Why prevent bolted joints from loosening
Anti-loose is for more effective long-term work.
Commonly used anti-loosening methods include friction anti-loosening, mechanical anti-loosening and permanent anti-loosening.
Mechanical locking and friction locking are called removable locking, and permanent locking is called non-removable locking.
Commonly used permanent anti-loose are: spot welding, riveting, bonding and so on. This method mostly destroys threaded fasteners during disassembly and cannot be reused.
Common frictions to prevent loosening include the use of washers, self-locking nuts and double nuts.
Commonly used mechanical anti-loosening methods: use split pins, stop gaskets, and string wire ropes.
Mechanical anti-loosening method is more reliable, and important connections should be mechanically anti-loosening method.
The following points are as follows.
(1) Anti-loose friction
① Spring washer to prevent loosening
The material of the spring washer is spring steel. After assembly, flatten the washer, its resilience can maintain the pressure and friction between the threads to prevent loosening
② Top nut locking
The bolt type takes the extra tension and extra friction by using a nut on top. Due to the use of an extra nut, the work is not very reliable and is rarely used at present.
③Self-locking nut to prevent loosening
One end of the nut is made non-circular closed or slotted and then closed radially. When the nut is tightened, the closure expands and the spring force of the closure acts to compress the threads. The anti-loosening structure is simple and reliable, and can be disassembled and assembled for many times without reducing the anti-loosening performance.
④Elastic ring nut to prevent loosening
Fiber or nylon is embedded in the threads to increase friction. The elastic ring also acts to prevent liquid leakage.
2) Mechanical anti-loosening
①Slot nut and cotter pin to prevent loosening
After the slotted nut is tightened, use a cotter pin through the small hole at the end of the bolt and the notch in the nut, or drill a hole in the pin after tightening with a regular nut.
②Round nut and stop washer
Insert the inner tongue of the washer into the groove of the bolt (shaft). After tightening the nut, insert one of the outer tongues of the washer into the groove in the nut.
③ Stop washer
After tightening the nut, bend the single lug or double lug stop washer and fit snugly against the side of the nut and the connected part, respectively, to prevent loosening. If double interlocking is required for both bolts, double interlocking washers can be used.
④ series steel wire anti-loosening
Run low carbon steel wire through the holes in the head of each screw to connect the screws in series to brake each other. This structure requires attention to the threading direction,
3) Permanent anti-loose
①Flushing method to prevent loosening
After tightening the nut, the thread ends are broken
② Bonding and anti-loosening
Anaerobic glue is usually applied to the thread surface. After tightening the nut, the adhesive can be cured by itself, and the anti-loosening effect is good.
