設計和制造技術(shù)的新局面。1總體設計方案11總體設計方案論證數(shù)控車床的進給系統(tǒng)包括橫向進給系統(tǒng)(X軸)和縱向進給系統(tǒng)(Z軸),它們是由伺服電機經(jīng)同步齒形帶傳動,驅(qū)動滾珠絲杠螺母副機構(gòu),來實現(xiàn)刀架的運動。根據(jù)GB/T16462-1996數(shù)控臥式車床精度檢驗,機床的位置精度包括重復定位精度、反向偏差和定位精度。當機床的中心距DC=3000mm時,其重復定位精度X軸0.0075mm,Z軸0.010mm;反向偏差X軸為0.006mm,Z軸為0.012mm;定位精度X軸為0.035mm,Z軸為0.040mm??梢钥闯?進給軸設計與主軸設計相比,具有相同的重要性。因而,進給軸的設計應從動、靜兩方面充分考慮,位置精度才能達到該標準的要求。在數(shù)控車床進給系統(tǒng)的設計中,根據(jù)橫向、縱向的不同精度要求,不同移動質(zhì)量及轉(zhuǎn)動慣量等特點,分別解決設計中的主要矛盾。以期望設計結(jié)果能滿足各項性能指標的要求,達到預期的結(jié)果,即滿足設計任務書的要求。111驅(qū)動元件: 各種數(shù)控機床加工的對象不同,工藝要求不同,所以對進給驅(qū)動的要求不盡相同,但基本要求是一樣的,大致有四個方面。(1)高精度 使用數(shù)控機床主要是解決零件加工質(zhì)量的穩(wěn)定性,一致性,減少廢品率;解決復雜空間曲面零件的加工;解決復雜零件的加工精度,縮短制造周期等。為了滿足這些要求,必須保證數(shù)控機床的定位精度和加工精度。要求定位精度和輪廓切削精度能達到機床要求的指標。在位置控制中要求有高的定位精度,而在速度控制中,要求有高的調(diào)速精度,強的抗負載擾動的能力,即靜態(tài)和動態(tài)速度降盡可能小。(2)快速響應 為了保證輪廓切削形狀精度和低的加工表面粗糙度,除了要求有較高的定位精度外,還要求有良好的快速響應特性,即要求跟蹤指令信號的響應要快。(3)調(diào)速范圍寬 在各種數(shù)控機床中,由于加工用刀具,被加工零件的材質(zhì)及加工要求的不同,為保證在任何情況下都能得到最佳切削條件,就要求進給驅(qū)動必須具有足夠?qū)挼恼{(diào)速范圍。(4)低速大轉(zhuǎn)矩 根據(jù)機床的加工特點,大都是在低速進行重切削,即在低速時進給驅(qū)動要有大的轉(zhuǎn)矩輸出。(一)元件選擇(1)步進電動機,直流伺服電動機,交流伺服電動機是目前常用的驅(qū)動元件。步進電機是一種將電的脈沖信號轉(zhuǎn)換成相應的角位移或線位移的機電執(zhí)行元件,它能快速的啟動,制動和反轉(zhuǎn);在一定頻率范圍內(nèi)各種運動方式都能任意的改變且不會失步,具有自整步的能力;沒有一周累計誤差,所以定位精度很高;價格便宜。但由于步進電機的動態(tài)特性遠不如交,直流伺服電機,尤其是運行的可靠性得不到保證,目前已使用的較少。(2)直流伺服電動機具有良好的調(diào)速特性,因此在對伺服電動機的調(diào)速性能和啟動性能要求較高的設備中,大都采用直流伺服電動機驅(qū)動。但由于直流伺服電動機存在著一些固有的缺點,如它的電刷和換向器易磨損,需要經(jīng)常維護;換向器換向時會產(chǎn)生火花,使電動機的最高轉(zhuǎn)速受到限制,也使應用環(huán)境受到限制;此外,它結(jié)構(gòu)復雜,制造困難,所用鋼鐵材料消耗大,制造成本高,因此,現(xiàn)在已很少選用直流伺服電動機。(3)交流伺服電動機則沒有直流伺服電動機的上述缺點,且轉(zhuǎn)子慣量較直流伺服電動機小,使得動態(tài)上響應更好。一般來說,在同樣的體積下,交流伺服電動機的輸出功率可比直流伺服電動機提高10%70%,另外,交流伺服電動機的容量也比直流伺服電動機大,達到更高的電壓和轉(zhuǎn)速。因此,本課題選用的是交流伺服電動機。112傳動機構(gòu)本課題選用的是滾珠絲杠螺母副。滾珠絲杠螺母副是一種新的傳動機構(gòu),它的傳動特點是在具有螺旋槽的絲杠螺母之間裝有滾珠作為中間傳動元件。當絲杠和螺母相對運動時,滾珠沿絲杠螺旋槽滾道滾動,因此絲杠和螺母之間基本上為滾動摩擦。由于滾珠絲杠螺母副屬于滾動摩擦,故與普通滑動螺母副相比有以下優(yōu)點:(1)傳動效率高??蛇_90%-95%,是普通絲杠傳動的24倍。(2)因摩擦系數(shù)小,無自鎖現(xiàn)象,即運動有可逆性,一般需要制動裝置。(3)摩擦力小。因靜動摩擦系數(shù)相差較小,因而傳動平穩(wěn),不易產(chǎn)生爬行,隨動精度和定位精度高。(4)滾珠絲杠螺母副主要零件均經(jīng)過熱處理,其滾道表面的硬度值可達6062HRC,因而耐磨性好,壽命長,精度穩(wěn)定性好。(5)可消除軸向間隙和預緊,提高軸的剛度。因為滾珠絲杠螺母副與普通絲杠螺母副相比有這么多的優(yōu)點,因此,作者選用滾珠絲杠螺母副。113聯(lián)軸器聯(lián)軸器有剛性聯(lián)軸器與彈性聯(lián)軸器之分,本課題選用的是ML-02型彈性膜片式聯(lián)軸器。剛性聯(lián)軸器雖然結(jié)構(gòu)簡單,成本低,但它無補償性能,不能緩沖減振,且對兩軸安裝精度要求較高,用于振動很小的工況條件,聯(lián)接中,高速和剛性不大的且要求對中性較高的兩軸。彈性膜片式聯(lián)軸器不但結(jié)構(gòu)簡單,尺寸小,重量輕,且承載能力大,強度高,傳動效率高,精度高,可用于高,低溫,高,中速,大轉(zhuǎn)矩和有油,水的場合,且可部分代替齒式聯(lián)軸器,工作溫度-20-250。ML-02型彈性膜片式聯(lián)軸器主要性能特點有:(1) 定位方便可靠,相位可調(diào);(2) 無反向間隙,傳動精度高,可不用鍵和錐銷,不須止推機構(gòu),傳遞扭矩大,能承受沖擊載荷和振動;(3) 可以反復裝卸,重復使用,不影響精度,拆裝方便;(4) 可補償軸的角度偏差,偏心,軸向竄動.無噪音,無磨損,能量損失小。114潤滑方式:常用的潤滑方式大致有以下幾種:1. 手工加潤滑油或手工加潤滑脂進行潤滑手工潤滑是人工的分散潤滑方式,大多用于各種軸承,開式齒輪和鏈條等處。其特點是結(jié)構(gòu)簡單,易于執(zhí)行,加油次數(shù)和油量靠人工掌握。2. 油池飛濺潤滑油池飛濺潤滑常用在閉式齒輪箱內(nèi),它依靠箱內(nèi)旋轉(zhuǎn)的齒輪或附加在軸上的甩油機件,將箱體內(nèi)底部的存油濺散到應該潤滑的機件軸承,或其他應該潤滑的位置上。有些軸承和潤滑點隱蔽在箱體內(nèi)部時,則通過油槽油路或油管油路進行潤滑。3.自動送油潤滑 自動送油潤滑主要是自動送油裝置。它的形式較多,有簡單也有復雜,常常用在機床或其他設備的齒輪箱內(nèi)。自動送油也可以采用潤滑油泵送油,但大多應用于集中潤滑的系統(tǒng)內(nèi),例如大量的潤滑點話潤滑部位,甚至整個車間的潤滑系統(tǒng)。本課題選用的是TM型電動潤滑器。TM型電動潤滑器采用彈簧活塞式往復泵,由微型同步電機和集成減速機構(gòu)驅(qū)動,結(jié)構(gòu)緊湊,注油量可在0.25毫升范圍內(nèi)調(diào)節(jié),注油周期時間可在6145分鐘內(nèi)選擇,可實現(xiàn)對油罐液化的自動監(jiān)測和報警,適用于中小型機床周期潤滑系統(tǒng)。該潤滑器配套安裝聯(lián)接件,計量件,配油管等附件后,可潤滑1-50個潤滑點,組成周期集中潤滑系統(tǒng)。TM型電動潤滑器由微型伺服電機經(jīng)蝸輪傳動系統(tǒng)減速,與蝸輪同軸轉(zhuǎn)動的凸輪,帶動擺桿上下運動。當活塞升起時,大氣將油罐內(nèi)的油液通過單向閥壓入油缸;壓縮彈簧使活塞復位,潤滑液通過出口后進入輸油管路中并到達各潤滑點。注油頻率由定時機確定。潤滑器配有液位報警傳感器(低油位開關(guān)),在油罐潤滑液低于規(guī)定液位時,可自動發(fā)出信號,以確定及時向油罐添加潤滑液。TM型電動潤滑器具有下列特點:(1) 結(jié)構(gòu)緊湊,安裝方便。(2) 清潔安全,潤滑液經(jīng)精細過濾后輸出至各潤滑點。(3) 能按事先確定的注油周期輸供潤滑液。(4) 潤滑液的流量可調(diào),并能精確的控制。(5) 潤滑時,無須中斷生產(chǎn)過程。(6) 維護容易,經(jīng)濟耐用。(7) 可以延長機器的壽命,對中小型機器更為理想。