What is a self-locking nut?

A locknut (also known as a self-locking nut) is a type of nut designed with a specialized structure to achieve fastening and anti-loosening functions. Its primary anti-loosening methods include mechanical locking, staking/crimping, friction-based locking, and structural locking. It employs a thread-deformation technology to ensure that the load is distributed evenly across the entire length of the thread, thereby avoiding the load-concentration phenomenon typical of traditional threaded fasteners. Furthermore, it achieves vibration resistance and anti-loosening capabilities by utilizing engineering plastic inserts within the threads or through a 30-degree wedge-shaped thread design to increase frictional force. This type of nut can be repeatedly removed and reinstalled-between 5 and 50 times-while still retaining its anti-loosening effectiveness. Common connection methods involve the use of self-locking bolts, spring washers, or thread-locking adhesives to achieve a self-locking threaded assembly.

 

Originally applied within the aerospace sector, this product's scope has since expanded to industries such as automotive manufacturing, medical devices, and sports equipment. It has also broadened its application scenarios within emerging fields, including new energy vehicles and wind power generation. In 2019, the market size for anti-loosening nuts in China stood at 7.747 billion RMB; this figure is projected to reach 13.797 billion RMB by 2026. Nylon-insert locknuts and all-metal locknuts represent the mainstream products in the current market, each suited to different operating conditions. Driven by the advancements of Industry 4.0, product development is increasingly focusing on trends toward intelligent functionality, lightweight design, and enhanced corrosion resistance.