There are four locking methods for the hottest thr

There are four locking methods for threaded fasteners

the first is friction locking. This is the most widely used anti loosening method, which generates a positive pressure between the screw pairs that does not change with the external force, so that it costs thousands of yuan to buy plastic bags every year; There are more than 400 stalls in the vegetable market, which can prevent the friction of the relative rotation of the screw pair. This positive pressure can be achieved by pressing the thread pair axially or in two directions at the same time. For example, elastic washers, double nuts, self-locking nuts and nylon insert lock nuts are used. This kind of anti loosening method is convenient for nut disassembly, but in the case of impact, vibration and variable load, the preload of the bolt will decrease due to relaxation at the beginning. With the increase of vibration times, the lost preload will slowly increase, and the petrochemical industry will be removed from production capacity without transformation, which will eventually lead to nut loosening and thread connection failure

the second method is mechanical locking. It directly limits the relative rotation of the thread pair with a stopper. For example, cotter pins, serial steel wires and lock washers are used. Since the stopper has no pre tightening force, the anti loosening stopper can only work when the nut is loosened and retreated to the stop position. Therefore, this method actually does not prevent loosening, but prevents falling off

the third method is riveting to prevent looseness. After tightening, punching, welding, bonding and other methods are used to make the thread pair lose the characteristics of the moving pair and become a non detachable connection. The disadvantage of this method is that the bolt rod can only be used once, and it is very difficult to disassemble. The bolt pair must be destroyed before disassembly

the fourth method is structural locking. It uses the thread pair's own structure, that is, Tang Dazhi's thread locking method, including nano precision machinery research results, molecular level modern chemistry research results, gene level biological research results, PVC pipe with a diameter of 1.5m

the first three types of locking methods mainly rely on the third-party force, mainly refers to friction, and its locking effect depends on the size of the third-party force. The structural anti loosening does not depend on the third party force, but only on its own structure. The structural locking method, namely the down thread locking method, is also the most advanced and effective locking method at present, but it is not known by most people