數(shù)控專業(yè)外文翻譯---寬槽圓柱凸輪數(shù)控加工技術(shù)的研究

1、<p><b>　　英文原文</b></p><p>　　Wide Trough Column Cam Numerical Control</p><p>　　Processing Research</p><p>　　Summary: Some questions produces which in view of the trad

2、itional milling method processing column cam, proposed one kind in view of the trough spaciously in the cutting tool diameter column cam path numerical control milling processing method. Through the analysis research, ha

3、s established one kind of correct coordinates transformation model, and processes according to this conforms to the request wide trough column cam.</p><p>　　Keywords: Numerical control processing Coordinates

4、 Transformation width trough</p><p>　　column cam</p><p><b>　　Main Text</b></p><p>　　The column cam path is generally surrounds according to the certain rule in the round

5、 cylinder and so on the wide trough. Must satisfy below to the column cam path numerical control milling processing requests: 1.The column cam path working surface namely two sides plane of normal section lines

6、must be strict parallel; 2.The column cam path must wait for the width in the work section. This is guarantees the roller in the column cam path the steady motion essential condition. When column</p><p>　　Re

7、garding the trough width size big column cam path, is very difficult to find the diameter and the trough width equal standard cutting tool. Even if has the corresponding cutting tool, but also must consider the engine be

8、d main axle output and the main axle and the work clothes jig rigidity limit, specially engine bed main</p><p>　　axle structure to cutting tool limit. For example the numerical control engine bed host axle n

9、eck is 7: 24 40 inner cones, uses for parts JT40 the tool system, then most greatly only can use φ20mm end mill (no matter straight handle bit holder). This regarding the trough width is the 38mm column cam (is processin

10、g cam which this article narrates) said is unable to process, must seek the new processing method.</p><p>　　Under and analyzes the research according to the experience, introduced one kind is smaller than th

11、e cam path width end mill with the diameter to carry on the numerical control processing to the column cam path the method, calls it the width trough column cam numerical control processing.</p><p>　　First,

12、Processing craft</p><p>　　The column cam path is surrounds in the round cylinder and so on the width trough, when its processing often is bigger than 360°. along the circumference surface milling scopeI

13、s suitable for with to have the numerical control rotary abutment the vertical numerical control milling machine to carry on the processing. According to the column cam actual structure, selects the belt key the spindle

14、makes when the cam processing the radial direction and the week to the localization datum, makes the axi</p><p>　　The column cam path base on each section usually is and so on deep, selects the flat base col

15、umn end mill processing generally. Before the column cam milling processing usually is a solid circular cylinder, must pass through working procedure and so on slot, rough machining, half precision work, precision work;

16、Because the trough cavity width is big, Therefore, except the trough working procedure and a rough machining working procedure part of knives positions path may along beside the trough ca</p><p>　　along the

17、trough cavity center alignment left, are right nearby two according to the</p><p>　　Corresponding .</p><p>　　Figure 1 column cam path two-dimensional developed view</p><p>　　Second,

18、 Solution model</p><p>　　In the column cam path numerical control processing, how extracts in each working procedure to process two sides surfaces the knife position path is key. Regarding the periphery on

19、 cam path, usually is launches first the round cylinder, extracts this working procedure in the XOS plane to process two sides surfaces the knife position path to launch curve XS; Then transforms through the coordinates,

20、 will launch the curve XS transformation will be on four coordinates engine beds knife position p</p><p>　　1.Launches curve XS the solution</p><p>　　Like chart 2 shows, Lo is the column cam pa

21、th middle line, regarding the i working procedure, Lli and Lri respectively the trough cavity which is going to process be this working procedure left, the right two sides surface launches the curve, this width is Bi

22、, processes the cutting tool radius is r (obviously 2r ≤ Bi), processes this cavity to be left, the right side knife position path launches the curve is CLli and CLri ,supposes Po is in a trough cavity middle line spot,

23、 Po is the troug</p><p><b>　　(1)</b></p><p>　　Figure 2 column cam path two-dimensional developed view</p><p>　　Po along the trough cavity middle line migration, namely m

24、ay extract this working procedure knife position path to launch curveXS in the XOS plane; According to the processing working procedure, changes in each working procedure in turn trough width Bi, then extracts the proces

25、sing to need the trough cavity all knives position path to launch the curve.</p><p>　　2.Along cam path middle line processing coordinates transformation method</p><p>　　Above the computation is

