Nut information introduction
Introduction 1. A nut is a nut, a part that is screwed together with a bolt or a screw for fastening. It is an original part that all manufacturing machinery must use. There are many types of nuts, and our common ones are national standard, British standard, American standard, and Japanese standard nuts. According to different materials, nuts are divided into carbon steel, high-strength, stainless steel, and plastic steel.
Nut principle: The working principle of the nut is to use the friction between the nut and the bolt for self-locking. However, the reliability of this self-locking will be reduced under dynamic load. In some important occasions, we will take some anti-loosening measures to ensure the reliability of nut locking. Among them, the use of lock nuts is one of the anti-loosening measures.
2. What is a lock nut
There are also two types of lock nuts. One is to screw two identical nuts on the same bolt, and add a tightening torque between the two nuts to make the bolt connection reliable. The other is a special anti-loosening nut, which needs to be used together with an anti-loosening washer.
The special anti-loosening nut is not a hexagonal nut, but a middle round nut. There are 6 notches on the circumference of the nut. These six notches are not only the force point of the tightening tool, but also the snap-in place of the bayonet of the anti-loosening washer. The second anti-loosening method is more reliable than the first, but the structure is relatively complicated. What is the difference between a lock nut and a self-locking nut? The function of the self-locking nut is mainly anti-loosening and anti-vibration. For special occasions. Lock nuts and self-locking nuts are the same concept, and nuts with self-locking function are called lock nuts. There are related standards for screwing in torque and screwing out torque, please refer to mechanical design manual or national nut standard.
3. Analysis of the difference between cold heading nuts and hot heading nuts
Cold heading: It is to use the plasticity of the metal to apply pressure or cold drawing by cold mechanics to achieve the purpose of solid deformation of the metal.
A forging method in which the top of a rod or wire is thickened at room temperature. Cold heading is mainly used to manufacture bolts, nuts, nails, rivets and steel balls and other parts. The forging blank material can be copper, aluminum, carbon steel, alloy steel, stainless steel and titanium alloy, etc., and the material utilization rate can reach 80-90%. Cold heading is mostly carried out on a special cold heading machine, which is convenient for continuous, multi-station and automatic production. The processes of material cutting, heading, accumulation, forming, chamfering, thread rolling, diameter reduction and edge trimming can be completed in sequence on the cold heading machine. The production efficiency is high, up to 300 pieces/min, and the diameter of the largest cold heading workpiece is 48 mm. Schematic diagram of cold heading bolt process is a typical process of cold heading bolt. Multi-station nut automatic cold heading machine is a multi-station nut automatic cold heading machine. The bar is automatically fed to a certain length by the feeding mechanism, and the cutting mechanism cuts it into blanks, and then sent to the accumulating and pressing station and punching station for forming by the clamp conveying mechanism.