1.2 總體設計方案的確定經(jīng)總體設計方案的論證后,確定的CA6140經(jīng)濟型中檔精度數(shù)控車床縱向進給機構(gòu)及導軌潤滑系統(tǒng)設計的總體方案圖如圖1-2所示。該系統(tǒng)由MCS-51系列單片機組成微機作為數(shù)控裝置的核心,由I/O接口,軟件環(huán)形分配器與放大控制功率伺服電機轉(zhuǎn)動,經(jīng)齒輪減速后帶動滾珠絲杠轉(zhuǎn)動,從而實現(xiàn)車床的縱,橫向進給運動。刀架改成由微機控制的經(jīng)伺服電機驅(qū)動的自動控制的自動轉(zhuǎn)位刀架。為保持切削螺紋的功能,必須安裝主軸脈沖發(fā)生器,為此采用主軸靠同步齒形帶使脈沖發(fā)生器同步旋轉(zhuǎn),發(fā)出兩路信號:每轉(zhuǎn)發(fā)出的脈沖個數(shù)和一個同步信號,經(jīng)隔離電路以及I/O接口送給微機。同時選用TM型電動潤滑器,實現(xiàn)潤滑功能。 圖1-2 CA6140車床數(shù)控改造的總體方案示意圖121縱向進給系統(tǒng)的改造:(1)撤除原機床的進給箱,溜板箱,光杠與絲杠以及安裝座,配上滾珠絲杠及其相應的安裝裝置,縱向驅(qū)動的伺服電機及減速箱安裝在車床的床尾,并不占據(jù)絲杠空間。利用原機床進給箱的安裝孔和重新配作銷釘安裝新設計的齒輪箱體;(2)滾珠絲桿仍安置在原絲桿的位置,兩端仍采用原固定方式,為便于安裝滾珠絲桿螺母副,絲桿不是整體的,而是采用分體式,即用連接套筒剛性連接。由于采用了滾珠絲杠可提高系統(tǒng)的精度和縱向進給整體剛度。(3)縱向進給機構(gòu)和橫向進給機構(gòu)均由伺服電動機、滾珠絲桿螺母副和中間傳動齒輪副(一級傳動)組成。2縱向進給機構(gòu)的設計與計算縱向伺服進給機構(gòu)設計的主要內(nèi)容有:滾珠絲杠副的設計計算與選擇,伺服電機的選擇,繪制縱向進給機構(gòu)的裝配圖,導軌潤滑機構(gòu)裝配圖以及各零件圖等。2.1 已知條件(1)、床身上最大回轉(zhuǎn)直徑:400mm;(2)、加工最大工件長度:1000mm(3)、快移速度:X軸 4m/min,Z軸 8m/min(4)、定位精度:X軸 0.035mm, Z軸 0.04mm (5)、重復定位精度:X軸 0.0075mm, Z軸 0.01mm(6)、數(shù)控車床工作臺質(zhì)量W:根據(jù)圖形尺寸粗略計算W=120Kg;22滾珠絲杠副主要參數(shù)的確定在數(shù)控機床的設計中,滾珠絲杠副的作用是將伺服電機的旋轉(zhuǎn)運動轉(zhuǎn)變?yōu)橹本€運動,用較小的轉(zhuǎn)矩可以獲得很大的推力。滾珠絲杠副的傳動是一種應用較廣的機構(gòu),尤其是將旋轉(zhuǎn)運動變?yōu)橹本€運動的各種機構(gòu)中,滾珠絲杠副的傳動是最簡單、經(jīng)濟而又可靠的。所以滾珠絲杠副的選擇對整個機床的制造起著不可忽視的作用。滾珠絲杠副的精度是影響機床的定位精度及重復定位精度的最主要的因素。為了在機床的設計中更合理的選用滾珠絲杠副,使其充分發(fā)揮效能,必須進行一系列的計算。滾珠絲杠副已經(jīng)標準化,因此滾珠絲杠副的設計歸結(jié)為滾珠絲杠副型號的選擇。一般情況下,設計滾珠絲杠時,已知條件為:最大工作負載Fd(或平均工作負載Fm)作用下的使用壽命,絲杠的工作長度(或螺母的有效行程),絲杠的轉(zhuǎn)速(或平均轉(zhuǎn)速),滾道的硬度及絲杠的運轉(zhuǎn)情況。2.2.1 設計步驟通常的設計步驟為:A、計算作用在滾珠絲杠上的最大動載荷;B、從滾珠絲杠列表指出相應最大動負載的近似值,并初選幾個型號;C、根據(jù)具體工作要求,對于結(jié)構(gòu)尺寸、循環(huán)方式、調(diào)隙方法及傳動效率等方面的要求,從初選的幾個型號中再挑出比較合適的直徑、導程、滾珠列數(shù)等,確定某一型號。D、根據(jù)所選的型號,列出或計算出其主要參數(shù)的數(shù)值,計算傳動效率,并驗算剛度及穩(wěn)定系數(shù)是否滿足要求。如不滿足要求,則另選其他型號,再作上述計算和驗算,直至滿足要求為止。2.2.2 設計計算簡況(1)選用CPG系列滾珠絲杠副。A、 CPG系列滾珠絲杠副主要參數(shù)的確定:按預期壽命Ln及軸向載荷Fa進行選擇: Ln=(Ca/Fa)106(轉(zhuǎn)) 21式中: Ca額定動載荷; 一般情況下Fa可以用平均軸向載荷Fm予以代替:Fm=(2Fmax+Fmin)/3 22式中: Fmax最大軸向載荷;Fmin最小軸向載荷。 Fmax=mg+F=1209.8+3860=5036 23 Fmin=mg=1209.8=1176 24所以:Fm=(2Fmax+Fmin)/3=3749N 25 對于機車和精密機械通常取Ln=20106(轉(zhuǎn))則:: Ca=(20)1/3Fm=2.71Fm=10161N 26 計算出Ca,可通過查表得到對應的滾珠絲杠副的尺寸,選取4006-6型號滾珠絲杠副,基本直徑為40mm,大徑位39.5mm,絲杠導程L0為6mm, 滾珠直徑為3.969mm, 滾珠列數(shù)為四列。B、 對選用的滾珠絲杠副的參數(shù)進行核算a、 最大軸向壓縮載荷F:對各種支承條件下所支承的最大軸向載荷,是否會超過臨界載荷而失去穩(wěn)定性,造成穩(wěn)定失效,因此對保持絲杠不失去穩(wěn)定性的軸向壓縮載荷進行驗算。滾珠絲杠受壓力作用后在彈性范圍內(nèi)的臨界穩(wěn)定載荷Fc由下式計算:Fc=m(d0-db)4/Ls2 27式中:m為支承系數(shù);G-J形式:m=20104(N/mm2);d0為公稱直徑(mm);db為滾珠直徑(mm);Ls為絲杠軸的支承距離(mm)。所以: Fc=20104(40-3.969)4/15772 =1.36105 N 28則: Fc/Fn F(1/4 Fc )=3.4104 NFmax 式中: n為許用穩(wěn)定安全系數(shù),當絲杠垂直安置時n=2.5,水平安置時n=4; F為最大軸向壓縮載荷。由以上計算可知條件滿足。b、 極限轉(zhuǎn)速的計算: 為使絲杠副在高速運轉(zhuǎn)時不發(fā)生共振現(xiàn)象,應對其極限轉(zhuǎn)速進行核算。當絲杠發(fā)生共振時的轉(zhuǎn)速稱為臨界轉(zhuǎn)速,以Nc表示: Nc=121106(d0-db)K1/2/L2 =2.80103 2-9式中: d0為公稱直徑(mm); db為滾珠直徑(mm); K為支承結(jié)構(gòu)系數(shù), G-J形式: K=2.5。 極限轉(zhuǎn)速n應滿足: n0.8 Nc=0.82.80103=2.24103r/min 2-10 n0=v/(2)=8000/(2)=1.27103r/min 2-11因為 n0n,所以條件滿足。c、 滾珠絲杠副的預加負載:為了消除螺母與絲杠間的軸向間隙,提高滾珠絲杠副的剛度與定位精度,在絲杠螺母間施加負載Fp,其預加負載的大小為:Fp= Ca/10=1016Nd、 臨界轉(zhuǎn)速的核算:絲杠的名義直徑d0=40mm,nmax=vmax/L0=200r/min 2-12查參考文獻5支承為“固定-自由”支承長度L=1577mm, 查參考文獻55.7-91,的交線點在d0=40mm左側(cè),所以安全。e、 效率計算:查參考文獻5201頁上:=tan/tan(+) 2-13式中: 螺紋的螺旋升角,可參考文獻55.7-41表,取=3o3; 摩擦角, tan=0.0030.004。所以: =1345則: =tan3o3/ tan(3o3+1345)=93% 2-14f、 剛度檢驗:查參考文獻5202頁上:=100F/(EA)+50T/(gjc),m/m 2-15式中: E彈性摸量,E=2.1102GPa;F工作負載, F=5036 N ; A滾珠絲杠橫截面積, A=/4(d0-db)2=0.785(40-3.969)2=10.19cm2;db滾珠直徑(mm);G切變模量,G=8.4104GPa;Jc滾珠絲杠截面慣性矩,Jc=2.2710-7m4;代入公式21得: =8.03m/m查參考文獻5表5-10和表5-17,B級精度為40m/300mm,七級精度=15m,八級精度=30m,所以FYND4006-6型絲杠的剛度是足夠的。由于選用滾珠絲杠的直徑為40mm,支承方式為G-J型,所以穩(wěn)定性不成問題。