26、launches in the plane in the round cylinder to carry on, in order to extract the processing column cam path cavity the knife position path, must launch the plane in the curve to transform to the round cylinder in.</p&

27、gt;<p>　　The supposition rotating axis for circles Xaxis A axis, pi is in a knife position path knife position spot, it launches in the curve in the two-dimensional surface the</p><p>　　coordinates f

28、or (x,s), on four coordinates engine beds coordinates is (x,y,z,a).</p><p>　　Because the column cam path cavity usually is and so on deep, therefore, the z coordinates in establish after depths whic

29、h needs to process, in the processing is invariable; Below</p><p><b>　　(2)</b></p><p>　　In the formula, R is the column cam shaft radius. The previous type is the present universal u

30、se coordinates transformation formula, regarding uses the standard cutting tool to process the column cam along the cam path middle line milling is correct.</p><p>　　3.Has the question analysis to the previo

31、us type in the width trough column cam processing</p><p>　　When applies the previous type promotion in the width trough column cam</p><p>　　numerical control processing, has had some

32、 questions actually through the coordinates transformation computation knife position path in the actual processing. Finished after the column cam path processing, in order to examine whether conforms to the requir

33、ement, with the diameter was equal to the column cam bowl examines has carries on the examination, discovered actually processes the trough width does not wait for the phenomenon which, has jams. The careful obs

34、ervati</p><p>　　Like chart 3 shows, (1) may know by the formula, processes the trough cavity two sides surfaces knife position path on-line pl and the pr spot is by the trough cavity middle line in po equal-

35、space bias but, (2) transforms after the formula, pl and the pr point correspondence corner is not equal to a Pocorner, also is pl and pr corresponding cutter bar vector vlvl and po point correspondence cut

36、ter bar vector vovo not parallel, therefore, processes the trough cavity has bec</p><p>　　δa＝(B/2－r)sinθ/R(3)</p><p>　　a)Cylindercamslotsketchmapb)The A-Acuts tofaceenlarge the

37、 sketch map</p><p>　　Chart 3 Column cam path processing schematic drawing</p><p>　　(3) may know by the formula, whenθ= 0°, when is the cam path middle line and the column spool thread verti

38、cal, the angle error is a zero, namely the trough cavity is</p><p>　　on the inferior width rectangular mouth; When θ= 90°, when is the cam path middle line and the column spool thread parallel, the angl

39、e error achieved biggest, this time the trough cavity trumpet-shaped object phenomenon is most serious; When 0 <θ <</p><p>　　90°, along withθ increasing, angle error bigger, the trumpet-sh

40、aped object</p><p>　　phenomenon is also more serious. The actual processing appears the phenomenon is completely consistent with the above analysis, this explained formula (3) the analysis is entirely accur

41、ate.</p><p>　　4.Widetroughcolumncamnumericalcontrolprocessingcoordinates transformation method</p><p>　　May know by the above analysis, the formula (2) creates the cam path for on width u

42、nder the narrow trumpet-shaped object main reason is, pl and the pr point correspondence corner is defers to these two, but sl and sr which selects own arc length value sl and sr calculates are is not equal to trough cav

43、ity central point po arc length value so. Therefore, if pl and the pr point correspondence corner defers to trough cavity central point po arc length value so to calculate, may eliminate this kind </p><p>　　

44、Two-dimensional launches in the plane in the round cylinder, supposes the trough cavity middle line to launch in the curve a spot is po (xo,So), processes on two sides surfaces to correspond the knife position

45、spot in to launch in the curve the spot is pl (xl,sl) and pr (xr,pr), then, the coordinates transformation formula is:</p><p><b>　　(4)</b></p><p>　　The application formu

46、la (4) produces when knife position path processing column cam path, the result conforms to the above tentative plan completely, processes the column cam path already did not have on under the width the

47、 narrow loudspeaker trough phenomenon, but was the true on inferior wide rectangle trough.</p><p>　　Reference：</p><p>　　1.Chang W C,Van Y T.Researching Design Trens for the Redesign of Product F

48、rom</p><p>　　Design Studies 2003.24(2):173-180</p><p>　　2.Mou J,Liu C R.An error correction method for CNC machine tools using reference parts.transactions of NAMRE/SME,1994.</p><p>

49、;　　3.Sutton G P.The machine tooltask forch. Bal HarbourBal Habour Hotel,1980.</p><p>　　4.Gene F.FranklinFeedback control of Dynamis .systems,4E.</p><p><b>　　譯文：</b></p><

