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徐 州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論 文 ) I 摘要 本課題是設(shè)計(jì)一種專(zhuān)門(mén)對(duì)法蘭盤(pán)進(jìn)行加工的帶自動(dòng)分度機(jī)構(gòu)的回轉(zhuǎn)工作臺(tái)的設(shè) 計(jì)，利用步進(jìn)電動(dòng)機(jī)進(jìn)行自動(dòng)分度的控制，再通過(guò)齒輪傳動(dòng)帶動(dòng)心軸和工件轉(zhuǎn)動(dòng)， 配合鉆床對(duì)法蘭盤(pán)進(jìn)行加工，使工件能任意角度的旋轉(zhuǎn)。在單片機(jī)的控制下，步進(jìn) 電機(jī)每秒鐘發(fā)出的脈沖數(shù)決定了工作臺(tái)的轉(zhuǎn)位角度。 關(guān)鍵詞 步進(jìn)電動(dòng)機(jī)；自動(dòng)分度；齒輪傳動(dòng) 徐 州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論 文 ) II Abstract This subject is a special design to the flange with automatic processing of the rotary table, the subject is to use a stepper motor of automatic control, then through the drive spindle and the workpiece rotation, and then processing flange plate of the drilling machine, the work piece can be revolving random angle. Under the control of the microcontroller, the pulse per second from the stepper motor decides the table of the transfer point. Keywords stepper motor automatic degrees gear 徐 州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論 文 ) 1 目 錄 1 緒論 .....................................................................1 1.1 回轉(zhuǎn)工作臺(tái)的簡(jiǎn)介和應(yīng)用 .................................................1 1.1.1 回轉(zhuǎn)工作臺(tái)的簡(jiǎn)介 ...................................................1 1.1.2 回轉(zhuǎn)工作臺(tái)的應(yīng)用 ...................................................2 2 方案的選擇 ................................................................3 2.1 數(shù)控回轉(zhuǎn)工作臺(tái) ........................................................4 2.2 分度工作臺(tái) .............................................................4 2.2.1 開(kāi)環(huán)數(shù)控轉(zhuǎn)臺(tái) ......................................................4 2.2.2 閉環(huán)數(shù)控回轉(zhuǎn)工作臺(tái) ................................................5 3 工作臺(tái)的設(shè)計(jì) ...............................................................7 3.1 加工零件分析 ...........................................................7 3.2 步進(jìn)電動(dòng)機(jī)的選擇 .......................................................8 3.2.1 步進(jìn)電動(dòng)機(jī)簡(jiǎn)介 .....................................................8 3.2.2 步進(jìn)電動(dòng)機(jī)的選擇和參數(shù) .............................................9 3.2.3 單片機(jī)控制步進(jìn)電機(jī)原理 .............................................11 3.2.4 單片機(jī)驅(qū)動(dòng)工作臺(tái)上步進(jìn)電機(jī)設(shè)計(jì) ....................................12 3.3 錐齒輪的選擇和計(jì)算 ....................................................21 3.3.1 齒輪設(shè)計(jì)輸入?yún)?shù) ...................................................21 3.3.2 齒輪的材料及熱處理 .................................................21 3.3.3 齒輪的基本參數(shù) .....................................................21 3.3.4 齒面接觸疲勞強(qiáng)度校核 ...............................................23 3.3.5 齒根彎曲強(qiáng)度校核 ...................................................24 3.4 心軸的設(shè)計(jì) ............................................................25 3.4.1 軸類(lèi)零件的技術(shù)要求 .................................................25 3.4.2 軸類(lèi)零件的材料、毛坯及熱處理 .......................................25 3.4.3 心軸的較核 .........................................................25 3.5 軸承的選擇 ............................................................30 3.5.1 軸承的分類(lèi) .........................................................30 3.5.2 推力球軸承的作用 ..................................................30 3.5.3 軸承的選定 ........................................................31 3.5.4 軸承的動(dòng)載荷和壽命計(jì)算 .............................................31 