外文翻譯---尺寸控制

1、<p><b>　　附錄</b></p><p><b>　　附錄1</b></p><p><b>　　英文翻譯</b></p><p>　　Dimensional Control</p><p>　　In the early days of engineer,

2、the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, u

3、ntil thedesired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit

4、 was obtained, the fitter the</p><p>　　1. Tolerance and Limits of size</p><p>　　Since it is accepted that it is virtually impossible to manufacture a part without error, or in the rare event of

5、a part being without error, to be able to proclaim it to be perfect (because the measuring instruments are subject to errors), it is necessary to indicate the maximum errors permitted. The draughtsman must indicate the l

6、argest and smallest sizes that the limits of size, and the difference between them is called the tolerance, the actual tolerance must be increased with size. The tole</p><p>　　(1) Unilateral limits. These ar

7、e usually used when the distance between two faces, or the diameter of a hole or shaft id specified. For example, when a diameter is being ground, the machinist would prefer to aim at the largest size permitted, so that,

8、 in the event of his reaching a diameter that is just a little larger than the maximum size permitted, he can take another cut, knowing that he can use up the whole of the tolerance before the job is rejected. A draughts

9、man might dimension a nominal</p><p>　　(2) Bilateral limits. These are usually applied when, for example, the position of a hole is specified. The machine operator may position he hole nearer the datum or fu

10、rther from the datum than intended, he must aim between the limits of position, so that the maximum error can be made without causing the part to be rejected. The center distance between two holes would therefore be spec

11、ified as, for example, 100+0.02mm.</p><p>　　2. Fits are concerned with the relationship between two parts. Consider a shaft and a hole combination: if the shaft is larger than the hole, the condition is said

12、 to be of interference; and if smaller than the hole, the condition is said to be of clearance. The interference may be such that the two parts can be assembled only by shrinking, or it may be very slight, so that the pa

13、rts can be assembled by hand-operated press. Similarly, the clearance can be slight, so that the shaft can rotate eas</p><p>　　(1) Classes of fit. These are classified as follows.Clearance fit. When the limi

14、ts of size of both the hole and the shaft are such that the shaft is always smaller than the hole, the fit id said to be a clearance fit.Interference fit. When the limits of size of both the hole and the shaft are such t

15、hat the shaft is always larger than the hole, the fit id said to be a interference fit.Transition fit. When the limits of size of both the hole and the shaft are such that the condition may be clearan</p><p>

16、;　　(2) Hole-based system and Shaft-based system. In order to obtain a range of degrees of clearance, and degrees of interference, it is necessary to use a wide variation of hole sizes and shaft sizes. For example, a manu

17、facturing company could be making a number of parts, all of a nominal 25-mm diameter, but which are all slightly different in actual limits of size, to suit the actual fit required of each pair of parts. This situation c

18、ould mean that a large number of drills, reamers, gauges, etc. </p><p>　　gauges; but a shaft-based system is usually also provided, because sometimes it is more convenient to employ a common shaft to which a

19、 number of components is assembled, each with a different fit, and sometimes it is convenient to use bar stock without further machining.</p><p>　　3. Systems of limits and fits It is convenient to establish

20、a standardized system of limits and fits, not only to eliminate the need for the draughtsman to determine the limits each time an assembly is detailed, but also to standardize the tools and gauges required. A system of l

21、imits and fits should cater for a wide range of nominal sizes. To satisfy the various needs of industry, and should cater for a wide range of quality of work. The system should, if possible, be tabulated, to save the use

22、</p><p>　　4. British Standard 4500: 1969, ISO limits and fits</p><p>　　This standard replace BS 4500 is essentially a revision of BS 1961 to bring the British Standard into line with the latest

23、recommendations of the International Organization for Standardization (ISO). The system refers to holes and shafts, but these terms do not only apply to cylindrical parts but can equally well be applied to the space cont

24、ained by. Or containing, two parallel faces or tangent planes. The system is tabulated,and covers sizes up to 3150mm.</p><p>　　The Numerical Control’s development</p><p>　　The first electronic c

25、omputer in the world emerged in 1946, this indicates the mankind has created the tool that can strengthen and replace the mental labour partly . It, and mankind those that create to strengthen tool of manual labor compar

26、e among agriculture, industrial society, the qualitative leap has arisen , has established the foundation that the mankind enters the information-intensive society . 6 years later, namely in 1952, the technology of the c