50、;p>　　寬槽圓柱凸輪數(shù)控加工技術(shù)的研究</p><p>　　摘要:針對傳統(tǒng)銑削方法加工圓柱凸輪所產(chǎn)生的一些問題，提出了一種針對槽寬 大于刀具直徑的圓柱凸輪槽的數(shù)控銑削加工方法。通過分析研究，建立了一種正 確的坐標(biāo)轉(zhuǎn)換模型，并依此加工出符合要求的寬槽圓柱凸輪。 </p><p>　　關(guān)鍵詞：數(shù)控加工坐標(biāo)轉(zhuǎn)換寬槽圓柱凸輪</p><p>　　圓柱凸輪槽一般是

51、按一定規(guī)律環(huán)繞在圓柱面上的等寬槽。對圓柱凸輪槽的數(shù) 控銑削加工必須滿足以下要求：1.圓柱凸輪槽的工作面即兩個(gè)側(cè)面的法截面線必 須嚴(yán)格平行；2.圓柱凸輪槽在工作段必須等寬。這是保證滾子在圓柱凸輪槽中平 穩(wěn)運(yùn)動(dòng)的必要條件。當(dāng)圓柱凸輪槽寬度不大時(shí)，可以找到相應(yīng)直徑的立銑刀沿槽 腔中心線進(jìn)行加工，比較容易加工出符合上述要求的圓柱凸輪槽。據(jù)現(xiàn)有資料介 紹，目前圓柱凸輪的銑削加工都是用這種辦法來實(shí)現(xiàn)。由于這種方法有太多的局 限性，給實(shí)際銑削加工帶來

52、許多困難。例如一旦找不到與槽寬尺寸相等的標(biāo)準(zhǔn)刀 具時(shí)，就必須對刀具進(jìn)行改制。</p><p>　　對于槽寬尺寸較大的圓柱凸輪槽，很難找到直徑與槽寬相等的標(biāo)準(zhǔn)刀具。即使有相應(yīng)的刀具，還要考慮機(jī)床主軸輸出功率及主軸和工裝夾具剛度的限制，特別是機(jī)床主軸結(jié)構(gòu)對刀 具的限制。例如數(shù)控機(jī)床主軸頭為 7∶24 的 40 號內(nèi)錐，配用 JT40 的工具系統(tǒng)，則最大只能 使用φ20mm 的立銑刀(不論直柄還是錐柄)。這對于槽寬為

53、38mm 的圓柱凸輪(就是本文所敘 述的加工凸輪)來說是無法加工的，必須尋求新的加工方法。</p><p>　　下面根據(jù)實(shí)踐經(jīng)驗(yàn)和分析研究，介紹一種用直徑小于凸輪槽寬的立銑刀對圓柱凸輪槽進(jìn) 行數(shù)控加工的方法，稱之為寬槽圓柱凸輪的數(shù)控加工。</p><p><b>　　加工工藝 </b></p><p>　　圓柱凸輪槽是環(huán)繞在圓柱面上的等寬槽，

54、其加工時(shí)沿圓周表面銑削的范圍往</p><p>　　往大于 360°，適于用帶有數(shù)控回轉(zhuǎn)臺的立式數(shù)控銑床進(jìn)行加工。根據(jù)圓柱凸輪 的實(shí)際結(jié)構(gòu)，選用帶鍵的心軸作凸輪加工時(shí)徑向和周向定位基準(zhǔn)，以心軸的臺肩 作軸向定位基準(zhǔn)，并用心軸前端部的螺紋通過螺母壓緊圓柱凸輪。圓柱凸輪的軸 向和徑向尺寸一般較大，為了克服由于懸臂加工時(shí)切削力所造成的心軸變形和加 工過程中產(chǎn)生的振顫，使用一個(gè)支承于尾座上的、與數(shù)控轉(zhuǎn)臺的回轉(zhuǎn)軸

55、線同軸的 頂尖頂住心軸中心孔作輔助支承。</p><p>　　圓柱凸輪槽的底部在每一個(gè)截面 上通常是等深的，一般選用平底圓柱立銑 刀加工。圓柱凸輪銑削加工前通常是一個(gè)實(shí)心的圓柱體，要經(jīng)過開槽、粗加工、 半精加工、精加工等工序；由于槽腔寬度較大，因此，除開槽工序及粗加工工序 的一部分刀位軌跡可以沿槽腔的中心線生成之外，其余刀位軌、跡則必須是沿槽 腔中心線向左、右兩邊按相應(yīng)的距離等距偏置生成，如圖 1 所示。<

