What are the main points of the use of fasteners?

       FastenersThe manufacturer believes that there are many important connections on the machine, such as the drive shaft, and most of the bolts are fine threads. If parts are lost during maintenance, some maintenance personnel will replace them with thick bolts, which should be avoided. The fine tooth bolt has large inner diameter, small pitch and outer angle, high strength, good self-locking performance, and strong ability to withstand impact, vibration and exchange load. Once the coarse tooth bolt is used, it is easy to loosen, fall off or break, and even cause mechanical accidents.

Fastener manufacturers believe that the bolts on the machine that bear lateral load and shear force, such as drive shaft bolts, flywheel bolts, etc., are in transition fit with the bolt holes, and the assembly should be firm and reliable, and can withstand lateral force. Some people do not pay attention to inspection during the assembly process, and continue to install when the gap between the bolt and the bolt hole is large, which may easily cause the bolt to loosen or cut off.

Fastener manufacturers believe that after the installation is completed, sometimes the bolt is too long, and some people add spring washers to the bolt. In this case, the spring washer will break due to uneven force during the strengthening process, reducing the pre-tightening force of the bolt, and may also generate eccentric load, reducing the reliability of the bolt connection. Many workers have the misconception that "bolts should be tightened rather than loosened", so they deliberately increase the tightening torque, causing the bolts to slip. In addition, some important bolts that need to be tightened with torque, but some people use adjustable wrenches to tighten them in order to save trouble, resulting in insufficient torque, loosening of bolts, and even mechanical failure.

Fastener manufacturers believe that sometimes due to the lack of the right size of the washer, some workers will use a larger inner diameter of the washer instead. In this case, the contact area between the lower part of the bolt head and the washer is small, which reduces the bearing force or locking force of the washer. If there is vibration and shock in the working environment, the bolts are easy to loosen. Important bolts should be locked with a locking device after assembly, which is described in four cases. If a cotter pin is used for locking, thin opening lock or half opening lock is not allowed; if a spring washer is used for locking, a washer opening with too small offset is not allowed; if a locking piece is used for locking, the locking piece shall not be locked at the corner of the nut; if a double nut is used for locking, the thin nut shall not be installed outside.

Fastener manufacturers believe that if bolts, nuts or threads are rusty, or have impurities such as scale and iron filings, clean them before assembly; burrs, silt and other impurities on the connector joint surface should also be removed. Otherwise, when the bolt is tightened, it appears to be tightened on the surface, but it is not actually pressed to the joint. Under such false firmness, if there is vibration, load shock, or temperature change, the bolt will soon loosen.

The above is aboutFastenersSome of the knowledge points, I hope you can help.