JB/T 7073-1993 Simplified Specifications for Drawings of Large, Medium and Small Electric Motors and Water Turbines JB/T7073-1993 Standard Download Decompression Password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Simplified Regulations for Drawings of Large, Medium and Small Motors and Turbines JB/T7073-93
This standard is formulated on the basis of implementing the simplified drawing method, schematic drawing method and simplified annotation method stipulated in the national standard "Mechanical Drawing", combined with the characteristics of motor and turbine products. Subject content and scope of application
This standard stipulates the simplified drawing method, schematic drawing method and simplified annotation method for drawing motor and turbine product drawings. This standard is applicable to motor and turbine product drawings, and other product drawings can also be used for reference. 2 Referenced standards
GB 4458.1
GB 4459.1
GB12212
3 General provisions
Scale of mechanical drawing
Mechanical drawing
Mechanical drawing
Mechanical drawing
Mechanical drawing
Mechanical drawing
Technical drawing
Section symbol
Two methods of drawing
Dimension annotation method
Dimension tolerance and fit annotation method
Drawing of threads and threaded fasteners
Dimensions, proportions and simplified representation of weld symbols 3.1 This standard adds reduction ratios of 1:6 and 1:8 on the basis of GB4457.2. 3.2 When marking the thickness symbol "\" for plate parts, if the surface maintains the condition of the previous process, the surface roughness symbol "\" may not be marked. 3.3 The tolerance grade of internal threads is 6H, the surface roughness parameter R, and the value is 6.3um. The tolerance grade of external threads is 6g, and the surface roughness parameter R. When the value is 3.2μm, the tolerance grade and surface roughness code can be omitted. 3.4 For individual length dimensions that are not drawn to scale (except for those drawn by shortening after disconnection), a thick solid line can be drawn under the size number (Figure 1, Figure 2).
In special cases, for drawings that are not drawn to scale, a slash should be drawn in the scale grid of the title bar (Figure 3). Figure
Approved by the Ministry of Machinery Industry on October 8, 1993
Implemented on January 1, 1994
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3.5 When drawing more complex adjacent auxiliary parts with double-dotted lines, it is allowed to cover the parts behind them. 3.6 Parts of the same type can be drawn using a table diagram (Figure 4). 4 Simplified drawing methods for general parts drawings
4.1 If the chamfers with smaller dimensions or the steps, arcs, and circles with similar dimensions have been clearly expressed in the main view, their projection lines are not allowed to be drawn in the remaining views (Figure 5).
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4.2 When the internal and external shapes and structures of simple parts can be correctly, completely and clearly expressed, it is allowed to draw only one view (Figure 6). (a)
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4.3 The uncut ribs and blades on the rotating parts such as brackets and fans can be simplified and not all projections can be drawn on the agent view (Figure 7).
4.4 For parts with the same groove at different positions on the front and back sides, the cross-sectional view of the groove can be drawn according to the method shown in Figure 8. A
4.5 The parts of the rotating body can be simplified when the positions, assembly structures and main dimensions of various parts can be fully and clearly expressed (Figure 9).
JB/T7073—93
4.6 The cross-sectional view of large-diameter ring parts can be drawn only partially (Figure 10a) or only the cross-sectional view (Figure 10b) without causing misunderstanding.
4.7 Small diameter round holes and screw holes on large workpieces can be represented by short cross lines (thin solid lines) (Figure 11). When the diameters of round holes or screw holes are different, the thin solid lines can be tilted 45° or the symbol "×" can be used to distinguish them (Figure 12). 321
Self-reading
12-$15
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4.8 Parts that need to be processed as a whole or used in pairs can be drawn on one drawing, as shown in Figure 13a. Parts that are used individually but are more reasonably processed as a whole can be drawn according to Figure 13b.
4.9 Several groups of parts of different sizes that need to be processed as a whole can be drawn on one drawing, but the code of the parts should be marked separately with guide lines, and the code, quantity and weight should be listed in a table (Figure 14). x
JB/T7073-93
8××·×××·×××
8××.××x
4.10 For left and right parts, upper and lower parts, or front and rear parts installed in symmetrical positions, only one of them needs to be drawn. In this case, it is necessary to indicate them on the drawing with guide lines and give their codes respectively (Figure 15). Left part 8)
4.11 For several holes or slots of various types with the same size and regular distribution, only one or several holes can be drawn, and the rest only need to be indicated by dotted lines to indicate their center positions, and the total number of holes should be indicated (Figures 16 and 17). 323
20(120
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4.12 Holes and screw holes evenly distributed on the flange can be drawn in the form of Figure 18; when there are more than two groups of identical holes, only one group can be drawn and the rest can be described in words.
Same at both ends
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4.13 When drawing a partially enlarged drawing, the enlarged part of the original drawing can be omitted, as shown in Figures 19 and 20. 2: 1
4.14 Simplification and Omission of Section Symbols
4.14.1 Section symbols can be omitted for the removed surface in the part drawing without causing misunderstanding (Figure 21). cL
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When drawing a part drawing, the section symbol in the section view can be omitted without causing misunderstanding (Figure 22). Figure 22
4.14.3 The section symbol at the fracture of a solid cylinder and a hollow cylinder can be omitted (Figure 23). Figure 23Www.bzxZ.net
4.14.4 Section symbols can be omitted for the section view cut from the center line of the part. However, the section symbol should be marked above the section view. \A--A" section, the sectioning position is indicated by the sectioning symbol on the corresponding view and the same letter is annotated. As shown in Figure 24. Al
4.14.5 When drawing the section view of a large and thin metal sheet, four section lines can be drawn at both ends of the section view (Figure 25). Figure 25
4.15 When drawing a pipe part drawing, it is allowed to use a single thick solid line to represent the pipe. For longer pipes, the break drawing method can be used. At this time, the boundary line of the fracture is drawn with a thin solid line, but the break position must not be taken at the bend of the pipe, and the pipe diameter can be marked on the thick solid line representing the pipe (Figure 26.27).
5 Simplified dimension annotation method
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5.1 For stepped shafts or holes with multiple coaxial dimensions, it is permitted to use a single arrow dimension line to mark the dimensions (Figures 28-30). If necessary, several dimensions can be marked on one dimension line (Figure 28). Parts with the same datum and multiple dimensions can be marked in the form of Figure 31. $69×5
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