滾珠絲杠副設計及相關技術研究【含7張cad圖紙+文檔全套資料】
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中 北 大 學 信 息 商 務 學 院
畢業(yè)設計任務書
學 院、系:
機械工程與自動化系
專 業(yè):
機械制造及其自動化
學 生 姓 名:
張曉飛
學 號:
12020144X21
設 計 題 目:
滾珠絲杠設計及相關技術研究
起 迄 日 期:
2016年 2月29日~ 2016年6月5日
指 導 教 師:
龐學慧
系 主 任:
暴建剛
發(fā)任務書日期: 2016年 2月29日
畢 業(yè) 設 計 任 務 書
1.畢業(yè)設計的任務和要求:
掌握機床傳動絲杠的基本知識;研究數(shù)控機床滾珠絲杠的關鍵技術,掌握其選型、應用及設計方法等;完成一種滾珠絲杠的設計,滿足精密數(shù)控機床20m/min進給速度的需求。
2.畢業(yè)設計的具體工作內容:
1) 分析題目要求,查閱相關的國內外文獻、設計資料、有關專利文獻等,在此基礎上,了解開題報告的撰寫方法、基本要求,完成開題報告;
2) 學習和掌握滾珠絲杠的有關知識,了解高速滾珠絲杠的關鍵技術及發(fā)展現(xiàn)狀;了解數(shù)控機床、加工中心對滾珠絲杠的要求;總結滾珠絲杠的設計要點、技術關鍵及發(fā)展方向;力爭提出滾珠絲杠設計的發(fā)展方向;
3) 按題目要求,設計一種滿足數(shù)控機床進給運動需要的滾珠絲杠,完成結構圖,給出必要的計算說明;
4) 編寫設計說明書;
5) 翻譯本專業(yè)外文科技文獻一份。
畢 業(yè) 設 計 任 務 書
3.對畢業(yè)設計成果的要求:
1)滾珠絲杠結構圖;
2)滾珠絲杠的研究及設計說明書一份;
3)本專業(yè)外文科技文獻譯文一份。
4.畢業(yè)設計工作進度計劃:
起 迄 日 期
工 作 內 容
2016年
02月29日 ~03月21日
03月22日 ~04月30日
05月01日 ~05月20日
05月21日 ~05月31日
06月01日 ~06月05日
分析課題要求,查閱相關文獻資料,了解滾珠絲杠的國內外現(xiàn)狀及發(fā)展趨勢,提出自己的設計思路,完成開題報告;
全面掌握滾珠絲杠的基本知識,了解高速機床對進給導軌的要求,了解滾珠絲杠的設計特點;分析總結滾珠絲杠的發(fā)展方向;
完成滾珠絲杠結構圖設計;
完成研究總結及設計說明書
撰寫答辯講稿,準備答辯;
學生所在系審查意見:
同意開題
系主任: 暴建崗
2016年3月 3日
滾珠絲杠副設計及相關技術研究
摘要:滾珠絲杠是因其自身良好的可靠性,精度等級高,使用及維護成本都比較低的優(yōu)勢被廣泛應用于多種場合,其中高精密機床上應用甚多。所以研究和優(yōu)化滾珠絲杠具有巨大的前景。本設計中具體對滾珠絲杠進行了多方面的學習,包括滾珠絲杠相關各種參數(shù)的計算及其校核。并對絲杠周圍部件進行了了解。除此之外,本設計還對滾珠絲杠的高速化及其優(yōu)化方案也進行了簡述。
關鍵詞:滾珠絲杠 設計方案 高速化
II
中北大學信息商務學院2016屆畢業(yè)設計說明書
Abstract:Ball is due to its own good reliability, high level of accuracy, use, and maintenance costs are relatively high advantages are widely used in a variety of situations, many of which use high-precision machine tools. Therefore, research and optimization ball screw has great prospects. The specific design of the ball screw conducted extensive research, including the calculation of various parameters related to ball screws and check. And screw around parts of the inquiry. In addition, this design also on the high-speed ball screw and its optimization program has also been outlined.
Keywords: high-speed ball screw design
目 錄
摘要 ……………………………………………………………………………I
Abstract ……………………………………………………………………………II
目錄………………………………………………………………………………III
1.緒論 ……………………………………………………………………………1
1.1滾珠絲杠概述………………………………………………………………3
1.2本課題研究的意義…………………………………………………………8
2.滾珠絲杠的設計 ………………………………………………………………8
2.1原始數(shù)據(jù)與技術條件………………………………………………………9
2.2滾珠絲杠的主體參數(shù)設計…………………………………………………9
2.2.1導程的選擇 ……………………………………………………10
2.2.2 絲杠軸長度的選擇 ………………………………………………11
2.2.3絲杠軸直徑的選擇 ………………………………………………13
2.2.4絲杠軸支撐方式的選擇 …………………………………………12
