What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Hexagon nuts are also called hexagon nuts. Generally, there are many types of nuts, such as hexagon nuts, round nuts, square nuts and so on. Some standards for nuts are still relatively clear. Some specifications and size standards, material requirements standards, electroplating standards, etc. are relatively clear. Different types of nuts also have different standards. Let's introduce the specifications and standards of the nuts in detail.
Spring washers are widely used in the load-bearing and non-load-bearing structures of general mechanical products. They are characterized by low cost and easy installation. They are suitable for parts with frequent assembly and disassembly. Quick and easy automatic selection of washers is included, but the anti-loosening ability of spring washers is very low! Especially in European and American countries that require high reliability, the adoption rate is extremely low, especially the important load-bearing structural connection parts have long been abandoned. Our country still has some applications in the military industry, but it has been improved to stainless steel. Steel spring washers have long been banned in CASC! It is also said to be very unsafe, because there are two reasons: 1 is circle rise and 2 is hydrogen embrittlement.
The standard specifies hexagon head bolts with thread specifications of M3~M64, grades A and B. Grade A is used for bolts with D<=24 and L<=10D or L<=150mm (whichever is smaller); grade B is used for bolts D > 24 or L > 10 D or L > 150 (according to the smaller value) bolt size specification mark: thread specification D = M12, nominal length L = 80mm, performance level is 8.8, the table is the same as oxidation, A level Hexagon head bolt tag example bolt GB / T5782-86-M12 × 80 national standard common hex bolt head on the side size and cooperation national standard wrench thread diameter \ pair of edge sidewalls Skin wrench Wrench Double-ended open-end wrench Double-ended Torx wrench. The outer hexagon bolt is the most frequently used type of bolts. The main function of the external thread it has is to cooperate with the nut. Using this threaded connection method, the two parts are integrated. Grade C hexagon bolts are mainly used in steel structure machinery and equipment with relatively rough surface and low precision requirements. Grade A and Grade B hexagon bolts are mainly used in machinery and equipment with smooth surface and high precision requirements. Most of the stainless steel outer hexagon screws are full-tooth and hexagonal head full-tooth bolts. Standard: DIN933, GB5783, ISO4017, ANSIB18. 2.1, JISB1180; non-full thread bolt standards DIN931, GB5782, ISO4014, ANSIB18.2.1, JISB1180.
In the prior art, the spring washer has a certain anti-loosening effect. However, due to the unreasonable design structure, the upper and lower pressing forces of the spring washer and the spring washer's anti-return force are poorly matched, resulting in the smooth surface and the bolt head. The friction between the nut and the connected parts is small. When the bolt or nut is subjected to strong vibration, the bolt or nut will still loosen. Therefore, the anti-loosening effect of the above spring washer still needs to be improved.
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