What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The classification of the second combination screw is divided according to the material of the screw wire and the hardness index of the screw wire. Generally, the two combination screws are divided into stainless steel and iron, and stainless steel is divided into stainless steel 201, stainless steel 304 and stainless steel 316. Iron is divided into three types: low carbon steel, medium carbon steel, and high carbon steel. Carbon steel combination screws refer to iron combination screws. Generally, iron combination screws are classified into grades 4.8, 8.8, 10.9, and 12.9. But in the market, the combination screws of grade 10.9 and grade 12.9 are rarely used, so we won't talk about it here. And the two combination screws on the market are more commonly used combination screws of grade 4.8 and 8.8. 4.8 grade combination screws are generally made of 1010A screw wire rods. After the screw wire rods are beaten into screws, they are combined with spring flat washers. After production, this 4.8 grade combination screw does not need to be hardened. Its hardness can reach 4.8. The 8.8 grade combination screw is generally made of 10B21 screw wire. After the screw wire is punched into a screw, it is equipped with a spring washer and a flat washer, and the three pieces can be combined and rubbed by an automatic spring-flat washer machine. Fasten the spring-flat washer combination on the screw, and the spring-flat washer will not fall off. After the combination screw is produced, it needs to be hardened to make the hardness reach 8.8. After the hardness reaches 8.8, we need to take it for electroplating. In order to prevent hydrogen embrittlement of the spring washer in the 8.8-level combination screw with added hardness, it is easy to break. In this way, it is necessary to carry out hydrogen removal treatment on the hardened combined screws, and the electroplating can only be done after the hydrogen removal.
When the nut is tightened on the stud, there will inevitably be an empty upstroke. That is, when the nut has not reached the part that needs to be tightened, the nut needs to be twisted on the non-locking (working) part of the front end of the stud by hand or tool, so that the nut runs along the axial direction of the stud and reaches the part to be locked. . When the idling stroke of the thread at the front end of the stud is long or the thread pitch is small, the idling stroke before locking will waste a lot of time, resulting in a huge occupation of personnel or tools.
Shaft retaining ring (hereinafter referred to as retaining ring) is a very common part and is widely used in shaft parts. The existing solution for pressing the retaining ring is: place the retaining ring sleeve in the chamfering section or the guiding section of the shaft head, and then use an indenter whose inner hole diameter is larger than the diameter of the shaft head to press the retaining ring into the groove, and then press the retaining ring into the groove through the shaft head. The retaining ring is combined with the slot to prevent the indenter from continuing to move downward.
The circlip is a common limiting element in the mechanical field, which is mainly used to limit the axial limit of mechanical parts. At present, the common circlips on the market are all circular rings with an opening. The circular ring has a certain elastic deformation capacity. When in use, the circlip can be detachably assembled to the mechanical on the part. However, the defect of the circlip adopting the one-piece ring is that the circlip is easily broken when frequently disassembled and used, and the service life is short.
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