Hex Nut Manufacturers describes how to prevent loosening of nuts and bolts:
1. Loosening is one of the main failure modes of threaded fasteners. The loosening of threads has always been a serious problem in industrial manufacturing and industrial products, and even a fatal hidden danger, which has caused unpredictable harm to our daily life, work, transportation, and national defense, and military.
2. Two requirements should be considered for the anti-loosening of the threaded coupling. One is to be reliable, and the other is to be easy to disassemble for frequent disassembly and maintenance. There are several types of anti-loosening, such as friction locking, mechanical locking, and material locking. The commonly used anti-loosing forms are mainly as follows: spring washers, elastic washers, stop washers, double nuts, lock nuts, bolts with holes Slotted nuts with split pins, adhesives, etc.
3. (Spring, elasticity, stop) washers, rely on elastic force and the insertion of the cut corners to prevent loosening, but due to uneven elasticity, it is not very reliable. It is mostly used for insignificant connections. It is not suitable for occasions where scratches and frequent disassembly are not allowed.
4. The locking principle of the non-metallic insert locking nut is that when the external thread is screwed in, the locking force is generated due to the good elasticity of the nylon material to achieve the locking. It can also be used to adjust the position under the condition of little vibration. However, due to the limitation of the melting point of nylon, the maximum working temperature of this kind of nuts should generally be less than 120°, preferably below 100°.
5. In addition, there are the following problems when installing non-metallic insert lock nuts: ① The tightening torque should be increased appropriately; ② The bolt selection requirements are relatively strict, the length is appropriate, and there should be no cotter pin holes and burrs on the bolts (for bolts The machining accuracy requirements are relatively high).
6. Bolts with holes, slotted nuts, and split pins are suitable for preventing the loosening of important parts of the connection in variable load and vibration occasions. The performance is reliable, but the design and assembly are inconvenient.
7. Adopting adhesive to bond the screw thread, the method is simple, economical, and effective. Its anti-loose performance is directly related to the adhesive. According to the loosening torque and temperature conditions, as well as the requirements of removable or non-removable, the appropriate adhesive is selected.
8. Thread locking glue can provide different loosening moments (loose breaking/dismounting moments), combined with customer requirements, to achieve a perfect relaxation effect.