If the tightening torque of Dongming fasteners is determined when tightening the nut, the problem of overloading may occur when tightening the bolt head with this torque. . Generally speaking, about half of the torque is required to overcome the friction force of the fastening surface, so if the friction radius is small, more torque will enter the screw fastening part, resulting in over-tightening. On the other hand, assuming that the torque is determined by the tightening of the bolt head, when the nut is tightened, the side with the larger friction radius is subjected to the torque. Insufficient preload on the tightening part of the input screw may cause loosening problems.
2. Why do Dongming fasteners use gaskets?
Washers are a very common standard in the process of threaded connections such as bolts and nuts. The appearance of gaskets is very common. It can be said that washers are always used in conjunction with threaded fasteners such as bolts, screws, etc.
1. When the substrate is very soft, the surface of the substrate will be damaged during the process of tightening the bolts and screws. By using gaskets, the pressure can be distributed over a larger area to avoid damaging the surface of the motherboard. The substrate is very soft. When the perimeter of the hole where the fastener is installed is damaged, sufficient force is often applied to pull the fastener against the mother plate of material during the threading process of the fastener. The presence of the gasket helps to create less cohesive pressure, so problems with tensile failure can occur. If the surface of the motherboard to which the bolts or screws are tightened is uneven, the heads of the fasteners are likely to get stuck on them. With washers, the surfaces of bolts and screws will slip and installation becomes easy.
2. Some washers are designed with a special structure and have a nut locking function. Commonly known as lock washers, there are many structural forms, such as open, star, wave and so on. This lock washer must be used with the nut.
three. The role of Dongming fasteners
When tightening with bolts and nuts, torque must be applied with a torque tool or hand wrench to lock. . Finally, the torque is converted into the force required to fasten the part. A certain amount of force ensures the joint's resistance to vibrational relaxation and fatigue.
Four. Application of Nuts
Nuts are very common in structural assembly and are mostly used in forgings, castings and mechanical parts. Especially when the threaded hole does not provide enough thread shearing area and the self-locking device cannot be used, the built-in nut is a very effective solution. In addition, some large forgings and castings will drive the wire directly into the base section. If the screw breaks, it can be dangerous to the entire part.
Through the above introduction, we know whether to apply torque to the bolt head or the nut, the corresponding situation, the role of the washer, the development of flange fasteners, and the method to ensure the required force for installation.