Is the standard hex nut a positive hexagon?

Mechanical engineer 2002.8 standard hex nut is Zhengliufang? Wang Xuexin Zhongyuan Petroleum Exploration Bureau Machinery Manufacturing Plant Mining Machinery Institute, Puyang, Henan 457001, China) In the mechanical design, because the hex nut is a standard part, few people carefully observe its characteristics, drawing It is also time to use a template or call a standard parts gallery. However, in the work, from time to time, you will encounter the situation of drawing hexagons. If you used to draw with a drawing board, then few people may consider the parameter % of the hex nut. It is natural to think that e is the diameter of the hexagonal circumcircle. However, nowadays designers use CAD drawings. Careful people may have found that the dimensions drawn by CAD are different from those given in the Mechanical Design Manual. However, some designers have discovered this problem but do not know why. The designer will mark the size of the smart label in the CAD drawing, and think that as long as it is a standard inscribed square. In fact, as long as you carefully observe, it is not difficult to find that the six corners of the standard hexagonal nut are not sharp corners, but arcs, that is, in the process of processing the hexagonal, it is not processed according to the standard inscribed hexagonal, this is This results in a dimension formed by drawing an inscribed regular hexagon when drawing with CAD, which is different from the size in the Mechanical Design Handbook.

The graphics drawn in true size should look like this.

Using CAD drawing, as shown, the dimension is: the difference between the two is that it is drawn according to the national standard size parameters, the hexagon is an arc, safe when manually operated; it is the choice of CAD 3.3 motor Nth; we choose With 200V voltage, 3000r/min 1.5kW motor, the model we choose here is: Made in Italy FS4T1902. 3. Determine the speed ratio because the maximum angular velocity is 75°/s, so it has a sharp angle and is potentially unsafe during manual operation. factor.

The reason for this is that the nut is a standard part and a common part, so we usually use a simplified drawing in the drawing, which is the circular inscribed regular hexagonal drawing, but the size is not subject to special requirements. , should be in line with the national standard, not the actual size measured according to the drawing.

It can be seen that the parameters in the Mechanical Design Manual are the standards that designers should follow, and they should be able to correctly understand the meanings they express in order to better implement and implement national standards.

(Editor Huang Wei) sends a job.

Taking into account the rotational error and redundancy, the speed ratio is set to 80: the transmission ratio of 80 is 80, and the remaining transmission ratio 2.5 is provided by the transmission gear.

4 performance test system performance test is divided into three steps: laboratory test, lake test and sea test. All tests are part of the trajectory measurement system test.

Reliability, real-time tracking, etc. all meet the design requirements of the entire system.

The electromechanical servo system has good performance, high reliability and precision, and low price. It is an optimal design for underwater servo systems.

Li Hua, et al. MCS-51 microcontroller uses interface technology. Beijing: Beijing University of Aeronautics and Astronautics Press, 1993. (Editor Ming Tao)

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