2012第4講尺寸注法-II

1、第 四 講 尺寸標(biāo)注2 Dimensioning2組合體尺寸標(biāo)注 Composite solid dimensioning尺寸標(biāo)注的一些規(guī)則 Some conventional rules常見機(jī)件結(jié)構(gòu)尺寸標(biāo)注 Dimensioning of general features一、標(biāo)注尺寸的基本要求 Basic requirements4.1 標(biāo)注尺寸的基本要求與規(guī)則Basic requirements for dimensioning 正確Correct：完全Complete：要符合國(guó)家標(biāo)準(zhǔn)的有關(guān)規(guī)定。Drawing of dimensions according to Standards or

2、 conventions.要標(biāo)注制造零件所需要的全部尺寸，不遺漏，不重復(fù)。All dimensions for manufacturing without missing and redundant清晰Clear：尺寸布置要整齊、清晰，便于閱讀。Dimensions layout should be clear and convenient for reading合理Rational：標(biāo)注的尺寸要符合設(shè)計(jì)要求及工藝要求。Dimensions represent requirements of design (function) and manufacturing 以毫米為單位，如采用其它單位時(shí)

3、，則必須注明單位名稱。Dimensions are given in millimeters without adding mm and the other units should be shown. 圖中所注尺寸為零件完工后的尺寸。Dimensioning part as it machined completely 每個(gè)尺寸一般只標(biāo)注一次，并應(yīng)標(biāo)注在最能清晰地反映該結(jié)構(gòu)特征的視圖上。Each dimension can be given only once ,generally , and on the view which demonstrate the feature most cl

4、early.二、標(biāo)注尺寸的基本規(guī)則Basic rules 尺寸數(shù)值為零件的真實(shí)大小，與繪圖比例及繪圖的準(zhǔn)確度無(wú)關(guān)Dimensions indicate the true size of the object and irrespective of the scale and drawing accuracy.三、尺寸三要素 Three key elements of a dimension 尺寸界線 尺寸線 尺寸數(shù)字C1.510C1.5162035尺寸數(shù)字Text數(shù)字高度3.5毫米尺寸線Dimension line這些間距7毫米最好不超過(guò)10毫米。尺寸界線超出箭頭約2毫米尺寸界線Extensi

5、on line16允許Fine10不可以Incorrect 用形體分析法將組合體分解為若干個(gè)基本體和簡(jiǎn)單體，在形體分析的基礎(chǔ)上標(biāo)注三類尺寸。Break down the complex part into basic geometric components , then give three types of dimensions: 定形尺寸 Size dimensions確定各基本體形狀和大小的尺寸。 Dimensions which show the shape and sizes of the basic geometric components. 定位尺寸 Location dime

6、nsions確定各基本體之間相對(duì)位置的尺寸。Dimensions which locate the basic components with each other. 要標(biāo)注定位尺寸，必須先選定尺寸基準(zhǔn)。零件有長(zhǎng)、寬、高三個(gè)方向的尺寸，每個(gè)方向至少要有一個(gè)基準(zhǔn)。Location dimensions must be measured from properly selected datums. At least one datum should be determined along each directions of the part : along length ,along width

7、 and along height directions.一、基本方法Primary method4.2 組合體的尺寸標(biāo)注方法 Dimensioning of complex part ( 總體尺寸) (Overall dimensions)零件長(zhǎng)、寬、高三個(gè)方向的最大尺寸。(不一定需要直接標(biāo)注)The maximum sizes in the directions of length, width and height which may be inferred by the other dimensions. 總體尺寸、定位尺寸、定形尺寸可能重合，這時(shí)需作調(diào)整，以免出現(xiàn)多余尺寸。Adjus

8、tment should be made if the three types of dimensions may be coincide to avoid redundant dimensions. 通常以零件的底面、端面、對(duì)稱面和軸線作為基準(zhǔn)。Datums can be the base, a main side face, symmetry plane ,or center line.二、一些常見基本體的定形尺寸30102030201025143025143025S25三、截切后基本體的定形尺寸標(biāo)注方法Dimensioning of truncated solid標(biāo)注基本體的尺寸，確定截

9、平面的位置。Dimension the full solid and locate the cutting plane.不標(biāo)注截交線的尺寸。 Dont dimension the intersections.SR18182056505220565020不標(biāo)注截交線的尺寸。 Dont dimension the intersections.四、一些常見形體的定位尺寸 Locating dimensions of some common-used features 一組孔的定位尺寸 group of holes 長(zhǎng)方體的定位尺寸 Cube 圓柱體的定位尺寸 Hollow cylinder基準(zhǔn)基準(zhǔn)基

