The size labeling requirements of the assembly picture are different from the size labeling requirements of the part. It does not need to mark all the size of each part. Just mark some necessary sizes. These necessary sizes can be roughly summarized as the following categories according to their effects:

(1) Specification size

     It is used to indicate the size of the performance or specifications of the machine (or component). This type of size is generally determined in the task book. It is the main basis for designing, understanding and choosing the machine or component, as shown in the valve body of the ball valve and the pore diameter of the valve body and valve cover in the figure above.

Second, assembly size

(2)In order to ensure the performance and quality of the machine or component, the size of the relevant parts must be injected in the figure.

1. Coordinate the size

     When the two parts have the requirements for cooperation, the size must be injected. The size of the valve body and valve cover of the ball valve as shown in the figure, the coordination size of the valve stem and the valve body.

2. Important relative position size

     During assembly, the distance between the distance and gap between the relevant parts must be guaranteed. The distance from the center of the valve pores to the wrench as shown in the figure is 82mm, and the distance from the valve stem to the right side of the surface is 46mm.

3. Connection size

     The connection size should be marked in the assembly figure to indicate the standard size of the standard zero and components (usually filled in the detailed column in the detailed column), which indicate the size of the thread fastener, key, sales, and rolling bearings. M22x1.5 and the nut M10X20, nut M10, etc. in the title bar.

(3) Installation size

     The correlation size of the machine or part installed to other zero, components or bases is called installation size. As shown in the figure above, the interface size of the ball valve M40X2 and so on.

(4)Shape size

    The shape size is the total length, total, and total width of the machine or component. It reflects the overall size of the machine or component, providing the size of the space size for installation, packaging, transportation, etc. The shape of the figure is 114mm.