徐 州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論 文 ) 2 3.6 夾緊裝置的設(shè)計(jì) ........................................................32 3.7 箱體 的設(shè)計(jì) ............................................................33 結(jié)論 .......................................................................33 致謝 .......................................................................36 參考文獻(xiàn) ...................................................................37 附錄 .......................................................................38 附錄 1 ....................................................................38 附錄 2 ....................................................................43
徐州工程學(xué)院
畢業(yè)設(shè)計(jì)（論文）任務(wù)書(shū)
徐州工程 學(xué)院 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專(zhuān)業(yè)
設(shè)計(jì)（論文）題目 帶自動(dòng)分度機(jī)構(gòu)的法蘭盤(pán)加工回轉(zhuǎn)工作臺(tái)設(shè)計(jì)
學(xué) 生 姓 名 陸愛(ài)軍
班 級(jí) 04機(jī)本2班
起 止 日 期 2008.02.25到2008.06.02
指 導(dǎo) 教 師 陳躍
教研室主任 李志
發(fā)任務(wù)書(shū)日期 2008 年 2月 25 日
1.畢業(yè)設(shè)計(jì)的背景：
回轉(zhuǎn)工作臺(tái)是各種機(jī)床上必不可少的配件，目前應(yīng)用在各種銑床和數(shù)控機(jī)床上，它配合步進(jìn)
電動(dòng)機(jī)的自動(dòng)分度加工在機(jī)械領(lǐng)域有更大的應(yīng)用。它能準(zhǔn)確的加工所需要的零件，而且加工方便
簡(jiǎn)單。
2.畢業(yè)設(shè)計(jì)(論文)的內(nèi)容和要求：
設(shè)計(jì)內(nèi)容：
1. 工作臺(tái)機(jī)械機(jī)構(gòu)設(shè)計(jì)
2. 自動(dòng)分度控制電路設(shè)計(jì)
設(shè)計(jì)要求：設(shè)計(jì)一種專(zhuān)門(mén)加工法蘭盤(pán)的鉆床工作臺(tái)，可以針對(duì)不同的法蘭盤(pán)，進(jìn)行自
動(dòng)分度加工，要求分度方便準(zhǔn)確，工作臺(tái)便于安裝。
1．A0圖紙三張，分別為系統(tǒng)裝配圖和各零件圖，電路圖；
2．畢業(yè)設(shè)計(jì)說(shuō)明書(shū)一本（2萬(wàn)字）；
3．相關(guān)外文資料翻譯（5000字）。
3.主要參考文獻(xiàn)：
[1] 實(shí)用機(jī)械設(shè)計(jì)手冊(cè)上冊(cè)，機(jī)械工業(yè)出版社，《實(shí)用機(jī)械設(shè)計(jì)手冊(cè)》編寫(xiě)組 編，1992 年9月。
[2] 機(jī)械精度設(shè)計(jì)基礎(chǔ)，科學(xué)出版社，孫玉芹，孟兆新主編，2004年2月。
[3] 電動(dòng)機(jī)的單片機(jī)控制，北京航空航天大學(xué)出版社，2002年。
[4] 金屬切削原理，上?？茖W(xué)技術(shù)文獻(xiàn)出版社，上海紡織工業(yè)專(zhuān)科學(xué)院，劉源燦主編，1984年4月。
[5] 自動(dòng)控制原理，機(jī)械工業(yè)出版社，陳玉宏主編，2003年。
4.畢業(yè)設(shè)計(jì)(論文)進(jìn)度計(jì)劃(以周為單位)：
起 止 日 期
工 作 內(nèi) 容
備 注
第1周
第2周
第3，4周
第5，6周
第7，8周
第9周
第10周
第11，12周
第13，14周
第15，16周
2008.6.2
了解設(shè)計(jì)的機(jī)本要求，查閱相關(guān)資料
查閱相關(guān)資料，寫(xiě)開(kāi)題報(bào)告
外文資料翻譯 設(shè)計(jì)方案比較選擇
工作臺(tái)設(shè)計(jì)計(jì)算
分度部分設(shè)計(jì)計(jì)算
分度控制電路設(shè)計(jì)
分度程序設(shè)計(jì)
繪制機(jī)械和電路圖
撰寫(xiě)畢業(yè)設(shè)計(jì)說(shuō)明書(shū)
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附錄
附錄1
英文翻譯
Dimensional Control
In the early days of engineer, 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, until 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 was obtained, the fitter therefore being a ‘fitter’ in the literal sense. It is obvious that the two parts would have to be done all over again. In these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations. When one part can be used ‘off the shelf’ to replace another of the same dimension and material specification, the parts are said to be to be interchangeable. A system of interchangeability usually lowers the production costs, as there is no need for an expensive ‘fiddling’ operation, and it also benefits the customer in the event of the need to replace worn parts. It also, however, demands that the dimension of mating parts be specified, and that dimensional variations, due to machine and operator shortcomings, be taken into account. Some form of inspection must be introduced to ensure that the manufacture is controlled; this is particularly important, because dimensional errors may not be revealed until some time has elapsed, and often many miles from the place where the machining was done.