27、omputer was applied to the lathe , the</p><p>　　Price performance on all these for improving been for lathe than,namely last mechanical performance and the working ability not higher with less money. So tran

28、sform ordinary lathe as numerical control lathe whether one improve numerical control effective way of rate. Generally speaking, carry on the transformation concrete method of numerical control to the existing ordinary l

29、athe, main transmission make change seldom, is it adopt high-accuracy ball guide screw is it is it give axle already exis</p><p>　　According to the function level of the numerical control system , can divide

30、 the numerical control system into high , middle and low three to block , the low-grade numerical control system can be regarded as the economy numerical control system. The economy numerical control system is as to stan

31、dard numerical control system, different periods, the meaning of different countries and regions is different. According to practising the instructions for use of the lathe, rational reduced system, lower</p><

32、p>　　As regards its function, economy numerical control system general resolution ratio is it give speed to be low moving axle count little , man-machine relatively simple excuse in succession to enter. If position /la

33、st control system sharply can last numerical control system not economy. As to its structure, make ring numerical control system general high performance, but of simple structure, the fabrication cost is cheap, can be th

34、e most economic numerical control system . So economy numerical con</p><p>　　Have close standard numerical control system of ring, economy numerical control system is it change numerical control system right

35、 away there is no ample scope for abilities to turn on. In fact , make ring numerical control system use quite extensive even in our country. The high-performance standard numerical control system costs an arm and a leg,

36、 a lot of enterprises are difficult to bear . In addition recommend precise festival produce now, with what whom equipment process with low costs and </p><p><b>　　附錄2</b></p><p><

37、b>　　中文譯文</b></p><p><b>　　尺寸控制</b></p><p>　　在早期的工程（問題）中，配合零件獲得的方法是，首先盡可能把一個零件加工到所</p><p>　　需的尺寸，再將與它相配合的零件加工到接近所需尺寸，不斷將這兩個零件試配，再進一</p><p>　　步加工直至獲得所

38、許的配合關系。如果加工中不便于將兩個零件進行試配，則最后的工作</p><p>　　是由鉗工在鉗工臺完成，鉗工刮削配合零件直至達到所許配合，因此“鉗工”在英文中用‘fitter’（適當?shù)?，適配的）這一詞。顯然，兩個配合件應該總是在一起（工作）當其中任意一個需要替換時，所有的適配刮削工作又要從頭開始。這時，我們期盼能購買到可以替換壞掉零件的替用品，而無須刮削或其它鉗工操作就能正常工作。</p><

39、;p>　　當一個零件一從架子上拿來就可以替換同樣尺寸同樣材料規(guī)格的另一個零件，就說這</p><p>　　個零件是可互換的。具有可互換性的系統(tǒng)不必進行高成本的輔助刮削工作，因此降低了產(chǎn)</p><p>　　品的成本。在要替換掉磨損的零件時，零件的可互換性對維護而言也是大有好處的。然而，</p><p>　　可互換系統(tǒng)要求配合件的 尺寸必須規(guī)格化，還必須考慮由于

40、加工操作的不足之處引入的尺寸變化。必須采用某種形式的檢測方法以確保對加工的控制。這一點非常重要。因為尺寸誤差有時可能要過一段時間才會發(fā)現(xiàn)，而此時卻已遠離加工的地方。</p><p>　　1． 公差與極限尺寸</p><p>　　大家知道，事實上零件不可能毫無誤差的加工出來，或者說沒有誤差的零件是不可能</p><p>　　的，要說明尺寸的好壞（因為測量儀器必然有誤差

41、），就有必要指出最大允許誤差。繪圖</p><p>　　人員必須標明零件正常工作時的最大允許尺寸和最小允許尺寸。這些尺寸的極限值就稱作</p><p>　　極限尺寸，它們之間的差值稱為公差。公差的大小取決于所涉及的加工操作類型、機械工</p><p>　　的技能、機床的精確度以及零件的尺寸。對于給定級別的公差，實際公差應隨著尺寸的增</p><p

42、>　　大而增大。公差應盡可能取大以使加工成本最小。</p><p>　　在圖上標注公差時，許用公差主要取決于所用操作類型，但也必須考慮本國的優(yōu)先級。</p><p>　　以下用例子說明用到的一些標注方法：</p><p>　　（1） 單邊極限。單邊極限通常用于當兩個面之間的距離，或孔徑、軸徑被指定的情況下。例如，當直徑要圓整時，機械工更愿意向最大允許尺寸圓整，