2.2.5螺母的選擇 ………………………………………………………13
3.各零部件的校核………………………………………………………………14
3.1容許軸向負載的計算 ……………………………………………………14
3.2絲杠軸容許轉速的計算 …………………………………………………15
3.3螺母運行距離的計算 ……………………………………………………15
3.4螺母軸向平均負荷及其壽命校核 ………………………………………16
4.定位精度的探討……………………………………………………………18
4.1導程精度的探討 …………………………………………………………18
4.2軸向間隙的校核 …………………………………………………………18
4.3軸向剛性的校核 …………………………………………………………18
4.4運行姿態(tài)的探討 …………………………………………………………19
4.5旋轉扭矩的校核 …………………………………………………………19
5.電動機的選擇 …………………………………………………………………20
5.1旋轉速度 …………………………………………………………………20
5.2最小進給量 ………………………………………………………………20
5.3電動機扭矩……………………………………………………………20
5.4扭矩的有效值 ……………………………………………………………21
6.滾珠絲杠高速化研究 ………………………………………………………21
1.精密滾珠絲杠副實現(xiàn)高速化要解決的主要矛盾 …………………………21
2.滾珠絲杠副高速化的技術對策 …………………………………………22
7.總結 ……………………………………………………………………23
參考文獻 ……………………………………………………………………24
致謝 …………………………………………………………………25
V
1.緒論
1.1滾珠絲杠的概述
滾珠絲桿是一種能在直線進給和周轉運動之間互相轉換的理想的機械產品。因具有傳動效率、運動平穩(wěn)、高精度、高耐磨性、高同步、高可靠性、無背隙和高剛性的諸多優(yōu)點,并被廣泛應用于機械行業(yè)。
傳統(tǒng)的滾珠絲杠采用循環(huán)方式主要有三種。
第一,外循環(huán),(管路式)其結構簡單易于使用。在滾珠滾道內通過一根插管將進口和出口相連接,從而達到無限循環(huán)。
圖1-5外循環(huán)
第二,內循環(huán),(哥德式)其結構緊湊,也比較易于小型化,但制造成本較高。
圖1-6 內循環(huán)
第三,端蓋式。(端面式)
1
圖1-7 端蓋式
滾珠絲杠至誕生以來,就得到了世人的許多關注,也進行了比較大的改進和融合。并發(fā)展出了許多不同用途,不同型號的滾珠絲杠產品。如在日本相關專利方面就有除了傳統(tǒng)內外循環(huán)的滾珠絲杠外,還出現(xiàn)了不使用循環(huán)的滾珠方案,并且得到了諸多應用。以下以舉例的形式表達一種非循環(huán)的滾珠絲杠方式:如圖,該發(fā)明滾珠絲杠螺母內加入彈性元件,并使其能夠很方便放入滾道內,使之隨著滾珠體一起進行運動。在1-1、1-2圖中,當滾珠體逆時針旋轉時,會壓迫彈性元件也向逆時針運動。當該方向運動結束后,彈性元件便會將滾珠體再壓回原來位置。同理也有另外一個方向,如圖1-3所示。
2
圖1-1 一種非循環(huán)方式的滾珠絲杠裝置
循環(huán)軌道中的彈性元件能夠在運動的開始和結束狀態(tài)起到儲能的作用,也是實現(xiàn)非循環(huán)方式運動的關鍵。
3
圖1-2 一種非循環(huán)方式逆時針方向動態(tài)圖解
圖1-3 一種非循環(huán)方式順時針方向動態(tài)圖解
可以想象如此設計能夠最大限度地縮小螺母的徑向長度,從而為滾珠絲杠的小型化開辟了道路。
圖1-4 一種非循環(huán)方式滾珠絲杠三維圖例
1.2本課題研究目的
CNC數(shù)控機床中,進給系統(tǒng)的主體實現(xiàn)元件是滾珠絲杠副。雖然滾珠絲杠已經出現(xiàn)了近百年的歷史,但其優(yōu)越性能仍然是現(xiàn)在許多元件無法替代的,并且具有很大的優(yōu)勢,啟動力矩小,定位精度高,運行可靠。并且隨著其他相關技術的成熟進步,尤其是材料性能的改善和工藝技術的改進優(yōu)化,滾珠絲杠副的優(yōu)勢將更加凸顯,所以我們很有必要將滾珠絲杠副的優(yōu)化設計放在自己的設計理念中,并將其優(yōu)點發(fā)揚光大。
2.滾珠絲杠的設計
2.1原始數(shù)據(jù)與技術條件
表1.1滾珠絲杠的主體設計要求
工作臺重量W1
25kg
工作及夾具最大重量W2
80kg
工作臺最大行程 LK
1000mm
快速進給速度Vmax
60m/min
動摩擦系數(shù)
μ=0.003
定位精度
0.02mm/300mm
重復定位精度
0.01mm
全行程定位精度
0.025mm
要求壽命
30000 h
導向面阻力
15N
額定轉速
3000 r/min
驅動電動機
AC伺服電機
減速器A
1
電動機的慣性扭矩
0.001
圖2-1 滾珠絲杠裝置整體受力圖
表1.2滾珠絲杠的主體參數(shù)
絲杠軸直徑
導程
螺母型號
精度
軸向間隙
絲杠軸支撐方式
電動機功率
2.2.1導程的選擇
導程的選擇必須與所需要的最高速度相配合,本設計中的滾珠絲杠裝置最高速度選取1m/s,也即60000mm/min。電動機擬采用AC伺服電機,其最大轉速為3000r/min。綜上,可計算出導程的許用最小值L為:
mm
在這里,根據(jù)機械手冊中查表數(shù)據(jù)可得滾珠絲杠的導程取L=20mm。
2.2.2絲杠軸長度選擇
絲杠軸的選擇必須考慮到螺母的長度,現(xiàn)在暫定其長度為160mm,絲杠軸兩末端支撐長度為160mm。