1. Tolerance and Limits of size
Since it is accepted that it is virtually impossible to manufacture a part without error, or in the rare event of 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 largest 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 tolerance should be as large as possible, to keep the cost to a minimum.The method of indicating, on a drawing, the permitted tolerance depends mainly upon the type of operation involved, but local preference must also be taken into account. The following examples will illustrate some of the methods used,
(1) Unilateral limits. These are 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, 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 draughtsman might dimension a nominal 75-0.012 mm diameter shaft as D75. Similarly, a nominal 75mm hole might dimensioned as D75-0.012, the same reasoning applies as for shafts.
(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 further 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 specified as, for example, 100+0.02mm.
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 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 parts can be assembled by hand-operated press. Similarly, the clearance can be slight, so that the shaft can rotate easily in the hole, or be large, so that there is ample clearance for bolts to pass through.In order that the precise condition is ensured, the limits of size of both the shaft and the hole must be stipulated.
(1) Classes of fit. These are classified as follows.Clearance fit. When the limits 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 that 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 clearance or interference, the fit id said to be a transition fit.
(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 manufacturing 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 could mean that a large number of drills, reamers, gauges, etc. were required.It is logical that, to reduce this number, a standard hole could be used for each nominal size, and the variation of fit e obtained by making the mating shaft smaller or larger than the hole. This is known as a hole-based system. Alternatively, a standard shaft could be used for each nominal size, and the variation of fit is obtained by making the mating hole larger or smaller, as required. This is known as a shaft-based system. a hole-based system is usually preferred, because it standardizes “fixed size” equipment such as reamer and plug
gauges; but a shaft-based system is usually also provided, because sometimes it is more convenient to employ a common shaft to which a number of components is assembled, each with a different fit, and sometimes it is convenient to use bar stock without further machining.
3. Systems of limits and fits It is convenient to establish 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 limits 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 user the trouble of having to calculate the limits of size to suit of the class of fit, the quality of the work, and the size of the part.
4. British Standard 4500: 1969, ISO limits and fits
This standard replace BS 4500 is essentially a revision of BS 1961 to bring the British Standard into line with the latest 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 contained by. Or containing, two parallel faces or tangent planes. The system is tabulated,and covers sizes up to 3150mm.
The Numerical Control’s development
The first electronic computer 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 compare 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 computer was applied to the lathe , the first numerical control lathe has emerged in U.S.A.. From then on, the traditional lathe had produced the change of the quality. In nearly half a century, the numerical control system went through two stages and six generations' development The numerical control lathe is regarded as the integrated typical products of electromechanics, play an enormous role among mechanical manufacturing industry , solve structure complicated , accurate , batch little , changeable processing problem of part in the modern machine-building well, and can stabilize the processing quality of the products , improve production efficiency by a large margin . But seen from situation which enterprises face at present, because the numerical control lathe price is relatively expensive, ambassador's enterprises are unable to do what one wants very much to do to relatively make the investment once only. Our country can yet be regarded as a kind of better good plan to the numerical control transformation of the ordinary lathe as the lathe big country . This text proposes to the domestic enterprise's current situation at present the economic numerical control of the simple and easy type transforms the thinking and design method for technical staff of numerical control's reference.Numerical control transformation mean to ordinary lathe some position make certain transformation generally, match the numerical control device, thus make the lathe have working ability of numerical control, its purpose is for improving machining accuracy of the old equipment and production efficiency, adapt to many variety and production , short run of part , can make industrial grade can process the high-quality part too than low worker at the same time, reduce investment of technological transformation of the equipment ,etc..
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 transform 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 lathe, main transmission make change seldom, is it adopt high-accuracy ball guide screw is it is it give axle already existing ordinary guide screw to enter to replace to enter the transmission of giving. Machinery some transformation after finishing , mix M C S - 51 one-chip computer as numerical control system , with walk into electrical machinery urge the component, first class to moderate gear wheel urge X , sport , Z of axle. In our country in the numerical control lathe is transformed , the microcomputers mostly adopt M C S - type 51 one slice of microcomputers of systematic form, it is a result of very large scale integration development, widely used in the controlled field, develop very fast.
According to the function level of the numerical control system , can divide 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 standard 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 costs , can be called economily. Different from the economy numerical control system , call the numerical control system with more complete function numerical control system of the whole function, or is called the standard numerical control system.
