Threaded fastener technology, how to prevent bolts from loosening and loosening: When the machine is in operation, it will generate strong vibration and impact forces, which will cause some screws and bolts on the machine to be loosened and loosened due to impact and vibration. It brings great troubles and hidden dangers to production. These problems often plague producers and consumers in the machinery industry. The problem of bolt loosening is a problem in real life, and how to solve this problem?
There are three commonly used methods to prevent loosening: frictional, mechanical, and permanent. Mechanical and frictional locks are called removable locks, and permanent locks are called non-removable. Common permanent locks are: spot welding, bonding, etc. This method often destroys the threaded fasteners during disassembly and cannot be reused. Common friction prevention methods: use gaskets, self-locking nuts and double nuts. Common mechanical anti-loosening methods: use split pins, stop washers and string steel ropes. The method of mechanical loosening prevention is relatively reliable. For important connections, the method of mechanical loosening prevention is as follows:
(1) Spring washers prevent loosening
The spring washer material is spring steel. After assembly, the washer is flattened. Its rebound force can maintain the compression and friction between the threads to achieve anti-loosening.
(2) Anti-loosening of top nut
The use of the nut against the top effect causes the bolt type to receive additional tensile force and associated friction. Since one more nut is used and the operation is not very reliable, it is recommended to use less
(3) Self-locking nut to prevent loosening
A section of the nut is made into a non-circular necking or a radial necking after slitting. When the nut is tightened, the closing mouth is expanded, and the elasticity of the closing mouth is used to compress the screw threads. The anti-loosening structure is simple and reliable, and can be disassembled and installed repeatedly without reducing the anti-loosening performance.
(4) Anti-loosening of elastic ring nut
Fibers or nylon are embedded at the thread entry to increase friction. The elastic ring also functions to prevent liquid leakage.
(1) Slot nut and cotter pin prevent loosening
After the slot nut is tightened, use a cotter pin to pass through the small hole at the end of the bolt and the slot of the nut. Or you can tighten it with a common nut for drill pin control
(2) Round nut and stop washer
Insert the inner tongue of the washer into the groove of the bolt (shaft). After tightening the nut, fold one of the outer tongue of the washer into a groove of the nut.
(3) Stop washer
After the nut is tightened, the one- or two-ear stop washers are respectively bent and attached to the side of the nut and the coupled part to achieve loosening prevention. If two bolts are required to be double-locked, double-locking washers can be used.
(4) Anti-loosening of tandem steel wire
Use a low-carbon steel wire to penetrate the hole in the head of each screw, and connect the screws in series to brake each other. This structure requires attention to the direction in which the wire penetrates.
(1) Punching method to prevent loosening
Punching point at the end of the thread after the nut is tightened to destroy the thread
(2) Bonding and loosening prevention
An anaerobic adhesive is usually applied to the threaded surface. After tightening the nut, the adhesive can be cured by itself, and the loosening effect is good.