What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Mine trucks are required for underground construction and coal transportation. With the vigorous development of energy, the output of coal has increased significantly, and the demand for mine trucks has increased. The axle card is an important part of the mine car. Its shape is irregular, and the blank is a casting. It needs to be finished on the semicircular surface whose upper center is matched with the mine car axle. At present, the mine truck axle card is generally processed by a milling machine, which has the problem of low efficiency.
As my digital TV technology becomes more and more mature, more and more people with digital-to-analog signal conversion function enter people's lives. Therefore, the number of production and processing is also increasing day by day. There are many requirements for the form, reliability and cost of PCB fixing screws in production. One of the existing fixing methods is to fix by means of bolts and nuts. The operation steps are to place the PCB board on the inner threaded copper column connected to the casing, and pass through the bolts with fine teeth. Screw holes on the PCB board, and then fix them on the copper posts with nuts. The connection method of this solution is reliable, but its manufacturing cost is high, and the copper column and the metal shell need to be screwed together, resulting in low production efficiency and high cost. In addition, there is also a common way that the PCB is supported by a plastic column, and the self-tapping screw is passed through the screw hole on the PCB board, and the PCB board and the metal bottom shell are connected by the self-tapping thread on the screw. The main disadvantage of this solution is that after the screw is fixed on the metal shell, the screw head is exposed at the bottom of the machine. If the user is not careful during use, the hand scratching phenomenon will occur, which will bring changes and harm to the user's use. . And when the machine slides on the desktop, if the screw head is too exposed, it will scratch the desktop. Therefore, how to provide a PCB fixing method with convenient operation, reliable connection and low production cost is a technical problem to be solved urgently in the industry.
In the current production process, the inner wall of the circlip is quantitatively and evenly lubricated, and then the rotating shaft is inserted into the circlip, so that the rotating axis can rotate in the circlip, thereby realizing the rotation function of the sun visor. However, since the circlip is tightly fitted with the rotating shaft, during the insertion process of the rotating shaft, the front end of the circlip can easily push the grease from the opening at one end of the circlip to the opening on the other end of the circlip, so that the rotating axis and the inner wall of the circlip are easily connected. There is little or no grease left between them, which can easily lead to a lack of lubrication between the shaft and the circlip, and dry friction between the shaft and the circlip, resulting in a series of problems such as abnormal noise, difficult operation, and poor durability.
As we all know, bolt and nut kits are commonly used fastening parts, but when ordinary bolt fasteners are used in a large number of parts, because the nuts and bolts are engaged by threads, manual or machine tightening is required, and during installation, It is easy to slip, and the bolts need to be operated in both directions, and a pair of bolts and nuts cannot be installed quickly, which reduces the installation efficiency.
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