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 /last 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 the most economic numerical control system . So economy numerical control system mainly refer to turning on the numerical control system of the ring at the present stage at home.
Have close standard numerical control system of ring, economy numerical control system is it change numerical control system right 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, a lot of enterprises are difficult to bear . In addition recommend precise festival produce now, with what whom equipment process with low costs and quality can guarantee, process some equipment, if pursue the high precise equipment blindly, then the production cost increases, this is unnecessary.
附錄2
中文譯文
尺寸控制
在早期的工程（問(wèn)題）中，配合零件獲得的方法是，首先盡可能把一個(gè)零件加工到所
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(gè)零件試配，再進(jìn)一
步加工直至獲得所許的配合關(guān)系。如果加工中不便于將兩個(gè)零件進(jìn)行試配，則最后的工作
是由鉗工在鉗工臺(tái)完成，鉗工刮削配合零件直至達(dá)到所許配合，因此“鉗工”在英文中用‘fitter’（適當(dāng)?shù)模m配的）這一詞。顯然，兩個(gè)配合件應(yīng)該總是在一起（工作）當(dāng)其中任意一個(gè)需要替換時(shí)，所有的適配刮削工作又要從頭開(kāi)始。這時(shí)，我們期盼能購(gòu)買(mǎi)到可以替換壞掉零件的替用品，而無(wú)須刮削或其它鉗工操作就能正常工作。
當(dāng)一個(gè)零件一從架子上拿來(lái)就可以替換同樣尺寸同樣材料規(guī)格的另一個(gè)零件，就說(shuō)這
個(gè)零件是可互換的。具有可互換性的系統(tǒng)不必進(jìn)行高成本的輔助刮削工作，因此降低了產(chǎn)
品的成本。在要替換掉磨損的零件時(shí)，零件的可互換性對(duì)維護(hù)而言也是大有好處的。然而，
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(cè)方法以確保對(duì)加工的控制。這一點(diǎn)非常重要。因?yàn)槌叽缯`差有時(shí)可能要過(guò)一段時(shí)間才會(huì)發(fā)現(xiàn)，而此時(shí)卻已遠(yuǎn)離加工的地方。
1． 公差與極限尺寸
大家知道，事實(shí)上零件不可能毫無(wú)誤差的加工出來(lái)，或者說(shuō)沒(méi)有誤差的零件是不可能
的，要說(shuō)明尺寸的好壞（因?yàn)闇y(cè)量?jī)x器必然有誤差），就有必要指出最大允許誤差。繪圖
人員必須標(biāo)明零件正常工作時(shí)的最大允許尺寸和最小允許尺寸。這些尺寸的極限值就稱(chēng)作
極限尺寸，它們之間的差值稱(chēng)為公差。公差的大小取決于所涉及的加工操作類(lèi)型、機(jī)械工
的技能、機(jī)床的精確度以及零件的尺寸。對(duì)于給定級(jí)別的公差，實(shí)際公差應(yīng)隨著尺寸的增
大而增大。公差應(yīng)盡可能取大以使加工成本最小。
在圖上標(biāo)注公差時(shí)，許用公差主要取決于所用操作類(lèi)型，但也必須考慮本國(guó)的優(yōu)先級(jí)。
以下用例子說(shuō)明用到的一些標(biāo)注方法：
（1） 單邊極限。單邊極限通常用于當(dāng)兩個(gè)面之間的距離，或孔徑、軸徑被指定的情況下。例如，當(dāng)直徑要圓整時(shí)，機(jī)械工更愿意向最大允許尺寸圓整，這樣，當(dāng)他加工到所得直徑尺寸略大于最大允許尺寸時(shí)，還可以在整個(gè)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(chēng)直徑是75-0.012mm 的軸標(biāo)注為D75mm。同樣的，公稱(chēng)直徑是75mm 的孔也可能標(biāo)的尺寸是D75-0.012mm，這同樣也適用于軸的標(biāo)注。