根據(jù)實際需求,絲杠長度行程長度選擇為1000mm。
則絲杠軸全長為:
2.2.3絲杠軸直徑的選擇
本設計中絲杠軸擬采用一端固定,一端支撐的方式
(公式2.1)
當安裝方式為固定,支撐時,查表:f=15.1
則Dr21.9mm
由機械設計手冊所示滾珠絲杠型號∶
絲杠軸直徑 導程
20mm —— 20mm
20mm —— 40mm
30mm —— 60mm
由上所述,根據(jù)機械手冊查表最終確定絲杠軸直徑40mm/導程20mm的設計方案。絲杠軸的設計到此為止,總體的設計圖例見下
圖4-1絲杠軸
2.2.4軸支撐方法的選擇
本設計中滾珠絲杠的最大行程為1000mm,屬于遠跨距安裝;速度為1m/s,屬高速使用;而且考慮到升溫比較有可能會導致絲杠軸變形彎曲。故而確定該支撐方法采用固定-支撐的方式。
圖2-2 絲杠形變
上圖為固定-支撐安裝方式的絲杠允許最大變形量的安裝間距,從圖上可以看出,安裝間距為1000mm的該滾珠絲杠符合要求。
圖紙設方案如圖:
圖2-3 絲杠軸左端支撐方式
圖2-4 絲杠軸右端支撐方式
絲杠軸被固定于四個軸承上,左邊的一端被緊固落螺母固定,從而達到固定的目的,如圖2-3右端為支撐端。如圖2-4所示為滾珠絲杠右端支撐方式,與左端不同之處在于這端并未采用緊固螺母,為自由端。兩端都采用角接觸球軸承和深溝球軸承疊加安裝,這樣既能夠使軸既能夠承受軸向載荷,又能夠承受徑向載荷,從而滿足滾珠絲杠正常工作時的實際要求。
2.2.5螺母的選擇
螺母旋轉型滾珠絲杠,是把滾珠絲杠螺母與支撐軸承一體的螺母旋轉式滾珠絲杠裝置。其螺母為使用外循環(huán)方式的鋼球循環(huán)結構,鋼球沿著滾道從入口到出口完成不間斷的循環(huán)。而傳統(tǒng)螺母外周嵌套有一個套筒。套筒外徑與一個調心滾子軸承相連接,通過調心滾子軸承將傳統(tǒng)螺母的徑向旋轉運動,與軸向的進給運動相互分離,從而達到螺母一邊旋轉,一邊軸向進給,而不影響與之相連接的工作臺只有軸向進給的需求。
圖3-1 螺母旋轉方式實現(xiàn)方案
兩臺電動機允許和絲杠軸、滾珠絲杠的螺母進行獨立聯(lián)接,并通過與螺母套筒相連接的齒輪將旋轉力矩傳遞給螺母和套筒,并可以使微量進給控制在電動機的穩(wěn)定旋轉范圍內。因其獨立運動的特性,該設計方案可以使用兩個伺服電機驅動,令兩臺電機同時驅動的方案,將兩個速度進行組合,可以擴大整個運動副的速度控制范圍。
3.零件的初步校核
3.1容許軸向負載的計算
最大軸向負荷的計算
導向面的阻力 (無負荷時)
工作臺質量
工件質量
導向面上的摩擦系數(shù)
最大速度
重力加速度
加速時間
由此可知,所需數(shù)值如下。
加速度(公式3.1)
去路加速時
去路等速時
去路減速時
返程加速時
返程等速時
返程減速時
作用在滾珠絲杠上的最大軸向負荷如下所示∶
現(xiàn)在選定直徑為40mm的絲杠軸、導程為20mm(最小溝槽谷徑37.4mm)的絲杠軸進行撓曲載荷和容許壓縮拉伸負荷的計算:
絲杠軸撓曲載荷:
與安裝方法相關的系數(shù)
絲杠軸溝槽谷徑
(公式3.2)
容許壓縮拉伸負荷:
由此可見, 絲杠軸的挫曲載荷和容許拉伸壓縮負荷至少等于最大軸向負,因此, 滿足這些條件的滾珠絲杠在使用上沒有問題。
3.2 絲杠軸容許轉速的計算
絲杠軸直徑:40mm; 導程:20mm;最大速度:60000mm/min
由絲杠軸的危險速度所決定的容許轉速:
與安裝方法(安裝方法按固定-支撐)相關的系數(shù)
安裝間距(推算)
絲杠軸直徑∶40mm;導程∶20mm
則許用的絲杠軸的最大轉速為:
(公式3.3)
絲杠軸直徑∶40mm;導程∶20mm和40mm(大導程滾珠絲杠)
按絲杠軸的危險速度計算可得選用絲杠軸直徑為40mm和導程為20mm的絲杠軸沒有問題。
3.3螺母運行距離的計算
最大速度
加速時間
減速時間
加速時的運行距離:
(公式3.4)
等加速時的運行距離:
(公式3.5)
減速時的運行距離:
(公式3.6)
3.4螺母軸向平均負荷及其壽命校核
正符號方向的軸向平均負荷
因載荷方向相異,取,計算軸向平均負荷:
(公式3.7)
負符號方向的軸向平均負荷
因載荷方向相異,取,計算軸向平均負荷:
(公式3.8)
因 ,所以軸向平均負荷為。
平均轉速
每分鐘往返次數(shù)
行程 LS =1000 mm
導程∶
(公式3.9)
工作額定壽命
額定壽命
每分鐘平均轉數(shù)
(公式3.10)
額定運行距離壽命
額定壽命
導程∶
(公式3.11)
4.定位精度的探討
4.1軸向剛性的探討
對軸向剛度影響最大的是發(fā)熱變形,所以在此僅對熱變形進行校核。
假設在滾珠絲杠在轉動過程中,系統(tǒng)溫度升高5℃。這時引起的軸向定位誤差為:
(公式4.1)
4.2運行中姿勢變化的探討
假設垂直公差在±10秒以下,絲杠L因垂直公差而引起的定位誤差為∶
Δa=L×sinθ
=150×sin(±10′′)
=±0.007 mm (公式4.2)
由此可知,定位精度如下∶
(公式4.3)
4.3旋轉扭矩的探討
由外部負荷引起的摩擦扭矩如下∶
(公式4.4)
滾珠絲杠副加速時所需的慣性力矩為,則絲杠軸全長1320mm的慣性力矩如下∶
= (公式4.5)
(公式4.6)
(公式4.7)
根據(jù)上述,加速所需要的扭矩如下∶
=4.61× N·mm (公式4.8)
因此,所需扭矩如下∶
加速時,
等速時,
減速時,
5.電動機的選擇
5.1旋轉速度
電動機選擇使用AC伺服電機。最高使用轉速∶3000 r/min,電動機額定轉速∶3000 rad/min
5.2電動機扭矩
設計中選擇的AC伺服電機能產生的最大扭矩為
5.3扭矩的有效值
加速時
等速時
減速時
停止時∶
(公式5.1)