10、準(zhǔn)基準(zhǔn)基準(zhǔn)Datum基準(zhǔn)基準(zhǔn)基準(zhǔn)R84030252016403016相貫形立體的尺寸標(biāo)注 dimensioning of solid with intersecting features不標(biāo)注相貫線的尺寸。 Dont dimension the intersections.151212不以回轉(zhuǎn)體的外形線作為定位基準(zhǔn)Contour line cannot be used as the datum既是定形尺寸也是定位尺寸This dimension determine both size and location7530304050 45100851051907518068559011090五、標(biāo)

11、注示例： 形體分析 Shape analysis?？傮w尺寸,調(diào)整 Overall dimension and adjustment if necessary 逐個(gè)標(biāo)注每一基本形體的定形、定位尺寸。Dimensioning size and location of the basic geometric solid one by one基準(zhǔn)基準(zhǔn)基準(zhǔn)41216例1：RRRRRR4.3 尺寸的清晰布置 The clarity of dimensions一、應(yīng)盡量標(biāo)注在視圖外面，以免尺寸線、尺寸數(shù)字與視圖的輪廓線相交。Place dimensions outside a view as much as

12、 possible for clarity。好Good不好Poor二、同心圓柱的直徑尺寸，最好注在非圓的 視圖上。Diameters of concentric cylinders are best placed on the linear view.好Good不好Poor44AAAAAA4RAAAAAA4R三、相互平行的尺寸，應(yīng)按大小順序排列，小尺寸在內(nèi)，大尺寸在外。Parallel dimensions are arranged as the larger outside of the smaller one.好Good不好Poor四、內(nèi)形尺寸與外形尺寸最好分別注在視 圖的兩側(cè)。Exter

13、ior and interior dimensions are best placed separately on the both side of the view.好Good不好Poor4.4 尺寸標(biāo)注必須合理 Reasonable dimension 所謂合理就是標(biāo)注尺寸時(shí)，既要滿足設(shè)計(jì)要求又要符合加工測(cè)量等工藝要求。Reasonable dimensioning meets design , machining and measurement requirements.一、正確地選擇基準(zhǔn) Correct datum 設(shè)計(jì)基準(zhǔn)Design datum 工藝基準(zhǔn) machining dat

14、um設(shè)計(jì)時(shí)用以確定零件在部件中的位置的基準(zhǔn)。Datum used to locate the part in the assembly during design period加工或測(cè)量時(shí)用以確定零件位置的基準(zhǔn)。Datum used to locate the part during its machining or measuring 設(shè)計(jì)基準(zhǔn)Design datum設(shè)計(jì)基準(zhǔn)Design datum工藝基準(zhǔn)Machining datum例如：AAAA二、主要的尺寸(或功能尺寸)應(yīng)直接注出Key dimension should be given directly 主要尺寸指影響產(chǎn)品性能、工作

15、精度和配合的尺寸。Key dimensions means those that influence the performance, working accuracy and assembling of the part. 非主要尺寸指非配合的直徑、長(zhǎng)度、外輪廓尺寸等。Secondary dimensions include the diameter , length or contour that does not have to match with the other featurescbcd正確Correct錯(cuò)誤Incorrectbcdebcd三、避免出現(xiàn)封閉的尺寸鏈 Avoid c

16、lose dimensions loop 長(zhǎng)度方向的尺寸 b、c、 e 、d 首尾相接，構(gòu)成一個(gè)封閉的尺寸鏈。Dimensions b, c, e and d form a close loop 由于加工時(shí)，尺寸 c、d、e 都會(huì)產(chǎn)生誤差，這樣所有的誤差都會(huì)積累到尺寸 b上，不能保證尺寸 b 的精度要求。All the machining errors added to dimensions c, d and e would be accumulated on dimension b such that the accuracy of b could not be guaranted. 錯(cuò)誤I

17、ncorrect 正確Correct262036458C1 1016四、應(yīng)盡量符合加工順序 Consider the machining order加工順序Machining order262036558C1 1016加工順序Machining order1015五、應(yīng)考慮測(cè)量方便 Dimensioning to measure conveniently 好Good不好Poor不好Poor好Good例：標(biāo)注組合體尺寸 Eg. Dimensioning1.底板Base board2.圓筒hollow cylinder3.凸臺(tái)bulge4.支撐板support board5.肋板rib六、尺寸配置

18、合理 Dimensioning reasonably 功能尺寸應(yīng)直接注出。Key size dimensioned directly 同一要素的尺寸應(yīng)盡可能集中標(biāo)注， 如孔的直徑和深度、槽的深度和寬度等。Place all dimensions of one feature together if possible, like the diameter and depth of on hole, or the depth and width of one groove. 盡量避免在不可見的輪廓線上標(biāo)注尺寸。Dimensioning on hidden lines should be avoided.作業(yè) 注尺寸：P69，P70補(bǔ)充 ：典型結(jié)構(gòu)的尺寸標(biāo)注 有一些典型結(jié)