（2） 雙邊極限。雙邊極限通常用于：比如當(dāng)孔的位置已確定的情況下。機(jī)床操作人員可能將孔的位置定得較接近或遠(yuǎn)離所需數(shù)據(jù)，而且，當(dāng)孔的加工已經(jīng)開(kāi)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(shí)不會(huì)使零件變成廢品。因此，應(yīng)將兩個(gè)孔的中心距規(guī)定出來(lái)，比如，為100+0.02mm。
2. 配合
配合是關(guān)于兩個(gè)零件之間的關(guān)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(chēng)為過(guò)盈配合；如果軸的尺寸小于孔的尺寸，這種情況稱(chēng)為間隙配合。過(guò)盈配合的兩個(gè)零件只有通過(guò)收縮才能裝配，或者過(guò)盈量非常小可通過(guò)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(zhuǎn)，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(guò)。為了確保精確，孔和軸的極限尺寸都必須予以規(guī)定。
（1）裝配分類(lèi)如下：
間隙配合 當(dāng)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。
過(guò)盈配合 當(dāng)孔和軸的尺寸界限滿足軸總是大于孔，則其配合為過(guò)盈配合。
過(guò)渡配合 當(dāng)孔和軸的尺寸界限所處的情況可能是間隙也可能是過(guò)盈，則稱(chēng)為過(guò)渡配合。
( 2 ) 基孔制和基軸制。為了得到不同程度的間隙和過(guò)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(shí)際尺寸都是在允許極限尺寸內(nèi)稍有不同，以滿足每對(duì)零件的實(shí)際裝配要求。這就是說(shuō)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(yīng)對(duì)每種基本的尺寸用一個(gè)標(biāo)準(zhǔn)的孔，通過(guò)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(guān)系，這就是基孔制。另一種方法，每種基本尺寸都 用一個(gè)標(biāo)準(zhǔn)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(guān)系，這就是基軸制。用基孔制更好些，因?yàn)樗墒埂肮潭ǔ叽纭痹O(shè)備如絞刀、測(cè)量?jī)x等標(biāo)準(zhǔn)化。但也可用基軸制，當(dāng)要用同一個(gè)軸和許多零件裝配實(shí)現(xiàn)不同配合關(guān)系時(shí)用基軸制更方便。有時(shí)，直接用棒料進(jìn)行裝配而無(wú)須進(jìn)一步加工，也使用基軸制。
3. 極限尺寸與配合系統(tǒng)
建立一個(gè)標(biāo)準(zhǔn)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(biāo)準(zhǔn)化。一種極限尺寸及配合標(biāo)準(zhǔn)應(yīng)適用于不同的質(zhì)量范圍的工件。如果可能，這個(gè)系統(tǒng)應(yīng)做成表格形式以免除使用者根據(jù)配合種類(lèi)工件質(zhì)量及零件尺寸來(lái)計(jì)算尺寸的麻煩。
4. 英制標(biāo)準(zhǔn)4500：1969，ISO極限尺寸及配合
這個(gè)標(biāo)準(zhǔn)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(jìn)把英國(guó)標(biāo)準(zhǔn)和最近推薦的國(guó)際標(biāo)準(zhǔn)化組織結(jié)合起來(lái)。這個(gè)系統(tǒng)引用的是軸和孔，但這些術(shù)語(yǔ)不僅適用于圓柱型的工件，也同樣適用于包含兩個(gè)平行面或矩形面的地方。把這個(gè)系統(tǒng)列成表，其尺寸范圍達(dá)到3150mm。
數(shù)控車(chē)床的發(fā)展
1946年誕生了世界上第一臺(tái)電子計(jì)算機(jī)，這表明人類(lèi)創(chuàng)造了可增強(qiáng)和部分代替腦力勞動(dòng)的工具。它與人類(lèi)在農(nóng)業(yè)、工業(yè)社會(huì)中創(chuàng)造的那些只是增強(qiáng)體力勞動(dòng)的工具相比，起了質(zhì)的飛躍，為人類(lèi)進(jìn)入信息社會(huì)奠定了基礎(chǔ)。6年后，即在1952年，計(jì)算機(jī)技術(shù)應(yīng)用到了機(jī)床上，在美國(guó)誕生了第一臺(tái)數(shù)控機(jī)床。從此，傳統(tǒng)機(jī)床產(chǎn)生了質(zhì)的變化。