電動機的額定扭矩通過以上計算必須為1305N·mm,而正常使用時電動機產生的扭矩必須為此數(shù)值之上。市面上CA伺服電機的種類繁多,選擇余地也比較大,所以在這里我們的選擇只需滿足上述條件的精度和扭矩即可。
6.滾珠絲杠高速化研究方案
6.1 精密滾珠絲杠副實現(xiàn)高速化要解決的主要矛盾
高速化不僅僅只是將滾珠絲杠副所連接的電動機的轉速提高了這一種實現(xiàn)方案,而應該采用整體優(yōu)化的設計方案。
1)速度較高時,整個滾珠絲杠系統(tǒng)可能會出 現(xiàn)加大的震動
系統(tǒng)共振時與臨界轉速的關系式為:
(公式6.1)
式中:
,支承系數(shù);
L,支承間距,mm;
E,材料縱向彈性模量,;
I,小徑最小慣性矩,mm4;
g,重力加速度,mm/s2;
γ,材料密度,N/mm3;
A,小徑橫截面積,mm2。
從上式可以看出,滾珠絲杠速度的控制因素不止一種[3]。
2)滾珠受安全轉速的限制
滾珠絲杠副通常使用d0n值(此處d0為絲杠的名義直徑,n為絲杠的轉速)表示滾珠絲杠副的速度極限,也稱作DN值。滾珠絲杠系統(tǒng)中的DN值越大,表明其運行的最高速度也最大,承載能力也最強。
3)溫升和熱變形的限制
高速轉動下的滾珠絲杠螺母副會發(fā)熱變形,進而降低滾珠絲杠的運動精度。
圖6-1 不同安裝方式下滾珠絲杠副的熱變形
從上圖可以看出,滾珠絲杠在不同安裝方式下,在正常工作狀態(tài)下,都會發(fā)熱變形,而不同的安裝方式下,其滾珠絲杠副的變形類型和性質又不近相同,其中固定-支承方式下可以允許絲杠副有微小的軸向變形,但不能過大;而固定-固定形式的支承方式因為軸向的變形不允許,其發(fā)生的彎曲變形較前者則大的多;而固定-自由型的安裝方法因其自身的類似懸臂梁的結構,所以決定了它并不能承受過大的載荷而只能使用在很小的范圍內。
4)噪聲較大,環(huán)保性差
任何機械在運行過程中都會或多或少地發(fā)出噪聲,而滾珠絲杠也不例外,高速條件下,其本身會隨著速度的提高而發(fā)出過多的噪音。
6.2 滾珠絲杠副高速化的技術對策
上述面臨的問題是滾珠絲杠副高速化的優(yōu)化目的最大的障礙。本設計依據(jù)以上的分析有針對性地提出了以下的技術和對策:
1)增大絲杠的導程和螺紋頭數(shù)
絲杠方面的資料和實際經驗告訴我們提高滾珠絲杠轉速或是加大滾珠絲杠導程都能夠提高滾珠絲杠的運行速度。
而導程的增加,會導致絲杠的運行精度下降,而且絲杠系統(tǒng)啟動力矩也會隨之升高,影響整體傳動的平穩(wěn)性。所以我們必須在轉速和導程之間取得一個平衡點。從而達到滾珠絲杠副的最優(yōu)化設計。
有設計方案采用雙頭螺紋,這既能提高其剛度和承載能力,又能提高運行中的平穩(wěn)性[5]。但也不是完全一味地增大。
2)采用強冷技術
圖6-2 螺母空心冷卻液強冷方式
如圖為滾珠絲杠的發(fā)明裝置。該裝置利用加在螺母上的空心孔,通過孔中流動的冷卻液達到為滾珠絲杠副降溫的目的。
4)改進滾珠循環(huán)返向裝置和滾珠的流暢性
5)優(yōu)化滾珠反向器的結構
發(fā)熱和噪聲都是由摩擦造成的,所以依據(jù)此原理,可以將滾道內的摩擦系數(shù)降到最低,從而達到最根本改善和優(yōu)化滾珠絲杠副。傳統(tǒng)的滾珠絲杠使用的都有一個反向器,而其精度也決定了滾珠在滾道內的順利運行。
6)無循環(huán)反向裝置
傳統(tǒng)循環(huán)方式中采用循環(huán)滾道的設計方案對 DN值有極大的制約,所以有人提出了無返向裝置的滾珠絲杠副。而本設計說明中緒論部分也進行過介紹,在此,將不再贅述。
圖6-3 行星滾柱絲杠副
上圖為一種新型的滾珠絲杠裝置,其使用非循環(huán)的滾柱絲杠形式,具有與滾珠絲杠不同的支撐部件,使用滾柱,加強了絲杠副的剛性和承載能力。使用壽命和正常使用速度也較普通滾珠絲杠有了很大的提升。
7)采用雙電動機驅動
兩臺獨立于絲杠軸和滾珠絲杠的螺母的電動機分別連接,并通過與螺母套筒相連接的齒輪將旋轉力矩傳遞給螺母和套筒,這樣做擴大了進給控制系統(tǒng)的穩(wěn)定旋轉速度范圍。因其獨立運動的特性,該設計方案可以使用兩個伺服電機驅動,令兩臺電機同時驅動的方案,將兩個速度進行組合,可以擴大整個運動副的速度控制范圍。
所以本課題的研究方向是探究一種能夠實現(xiàn)滾珠絲杠的高速運行的創(chuàng)新裝置。能夠在保證精度和機械運行的穩(wěn)定性的基礎上,達到高速,自鎖的優(yōu)化型滾珠絲杠。
總 結
經過這段時間的系統(tǒng)性公關,對自己能力又是一次新的歷練。經過這段時間,在老師的教導下,我也學會了許多新的知識和技能,畢業(yè)設計促進了自己對所學知識的掌握,并且學到了許多實踐性的東西,對自己是很有意義的。其中,有老師的諄諄教誨,龐老師對我也很嚴格,自己的也在虛心接受老師的指導,我最應該謝謝的人便是我的老師,他不僅僅是一個學術專業(yè)的教授,更是我在日后從事機械行業(yè)研究工作的人生導師。在此我也對我學到的東西進行一下簡單的總結:
1) 經過了本次畢業(yè)設計,更加鞏固了我對CAD制圖技術的熟練程度,為我日后進一步學習打下來堅實的基礎。
2) 老師的學術品格深深把我折服,這將是我以后人生道路中又一個指路明燈,這里我應該好好謝謝老師。
3) 嚴謹?shù)墓接嬎闶菑氖聶C械研究的重要品行,小到微米級的計算單位大到米級的大型機械,每一個裝配尺寸都是嚴格有依據(jù)的,決不能憑空捏造,應做到實事求是。
4) 機械工程是份神圣的行業(yè),我們每一個中國人在現(xiàn)在嚴峻的技術革命形勢下,決不能無動于衷,甘于沉浸在已經取得的成就中,而應該向前看,以不一樣的思維,開拓創(chuàng)新,為新機械制造業(yè)注入自己強大的動力。
參 考 文 獻
[1]二宮瑞穗.マシニングセンタたあの高速高精度送リ技術1997(04).
