Unit-5-Engineering-Drawing-機電專業(yè)英語-圖文課件

1、Unit 5 Engineering DrawingContentsNew Words & Expressions Text & TranslationComplex Sentence AnalysisKey to ExercisesNew Words & Expressionscoordinate system 坐標系Cartesian k:tizin adj. 笛卡爾的 keep track of 跟蹤定位于 World Coordinate System (WCS) 世界坐標系 User Coordinate System (UCS) 用戶坐標系 axis ksis n. 軸perpen

2、dicularly p:pndikjulli adv. 垂直地projection prdekn n. 投影New Words & Expressionsorthographic projection 正交投影auxiliary :gziljri adj. 輔助的，補助的datum plane 基準面orientation :rientein n. 定位, 校準revolve rivlv v. 旋轉planar plein adj. 平面的，二維的exploded drawing 爆炸圖, 分解圖pictorial pikt:ril adj. 圖示的New Words & Expression

3、spartial view 局部視圖symmetrical simetrikl adj. 對稱的 configuration kn,figjurein n. 構造，配置mate meit v. 配合，連接 align lain v. 配直，校直，調(diào)準 assembly constrain 裝配約束 third-angle projection 第三角投影法quadrant kwdrnt n. 象限, 四分儀profile plane 側面dashed line 虛線，短畫線Text & Translation1.Coordinate SystemThe basic of all input A

4、utoCAD is the Cartesian coordinate system, and the various methods of input (absolute or relative) rely on this system. In addition, AutoCAD has two internal coordinate systems to help you keep track of where you are in a drawing: the World Coordinate System(WCS) and the User Coordinate System(UCS).

5、Text & TranslationThe fixed Cartesian coordinate system locates all points on an AutoCAD drawing by defining a series of positive and negative axes to locate positions in space. Fig. 5-1(a) illustrates the axis for two-dimension (2D) drawing. There is a permanent origin point (0, 0) which is referen

6、ced, an x axis running horizontally in a positive and negative direction from the origin, and a y axis traveling perpendicularly in a vertical direction. 1 When a point is located, it is based on the origin point unless you are working in the three dimensions, in which case, you will have a third ax

7、is , called the z axis (Fig. 5-1 b).Text & TranslationFig. 5-1 The coordinate systemText & Translation2. Types of Views There are many view types which may be shown, as illustrated in Fig. 5-2.Text & TranslationFig.5-2 Types of viewsText & Translation（1）Projection. An orthographic projection of an o

8、bject as seen from the front, top, right side, etc.（2）Auxiliary. Any view created by projecting 90 to an inclined surface, datum plane, or along an axis.（3）General. Any view which is oriented by the user and is not dependent upon any other view for its orientation.（4）Detailed. Any view which is deri

9、ved by taking a portion of an existing view and scaling it for dimensioning and clarification purposes.（5）Revolved. A planar, area cross-section was revolved 90 about the cutting plane line and offset alone, its length.（6）Full View. Show the entire model.Text & Translation（7）Half View. Show only the

10、 portion of the model on one side of a datum plane.（8）Broken View. Used on large objects to remove a section between two points and move the remaining sections close together.（9）Section. Display a cross-section for a particular view.（10）Exploded Drawing. The exploded drawing is a type of pictorial d

11、rawing designed to show several parts in their proper location prior to assembly，see Fig. 5-3. Although the exploded view is not used as the working drawing for the machinist, it has an important place in mechanical technology. Exploded views appear extensively in manuals and handbooks that are used

12、 for repair and assembly of machines and other mechanisms.Text & TranslationFig. 5-3 Exploded Drawing Text & Translation（11）Partial view. When a symmetrical object is drafted, two views are sufficient to represent it （typically, one view is omitted）. A partial view can be used to substitute one of t

13、he two views. 2Sectional and auxiliary views are also commonly used to present part detail. Sectional views are extremely useful in displaying the detailed design of a complicated internal configuration. If the section is symmetrical around a centerline, only the upper half needs to be shown. The lo

14、wer half is typically shown only in outline. Casting designers often employ sectional views to explode detail. When a major surface is inclined to three projection planes, only a distorted picture can be seen. An auxiliary plane that is parallel to the major surface can be used to display an undisto

15、rted view.Text & TranslationStudy this diagram describing mate, align, orient and insert assembly constrains, see Fig. 5-4.Text & TranslationFig. 5-4 Constrain for assembly the BRACKET and BUSHING partsText & Translation3. Multiview DrawingEngineering drawing is an abstract universal language used t

16、o represent a designers idea to others. It is the most accepted medium of communication in all phases of industrial and engineering work.Text & TranslationIn todays modern manufacturing industry, several types of drawing are acceptable. However, the standard is the multiview drawing，see Fig. 5-5. A

17、multiview drawing usually contains two or three views (Front, Top, and Side). Each view is an orthographic projection of a plane. In the United States and Canada, the third-angle projection is the system used, see Fig. 5-6. In the figure, the four quadrants of the x-z plane (called the, , and angles

18、) are illustrated. 3For the third-angle projection, we always place the object in the third quadrant and project the object in three planes. This is done by projecting the object onto the frontal, horizontal, and profile planes. The projection on the frontal plane (x-z) is fixed and the image is cal

19、led the front view. With the projected image, the horizontal plane (x-y) is rotated 90 clockwise on the x axis, the result is a top view of the object. The profile plane (c-z) is rotated 90 clockwise about the z axis to obtain a right-hand side view. Hidden lines are shown by using dashed lines on t

