What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Commonly used national standard GB41Ⅰ type hexagon nut——C grade GB6170Ⅰ type hexagonal nut——, B grade GB6171Ⅰ type hexagonal nut-fine thread-, B grade GB6172 hexagonal thin nut——, B grade - chamfering GB6173 hexagonal thin nut—— Fine thread—, B grade GB6174 hexagonal thin nut—B grade—without chamfering
Other names of lock nut: root nut, locknut, nut. Purpose: To lock the outer joint of the through wire or other pipe fittings. The working principle of the nut is to use the friction between the nut and the bolt for self-locking. However, the reliability of this self-locking is reduced under dynamic loads. In some important occasions, we will take some anti-loosening measures to ensure the reliability of the nut locking. Among them, the use of lock nuts is one of the anti-loosening measures. There are also three types of lock nuts: The first is to use two identical nuts to screw on the same bolt, and add a tightening torque between the two nuts to make the bolt connection reliable. The second is a special anti-loosening nut, which needs to be used together with a kind of anti-loosening washer. The special lock nut is not a hexagonal nut, but a medium round nut. There are 3, 4, 6 or 8 notches on the circumference of the nut (depending on the size of the nut and the product series of the manufacturer). Several notches are both the focal point of the tightening tool and the snap-in of the lock washer bayonet. The third type is to drill through threaded holes from the outer surface of the nut to the inner thread surface (usually 2, which are distributed at 90 on the outer surface), which are used to screw in small-diameter countersunk head screws. The purpose is to give the thread Apply a centripetal force to prevent the locknut from loosening. The better quality lock nut sold on the market is inlaid with a small copper block that is consistent with the thread of the lock nut on the inner surface of the nut to prevent the radial jacking screw from directly contacting the locked thread and damaging the latter. . This kind of lock nut is gradually applied in the shaft end locking of rotating motion parts, such as the anti-looseness of the bearing at the mounting end of the ball screw. The second anti-loosening method is more reliable than the first, but the structure is relatively complex. Compared with the first two, the third clock has the characteristics of better anti-loosening effect, simpler and more beautiful structure and smaller axial size.
The flat washer is mainly used to reduce the pressure. When some parts are tightened with a large axial force, it is easy to press the washer into a dish shape. At this time, it can be solved by changing the material and increasing the hardness.
Nuts cooperate with screws to achieve the fixing and connection of components. SMD nuts are generally used in the circuit board industry to fix electronic components. That is, the chip nut is soldered on the circuit board by solder, and the electronic components are fixed by turning the screw. However, when the current chip nut is soldered on the circuit board, there may be uneven soldering, which makes the soldering untidy. At the same time, during soldering, the excess solder overflows from the periphery of the nut, which affects the appearance and may affect its appearance. electrical properties. In addition, the nut is only welded with the circuit board on one end face, and its firmness and reliability after welding are low.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
