Choosing Views of Assembly Drawings (装置图的视图选择)

The working principles of a machine or assembly, the relationship of each part, and the fundamental structures of major parts should all be clearly represented by accurate applications of various representations in the assembly drawing to meet the requirements of production. The views should be brief, clear, and easyto read. 

为了满足生产的需要,应正确运用装配图的各种表达方法,将机器或部件的工作原理、各零件间的关系及主要零件的基本结构清晰地表达出来。视图表达方案力求简明,便于读图。

Choosing the front view(主视图的选择)

According to the contents and the requirements of assembly drawings, the following items should be considered while choosing the front view: 

根据装配图的内容和要求,在选择主视图时应着重考虑以下两点:

1. Working position

Normally, the part is positioned in the working position for producing the front view. For example, the gear pump is positioned based on its working position, shown in the assembly drawing of a gear pump in Fig. 9-11. 

2. Fitting relationships

One should show as much as possible the structures and features, especially the main fitting relationships,the function and working principles of the machine or assembly.

As shown in Fig. 9-11, the gear pump is positioned in its working position, through the axis of a couple of engaging gears, the section plane in the front view clearly represents the main fitting relationship of the gear pump.

1.工作位置

通常将部件摆放成工作位置。画其主视图。如图9-11所示的齿轮泵就是以其工作位置摆放的。

2.装配关系

应考虑尽可能多地显示部件的结构特征,特别是能清楚地表达机器或部件的主要装配关系、功能和工作原理。

如图9-11所示,主视图中的剖切面通过一对啮合齿轮的轴线,清楚地反映了齿轮泵的主要装配关系。

Choosing other views(其他视图的选择)

One may use different views to represent various other portions not  clearly represented in the  front view. In such cases, one needs to consider the fitting relationship and working principle before considering the structural shape of the major part. For example, as shown in Fig. 9-11, the left side view of the gear pump, the mounting position of the screw(part 12), and the external structure of the pump body(part 3)and pump cover(part 1), are all functional representations. The shape of the oil entrance is also represented in a partial sectional view. The left side view describes its working principle: If two gears rotate in accordance with the direction of the arrow shown in Fig. 9-13,the portative force generated in the left of the gear transports oil into a pump from the oil entrance. As the pump runs, it outputs oil from the exit at acertain pressure.   

针对主视图中未表达清楚的部分,还应辅以其他视图进行补充表达。此时应将装配关系及工作原理的表达放在首位,其次考虑主要零件的结构形状等。图9-11左视图中补充表达了齿轮泵的工作原理、螺钉(件12)的装配位置以及泵体(件3)和泵盖(件1)的外形结构,并采用局部剖视反映了进油口的形状。由左视图可知其工作原理为:当两个齿轮按图9-13中箭头所示方向旋转时,在齿轮啮合区的左侧产生真空吸力,将油从吸油口吸入泵内,随着齿轮的转动,不断地从出油口将具有一定压力的油输送出去。

After determining the left side view, check what other structure is not clearly represented in accordance with the needs of an assembly drawing. With this content in mind,choose other views and ensure that each view has a clear purpose. For example,as shown in Fig. 9-11, the C-view is added in the assembly drawing of the gear pump to express the shape of the dummy club at the oil entrance and exit on pump body(part3).the B—B view is added to show the structural shape at the base and the bottom cutting of pump body(part3).The selection of the gear pump is now complete, but one needs to keep in mind other representation views for comparison in order to select the best representation.

左视图确定后,再根据装配图应表达的内容,检查还有哪些内容是没有表达清楚的。据此再选择其他视图,使每个视图都有明确的表达目的。图9-11所示的齿轮泵装配图中,增加C向局部视图,以表达泵体(件3)上吸油口、出油口处凸台的形状,增加B—B剖视图,用来表达泵体(件3)的底座结构和下部的断面形状;至此, 齿轮泵的视图选择就算完成了。但有时为了能选定一个最佳方案,最好多考虑几种表达方案,以供比较和选用。