Bolted joints play an important role in mechanical equipment, but if the bolts are loose, they can cause serious safety hazards or shorten the life of the joint. Therefore, it is very important to take appropriate anti-loosening measures in the design to ensure that the bolts will not loosen in practical use. Here are 10 classic bolt anti-loosening designs.
Double nut
Double nut anti-loosening is a common anti-loosening design method for bolts. It works by installing two opposite nuts on the bolt so that the pressure of interaction between them is created, creating friction that prevents the nut from loosening.
When the two opposite nuts are tightened, the pressure between them is always present. For any nut to turn, it needs to overcome the friction between the screwing threads. Even if the external load changes, the pressure between the top nuts is always there, so the nut can be effectively prevented from loosening.
Self-locking nuts
The self-locking nut design is simple and easy to use, making it suitable for a variety of scenarios where it is necessary to prevent the nut from loosening. It uses friction to prevent the nut from loosening, usually with embossing teeth designed on the nut and pressing them into the preset holes of the sheet metal so that the hole diameter of the preset holes is slightly smaller than the diameter of the embossing teeth.
When the self-locking nut is tightened, the embossing teeth are embedded in the preset holes, creating friction. This friction can provide enough resistance to make the nut less likely to loosen. The anti-loosening effect of a self-locking nut mainly depends on the action of friction.
Nylon self-locking nut inset
This nut has a nylon washer or insert embedded inside that uses the elasticity and friction of the nylon material to provide an anti-loosening effect. When the nut is tightened, the nylon washer or insert creates additional friction to prevent the nut from loosening.
Spring washers
The addition of a spring washer between the nut and bolt head provides additional elastic deformation, keeping the tightening force stable and preventing the nut from loosening.
Double-layered self-locking gaskets
Double-layer self-locking washers are a commonly used bolt anti-loosening device. It consists of two circular washers, which are locked between each other by a series of flanges and grooves. The flange of the inner washer is in close contact with the bolt, providing friction to prevent the bolt from loosening. The grooves of the outer gasket are matched to the flange of the inner gasket, so that a self-locking structure is formed between the two gaskets, which further increases the anti-loosening ability.
Threadlocker
Threadlocker is an adhesive that consists of methacrylates, initiators, co-accelerators, stabilizers, dyes, and fillers. Threadlocker fills the thread gap, creating a tight connection and preventing the nut from loosening. It has good resistance to high temperature and chemical corrosion.
Slotted nuts
Slotted nuts are used in conjunction with screw holed bolts and cotter pins to prevent the bolt from turning relative to the nut. After the nut is tightened, insert the cotter pin into the nut groove and the bolt tail hole, and pull the tail of the cotter pin open to prevent the relative rotation of the nut and the bolt.
Lock bolts
Lockbolts are designed with a special flange or locking structure in their threaded structure that provides additional tightening force through elastic deformation when fastening to prevent the bolt from loosening.
The above are common anti-loosening design methods for bolts, and designers can choose appropriate anti-loosening measures according to actual needs. By adopting these designs, the reliability and working life of bolted joints can be improved, and the safe operation of machinery and equipment can be ensured.