[2]宮口和男.Ball screws for high speed drive[J] 2002(673).
[3]孫健利.滾珠絲杠副的高速化技術研究[J].制造技術與機床2010.
[4]Yamaguchi H;Ohkubo TDevelopment of "NSK S1 Seris" ball screuls and linear guides2008(671).
[5]郭慶鼎;王成元;周美文.高速化滾珠絲杠技術研究,2000.
[6]Bork B;Gao Hua;羅冬梅.直線電機應用之經濟性與應用領域有關,1999(04).
[7]王先逵;陳定績;吳丹.精密滾珠絲杠綜述[J]制造技術與機床2001(08).
[8]寧立偉.滾珠絲杠副. 機床數(shù)控技術,高等教育出版社.2010-1
[9]肖正義.滾珠絲杠副的發(fā)展趨勢.制作技術與機床.2000-04
[10]黃祖堯.21世紀初海外滾動功能部件發(fā)展動態(tài).世界制作技術與裝備市場.2003-2
[11]程光仁.施祖康.滾珠螺旋傳動設計基礎.北京.機械工業(yè)出版社.1987-08
[12]喻忠志.我國滾動功能部件產業(yè)現(xiàn)狀分析.制造技術與機床.2004.04
[13]中國藝工滾動功能部件產品綜合樣本及資料
[14]肖正義.焦?jié)?高速滾珠絲杠副的研發(fā)與測試技術.制造技術與機床.2004-04
[15]滾珠絲杠譯文集.南京工藝裝備廠.1980-08
[16]THK綜合產品目錄.臺灣THK滾珠絲杠設計公司.互聯(lián)網.2013-06/2016-05
[17]PMI產品目錄.PMI滾珠絲杠設計公司.互聯(lián)網.2013-05/2016-05
[18]上銀產品目錄.上銀滾珠絲杠設計公司.互聯(lián)網.2013-06/2016-05
致 謝
這次畢業(yè)設計中,我領悟了很多東西。要十分感謝我的導師的指導,還有他的理解與包容。沒有老師我很難完成這篇設計。從設計資料的搜集,到最后設計的修改的整個過程中,耗費了老師很多心血和努力,我在這里表達我最真摯的感情。以后我一定以自己最大的努力,積極獻身新型機械制造業(yè),為實現(xiàn)自己的人生價值和社會價值而奮斗。以報答您對我的恩情。
九層之臺,起于累土,沒有前面其他機械老師的努力培養(yǎng),我也不可能學到如此有用的知識和能力,也非常感謝曾經幫助過我的老師的悉心教導。設計過程中也有其他同學的幫助,在這里我也非常謝謝他們在大學四年最后時光的陪伴。
26
International Journal of Machine Tools & Manufacture 47 (2007) 19781987A novel simple and low cost 4 degree of freedom angular indexingcalibrating technique for a precision rotary tableW. Jywea,?, C.J. Chenb, W.H. Hsieha, P.D. Linb, H.H. Jwoa, T.Y. YangaaNational Formosa University, Department of Automation Engineering, No. 64 Wenhua Rd., Huwei, Taiwan, ROCbNational Cheng-Kung University, Department of Mechanical Engineering, No. 1, University Rd., Tainan, Taiwan, ROCReceived 30 October 2006; received in revised form 1 February 2007; accepted 13 February 2007Available online 25 February 2007AbstractFor calibrating an angular rotary table, either a high precision standard table or a laser interferometer and related optics are normallyemployed at high cost. This paper establishes a novel, simple and low cost technique to calibrate the 4-degrees-of-freedom (DOF) errorsof a rotary table (three angular position errors and one linear position error) for a 3601 full circle by employing one reference rotary table,one 1 dimensional (1D) grating and two 2 dimensional (2D) position-sensing-detectors (PSD). With this technique, no highly accuratereference rotary table, but with good repeatability is needed. After two full circle tests, the 4-DOF errors of both the target rotary tableand the reference rotary table could be obtained. The system calibration, stability test, system verification and full circle test werecompleted. The angular stability of this system was less then 2arcsec, while the displacement stability was less than 1.2mm.r 2007 Elsevier Ltd. All rights reserved.Keywords: Rotary table calibration; Full circle test; Grating; Position sensing detector; 4 Degree of freedom measurement; Error separation1. IntroductionA rotary table is frequently used in industry in suchthings as machine tools, CMM and assembly lines.Therefore, the calibration of the rotary table is veryimportant. The calibration of the rotary table requires anangle measurement instrument, and the conventionalinstruments are the rotary encoder, the laser interferom-eter, the autocollimator and the precision level. A rotaryencoder 1 is commonly used in indexing measurement in arotary machine, e.g. a rotary table of the multi-axismachine tool, the joint of a robot, the spindles of machinetools and the indexing of a ball screw. However, the rotaryencoder is only suitable for the indexing error measure-ment. A laser interferometer 2 has often been used tomeasure a small angle, but it can only obtain indexing errorduring an indexing test. An autocollimator 3 is frequentlyused to measure small angles and it can be applied to twodimensional (2D) angle measurement (pitch error and yawerror), but its measurement range is small and it requireone standard polygon mirror. A rotary table has 6 DOFerrors (3 linear position errors and 3 angular positionerrors), but conventional instruments can only measureeither one dimensional (1D) error or 2D errors. Thecomplete calibration procedure of a rotary table requires 6DOF measurement for a 3601 full circle, but the measure-ment range of most measurement systems is smaller than101.Thereforethemeasurementrangeofthelaserinterferometer and autocollimator are not enough and, inaddition, they are expensive. The conventional calibrationtechnique of the rotary table for a 3601 full circle requiresone reference rotary table, which must have high accuracyand high repeatability. The error of the reference rotarytable could then be ignored from the measurement results.The instrument usually recorded one time when the targetrotary table was rotated clockwise and the reference rotarytable was rotated counterclockwise. In general, one rotarytable calibration for a 3601 full circle requires 36 recordingif the sampled period of measurement system is 101. If aARTICLE IN PRESS front matter r 2007 Elsevier Ltd. All rights reserved.doi:10.1016/j.ijmachtools.2007.02.004?Corresponding author. National Formosa University, Department ofAutomation Engineering, No. 64 Wenhua Rd., Huwei, Taiwan, ROC.Tel.: +88656315402; fax: +88656311500.E-mail addresses: jywesunws.nfu.edu.tw (W. Jywe),pmc2sunws.nfu.edu.tw (C.J. Chen), allennfu.edu.tw (W.H. Hsieh),pdlinmail.ncku.edu.tw (P.D. Lin), schongnfu.edu.tw (H.H. Jwo), (T.Y. Yang).more complete test is implemented, the calibration processwill takes a long time.In general, the rotary table includes the index error,wobble error and eccentricity. But conventional rotarytable calibration techniques (laser interferometer or auto-collimator) only calibrate the index error and the wobbleerror. However, the high precision rotary table must becalibrated in more details. Through the complete rotarytable calibration, the errors of rotary table can becompensated. In this paper, the errors of rotary table weredefined by 6 DOF, i.e. three linear position errors (dx, dy,dz) and three angular position errors (ex, ey, ez). The indexerror was represented by ez, the wobble error wasrepresented by exand ey, the eccentricity was representedby dxand dy.In recent years, angular measuring techniques havefocused on the interferometric methods. In 1992, Huanget al. 4 developed a small angle measurement systemwhich was based on the internal reflection effect in a glassboundary and Fresnels law. In Huangs system, theresolution was 0.2arcsec and the measuring range was3arcsec. In 1996, Xiaoli et al. 5 established a 2D smallrotation angle-measurement system using two differentparallel interference patterns (PIP) that were orthogonal toeach other. The standard deviation of Xiaolis system was0.6arcsec. In the following year Xiaoli et al. 6 improvedtheir system so that its resolution was 0.2arcsec andmeasuring range was 730arcmin. In 1997, Chiu et al. 7established a modified angle measurement technique with aresolution of 0.333arcsec and a measuring range of 75.61.At its optimum performance, the systems resolution was0.288arcsec. In 1998, Zhou and Cai 8 established anangle measurement technique which was based on thetotal-internal reflection effect and heterodyne interferome-try. The system resolution was better than 0.3arcsec,depending on the refractive index selected. In 1998, Huanget al. 9 established a method of angle measurement, basedon the internal reflection effects, that used a single right-angle prism. They demonstrated that angle measurementwith a range of 7500arcmin, a nonlinearity error of70.1%, and a resolution of 0.1arcsec could be readilyachieved. In 1999, Guo et al. 10 developed an opticalmethod for small angle measurement based on surface-plasma resonance (SPR), and a measurement resolutionof 0.2arcsec was achieved experimentally. In 2003, Geand Makeda 11 developed an angle-measurement tech-niquebasedonfringeanalysisforphase-measuringprofilometry. The measurement range was 72160arcsecand the deviation from linearity was better than 70.02arcsec. In 2004, Chiu et al. 12 developed an instru-ment for measuring small angles using multiple totalinternal reflections in heterodyne interferometry, and theangular resolution was better than 0.454arcsec over themeasurement range ?2.121pyp2.121 for 20 total-internalreflections.Most angle-measurement technique research focuses on 1Dangle measurement and interferometric angle measurement,and2Dmeasurementalsofocusesoninterferometrictechniques. However, interferometric systems are expensiveand complex, and cannot be used extensively in industry.Therefore, the low cost and multiple DOF measurementsystem is needed for rotary table calibration. The positionsensing detector (PSD) could be used to measure the rotarypart error, the speed of rotary part, the rotation directionof rotary part, the angular position, and the indexing error13,14. Jywe et al. employed two PSDs and one reflectivegrating to test rotary table performance 15, but itsmeasurement range was small (o11). In 15, no full circletest was implemented and no analytic solution wasprovided. However, for the general rotary table calibra-tion, the 3601 full circle test is necessary. This paper bothdescribes the building of one 4-DOF measurement systemand establishes a novel technique for rotary table full circletest. The 4-DOF system presented in this paper comprisesone 1D reflection grating, one laser diode, four PSDs andone reference rotary table.The laser interferometer and the autocollimator weremost used rotary table measurement system. However, inrotary table calibration process, the laser interferometerand the autocollimator need a high accuracy referencerotary table and a polygon mirror, respectively. Therefore,using the laser interferometer or autocollimator to calibraterotary table is expensive. Because , the cost of 1D reflectiongrating, PSD, signal conditioning unit of PSD and laserdiode and rotary table is about15of one laser interferometersystem or12of one autocollimator system. Moreover, in thepresented method, no high accurate reference rotary table,but with good repeatability is needed. Even the indexingerror and the geometric error of the reference rotary tableis large, they will be obtained by the presented method.2. The 4-DOF measurement systemIn this paper, the 4-DOF measurement system includesone reference rotary table, one 1D grating, one laser diode,two PSDs, two PSD processors, one A/D card and onepersonal computer (PC). Fig. 1 shows the schematicdiagram. The reference rotary table was placed on thetarget rotary table then the 1D grating was mounted on therotary table by the fixture. The laser diode