第6章剖视图

Sections剖视图Section summarization剖视图概述Section drawing methods剖视图画法Sections sorts剖视图的种类Cutting plane sorts剖切面的种类Examples of draw sections画剖视图举例Exercises练习题请点击相应标题显示其内容The purpose of using sections is to express the unseen structures by heavy lines so as to easy to read views and label dimensions.采用剖视的目的，是使机件上一些原来看不见的结构能清楚表示出来，这样便于看图和标注尺寸。

Section summarization 剖视图概述Cutting plane 剖切面1.Purpose of sectional views 剖视图的作用Sectional views are drawn to explain the construction of a complex object, to clarify internal details.剖视图是用来表达复杂机件内部形状的视图。

请点击鼠标左键显示后面内容Sectional view 剖视图When the drawing have a lot of dash lines, it is difficult to explain and dimension.视图中有太多虚线,给看图增加困难,且标注尺寸也很不方便。

2. To form a sectional view 剖视图的形成请点击鼠标左键显示后面内容A AAA Draughtsman Imagine the object to be cut by a plane.假想用一个平面通过机件的某一位置剖开它。

Assume the part of the object between observer and the plane to be removed. 假想将处于观察者与剖切面之间的部分移去。

Draw a sectional view that includes all visible lines behind the section plane.将所看到的位于剖切面之后的所有可见部分全部画出来。

Section summarization 剖视图概述Cutting 剖Remove 去View 视1.Rules to draw sections 画剖视图的规则(1)Cutting plane shall be passed through symmetrical plane or axes of an object.剖切面一般应通过机件的对称面或轴线。

(2)Because cutting is assumption, other views must be drawn fully except the section view. 由于剖切是假想的，所以一个视图取剖视后，其他视图仍应完整画出。

请点击鼠标左键显示后面内容(3)In order to illustrate more clearly, section view and hidden lines must be omitted. But if the hidden line would help to read views, it can be drawn.为了使图形更加清晰，剖视图中应省略不必要的虚线，但若画出某一虚线有助于读图时，也可画出虚线。

虚线可省略剖切面选在对称面虚线有助于读图可画出A A A A 2. The position of a cutting plane 剖切面位置标注1）Using short heavy lines with width of 1−1.5b and length of 5−10 mm as section symbol, which shall not be crossed the outline of the view, to show the cutting plane position in the corresponding views.用宽1～1.5d 、长约5～10mm 短粗实线为剖切符号表示剖切面位置，剖切符号尽量不与图形的轮廓线相交。

请点击鼠标左键显示后面内容A AA-A 3）All labeling could be omitted when there is single cutting plane crossing the symmetrical plane and no other views to separate sections and standard views, when the sections are placed following the projection rules. If an object is not symmetrical the section plane Chosen should be clearly stated.当剖切面通过机件的对称平面或基本对称平面，且剖视图按投影关系配置，中间又没有其他图形隔开时，可省略标注。

如果机件不对称,则必须明确地标注其剖切面位置。

2）The same letters must be signed beside them and arrows are used to show projective direction. Using the same letters as those of cutting position to show its name “×−×” on the top of the section.在剖切符号的起、止和转折处标注上相同的字母,并在起、止处画出箭头表示投射方向。

剖视图的上方，用与标注剖切位置相同的字母标出剖视图的名称“×-×”。

4）When the main outlines are slanted at 45°, the section lines are usually drawn with a slanted angle of 30°or 60°, but the slanted direction must accord with the original views.当图形中的主要轮廓线与水平成45°时，剖面线应画成与水平成30°或60°的平行线，但方向应与原图剖面线方向一致。

The hatchings should be equispaced and touch theoutline 剖面线间距应相等,应与轮廓线接触上If two adjacent parts are sectioned, the section lines are drawn in opposite directions 二相邻机件的剖面线倾斜方向应相反Where more than two parts of an assembly are to be sectioned ，Section lines are closer together on the third area usually the smallest当装配件多于二个时,通常第三零件（面积最小）的剖面线间距更密些Preferably size of line spacing —not less than 4mm or 1mm for very small areas 推荐剖面线间距:一般不小于4mm;面积很小时应不小于1mm Lines are staggered where the parts are in contact 剖面线应在接触处错开请点击鼠标左键显示后面内容3）Section lines of the same part should be drawn in the same direction and spacing.同一机件各视图中剖面线应画成方向相同、间隔相等的平行线。

Section drawing methods剖视图画法3. Section line 剖切符号的画法1）The symbol lines must to be drawn on the entity to distinguish between solid and hollow.应在剖切面剖到的机件实体部分画上剖面符号,以区别实心与空心结构。

2）The symbols distinguish between different materials in sections. Cast-iron symbols are usually drawn in thin lines slanted at 45°.剖面符号随机件材料的不同而不同,金属材料剖面线是与水平成45 斜向的细实线。

Sections sorts 剖视图的种类请点击下划线部分显示其内容1.Full sections ：A full section is a view formed by passing a cutting plane fully through an object and removing half of it.全剖视图用剖切面完全剖开机件后所得到的剖视图。

2. Half sections: A half-section is a view that results from passing a cutting plane halfway through an object and removing a quarter of it to show external and internal features.半剖视图当机件具有对称平面时, 以对称中心线为界,一半画成剖视图,另一半画成视图。

3. Local or broken-out sections: A broken-out section is used to show interior features by breaking away a portion of a view.局部剖视图用剖切面局部地剖开机件所得的剖视图。

2)In the section, one more partial cutting can be done.在剖视图中再作一次局部剖切Full section 全剖视图2) Section with inclined cutting plane 用不平行于任何基本投影面的剖切面剖切1)Paralleling to a principle projective plane 用平行于某一基本投影面的平面剖切2. Several paralleling cutting planes 几个平行剖切平面3. Several intersectant cutting planes几个相交剖切面Full section 全剖视图Cutting plane sorts 剖切面的种类Full section 全剖视图Half section 半剖视图Local section 局部剖视图Full section 全剖视图Full section 全剖视图1.Single cutting plane 单一剖切平面4. Others 其他剖切面1)The section being cut with cylinder. 用柱面剖切请点击鼠标左键显示后面内容请点击下划线部分显示其内容Examples of draw sections 画剖视图举例1. Full sections全剖视图2. Half sections半剖视图3. Local sections 局部剖视图6.Section with several intersection cutting planes几个相交剖切面剖切的剖视图5. Section with several paralleling cutting planes 几个平行剖切面剖切的剖视图7.Section with compounding cutting planes几个剖切面剖切的剖视图4. Section with inclined cutting plane 不平行任何基本投影面剖切的剖视图Exercises练习题1. Find out incorrect drawing from sectional views.分析并指出剖视图中的错误画法。