近半個(gè)世紀(jì)以來(lái)，數(shù)控系統(tǒng)經(jīng)歷了兩個(gè)階段和六代的發(fā)展。數(shù)控機(jī)床作為機(jī)電一體化的典型產(chǎn)品，在機(jī)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(jī)械制造中結(jié)構(gòu)復(fù)雜、精密、批量小、多變零件的加工問(wèn)題，且能穩(wěn)定產(chǎn)品的加工質(zhì)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(jī)床價(jià)格較貴，一次性投資較大使企業(yè)心有余而力不足。我國(guó)作為機(jī)床大國(guó)，對(duì)普通機(jī)床數(shù)控化改造不失為一種較好的良策。本文針對(duì)目前國(guó)內(nèi)企業(yè)現(xiàn)狀，提出簡(jiǎn)易型經(jīng)濟(jì)數(shù)控改造思路和設(shè)計(jì)方法供數(shù)控技術(shù)人員參考。
數(shù)控改造一般是指對(duì)普通機(jī)床某些部位做一定的改造,配上數(shù)控裝置,從而使機(jī)床具有數(shù)控加工能力,其目的是為了提高老設(shè)備的加工精度和生產(chǎn)效率,適應(yīng)多品種和小批量零件的生產(chǎn),同時(shí)可以使技術(shù)等級(jí)較低的工人也能加工出高質(zhì)量的零件,減少設(shè)備技術(shù)改造的投資等。所有這些都是為了提高機(jī)床的價(jià)格性能比,即用較少的錢(qián)得到較高的機(jī)械性能和加工能力。因此,把普通機(jī)床改造為數(shù)控機(jī)床是一條提高數(shù)控化率的有效途徑。一般來(lái)說(shuō),對(duì)現(xiàn)有普通車(chē)床進(jìn)行數(shù)控改造的具體做法是,主傳動(dòng)系統(tǒng)一般不作變動(dòng),進(jìn)給傳動(dòng)系統(tǒng)中采用高精度的滾珠絲杠替換進(jìn)給軸原有的普通絲杠。機(jī)械部分改造完成后,配上ＭＣＳ-51單片機(jī)作為數(shù)控系統(tǒng),用步進(jìn)電機(jī)作驅(qū)動(dòng)元件,經(jīng)過(guò)一級(jí)減速齒輪驅(qū)動(dòng)Ｘ、Ｚ軸的運(yùn)動(dòng)。在我國(guó)數(shù)控機(jī)床改造中,微型計(jì)算機(jī)大多采用ＭＣＳ—51型系統(tǒng)單片微型計(jì)算機(jī),它是超大規(guī)模集成電路發(fā)展的產(chǎn)物,在控制領(lǐng)域中得到廣泛的應(yīng)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(rèn)為是經(jīng)濟(jì)型數(shù)控系統(tǒng)。經(jīng)濟(jì)型數(shù)控系統(tǒng)是相對(duì)標(biāo)準(zhǔn)數(shù)控系統(tǒng)而言的，不同時(shí)期，不同國(guó)家和地區(qū)的含義是不一樣的。根據(jù)實(shí)習(xí)機(jī)床的使用要求，合理簡(jiǎn)化系統(tǒng)，降低成本，即可稱(chēng)為經(jīng)濟(jì)型。區(qū)別于經(jīng)濟(jì)型數(shù)控系統(tǒng)，將功能比較齊全的數(shù)控系統(tǒng)稱(chēng)為全功能數(shù)控系統(tǒng)，或稱(chēng)為標(biāo)準(zhǔn)型數(shù)控系統(tǒng)。
就其功能而言，經(jīng)濟(jì)型數(shù)控系統(tǒng)一般分辨率和進(jìn)給速度較低、連動(dòng)軸數(shù)少、人機(jī)借口較簡(jiǎn)單。如點(diǎn)位/直線切削控制系統(tǒng)都可以認(rèn)為是經(jīng)濟(jì)型數(shù)控系統(tǒng)。對(duì)其結(jié)構(gòu)而言，開(kāi)環(huán)數(shù)控系統(tǒng)一般性能不高，但結(jié)構(gòu)簡(jiǎn)單，造價(jià)低廉，可以說(shuō)得上是最經(jīng)濟(jì)的數(shù)控系統(tǒng)。所以，經(jīng)濟(jì)型數(shù)控系統(tǒng)在國(guó)內(nèi)現(xiàn)階段主要是指開(kāi)環(huán)數(shù)控系統(tǒng)。
并不是有了閉環(huán)的標(biāo)準(zhǔn)型數(shù)控系統(tǒng)，經(jīng)濟(jì)型數(shù)控系統(tǒng)或開(kāi)換數(shù)控系統(tǒng)就無(wú)用武之地了。事實(shí)上，開(kāi)環(huán)數(shù)控系統(tǒng)在我國(guó)應(yīng)用還相當(dāng)廣泛。高性能的標(biāo)準(zhǔn)型數(shù)控系統(tǒng)價(jià)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(shè)備加工的成本低并且質(zhì)量能保證，就用什么設(shè)備加工，若盲目追求高精設(shè)備，則生產(chǎn)成本增加，這是不必要的。