机械设计基础A课件：第 二 讲 表达机件的常用方法-I.ppt

* ⑤ 不需在剖面区域中表示材料的类别时，剖面符号可采用通用剖面线表示。通用剖面线为与主要轮廓或剖面区域的对称线成45°角的细实线；同一物体的各个剖面区域，其剖面线画法应一致。Different section line symbols can be used to represent various types of materials. However, the general purpose section line symbol used in most section view drawings is thin solid lines being drawn at a 45 degree angle . If the visible outline to be sectioned is drawn at a 45 degree angle, the section lines are drawn at a different angle, such as 30 degrees. 不好 Poor 好 Good 不好 Poor 好 Good * 二、剖视的种类 Section view types 1.全剖视Full Section 用剖切面完全地剖开物体所得的剖视图。 A full section view is made by passing the cutting plane fully through the object. 　　外形较简单，内形较复杂，而图形又不对称时。Full section is used to represent object which has simple exterior feature but complicated interior and nonsymmetrical. 适用范围： A A A－A * 不能清楚表达外形 Can’t tell the external feature clearly. A A A—A 存在什么问题？ What is the problem? * 解决办法Solution： 以对称线为界,一半画视图,一半画剖视。Cutting plane passes through half way through the object. Half section and half external feature are drawn symmetric to the axis. 2. 半剖视 Half Section 已表达清楚的 内形虚线不画 Hidden lined are omitted A—A 分界线为中心线 Center line to separate the sectioned half from the unsectioned half of the half section view. * B B 适用范围： 　　内、外形都需要表达，而形状又基本对称时。 Half section views are most often used on objects that are symmetrical and complicated in both interior and external. A A A－A B－B 半剖视 Half Section * B B 3. 局部剖视 Broken-out section A A A－A B－B 　　用剖切平面局部地剖开物体所得的剖视图。A broken-out section is used to show interior features of a part by breaking away some of the object. 　　局部剖视部分义波浪线与周围断开。A wavy break line separates the sectioned from un-sectioned half of the view. * B B 3. 局部剖视Broken-out section B－B A A A－A 可用双折线代替波浪线。 The break lines can be zigzag lines. * 适用范围： 局部剖是一种较灵活的表示方法，适用范围较广。Broken-out section is a rather flexible and widely used method. 只有局部内形需要剖切表示时。 When the interior feature of only part of an object * 实心杆上有孔、槽时，应采用局部剖视。 Solid shaft with only local hole or slot. * ③