20、he drawing.Text & TranslationFig. 5-5 Multiview drawing of a bracketText & TranslationFig. 5-6 Third-angle projectionText & Translation1.坐標系笛卡爾坐標系是輸入AutoCAD的全部基礎，各種輸入方法（如絕對坐標，相對坐標）都依賴于這個系統(tǒng)。此外，AutoCAD有兩個內(nèi)部坐標系：世界坐標系（WCS）和用戶坐標系（UCS），來幫助你確定所在繪圖區(qū)中的位置。通過定義一系列空間固定位置的正負軸，固定的笛卡爾坐標系可以對AutoCAD圖面上的所有點進行定位。如圖5-1

21、(a) 所示為用于二維繪圖的坐標軸。有一個固定的參考原點（0，0），x軸從原點出發(fā)沿水平方向正負延伸，y軸從原點出發(fā)沿垂直方向上下延伸。根據(jù)原點（0，0）對其他任意一個點定位，但是在三維空間中繪圖時，應該具有第三根軸，該軸叫y軸。如圖5-1(b)示。Text & Translation圖5-1 坐標系Text & Translation2.視圖類型有許多可以來表達的視圖類型，如圖5-2所示。Text & Translation圖5-2 視圖類型Text & Translation（1）投影視圖。從前面、頂面、右側面等觀察物體的正交投影圖。（2）輔助視圖。向斜面、參考面或沿一個軸線做90投影所產(chǎn)

22、生的視圖。（3）總圖。由用戶自行決定方位的視圖，它不依賴于其方位的視圖。（4）局部放大圖。為了標注尺寸和看清圖形而從已知視圖中取出一部分并將其放大的一種視圖。（5）旋轉視圖。二維平面中，橫截面繞剖切線旋轉90后移出一定距離的視圖。（6）全視圖。顯示整個模型的視圖。Text & Translation（7）半視圖。只顯示在參考面一側的部分視圖。（8）折斷視圖。為了表達大的物體，移去（中間）兩點間的截面并將留下的部分移動到截面視圖。（9）剖面圖。用于顯示一個特定視圖的橫截面。（10）分解圖。分解圖是在裝配前顯示每個零件位置關系的一種示意圖，如圖5-3所示。盡管機械工程師不把分解圖用作工作圖，但它在

23、機械技術上占有重要位置。分解圖廣泛出現(xiàn)在維修、機器及其他機構裝配的說明書和手冊中。機器部件裝配的分解視圖：Text & Translation 圖5-3 分解視圖Text & Translation（11）局部視圖。當畫一個對稱結構的物體時，兩個視圖便足以表達（習慣上一個視圖被省略）。局部視圖可用于代替兩個圖之一。剖面圖和輔助視圖通常用于表達零件的局部細節(jié)。剖面圖在用于顯示一個復雜內(nèi)部結構的細節(jié)設計時尤其有用。如果截面沿著中心線對稱，只有上半部需要表達。下半部通常只用輪廓線顯示出來。鑄件設計師們利用剖面圖來分解局部。當一個主要面傾斜于三個投影面時，只能看到歪曲了的圖形，一個平行于主要面的輔助平

24、面，可以來顯示物體未被歪曲的視圖。研究如圖5-4所示描述匹配、對齊、定位以及插入等裝配約束。Text & Translation 圖5-4 裝配支架與軸襯零件時的約束Text & Translation3.多視圖工程圖是用來向別人表達設計者思想的一種抽象的通用語言。它是工業(yè)和工程中各個方面交流溝通的媒體。在現(xiàn)代制造業(yè)中，有幾種圖紙類型是可以接受的。然而，標準的圖形是視圖圖紙，如圖5-5所示。一張多視圖圖紙通常包含有兩個或三個視圖（前、俯和側視圖）。每個視圖是一個面的正交投影。在美國和加拿大，使用的系統(tǒng)是第三角投影，如圖5-6所示。在圖中顯示了x-z平面的四個象限（分別稱為I和N角）。對于第三角

25、投影來講，總是將物體放在第三象限，同時將物體投影到三個面上。這是通過將物體投影到正面、水平面和側面上來實現(xiàn)的。物體在前平面（x-z平面）上的投影是固定的，其圖像稱為前視圖。水平面（x-y平面）上的投影圖沿x軸順時針轉90,得到物體的俯視圖。側面（y-z平面）上的投影圖繞z軸順時針轉90，得到右視圖。被遮隱的線在視圖中用虛線表示。Text & Translation圖5-5 支架的多視圖Text & Translation圖5-6 第三角視圖 Complex Sentence Analysis1 When a point is located, it is based on the origin

26、 point unless you are working in the three dimensions, in which case, you will have a third axis, called the z axis. 根據(jù)原點（0，0）對其他任意一個點定位，但是在三維空間中繪圖時，應該具有第三根軸，該軸稱為z軸。unless:引導讓步狀語從句 in. case 在情況下， which指代you are working in the three dimensionsComplex Sentence Analysis2 Sectional and auxiliary views are also commonly used to present part detail. 剖面圖和輔助視圖同樣經(jīng)常被用來表示零件視圖。be used to do: 被用來做，注意區(qū)分該短語與be used to doing 的區(qū)別，be used to doing表示習慣做某事Complex Sentence Analysis 3 For the third-angle projection, we always place the object in the third quadrant and project t