43、這樣，當他加工到所得直徑尺寸略大于最大允許尺寸時，還可以在整個公差范圍內(nèi)再切一次而不產(chǎn)生廢品。制圖員可能將公稱直徑是75-0.012mm 的軸標注為D75mm。同樣的，公稱直徑是75mm 的孔也可能標的尺寸是D75-0.012mm，這同樣也適用于軸的標注。</p><p>　　（2） 雙邊極限。雙邊極限通常用于：比如當孔的位置已確定的情況下。機床操作人員可能將孔的位置定得較接近或遠離所需數(shù)據(jù)，而且，當孔的加工已經(jīng)

44、開始，操作人員不可能改變孔的位置，他必須在尺寸位置限度間加工，以便在最大誤差時不會使零件變成廢品。因此，應將兩個孔的中心距規(guī)定出來，比如，為100+0.02mm。</p><p><b>　　2. 配合</b></p><p>　　配合是關于兩個零件之間的關系?？紤]孔和軸的裝配；如果軸的尺寸大于孔的尺寸，這種情況稱為過盈配合；如果軸的尺寸小于孔的尺寸，這種情況稱為間隙

45、配合。過盈配合的兩個零件只有通過收縮才能裝配，或者過盈量非常小可通過用手壓力的操作裝配零件。同樣，間隙非常小，軸可以很容易的在孔中旋轉，或者孔的尺寸大一些，以便于有足夠的間隙供螺栓從中穿過。為了確保精確，孔和軸的極限尺寸都必須予以規(guī)定。</p><p>　?。?）裝配分類如下：</p><p>　　間隙配合 當孔和軸的尺寸界限滿足軸總是小于孔，則其配合為間隙配合。</p>&

46、lt;p>　　過盈配合 當孔和軸的尺寸界限滿足軸總是大于孔，則其配合為過盈配合。</p><p>　　過渡配合 當孔和軸的尺寸界限所處的情況可能是間隙也可能是過盈，則稱為過渡配合。</p><p>　　( 2 ) 基孔制和基軸制。為了得到不同程度的間隙和過盈，有必要使孔和軸的尺寸有變化范圍。比如，制造公z_j_(躝_z_司可能生產(chǎn)許多零件，它們的基本直徑都是25mm，但它們的實際尺寸

47、都是在允許極限尺寸內(nèi)稍有不同，以滿足每對零件的實際裝配要求。這就是說需要大量的鉆頭、絞刀和量具等。從邏輯上看，要減小鉆頭、絞刀和量具等的數(shù)量，應對每種基本的尺寸用一個標準的孔，通過把與它配合的軸的尺做得稍大或稍小以獲得不同的配合關系，這就是基孔制。另一種方法，每種基本尺寸都 用一個標準的軸，用比它的尺寸稍大后稍小的孔與它配合以獲得不同的配合關系，這就是基軸制。用基孔制更好些，因為它可使“固定尺寸”設備如絞刀、測量儀等標準化。但也可用基軸

48、制，當要用同一個軸和許多零件裝配實現(xiàn)不同配合關系時用基軸制更方便。有時，直接用棒料進行裝配而無須進一步加工，也使用基軸制。</p><p>　　3. 極限尺寸與配合系統(tǒng)</p><p>　　建立一個標準化的極限尺寸及配合系統(tǒng)是很方便的，它不但省略了繪圖員每次確定裝配確定極限尺寸的需要，而且還可使刀具及量具標準化。一種極限尺寸及配合標準應適用于不同的質量范圍的工件。如果可能，這個系統(tǒng)應做成表

49、格形式以免除使用者根據(jù)配合種類工件質量及零件尺寸來計算尺寸的麻煩。</p><p>　　4. 英制標準4500：1969，ISO極限尺寸及配合</p><p>　　這個標準取代了bs1961，可以是英制的尺寸也可以是公制的尺寸 。除了完全采用公制外，基本上是的改進把英國標準和最近推薦的國際標準化組織結合起來。這個系統(tǒng)引用的是軸和孔，但這些術語不僅適用于圓柱型的工件，也同樣適用于包含兩個平行

