Once the bolt connection in mechanical equipment is loosened, it will cause the bolt to fall off and cause a major safety hazard, or the pre-tightening force of the bolt will decrease and the fatigue life of the bolt connection will be greatly shortened. Therefore, appropriate anti-loosening measures should be selected in the design to ensure that the bolts do not loosen in actual use.
The commonly used anti-loosening measures in design are as follows:
01
double nut
The double nut anti-loosening is also called the top nut anti-loosening. When the two top nuts are tightened, there is always an interaction pressure between the two top nuts. Any one of the two nuts needs to overcome the screw thread if it wants to rotate. the friction between them. Even if the external load changes, the pressure between the top nuts will always exist, so it can play a role in preventing loosening.
02
Self-locking nuts
Self-locking nuts generally rely on friction. The principle is to press into the preset holes of the sheet metal through embossing teeth. Generally, the diameter of the square preset holes is slightly smaller than that of the rivet nut. The nut is connected with the locking mechanism. When the nut is tightened, the locking mechanism locks the bolt thread.
Embedded nylon self-locking nut
Deformed Thread Locknuts
Wedge and hammer nut in one
Wedge Action Locknuts
03
Threadlocker
Thread locking adhesive is an adhesive composed of (meth)acrylate, initiator, co-accelerator, stabilizer (inhibitor), dye and filler in a certain proportion.
04
cotter pin
After the nut is tightened, insert the cotter pin into the nut groove and the hole at the end of the bolt, and open the tail of the cotter pin to prevent the relative rotation of the nut and the bolt.
05
slotted nut
Slotted nuts are used in conjunction with threaded rod eye bolts and cotter pins to prevent relative rotation of the bolt and nut.
06
Series wire anti-loosening
The series steel wire anti-loosening is to pass the steel wire into the hole of the bolt head, connect the bolts in series, and play the role of mutual containment. This loosening method is very reliable, but it is troublesome to disassemble.
07
preload
High-strength bolt connections generally do not require additional anti-loosening measures, because high-strength bolts generally require a relatively large pre-tightening force, such a large pre-tightening force creates a strong pressure between the nut and the connected parts, This pressure creates a frictional torque that stops the nut from turning, so the nut does not loosen.
08
Stop washer
After the nut is tightened, the single-ear or double-ear stop washer is respectively bent and tightly attached to the side of the nut and the connecting piece, so that the nut can be locked. If the two bolts need to be double locked, the double brake washer can be used, and the two nuts brake each other.
