The substantial difference between anti-loosening thread and self-locking thread

The substantive difference between anti-loosening thread and self-locking thread and the formulation and inspection of self-locking performance standards

The threaded fasteners we currently use have anti-loosening properties and self-locking properties. Some are originally anti-loosening threads, but they are said to be self-locking threads. So, how to distinguish and distinguish?

1. The basic judgment of the self-locking thread pair is based on the self-locking thread and the anti-loosening thread. The most basic difference is: the self-locking thread refers to a thread pair composed of an external thread and an internal thread. With self-locking performance. The auxiliary evaluation index should be: the main profile of the internal and external threads should be the same, and it should be the same as the traditional profile, not one is triangular thread, the other is a combination of rectangular thread, trapezoidal thread, sawtooth thread, and wedge thread. Among them, the American product Spilao belongs to the self-locking thread pair composed of triangular thread and wedge thread. Another indicator is that the self-locking thread pair can be repeatedly assembled and disassembled and used repeatedly; the anti-loosening performance generated by adding some auxiliary means or measures in addition to a thread pair, such as adding spring washers, adding nylon inserts Fillings such as, threaded sleeves, damage to the thread profile, and even welding are all anti-loosening measures. This kind of thread pair can only be said to be an anti-loosing thread pair; in another case, it is the self-realization of double thread pair For locking and anti-loosening performance, this thread pair cannot be integrated into the category of self-locking threads. Such as double nut anti-loosening, grooved nut, high lock nut, etc. (Guide: practical knowledge of stainless steel)

2. There are two national standards for judging the self-locking performance of the thread pair. There are two standards in my country, one is the national standard and the other is the national military standard. The testing equipment for testing according to national standards is very complicated. It is said that only a certain department of the country is equipped with one, but no other standard parts factories in China have been equipped with this testing equipment. The national military standard only stipulates the detection method, which is a method standard. As long as it is equipped with a standard vibrating table device and the relevant fixtures are manufactured according to the standard, the self-locking performance of the relevant thread pair can be checked. Detected. It is designed to simulate the anti-transverse vibration of the thread pair according to the actual use situation. 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 a little lower. According to the comparison of domestic experts, if the self-locking thread pair can pass the national military standard test, it will definitely pass the national standard test. Conversely, it is more difficult to pass national military standards than to pass national standards. Our aerospace and aviation products, and the self-locking performance of their thread pairs, are tested according to this standard.

3. The recommendations for the formulation of self-locking performance standards suggest that our manufacturers should cite our national military standard 'GJB 715.3' as the basic standard when formulating self-developed self-locking threaded fastener product standards. This standard is also a standard equivalent to US military standards, which is international and highly credible.

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