What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
It is used for fastening in the machinery, construction and electrical industries. One end is a hexagonal head for wrench tightening, and the other end is a thread. According to different thread lengths, it is divided into full thread and half thread, abbreviated as: GB bolt.
With the rapid development of China's machinery industry, especially the development of heavy industry, the demand for large-scale metal processing equipment is increasing; at the same time, higher requirements are also placed on the technical parameters of the equipment. For some large-scale CNC equipment, to ensure the machining accuracy of the whole product, it is not only necessary to rely on high-performance components such as full closed-loop control and precision transmission components, but also requires the positioning and stability of the joint surfaces between the large and medium-sized components of the equipment. The common positioning of the joint surface between large components adopts flat key positioning, and this method requires processing the keyway at the joint surface of the large components. Since the joint surface of large parts is affected by factors such as processing and splicing, it cannot guarantee that the keyways on the large parts combined can be matched according to the theoretical requirements. Therefore, the positioning flat key needs to press the flat key in the two parts of large parts. Different repair allowances Trim into a stepped shape. The height difference of this keyway in different large components makes a single flat key need to be repaired on four sides, which increases the difficulty of the key repair process and makes it difficult to improve work efficiency. Not only that, when the flat key is repaired and assembled, it must be in an interference fit with the keyway, which makes the disassembly and assembly of the flat key more laborious.
Pull rivets, * marked as blind rivets, are based on the principle of Hooke's law. After the two joints are clamped with special equipment for pull rivets, the metal of the ring-shaped collar is squeezed and filled to the point where there are many rivets. In the groove of the bolt column of the annular groove, a fastening method that tightly combines the collar and the bolt column. A riveting machine is a mechanical device that uses rivets to riveted items together in batches. The riveting machine is mainly assembled by rotation and pressure. The riveting machine is mainly used in the occasions where rivet riveting is required. The common specifications and models include pneumatic, hydraulic and electric, single-head and double-head.
However, due to a radial external tension, the external tension is caused by the tightening axial force generated by the tightening torque, and the phenomenon of open ring expansion occurs, and the spring washer often breaks due to hydrogen embrittlement. The nut exerts uneven pressure on the flat washer through the spring washer. And the friction coefficient between the spring washer and the nut and the flat washer is very small, and the phenomenon of vibration, rotation and relaxation occurs.
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