運動部重量 W 120 Kg摩擦系數(shù) 0.15外界施加的力 F 3860N/9.8螺桿螺距 P 6 mm螺桿直徑 D 40 mm螺桿長度 L 1350 mm傳遞效率 0.85驅(qū)動部件比重 7.210-3傳動裝置減速比 1/G 3/523 伺服電機的選擇 231選用螺桿驅(qū)動方式的伺服電機 232求換算到電機軸上的負荷力矩TL=(F+W)/D/21/G9.8/100 3-1 =(3860/9.8+0.15120)/0.85(P/2)(3/5)(9.8/100) =(3860/9.8+0.15120)/0.85(6/2) (3/5)(9.8/100) =2.72 Nm要求 TLTR 233求換算到電機軸上的負荷慣性 (JL不大于電機轉(zhuǎn)子慣量的5倍)運動部的慣性JB=(1/G) 2(D4 A)/32104 3-2 =(3/5) 2(3.147.210-34041.35)/32104 =0.8810-4 Kgm2工作慣性JW =(1/G) 2W/104(D/2)2 3-3=(3/5) 2120/104(6/2) 2=0.3910 -4 Kgm2JL = JB+ JW =9.1710 -4 Kgm2 3-4234電機的假擬選定從產(chǎn)品目錄中選出滿足上述(TL, JL,NP)條件的電機, 假擬選用P20B10200DS,2.0的交流伺服電動機。235加減速力矩(Ta, Tb)的計算:加速力矩 Ta=2(N1N2)(JL+ JM)/60ta+ TL 3-5 =23.14(4500-3000)(9.17+2.04) 10 -4/(601/6)+ 2.72 =3.78 Tb=2(N1N2)(JL+ JM)/60ta- TL 3-6 =-1.66236實際力矩的計算 Trms= 3-7 = =2.65 假擬選用的P20B10200DS,2.0的交流伺服電動機滿足上述條件。備注:標注公式2-1-2-15出自參考文獻5備注:標注公式3-1-3-7出自參考文獻6小結(jié) 通過對CA6140經(jīng)濟型中檔精度數(shù)控車床縱向進給機構(gòu)及導軌潤滑系統(tǒng)的設計與改造,使其尤其適合我國機床擁有量大,生產(chǎn)規(guī)模小的具體國情。數(shù)控機床以伺服電機直接驅(qū)動滾珠絲杠進行位置控制,減少了中間傳動環(huán)節(jié),改善了傳動系統(tǒng)的動態(tài)特性,避免了多級傳動帶來的累積誤差。經(jīng)改造后的機床完全能實加工外圓、錐度、螺紋、端面等的自動控制, 加工的零件精度高,尺寸一致性好,自動化程度高,提高了原機床的生產(chǎn)效率,降低了勞動強度.而且使用方便,改造費用低,采用數(shù)控技術(shù)對企業(yè)原有機床進行改造,即發(fā)展經(jīng)濟型的數(shù)控機床是當前工礦企業(yè)機床技術(shù)改造的有效途徑。當然,由于本人經(jīng)驗有限,在設計與改造過程中難免有缺陷和欠慮的地方,有待今后不斷的提高與完善。 致謝通過本次的畢業(yè)設計,我們受到了很大的啟發(fā),學到了很多東西。在此要特別感謝我們的指導老師沙愛民工程師,她在整個畢業(yè)設計的指導過程中為我們盡心盡力,排憂解難。讓我們進一步學會了如何查閱文獻,如何分析處理設計過程中出現(xiàn)的問題,如何寫好論文、做好答辯等。當然取得這樣的成績是多方面的:有學校圖書館為我們準備的充足完備的專業(yè)資料;有計算機房通宵達旦的辛勤工作;有系領(lǐng)導給予的多方面的大力支持等等。在本次畢業(yè)設計結(jié)束之際,請允許我向他們表示衷心的感謝!參考文獻1 余良英. 機床數(shù)控技術(shù)改造設計與實例.第1版.北京:機械工業(yè)出版社,19822 李峻勤 ,費仁元. 數(shù)控機床及其使用與維修.北京:機械工業(yè)出版社,1985 3 楊學桐 ,李冬茹. 我國數(shù)控產(chǎn)業(yè)的現(xiàn)狀與發(fā)展舉措. 中國機械工程,1999(10) 4 徐亞明.大型數(shù)控車床的進給系統(tǒng)設計與分析.甘肅:機械制造,1998(6)5 陳秀義,施高義.機械設計課程設計.浙江:浙江大學出版社,1995(1)6 徐錦康.機械設計.北京:機械工業(yè)出版社,2001(2)7 袁國定,朱洪海.機械制造基礎.南京:東南大學出版社,2000(2)8 鄭文緯,吳克堅.機械原理.南京:高等教育出版社,19959 王辰寶.機械加工工藝基礎. 南京:東南大學出版社,199610 龐懷玉。機械制造工程學. 北京:機械工業(yè)出版社,1998附件清單 1.畢業(yè)設計任務書 1份 2. 畢業(yè)設計說明書 1份 3.總裝圖 CK000 A3 1份 4. 進給系統(tǒng)裝配圖 CK001 A0 1份 5.潤滑機構(gòu)裝配圖 CK002 A1 1份 6. 床鞍零件圖 CK124 A1 1份 7.電機支座零件圖 CK117 A1 1份 8.螺母支架零件圖 CK110 A2 1份 9連接軸零件圖 CK101 A3 1份 10面板零件圖 CK102 A3 1份 11端蓋零件圖 CK106 A3 1份 12法蘭零件圖 CK108 A3 1份 13滾珠絲杠副零件圖 CK112 A3 1份 14支座零件圖 CK114 A3 1份 15墊圈零件圖 CK103 A4 1份 16套筒零件圖 CK104 A4 1份 17連接法蘭零件圖 CK105 A4 1份 18側(cè)板零件圖 CK107 A4 1份 19法蘭零件圖 CK109 A4 1份 20法蘭零件圖 CK111 A4 1份 21法蘭零件圖 CK113 A4 1份 22小端蓋零件圖 CK115 A4 1份 23防護罩零件圖 CK116 A4 1份 24錐銷零件圖 CK118 A4 1份 25連接管零件圖 CK119 A4 1份 26墊板零件圖 CK121 A4 1份 27防護罩零件圖 CK122 A4 1份 28接頭零件圖 CK123 A4 1份 15 學科門類: 工學 單位代碼 : 畢業(yè)設計說明書 數(shù)控車床縱向進給及導軌潤滑機構(gòu)設計學生姓名沈燕所學專業(yè)機械設計制造及其自動化 班 級材機99(5) 學 號B9912003 指導教師沙愛民 鹽城工學院機械工程系二三年六月編號無錫太湖學院畢業(yè)設計(論文)相關(guān)資料題目: 換刀機器人機械系統(tǒng)的設計 信機 系 機械工程及自動化專業(yè)學 號: 0923006 學生姓名: 王維維 指導教師: 過金超 (職稱:副教授) (職稱: )2013年5月25日目 錄一、畢業(yè)設計(論文)開題報告二、畢業(yè)設計(論文)外文資料翻譯及原文三、學生“畢業(yè)論文(論文)計劃、進度、檢查及落實表”四、實習鑒定表無錫太湖學院畢業(yè)設計(論文)開題報告題目: 換刀機器人機械系統(tǒng)的設計 信機 系 機械工程及自動化專業(yè)學 號: 0923006 學生姓名: 王維維 指導教師: 過金超 (職稱:副教授) (職稱: )2013年5月25日 課題來源 實驗室課題。科學依據(jù)(包括課題的科學意義;國內(nèi)外研究概況、水平和發(fā)展趨勢;應用前景等)(1)課題的科學意義 當今的世界,制造業(yè)在經(jīng)濟發(fā)展中占有十分重要的地位,機械制造業(yè)更加是制造業(yè)中的支柱與核心。(2)國內(nèi)外研究概況、水平和發(fā)展趨勢從近幾年世界上推出的機器人產(chǎn)品來看,工業(yè)機器人技術(shù)正在向智能化、模塊化和系統(tǒng)化的方向發(fā)展。其發(fā)展趨勢為:結(jié)構(gòu)的模塊化和可重構(gòu)化;工作環(huán)境設計的優(yōu)化和作業(yè)的柔性化,以及網(wǎng)絡化和智能化等方面。:(3)應用現(xiàn)狀及其前景目前工業(yè)機械手主要用于機床加工、鑄造、熱處理等方面,無論數(shù)量、品種和性能方面還是不能滿足工業(yè)發(fā)展的需要。在國內(nèi)主要是逐步擴大應用范圍,重點發(fā)展鑄造、熱處理方面的機械手,以減輕勞動強度,改善作業(yè)條件,在應用專用機械手的同時,相應的發(fā)展通用機械手,有條件的還要研制示教式機械手、計算機控制機械手和組合機械手等。將機械手各運動構(gòu)件,如伸縮、擺動、升降、橫移、俯仰等機構(gòu)以及根據(jù)不同類型的加緊機構(gòu),設計成典型的通用機構(gòu),所以便根據(jù)不同的作業(yè)要求選擇不同類型的基加緊機構(gòu),即可組成不同用途的機械手。既便于設計制造,有便于更換工件,擴大應用范圍。同時要提高速度,減少沖擊,正確定位,以便更好的發(fā)揮機械手的作用。研究內(nèi)容自動換刀機器人的機械系統(tǒng),結(jié)構(gòu),機構(gòu),受力,驅(qū)動形式,傳動系統(tǒng)。