The first is to screw on the same bolt with two identical nuts, and add a tightening torque between the two nuts to make the bolt connection reliable.
The second is a special locknut, which needs to be used with a lockwasher. The special anti-loosening nut is not a hexagonal nut, but a medium round nut. There are 3, 4, 6 or 8 gaps on the circumference of the nut (depending on the size of the nut and the manufacturer's product series). Several notches are not only the focus of the tightening tool, but also the snap-in place of the lock washer bayonet.
The third is to drill through threaded holes (usually 2, distributed at 90 degrees on the outer surface) from the outer surface of the nut to the inner thread surface, which are used to screw in small-diameter countersunk screws. Apply a centripetal force to prevent the locknut from loosening. The lock nuts with better quality sold in the market are inlaid with small copper pieces consistent with the lock nut thread on the inner surface of the nut, which is used to prevent the radial jacking screw from directly contacting the locked thread and damaging the latter . This kind of lock nut is gradually used in the shaft end locking of rotating parts, such as the anti-loosening of the bearing at the installation end of the ball screw.
The second anti-loosening method is more reliable than the first, but the structure is relatively complicated. Compared with the first two types, the third type has the characteristics of better anti-loosening effect, simpler and more beautiful structure and smaller axial dimension.
