When choosing Dongming fasteners, first choose the options from the national standard varieties and specifications, choose in the industry, and design according to the special needs of the main body when necessary. Among the many requirements, anti-loosening and anti-fracture are the two main considerations. Then, let's learn about the common misunderstandings in the selection of Dongming fasteners!
1. Coarse and fine
Dongming fasteners drive shafts, drive shafts and other important mechanical couplings, the bolts mostly use thin screws. When there are not enough parts in maintenance, some people will use coarse thread bolts instead. Due to the large inner diameter of the thread and the small outer angle of the pitch, it has the advantages of high strength, good self-locking performance, and strong impact resistance, vibration resistance and replacement load capacity; if it is replaced with coarse thread bolts, it will be easy to loosen, fall off, and break, resulting in mechanical accidents.
2. The gap is not suitable
Dongming fasteners are mechanically subjected to lateral loads and shearing bolts, such as drive shaft bolts and flywheel bolts. Someone neglected to check in the assembly, and even if there was a large gap between the bolt and the bolt hole, it was still installed, causing the bolt to loosen and cut off.
3. Thickened nut
Some people mistakenly think that thickening the nut will increase the number of working turns of the screw and improve the reliability of the coupling, but in fact, the thicker the nut, the more uneven the load distribution between the screws in each circle, and the easier the coupling is to loosen.
4. One mother has more pads
During the installation of Dongming fasteners, the assembled bolts may be too long. So someone installs a lot of spring washers on a certain bolt. In this way, the spring washer is subjected to force during the firming process and will be broken, and the force of the bolt will be reduced. Or an eccentric load is generated, and the fastening reliability of the bolt is reduced.
5. The washer is too big
Due to the lack of suitable washers for Dongming fasteners, some people also use washers with large inner diameters instead. In this way, when the contact area between the underside of the bolt head and the washer is small, the pressure and locking force of the washer are reduced, and the bolt is easily loosened due to vibration and shock loads.
6. Torque incompatibility
Many people in Dongming Fastener think that the bolt "should be tightened, not loosened", so they will consciously increase the tightening torque of the bolt, causing the bolt to slip, thereby releasing the button. On the other hand, for important bolts that need to be tightened with torque, even if they are easily tightened with an adjustable wrench, they tend to loosen due to insufficient torque, resulting in mechanical failure.
7. Improper locking
After the important bolts are assembled, please lock them with the anti-loosening device. When using a split pin lock, the common mistake is to use a fine open lock or a semi-open lock; when locking with a spring washer, a common mistake is that the opening of the washer is too small and loses elasticity; The piece is locked on the nut corner; when locking with a double nut, a common mistake is to install a thin nut on the outside and not tighten it.
8. False solidity
There are foreign objects such as rust, scale, iron filings, sand particles in the threads of bolts, nuts and screw holes, or foreign objects such as burrs and sediment on the connecting surface of the coupling, which are not removed before assembly. When tightening the bolt, due to the blocking effect of foreign objects, the surface is strongly tightened, and the torque value is required, but the actual coupling is not actually compressed; The torque of the bolt is as specified, but sometimes the tool is not pressed. With this false firmness, bolts tend to loosen quickly due to vibration, load shock, and temperature changes. When selecting fasteners, first select the options from the national standard varieties and specifications, select them in the industry, and design them according to the special needs of the main body as a last resort. Among the many requirements, anti-loosening and anti-fracture are the two main considerations.
The above are the common misunderstandings in the selection of Dongming fasteners. If you want to know more, please feel free to contact us!