擬采取的研究方法、技術(shù)路線、實驗方案及可行性分析(1)實驗方案 通過對目前最常用的幾種數(shù)控車床自動換刀系統(tǒng)的研究,對所研究的數(shù)控機床提出幾個最為可行的工作系統(tǒng),通過對方案的論證分析,選擇最為理想的完成整個設計。對整個換刀裝置,各組成機構(gòu),及各個自由度的實現(xiàn)進行分析。對換刀機械手的手指夾緊力進行分析,計算,對系統(tǒng)的關(guān)鍵部位進行校核,以確保換刀可靠性。對整個設計中涉及到的液壓缸,計算確定其各個部分結(jié)構(gòu)的具體尺寸,同時對活塞桿的強度,穩(wěn)定性及螺栓的強度進行校核,以確保整個系統(tǒng)工作狀態(tài)的準確可靠。(2)研究方法 選擇最合理的換刀系統(tǒng),通過比較,計算,設計出關(guān)鍵零件,結(jié)合前人的換刀系統(tǒng)設計出整個換刀裝置,系統(tǒng)。研究計劃及預期成果研究計劃:2012年11月12日-2012年12月2日:教師下達畢業(yè)設計任務,學生初步閱讀資料,完成畢業(yè)設計開題報告。2013年1月21日-2013年3月1日:指導畢業(yè)實習。2013年3月4日-2013年3月15日:確定總設計方案。2013年3月18日-2013年3月22日:總體設計(包括參數(shù)計算及結(jié)構(gòu)分析計算)。2013年3月25日-2013年4月5日:總體設計(完成參數(shù)計算及結(jié)構(gòu)分析計算后繪制草圖:裝配圖)。2013年4月8日-2013年4月26日:零件設計。2013年4月29日-2013年5月20日:畢業(yè)論文說明書撰寫和修改工作。預期成果:跟緊老師的腳步,認真的完成每一步設計,完善整個機械手的設計,熟悉掌握整個系統(tǒng)的原理。在學業(yè)將要完成之時,我將大幅提高我的機械研究能力,將會成為一名優(yōu)秀的機械技術(shù)工作者。特色或創(chuàng)新之處快速,精確,大容量,的換刀系統(tǒng)。兼容隨機刀具定位和固定刀具定位到位達到005mm。已具備的條件和尚需解決的問題 我已學習數(shù)控專業(yè)三年之久,掌握了一些這專業(yè)的部分知識,老師也給了一些參照資料,可以進行這方面的研究。 尚需解決的問題:(1)設計水平移動系統(tǒng)、垂直升降系統(tǒng)和末端操作器的驅(qū)動及傳動系統(tǒng);(2)設計水平移動系統(tǒng)、垂直升降系統(tǒng)和末端操作器的結(jié)構(gòu);(3)自動換刀機械手的升降機構(gòu)的繪圖(4)裝卸刀手手臂和手部結(jié)構(gòu)的設計指導教師意見 指導教師簽名:年 月 日教研室(學科組、研究所)意見 教研室主任簽名: 年 月 日系意見 主管領(lǐng)導簽名: 年 月 日英文原文 On the NC lathe and tool changing systemCNC machine tool numerical control machine tools (Computer numerical control machine tools) abbreviation, is provided with a program control system of automatic machine tools. The logic control system can deal with the control code or other symbolic instruction specified program, and decoding the digital code, said information carrier, through the numerical control device input. After processing by CNC device control signals, control the machine movements, by drawing the shape and size requirements, will be automatically processed by the parts.Features: CNC machine tool operation and monitoring of all completed in the numerical control unit, it is the brain of CNC machine tools. Compared with the general machine tools, CNC machine tools has the following characteristics: the processing object adaptability, adapt to the characteristics of mold products such as a single production, provide the appropriate processing method for die and mould manufacturing; high machining accuracy, processing with stable quality; can coordinate linkage, processing complex shape parts; machining parts change, only need to change the program, can save the preparation time of production; the machine itself high precision, rigidity, can choose the amount of processing good, high productivity (typically 3 to 5 times that of ordinary machine tool);The machine is a high degree of automation, reducing labor intensity; conducive to the production management modernization. The use of CNC machine tools and the standard code of digital information processing, information transmission, the use of computer control method, has laid the foundation for the integration of computer aided design, manufacturing and management; on the operators of higher quality, higher demands for the repair of the technical staff; high reliability.Composition: CNC machine tools in general by the input medium, man-machine interactive equipment, CNC equipment, feed servo drive system, spindle servo drive system, the auxiliary control device, feedback apparatus and adaptive control device etc. 4 in NC machining, NC milling processing is the most complex, need to solve most problems. NC programming of NC line in addition to CNC milling, cutting, CNC EDM, CNC lathe, CNC grinding, each with its own characteristics, servo system is the role of the motion signal is converted into the machine moving parts from the numerical control device of pulse. Concrete has the following parts: the structure of CNC machine tools.Driver: he is driving parts of CNC machine tools, actuator, including spindle drive unit, feeding unit, spindle motor and feed motor. He through the electric or electro-hydraulic servo system to realize the spindle and feed drive under the control of numerical control device. When several feed linkage, can complete the positioning, processing line, plane curve and space curve.The main performance(1) the main dimensions.