and PSDs wereplaced near the 1D grating. The laser beam from the laserdiode was projected onto a 1D grating and then the 1Dgrating produced many diffraction light beams. In thispaper, the +1 order and ?1 order diffraction light beamare used, and two PSDs were used to detect the diffractionlight beam. Generally six geometric errors are defined on arotary table, namely three linear position errors and threeangular position errors (pitch, roll, and yaw). The threelinear position errors are dx, dyand dz, and the threeangular position errors are ex, eyand ez, respectively. Inaddition, there are eccentricity between the grating and theaxis of the rotary table, which are defined as Dxand Dy.The distance from the light point on the grating to therotary table origin point is h0.ARTICLE IN PRESSW. Jywe et al. / International Journal of Machine Tools & Manufacture 47 (2007) 197819871979The outputs of PSDs were effect by the Dy, dy, ex, eyandez. Therefore, the PSD A x-axis output isPAx l1siny 2?z ? siny? Dy dytany l1sinycos2?z cosysin2?z? siny? Dy dytany,1where y is the diffraction angle of the grating, l1is thedistance between the PSD and the grating. The diffractionequation of the grating isnl dsiny ? siny0,(2)where n is the order of diffraction, d is the grating constant,l is the wavelength of the laser source, y0is the incidentangle and y is the diffraction angle. In this paper, d is1/600mm, l 650nm and n 1. Therefore, the diffractionangle y is 22.9541.The PSD A y-axis output isPAy h0sin?x l1tan2?x l1siny h0sin?ytan?y.(3)The PSD B x-axis output isPBx l1siny ? siny ? 2?z? ? Dy dytany l1siny ? sinycos2?z cosysin2?z? Dy dytany.4The PSD B y-axis output isPBy h0sin?x l1tan2?x? l1siny ? h0sin?ytan?y.(5)From the above equations, the four geometric errors can bederived. ezis?z12sin?1PAx PBx2l1cosy?,(6)orl1PAx PBx2cosysin2?z.(7)From Eq. (7), the distance between the grating and PSDcan be calculated, if the ezis known. The linear error in they direction isDy dyPAx? l1sinycos2?z cosysin2?z? siny?tanyl1siny ? sinycos2?z cosysin2?z? ? PBxtany. 8In a full circle test, Dyis constant, dyis the function valueof the rotary angle and the summation of dyis zero.Therefore, Eq. (8) can be rewritten asdyl1siny ? sinycos2?z cosysin2?z? ? PBxtany? Dy.(9)From Eqs. (3) and (5), eyis?y tan?1PAy? PBy2l1siny?.(10)The summation of the PSD A y-axis and the PSD B y-axisisPAy PBy 2h0sin?x l1tan2?x 2h0sin?ytan?y.(11)Because h0sin?x5l1, Eq. (11) can be written as?x12tan?1PAy PBy? 2h0sin?ytan?y2l1?.(12)From Eqs. (6), (9), (10) and (12), the dy, ex, eyand ezcan beobtained throughout the PSD A and PSD B outputs.ARTICLE IN PRESSFig. 1. The schematic diagram of the 4-DOF measurement system.W. Jywe et al. / International Journal of Machine Tools & Manufacture 47 (2007) 1978198719803. The model of the full circle testThe measurement range of most instruments is lessthan 101, so the complete calibration of a rotary tablerequires a special method. In normal rotary table calibra-tion, the autocollimator uses one polygon mirror and thelaser interferometer uses one reference rotary table. In thispaper, the technique also requires one reference rotarytable, but the requirement of the reference rotary table isonly that the errors of reference rotary table must berepeatable. In 1994, Lin 16 established a rotary tablecalibration technique which could measure the indexingerror of the rotary table for a 3601 full circle. However,the technique could only measure the indexing error.Consequently, an improved technique is established inthis section. When the errors of the reference rotarytable were considered, the geometric errors of the rotarytable are?x ?xt ?xr;dx dxt dxr,?y ?yt ?yr;dy dyt dyr,?z ?zt? ?zr;dz dzt dzr,13where ezis the index difference between the target rotarytable and the reference rotary table, and it accumulativelyvaries during the calibration procedure. The ex, ey, dx, dyand dzare not accumulative. Because one full circle testneeds two tests, the repeatability of the target rotary tableand the reference rotary table must be good, otherwise themeasured results will not repeat.The basic requirement of the calibrating technique isthat the target rotary table under calibration can berotated the same step size as the reference rotary table indifferent orientations, say on for clockwise and the othercounter-clockwise. Each sector of the table under testhas been compared with every sector of the referenceone in order to build the first set of data. For example,one rotary table was tested at 12 angular positionpoints around 3601 (i.e. at 01,301,601,y,3301), whichwere equally spaced segmented in the target rotarytable and the reference rotary table. At the start inthe first test, after the target rotary table and referencerotary table were set at 01 the first set of sample was takenby personal computer. Then, the target rotary table wasrotated 301 clockwise and the reference rotary table wasrotated 301 counter-clockwise and the other sets of samplewere taken by personal computer. From the aboveexperiment process, the following relationship can bederived:?z11 ?zt1? ?zr1,?z12 ?zt2? ?zr2,.?z1n ?ztn? ?zrn,14where ez1nis the first set of angular readings and n is thenumber of increments over 3601. The subscript t of thesymbol ezt1means the error