56、/p><p>　　圖 1 圓柱凸輪槽的二維</p><p><b>　　二、求解模型</b></p><p>　　在圓柱凸輪槽的數(shù)控加工中，如何求出每道工序中加工兩個(gè)側(cè)表面的刀位軌跡是其中的關(guān)鍵。對于圓柱表面上的凸輪槽，通常是先將圓柱面展開，在 XOS 平面內(nèi)求出該工序加工兩個(gè)側(cè)表面的刀位軌跡的展開曲線 XS；然后通過坐標(biāo)轉(zhuǎn)換，將展開曲線 XS 轉(zhuǎn)

57、換為四坐標(biāo)機(jī)床上的刀位軌跡。下面討論任一加工工序中 展開曲線 XS 的求解方法，以及生成最后刀位軌跡的坐標(biāo)轉(zhuǎn)換方法。</p><p>　　1.展開曲線 XS 的求解</p><p>　　如圖 2 所示，其中 Lo 為圓柱凸輪槽的中心線，對于第 i 道工序，Lli 和 Lri 分 別為該工序?qū)⒁庸さ牟矍坏淖?、右兩個(gè)側(cè)表面展開曲線，此槽寬為 Bi，加工刀 具半徑為 r(顯然 2r≤Bi)，加

58、工此槽腔左、右側(cè)面的刀位軌跡展開曲線為 CLli 和 CLri，設(shè) Po 為槽腔中心線上的一個(gè)點(diǎn)，no 為槽腔中心線在 Po 點(diǎn)處的法矢，那么左、 右刀位軌跡展開曲線上對應(yīng)點(diǎn) Pli 和 Pri 的計(jì)算方法為：</p><p><b>　　(1)</b></p><p>　　圖 2圓柱凸輪槽的二維展開圖</p><p>　　將 Po 點(diǎn)沿著槽

59、腔中心線移動(dòng)，即可以求出該工序刀位軌跡在 XOS 平面內(nèi)的展開 曲線 XS；按照加工工序，依次改變每道工序中的槽寬度 Bi，即可求出加工所需 槽腔所有刀位軌跡的展開曲線。</p><p>　　2.沿凸輪槽中心線加工的坐標(biāo)轉(zhuǎn)換方法 </p><p>　　以上計(jì)算是在圓柱面的展開平面內(nèi)進(jìn)行的，為了求出加工圓柱凸輪槽腔的刀位軌跡，必須將平面內(nèi)的展開曲線轉(zhuǎn)換到圓柱面上。</p>&l

60、t;p>　　假設(shè)轉(zhuǎn)動(dòng)軸為繞 X 軸的 A 軸，Pi 為刀位軌跡上的一個(gè)刀位點(diǎn)，它在二維平 面展開曲線上的坐標(biāo)為(x,s)，在四坐標(biāo)機(jī)床上的坐標(biāo)為(x,y,z,a)。由于圓柱凸輪槽 腔通常是等深的，因此，z 坐標(biāo)在設(shè)置為所需要加工的深度值之后，在加工中是 不變的；對于其余三個(gè)坐標(biāo)，構(gòu)造出以下坐標(biāo)轉(zhuǎn)換公式：</p><p><b>　　(2)</b></p><p>

61、;　　式中，R 為圓柱凸輪軸的半徑。上式是目前普遍使用的坐標(biāo)轉(zhuǎn)換公式，對于用標(biāo) 準(zhǔn)刀具沿凸輪槽中心線銑削加工圓柱凸輪是正確的。</p><p>　　3.對上式在寬槽圓柱凸輪加工中產(chǎn)生問題的分析 </p><p>　　當(dāng)將上式推廣應(yīng)用于寬槽圓柱凸輪的數(shù)控加工時(shí)，通過坐標(biāo)轉(zhuǎn)換計(jì)算的刀位</p><p>　　軌跡在實(shí)際加工中卻產(chǎn)生了一些問題。在圓柱凸輪槽加工完畢后，為了檢