(2) the spindle system.(3) feed system.(4) tool system.(5) electrical. Including the main motor, servo motor specifications and power etc.(6) cooling system. Including the cooling capacity, cooling pump output.(7) dimensions. Expressed as length * width * height.Development trend of CNC lathe:High speed, precision, complex, intelligent and green is the general trend in the development of CNC machine tool technology, in recent years, made gratifying achievements in practicality and industrialization. Mainly in the:1 machine tool composite technology to further expand with the CNC machine tool technology, composite processing technology matures, including milling - car compound, car milling compound, car - boring - drill - gear cutting compound, composite grinding, forming, composite processing, precision and efficiency of machining is greatly improved. One machine is a processing factory, one card, complete processing concept is being accepted by more people, the development of compound processing machine tool is the trend of diversified.Intelligent technology 2 CNC machine tools have a new breakthrough, in the performance of NC system has been reflected more. Such as: automatically adjust the interference anti-collision function, after the power of workpiece automatically exit safety power-off protection function, machining parts detection and automatic compensation function of learning, high precision machining parts intelligent parameter selection function, process automatic elimination of machine vibration functions into the practical stage, intelligent upgrade the function of machine and quality.The 3 robots enable flexible combination of flexible combination of higher efficiency of robot and the host are widely used, make flexible line more flexible, extending the function, flexible line shorten further, more efficient. Robot and machining center, milling composite machine, grinder, gear processing machine tool, tool grinding machine, electric machine, sawing machine, punching machine, laser cutting machine, water cutting machine etc. various forms of flexible unit and flexible production line has already begun the application.4 precision machining technology has the machining precision of CNC metal cutting machine tools from the yarn in the original (0.01mm) up to micron level (0.001mm), some varieties has reached about 0.05 M. Micro cutting and grinding machining of ultra precision CNC machine tools, precision can reach about 0.05 m, shape precision can reach about 0.01 M. Special processing precision by using optical, electrical, chemical, energy can reach nanometer level (0.001 m). By optimizing the design of machine tool structure, machine tool parts of ultra precision machining and precision assembly, using high precision closed loop control and temperature, vibration and other dynamic error compensation technology, improve the geometric accuracy of machine tool processing, reduce the shape of error, surface roughness, and into the submicron, nano super finishing tiThe 5 functional component to improve the performance of functional components are at a high speed, high precision, high power and intelligent direction, and obtain the mature