曲面体三视图的识读 reading of curved solids

       曲面体三视图的读图依据是曲面体三视图的图形特征。无论是完整还是部分曲面体的三视图都具有上述的图形特征。

       The rule of reading curved solids is the projection feature of curved solids. Whenever the solid is complete or partial [ˈpɑ:ʃəl].

【例 4-8】识读图 4-9 所示曲面体的三视图。Please imagine the solids based on given views.

                        图4-9 曲面体三视图的识读举例  Fig 4-9 samples of reading curved solids

分析 analyze

       图 4-9(a)所示三视图，主视图和俯视图两个视图为矩形，是柱体，特征图左视图是圆，可知该形体是轴线垂直 W 投影面的圆柱。

       Figure 4-9 (a) shows that the front and top views are both rectangles and the solid must be a column. The feature view is a circle. So the solid is a cylinder and its axis is perpendicular to the W – projection plane. 

       图 4-9(b)所示三视图，俯视图和左视图都是梯形，主视图是特征图为上半圆，可知该形体是轴线垂直 V 投影面的上半圆台。

       Figure 4-9(b) shows the front and left views are both trapezoids, and its feature view is a semi- circle, so the solid is a frustum of cone and its axis is perpendicular to the V–projection plane.

       图 4-9(c)所示三视图是直径相等的三个圆形线框，但主视图、俯视图为半圆，是左半部，可知该形体是左半圆球。

       Figure 4-9 (c) shows the front and top views are both half circles and the left view is a circle,so the solid is a semi-sphere.

       基本体三视图的图形特征是今后画图和读图的依据之一，必须熟记。

       Feature characteristics of basic solids are not only the fundamental of drawing but also the basis of reading. One needs to keep them in mind during learning engineering drawing.