62、驗(yàn)是否 符合要求，用直徑等于圓柱凸輪滾子的檢具進(jìn)行檢驗(yàn)，卻發(fā)現(xiàn)所加工的槽寬窄不</p><p>　　等、有卡殼的現(xiàn)象。仔細(xì)觀察，原來加工出來的槽腔的法截面并不總是上下等寬 的矩形槽，而有時(shí)是上寬下窄的喇叭槽。為了弄清楚其中的原因，對公式(2)所 表示的坐標(biāo)轉(zhuǎn)換方法進(jìn)行了深入的分析和研究。</p><p>　　如圖 3 所示，由公式(1)可知，加工槽腔兩個(gè)側(cè)表面的刀位軌跡線上的 Pl 和 P

63、r 點(diǎn)是由槽腔中心線上的 Po 等距偏置而得，按公式(2)轉(zhuǎn)換之后，Pl 和 Pr 點(diǎn)對應(yīng) 的轉(zhuǎn)角并不等于 Po 點(diǎn)的轉(zhuǎn)角，也即 Pl 和 Pr 對應(yīng)的刀軸矢量 VlVl 與 Po 點(diǎn)對應(yīng)的 刀軸矢量 VoVo 不平行，因此，加工出來的槽腔自然就成了上寬下窄喇叭槽，而不是所需要的上下等寬的矩形槽。設(shè)截面與軸線的夾角為θ，圓柱凸輪軸的半徑為 R，刀軸矢量 VlVl 與 VoVo 的角度誤差為： </p><p>　

64、　Δa＝(B/2－r)sinθ/R(3)</p><p>　　圖 3圓柱凸輪槽加工示意圖 </p><p>　　由公式(3)可知，當(dāng)θ＝0°，也即凸輪槽中心線與圓柱軸線垂直時(shí)，角度誤</p><p>　　差為零，即槽腔是上下等寬的矩形口；當(dāng)θ＝90°，也即凸輪槽中心線與圓柱軸 線平行時(shí)，角度誤差達(dá)到最大，此時(shí)槽腔的喇叭口現(xiàn)象最嚴(yán)重；當(dāng) 0＜θ

65、＜90° 時(shí)，隨著θ的增大，角度誤差越大，喇叭口現(xiàn)象也就越嚴(yán)重。實(shí)際加工出現(xiàn)的現(xiàn) 象與上述分析完全一致，這說明公式(3)的分析是完全正確的。</p><p>　　4.寬槽圓柱凸輪數(shù)控加工的坐標(biāo)轉(zhuǎn)換方法 </p><p>　　由上面的分析可知，公式(2)造成凸輪槽為上寬下窄喇叭口的主要原因是，</p><p>　　Pl 和 Pr 點(diǎn)對應(yīng)的轉(zhuǎn)角是按照這兩個(gè)點(diǎn)自

66、己的弧長值 Sl 和 Sr 來計(jì)算的，而 Sl 和 Sr 是不等于槽腔中心點(diǎn) Po 的弧長值 So。因此，如果 Pl 和 Pr 點(diǎn)對應(yīng)的轉(zhuǎn)角均按照槽 腔中心點(diǎn) Po 的弧長值 So 來計(jì)算，就可以消除這種喇叭槽現(xiàn)象。根據(jù)這種思路，重新構(gòu)造坐標(biāo)轉(zhuǎn)換公式。</p><p>　　在圓柱面的二維展開平面上，設(shè)槽腔中心線展開曲線上的一個(gè)點(diǎn)為 Po(xo,so)， 加工兩個(gè)側(cè)表面上對應(yīng)刀位點(diǎn)在展開曲線上的點(diǎn)為 Pl(xl,s

67、l)和 Pr(xr,sr)，那么，坐標(biāo)轉(zhuǎn)換公式為：</p><p><b>　　(4)</b></p><p>　　應(yīng)用公式(4)生成的刀位軌跡加工圓柱凸輪槽時(shí)，結(jié)果完全符合上述的設(shè)想，加工出來的圓柱凸輪槽已經(jīng)沒有了上寬下窄的喇叭槽現(xiàn)象，而是真正的上下等寬矩形槽。</p><p><b>　　參考文獻(xiàn)：</b></p

68、><p>　　1.Chang W C, Van Y T. Researching Design Trens for the Redesign of Product . Design Studies , 2003, 24(2):173-180.</p><p>　　2.Mou J, Liu C R. An error correction method for CNC machine tool

69、s using reference parts. Transactions of namre/sme, 1994.</p><p>　　3.Sutton G P. The machine tooltask forch. Bal HarbourBal Habour Hotel, 1980.</p><p>　　4.Gene F.FranklinFeedback control of