application. A full digital AC servo motor and drive device, high technology content of the electric spindle, linear motor, torque motor, linear motion components with high performance, application of high precision spindle unit and other function parts, greatly improving the technical level of CNC machine tools.The feed drive system of CNC lathe:Effect of feed drive system,The feed drive system of CNC machine tools will be received pulse command issued by the numerical control system, and the amplification and conversion machine movements carry the expected movement.Two, the feeding transmission system requirementsIn order to guarantee the machining accuracy of NC machine tool is high, the feed drive system of transmission accuracy, sensitivity high (fast response), stable work, high stiffness and friction and inertia small, service life, and can remove the transmission gap.Category three, feed drive system1, stepping motor servo systemGenerally used for NC machine tools.2, DC servo motor servo systemPower is stable, but because of the brush, the wear resulting in use need to change. Generally used for middle-grade CNC machine tools.3, AC servo motor servo systemThe application is extremely widespread, mainly used in high-end CNC machine tools.4, the linear motor servo systemNo intermediate transmission chain, high precision, the feed speed, no length limit; but the poor heat dissipation, protection requirements are particularly high, mainly used for high-speed machine.Driving component four, feed system1, the ball screw nut pairNC machining, the rotary motion into linear motion, so the use of screw nut transmission mechanism. NC machine tools are commonly used on the ball screw, as shown in Figure 1-25, it can be a sliding friction into rolling friction, meet the basic requirements of the feed system to reduce friction. The transmission side of high efficiency, small friction, and can eliminate the gap, no reverse air travel; but the manufacturing cost is high, can not lock, size is not too big, generally used for linear feed in small CNC machine tool.2, rotary tableIn order to expand the scope of the process of NC machine tools, CNC machine tools in addition to make linear feed along the X, Y, Z three coordinate axes, often also need a circumferential feed movement around Y or Z axis. Circular feed motion of CNC machine tools in general by the rotary table to realize, for machining center, rotary table has become an indispensable part of.Rotary table of commonly used CNC machine tools in the indexing table and NC rotary table.(1) indexing tableIndexing table can only finish dividing movement, not circular feed, it is in accordance with the instructions in the NC system, when indexing will work together with the workpiece rotation angle. When indexing can also use manual indexing. Provisions of indexing table is generally only rotary angle (such as 90, 60 and 45 degree).(2) NC rotary tableNC rotary table appearance similar to the indexing table, but the internal structure and function is not the same. The main function of the NC rotary table is based on the numerical control device sends command pulse signal, complete circumferential feed movement, various arc processing and surface processing, it can also be graduation work.3, guideRail is an important part of feed drive system, is one of the basic elements of the structure of machine tool, rigidity, precision and accuracy of NC machine tool which determines to a large extent retention. At present, guide the NC machine tool are sliding rail, rolling guideway and hydrostatic guideway.