The threaded fasteners we currently use are either anti-loosening or self-locking. Some are originally lock nuts, but they are said to be self-locking nuts. So how to distinguish and distinguish?

  1. The basic judgment of the self-locking nut pair is based on the self-locking nut and the lock nut. At least one difference is that the self-locking nut refers to a thread pair consisting of an external thread and an internal thread. With self-locking performance.

辅助 The auxiliary evaluation index should be: the main tooth profile of the internal and external threads should be the same, and it should be the same as the traditional tooth profile. One cannot be a triangular thread, the other is a combination of rectangular, trapezoidal, serrated, and wedge threads.

Another indicator is that the self-locking nut pair should be able to be repeatedly assembled and disassembled and reused; the anti-loosing performance caused by adding some auxiliary means or measures in addition to a thread pair, such as adding spring washers, and adding nylon inserts Filling materials such as screws, screw sleeves, damage to the thread profile, and even welding are all measures to prevent loosening. This type of thread pair can only be said to be a lock nut pair;

There is also a case where the self-locking and anti-loosing properties of the double-threaded pair are achieved, and this kind of threaded pair cannot be merged into the category of self-locking nuts. Such as double nut anti-loosening, slot nut, high lock nut and so on.

  2. There are two national standards for judging the performance of the screw pair self-locking performance. There are two standards in our country, one is the national standard and the other is the national military standard.

的 The testing equipment for testing according to national standards is very complicated. It is said that only one department in the country is equipped with one, but no other standard parts factory in China has configured the testing equipment.

The national military standard only specifies the detection method. It is a method standard. As long as it is equipped with a standard shake table device and the relevant fixtures are manufactured according to the standard, the self-locking performance of the relevant thread pair can be performed. Detected. It is designed according to the actual use situation, and simulates the situation that the thread pair is resistant to lateral vibration. As far as the realization of testing conditions is concerned, testing according to national military standards is much simpler and easier than testing according to national standards, and the testing cost is also lower.

According to the comparison of domestic experts, if the self-locking nut pair can pass the national military standard test, it will definitely pass the national standard test. Conversely, passing national military standards will be more difficult than passing national standards. The self-locking performance of our threaded pair of aerospace and aviation products is tested according to this standard.

3. Recommendations for the development of self-locking performance standards suggest that our manufacturers should reference our national military standard "GJB715.3" as the basic standard when formulating self-developed self-locking nut fastener product standards. This standard is also a standard equivalent to the US military standard, which is international and highly reliable.