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There are three commonly used anti-loosening methods for hex nuts: frictional anti-loosening, mechanical anti-loosening and permanent anti-loosening.

1. Friction and anti-loosening, use: hexagonal nuts, spring washers, self-locking hexagonal nuts, etc.

① Spring washer anti-loosening

The material of the spring washer is spring steel, and the washer is flattened after assembly, and its rebound force can keep the pressing force and friction between the threads, so as to achieve anti-loosening

② Anti-loosening of hex nuts

The hexagonal nut is used for the jacking action to make the bolt type be subjected to additional pulling force and additional frictional force. Due to the use of one more hexagonal nut, and the work is not very reliable, it has been used less and less at present.

Hex lock nut

③Self-locking hexagonal nut anti-loosening

One end of the hexagon nut is made into a non-circular closing or a radial closing after slit. When the hexagonal nut is tightened, the closing mouth expands, and the elastic force of the closing mouth is used to compress the screw threads. The anti-loosening structure is simple, the anti-loosening is reliable, and can be disassembled and assembled many times without reducing the anti-loosening performance.

④ Elastic ring hexagonal nut anti-loosening

Fiber or nylon is embedded in the threaded entry to increase friction. The elastic ring also acts to prevent liquid leakage.

2. Mechanical anti-loosening, use: cotter pin and hexagonal slotted hexagonal nut, stop washer, series steel wire, etc.

The method of mechanical anti-loosening is more reliable, and the method of mechanical anti-loosening should be used for important connections.

①Slotted hexagon nut and cotter pin to prevent loosening

After the slotted hexagon nut is tightened, use a cotter pin to pass through the small hole at the end of the bolt and the slot of the hexagon nut, or use an ordinary hexagon nut to tighten and drill the pin hole.

②Round hex nut and stop washer

Insert the inner tongue of the washer into the groove of the bolt (shaft), and fold one of the outer tongues of the washer into a groove of the hexagon nut after tightening the hex nut.

③Stop washer

After the hexagon nut is tightened, the single-ear or double-ear stop washer is respectively bent and attached to the side of the hexagon nut and the connected part to prevent loosening. If two bolts need to be double-locked, a double-joint stop washer can be used.

④Series wire anti-loosening

Use low-carbon steel wires to penetrate the holes in the head of each screw, connect the screws in series, and make them brake each other. This structure needs to pay attention to the direction in which the steel wire penetrates.

3. Permanent anti-loosening, use: spot welding, riveting, bonding, etc.

This method mostly destroys the threaded fasteners during disassembly and cannot be reused.

In addition, there are other anti-loosening methods, such as: applying liquid adhesive between the screw threads, inlaying nylon rings at the end of the hex nut, riveting and punching anti-loosening, mechanical anti-loosening and frictional anti-loosening are called detachable anti-loosening, while permanent anti-loosening Loose is called non-detachable anti-loose.

①Punching method to prevent loosening

After the hex nut is tightened, the punch point at the end of the thread destroys the thread

② Bonding and anti-loosening

Usually, the anaerobic adhesive is applied to the threaded surface, and the adhesive can be cured by itself after tightening the hex nut, and the anti-loosening effect is good.