(1) sliding guideSliding guide rail has the advantages of simple structure, easy manufacture, good stiffness, vibration resistance and high performance, widely used in CNC machine tools, the use of most metal plastic form, known as the plastic guide rail, as shown in figure 1-26.On characteristics of the plastic sliding guide: friction characteristic is good, good wear resistance, stable movement, good manufacturability, low speed.(2) rolling guideRolling guide is placed in the rail surface between the ball, roller or needle roller, roller, the rolling friction instead of sliding surface of the guide rail between wipe.Rolling guide rail and the sliding rail, high sensitivity, small friction coefficient, and the dynamic, static friction coefficient is very small, so the motion is uniform, especially in the low speed movement, the stick-slip phenomenon is not easy to occur; high positioning accuracy, repeatability positioning accuracy is up to 0.2 m; traction force is small, wear small, portable in movement; good precision, long service life. But the vibration of rolling guide, high requirements on protection, complicated structure, difficult manufacture, high costAutomatic tool changer:One, the function of automatic tool changerAutomatic tool changing device can help save the auxiliary time of CNC machine tools, and meet in an installation completed procedure, step processing requirements.Two, on the requirement of automatic tool changerNumerical control machine tool for automatic tool changer requirement is: tool change quickly, time is short, high repetitive positioning accuracy, tool storage capacity is sufficient, small occupation space, stable and reliable work.Three, change the knife form1, rotary cutter replacementIts structure is similar to the ordinary lathe turret saddle, according to the processing of different objects can be designed into square or six angle form, consists of the NC system sends out the instruction to the rotary cutter.2, the replacement of the spindle head tool changeThe spindle head pre-loaded required tools, in order to machining position, the main motor is switched on, drives the cutter to rotate. The advantage of this method is that eliminates the need for automatic clamping, cutting tool, clamping and cutting tool moving and a series of complex operation, reduce tool change time, improve the reliability of the tool change.3, the use of changing toolThe processing required tools are respectively arranged in the standard tool, adjust the size of the machine after certain way add to the knife, the exchange device from the knife and the spindle take knife switch.Four, the tool switching deviceAutomatic tool change device, device for knife library and the main shaft transmission and handling tool for tool exchange device. Tool exchange often have two kinds: mechanical hand tool exchange and by relative motion of knife and machine tool spindle exchange tool (cutter to the spindle tool change or movement of the spindle to the knife knife tool change position), the mechanical hand tool change is most common.Five, the knifeThe knife is one of the most important parts in automatic tool changer, have great influence on the overall design of NC machine tool and its capacity, layout and structure.1, the capacity of the tool storageA number of knife inventory cutters, generally depending on the processing requirements. The capacity of small knife, can not meet the processing needs; capacity is too large, will make the knife database size, covers an area of large, tool selection process for a long time, and the knife library utilization rate is low, the structure is too complex, causing great waste. 