What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. For the lock ring of the anti-dropping nut, snap the ring into the lock, tighten the lock claw, and the lock claw is fastened into the thread. The lock claw does not have thread characteristics, and it is difficult for the nut to be threaded during the vibration process of the machine. If it fails, the locking claw acts as a tightening nut, but it does not have the problem of loosening itself like the locking nut.
Stainless steel rivet nuts are used on rail passenger cars, highway passenger cars, and ship parking. The main function is the non-structural bearing bolt connection. The main advantage of stainless steel rivet nuts is that there is no operating space on the back of the substrate, and the quality is extremely light. Today, the editor will talk about the selection principles of stainless steel rivet nuts and their uses: 1. The mechanical properties of stainless steel rivet nut materials, especially the strength requirements; Corrosion resistance requirements of materials;
5. After the closing value material and the geometric parameters of the nut are determined, the change of the closing value has an important influence on the repeated use characteristics of the lock nut. When the closing value becomes larger, the deformation of the threaded piece increases, the strain of the threaded piece increases, the strain cycle hardening phenomenon intensifies, and the pressure FN of the threaded piece increases, which has a tendency to increase the unscrewing torque; on the other hand, the width of the threaded piece decreases. , the total area of the threaded piece decreases, the friction with the bolt decreases, the strain of the threaded piece increases, the low-cycle fatigue performance decreases, and the maximum unscrewing torque tends to decrease. Under the combined action of various factors, the change of the maximum unscrewing torque with the number of repeated uses is difficult to predict, and it can only be observed through experiments.
High-strength bolt connection has the advantages of simple construction, good mechanical performance, disassembly and replacement, fatigue resistance, and no loosening under dynamic load. It is a promising connection method. High-strength bolts use a special wrench to tighten the nut, so that the bolt generates a huge and controlled pre-tension. Under the action of pre-pressure, a large frictional force will be generated along the surface of the connected parts. Obviously, as long as the axial force is less than this frictional force, the components will not slip and the connection will not be damaged. This is the high-strength bolt connection. principle. High-strength bolted connections rely on the friction between the contact surfaces of the connectors to prevent them from sliding each other. In order to make the contact surfaces have sufficient friction, it is necessary to increase the clamping force of the components and increase the friction coefficient of the contact surfaces of the components. The clamping force between the components is achieved by applying pretension to the bolts, so the bolts must be made of high-strength steel, which is why it is called high-strength bolted connections. In high-strength bolted connections, the friction coefficient has a great influence on the bearing capacity. Tests show that the coefficient of friction is mainly affected by the form of the contact surface and the material of the components. In order to increase the friction coefficient of the contact surface, methods such as sandblasting and wire brush cleaning are often used to treat the contact surface of the components within the connection range during construction.
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