50、面或矩形面的地方。把這個系統(tǒng)列成表，其尺寸范圍達到3150mm。</p><p><b>　　數(shù)控車床的發(fā)展</b></p><p>　　1946年誕生了世界上第一臺電子計算機，這表明人類創(chuàng)造了可增強和部分代替腦力勞動的工具。它與人類在農(nóng)業(yè)、工業(yè)社會中創(chuàng)造的那些只是增強體力勞動的工具相比，起了質的飛躍，為人類進入信息社會奠定了基礎。6年后，即在1952年，計算機技術應

51、用到了機床上，在美國誕生了第一臺數(shù)控機床。從此，傳統(tǒng)機床產(chǎn)生了質的變化。近半個世紀以來，數(shù)控系統(tǒng)經(jīng)歷了兩個階段和六代的發(fā)展。數(shù)控機床作為機電一體化的典型產(chǎn)品，在機械制造業(yè)中發(fā)揮著巨大的作用，很好地解決了現(xiàn)代機械制造中結構復雜、精密、批量小、多變零件的加工問題，且能穩(wěn)定產(chǎn)品的加工質量，大幅度地提高生產(chǎn)效率。但從目前企業(yè)面臨的情況看，因數(shù)控機床價格較貴，一次性投資較大使企業(yè)心有余而力不足。我國作為機床大國，對普通機床數(shù)控化改造不失為一種較好

52、的良策。本文針對目前國內(nèi)企業(yè)現(xiàn)狀，提出簡易型經(jīng)濟數(shù)控改造思路和設計方法供數(shù)控技術人員參考。</p><p>　　數(shù)控改造一般是指對普通機床某些部位做一定的改造,配上數(shù)控裝置,從而使機床具有數(shù)控加工能力,其目的是為了提高老設備的加工精度和生產(chǎn)效率,適應多品種和小批量零件的生產(chǎn),同時可以使技術等級較低的工人也能加工出高質量的零件,減少設備技術改造的投資等。所有這些都是為了提高機床的價格性能比,即用較少的錢得到較高的機

53、械性能和加工能力。因此,把普通機床改造為數(shù)控機床是一條提高數(shù)控化率的有效途徑。一般來說,對現(xiàn)有普通車床進行數(shù)控改造的具體做法是,主傳動系統(tǒng)一般不作變動,進給傳動系統(tǒng)中采用高精度的滾珠絲杠替換進給軸原有的普通絲杠。機械部分改造完成后,配上ＭＣＳ-51單片機作為數(shù)控系統(tǒng),用步進電機作驅動元件,經(jīng)過一級減速齒輪驅動Ｘ、Ｚ軸的運動。在我國數(shù)控機床改造中,微型計算機大多采用ＭＣＳ—51型系統(tǒng)單片微型計算機,它是超大規(guī)模集成電路發(fā)展的產(chǎn)物,在控制領

54、域中得到廣泛的應用,發(fā)展非常迅速。按數(shù)控系統(tǒng)的功能水平，可以把數(shù)控系統(tǒng)分為高、中、低三擋，低檔數(shù)控系統(tǒng)即可認為是經(jīng)濟型數(shù)控系統(tǒng)。經(jīng)濟型數(shù)控系統(tǒng)是相對標準數(shù)控系統(tǒng)而言的，不同時期，不同國家和地區(qū)的含義是不一樣的。根據(jù)實習機床的使用要求，合理簡化系統(tǒng)，降低成本</p><p>　　就其功能而言，經(jīng)濟型數(shù)控系統(tǒng)一般分辨率和進給速度較低、連動軸數(shù)少、人機借口較簡單。如點位/直線切削控制系統(tǒng)都可以認為是經(jīng)濟型數(shù)控系統(tǒng)。對其

55、結構而言，開環(huán)數(shù)控系統(tǒng)一般性能不高，但結構簡單，造價低廉，可以說得上是最經(jīng)濟的數(shù)控系統(tǒng)。所以，經(jīng)濟型數(shù)控系統(tǒng)在國內(nèi)現(xiàn)階段主要是指開環(huán)數(shù)控系統(tǒng)。</p><p>　　并不是有了閉環(huán)的標準型數(shù)控系統(tǒng)，經(jīng)濟型數(shù)控系統(tǒng)或開換數(shù)控系統(tǒng)就無用武之地了。事實上，開環(huán)數(shù)控系統(tǒng)在我國應用還相當廣泛。高性能的標準型數(shù)控系統(tǒng)價格昂貴，許多企業(yè)難以承受。此外，現(xiàn)在都提倡精節(jié)生產(chǎn)，用什么設備加工的成本低并且質量能保證，就用什么設備加工，若