2, the knife typeGenerally, the chain disc and drum type knife several.Disc cutter tool was circular arrangement, low utilization of space, size is not large but simple structure.Chain magazine compact structure, large capacity, link shape can also be random bed made of various forms and flexible layout, but also will change the cutter location prominent for tool change, widely used.Drum type or lattice type knife, covers an area of small, compact structure, large capacity, but cutter selection, tool movements are complicated, for centralized knife system for FMS.3, tool selectionOften order tool selection and random selection tool two.The order of tool selection is before processing, the processing required tools to process sequence of insert knife knife, order not wrong, processing adjust knife in order. The work piece changes, the need to reset the tool sequence, the operation is simple, and the processing tool with a workpiece can not be repeated use.A knife is the cutting tool has its own code, optional and can be repeatedly used in processing, also do not put in the fixed knife, knife, the knife is convenient.Technology file is the guiding file workers during processing, process scheme is reasonable, not only affect the efficiency of NC machining, and will directly affect the machining quality. Therefore, before NC programming, NC machining process follows the process of certain principles and combined with the characteristics of CNC lathe seriously and develop in detail the good parts.In the CNC lathe processing parts, should according to the principle of dividing process concentrated, in a fixture as far as possible to complete the most or even all of the surface processing. Part positioning, according to the structure of different shapes, usually cylindrical, face or end clamping, and strive to design basis, process reference and programming the unification datum.The main contents are: analysis of NC machining technology of part drawings, clear processing content; determination method, workpiece on lathe the surface processing sequence and tool feed line and cutting tools, fixtures and cutting the amount of choice.Analysis, part drawing processIn the machining process planning of parts, first of all to carry on in-depth analysis to the processing object. For NC turning process should consider the following aspects:1 reading part drawing, analysis of geometric conditions of part contourIn turning process of manual programming, to calculate each node coordinates; in automatic programming, to define the components outline all geometric elements. Therefore, in the analysis of parts should pay attention to:Parts of the map is missing a dimension, the geometric conditions are not sufficient to constitute the part outline, influence;Map location map parts of the ambiguity or dimension is not clear, so that the program cant start;The part drawing geometry given is not reasonable, resulting in mathematical difficulties.The part drawing dimensioning methods should adapt to the characteristics of CNC lathe processing, should size or directly given coordinate dimension with the same standard.2 dimensional accuracy requirementsAnalysis of the pattern of parts size precision requirements, to determine whether achieve the turning process, and determine the process method to control the dimension precision. In the analysis process, but also can convert some dimensions such as size, incremental and absolute size and dimension chain calculation. In the use of NC lathe turning parts, average value of components often required size and maximum and minimum limit of size size as the basis of programming.3 shape and position accuracy requirementsPattern of parts tolerance of shape and lo
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