of the target rotary tableand the subscript r means the error of the referencerotary table.In the second test of full circle test, the target rotarytable and reference rotary table was set to 01 again andthereferencerotarytablewasincrementedbyonenominal step (ex. 301). After the rotation of the referencerotary table, the first set of sample was taken. Then,the target rotary table was rotated 301 clockwise andthe reference rotary table was rotated 301 counter-clock-wise and the other sets of sample were taken. Fromthe above experiment process, the results of second testwere obtained. Then, the flowing relationship can bederived:?z21 ?zt1? ?zr2,?z22 ?zt2? ?zr3,.?z2n ?ztn? ?zr1,15where ez2nis the second set of angular readings and n is thenumber of increments over 3601. The two sets of measureddata can then be rearranged as follows:ARTICLE IN PRESS1000?10000?00100?0?1000?00010?00?100?0.1000?0?1000?00100?00?100?00010?000?10?0.0.0.0.0?1.?1.0.0.0.0?.02666666666666666666437777777777777777775?zt1?zt2?zt3.?zr1?zr2?zr3.?zrn2666666666666666666437777777777777777775?z11?z12?z13.?z21?z22?z23.?z2n2666666666666666666437777777777777777775(16)W. Jywe et al. / International Journal of Machine Tools & Manufacture 47 (2007) 197819871981and the original augmented matrix is shown as:1000?10000?z110100?0?1000?z120010?00?100?z13.1000?0?1000?z210100?00?100?z220010?000?10?z23.0.0.0.0?1.?1.0.0.0.0?.?z2n2666666666666666666437777777777777777775.(17)An augmented matrix of the reduced system can then bederived as follows:1000?10000?0?z110100?0?1000?0?z120010?00?100?0?z13.0000?1?1000?0?z21? ?z110000?01?100?0?z22? ?z120000?001?10?0?z23? ?z13.0000?10000?1Pn?1i1?z2i? ?z1i0000?10000?1?z2n? ?z1n266666666666666666666664377777777777777777777775.(18)From the last two rows in the reduced matrix, it can beshown that?zr1? ?zrnXn?1i1?z2i? ?z1i ?z2n? ?z1n,(19)orXn?1i1?z2i? ?z1i 0.Since Eq. (18) is linear-dependent, more equations arerequired. An assumption is again made to presume that noclosing error exists within the reference rotary table andconsequently the following equation can be derived:?zr1 ?zr2 ?zr3 ? ? ? ?zrn?1 ?zrn 360?.(20)ARTICLE IN PRESSFig. 2. Photograph of the 4DOF measurement system with 4 PSD.Table 1Components of the prototype 4-DOF measurement systemPSDUDT SC-10D, active area 100mm2PSD signalprocessorOn-Trak OT-301PCIntel Pentium4 2.0G 256MB RAM 40G HDA/D CardAdvantech PCI-1716, 16 bit, sampling range710V, Max. sampling frequency 250kHzLaser diodel 635nm, 5mW1D GratingRolled diffraction grating, 600grooves per mm,AutocollimatorNewPort LDS Vector, measurement range:2000mradFig. 3. Calibration results (b) standard deviation.W. Jywe et al. / International Journal of Machine Tools & Manufacture 47 (2007) 197819871982Eq. (20) is then incorporated into the augmented matrix inEq. (18) to give the following:1000?10000?0?z110100?0?1000?0?z120010?00?100?0?z13.1000?0?1000?0?z210100?00?100?0?z220010?000?10?0?z23.0000?1?10000?0?z2n0000?011111?136026666666666666666666643777777777777777777775.(21)Finally, using the Gaussian Elimination method, the actualindividual angle eztiand ezriat each target position can becalculated. The calculation of exti, exri, eyti, eyri, dxti, dxri, dyti,dyri, dztiand dzriis different to eztiand ezri. For instance,?x11 ?xt1 ?xr1,?x12 ?xt2 ?xr2,.?x1n ?xtn ?xrn22and?x21 ?xt1? ?xr2,?x22 ?xt2? ?xr3,.?x2n ?xtn? ?xr1.23The summation of exriis?xr1 ?xr2 ?xr3 ? ? ? ?xrn?1 ?xrn 0?.(24)ARTICLE IN PRESSFig. 4. Stability test results (a)(d).W. Jywe et al. / International Journal of Machine Tools & Manufacture 47 (2007) 197819871983Therefore, the matrix of extiand exriis1000?10000?0?x110100?0?1000?0?x120010?00?100?0?x13.1000?0?1000?0?x210100?00?100?0?x220010?000?10?0?x23.0000?1?10000?0?x2n0000?011111?1026666666666666666666643777777777777777777775.(25)Similarly,1000?10000?0?y110100?0?1000?0?y120010?00?100?0?y13.1000?0?1000?0?y210100?00?100?0?y220010?000?10?0?y23.0000?1?10000?0?y2n0000?011111?102666666666666666666666437777777777777777777775,(26)1000?10000?0dy110100?0?1000?0dy120010?00?100?0dy13.1000?0?1000?0dy210100?00?100?0dy220010?000?10?0dy23.0000?1?10000?0dy2n0000?011111?102666666666666666666666437777777777777777777775.(27)This technique can be used in the rotary table 6-DOFcalibration, but in this paper, the measurement systemcould only measure 4-DOF errors, so this paper lists onlyfour equations (Eqs. (21), (25)(27).The recorded count was based on the measurementrange of the system. For example, the measurement rangeof Lins system (laser interferometer) 16 was about 101.Therefore, one full circle test must record at least 36 pointsduring the first and second tests, respectively.4. Experimental results and discussionIn this paper, the calibration of the 4-DOF measurementsystem, system stability, system verification and full circletest were accomplished. The photograph of this system wasshown in Fig. 2. Components not shown in Fig. 2 include adesktop PC connected to the PSD signal processor via anA/D card. The component specifications were listed inTable 1.4.1. System calibrationSystem calibration was the first experiment. In thisexperiment, the NewPort autocollimator was used toprovide the reference angular position. Its measurementrange was 7410arcsec, r
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