Why do hex bolts need to be anti-loosening? It is because it can do better, longer and more valuable things. So, what is the anti-loosening method of the hex bolt connection? Bolt manufacturers will describe five types below, one: friction anti-loosening method; two: mechanical anti-loosening method; three: long-term anti-loosening method; Friction anti-loosening is also a widely used anti-loosening method. This method creates a positive pressure that does not change with the external force in the middle of the thread pair to create a sliding friction that can inhibit the relative rotation of the thread pair. This type of positive pressure can be accomplished using radial or other two-way clamping thread pairs. Such as the implementation of elastic sealing rings, double nuts, lock nuts and polyester insert locknuts, etc. This kind of anti-loosening method solves the disassembly of the nut very conveniently, but in the environment of severe blow, vibration and variable load, the bolt will cause the pre-tightening force to drop due to looseness at the beginning, and as the vibration frequency increases, the missing pre-tightening force A slow increase in tightening force may cause the nut to loosen and the threaded connection to fail. Pins, stop washers and strings of galvanized steel wire ropes are used to prevent loosening of mechanical equipment. The method of mechanical equipment anti-loosening is more reliable, and the method of mechanical equipment anti-loosening should be used to deal with key connections. Long-term anti-loose welding, riveting, bonding, etc. Most of these methods will break the threaded standard parts during disassembly and assembly, and cannot be reused. Riveting and anti-loosening are subjected to punching points, welding, bonding and other methods after tightening, so that the thread pair loses the main activity feature and the connection becomes difficult to disassemble. The disadvantage of this method is that the bolt rod can only be used once, and it is very difficult to disassemble and assemble. It is necessary to break the bolt side and detach it. The structure is anti-loose and the anti-loose structure does not rely on other manpower, but only on its own structure. The structural anti-loosening method, that is, the Down syndrome thread anti-loosening method, is also a progressive and effective anti-loosening method, but it is not known to most people.