1、 Spring washer is used to prevent looseness
The combined bolt design method of bolt with spring washer and flat washer is a common design method. Many designers regard this design method as inertia thinking. As long as bolts are used, bolts, flat washers and spring washers must be used. It can be seen from the analysis of the transverse vibration anti loosening test results that the spring washer has no anti loosening effect at all, and the vibration test results of the spring washer are even worse than those of the flat washer. When we tighten the bolt of spring washer until the bolt breaks, we will find that when the bolt continues to tighten, the spring washer will even be slowly screwed out, and the spring washer will rotate out.
Spring washer locking is mainly used for small bolts, such as electrical connections. If the preload is relatively large, two sides of the spring washer will appear, which was originally used to prevent loosening. When the preload is large, reverse cutting into the connected part may occur, which will cause uneven contact surface of the bolt and even damage the surface of the bolt and the connected part.
2、 Locking steel wire locking
Locking steel wire to prevent looseness is a commonly used method, especially in the connection of some large machinery and equipment. This locking method is not suitable for the production of large quantities of products and does not use mechanized and automated installation. The winding direction of the steel wire needs to be paid attention to. It must be the tightening direction of the tightening bolt. And locking the steel wire to prevent looseness generally requires two bolts or one bolt in series with the perforation of another part. The locking method of locking steel wire can not only have a certain locking effect, but also play a role of falling after the bolt is loosened or the bolt is broken.
3、 Self locking nut locking
Self locking nuts are also divided into two types: all metal self-locking nuts and nylon insert self-locking nuts. All metal self-locking nuts have opposite side pressing and head pressing, as well as adding metal ferrules, which are mainly used to deform threads and increase a certain amount of screw in and screw out torque. This kind of anti loosening has no great anti loosening effect, and its anti loosening effect can be clearly seen in the transverse vibration test. The anti loosening effect is slightly better than that of ordinary bolts and nuts, but the effect is also very limited.
Other commonly used locking methods include gluing, nordlock, double nuts, cotter pins and other methods, which are common in actual processing and production.