What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
The circlip is also called a retaining ring or a retaining ring. It is a kind of fastener and is installed in the shaft groove or hole groove of the machine and equipment to prevent the axial movement of the parts on the shaft or hole. The circlip includes an arc-shaped elastic bending portion and a circlip protrusion at the end of the elastic curved portion, and the circlip protrusion is provided with a small hole for matching with needle-nose pliers or circlip pliers. This part is a commonly used part on the equipment. Once the assembly is not in place, it will affect the overall performance of the equipment and cause safety hazards. At present, the most common assembly method is to manually clamp and deform the circlip with circlip pliers or needle-nose pliers, put the circlip into the annular groove of the inner hole of the end cover, and then release the needle-nose pliers or circlip pliers. . The assembly of the circlip is very troublesome, labor-intensive, and has low assembly efficiency. Once mass production is required, this process often becomes a bottleneck restricting production.
The research on rivet nuts started in the 1970s in my country and is still in the design and development stage. In the mid-1980s, equipment for the production of blind rivets was introduced from abroad, but no rivet nut has been produced so far. After the inventor's search, no low-carbon steel rivet nut was found to be publicly used.
1. Other names: root nut, anti-loosening nut, nut. 2. 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. The lock nut is one of the anti-loosening measures. The anti-loosening effect of the lock nut mainly depends on the interaction force between the nut and the thread of the bolt. There are many ways to improve the interaction force between meshing threads, such as structural improvement of nut threads, nylon roughening of nylon nuts, and surface treatment of threads.
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