What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Locking of screws belongs to the prior art. Or by means of a visual method (X-ray control) a more or less complex aiming device is inserted into the transverse hole of the screw. In both cases a certain misalignment is unavoidable, ie the screw may not be coaxial with the central axis of the transverse hole and deviate from it by a certain value. In order for the locking screw to pass into and through the transverse hole despite this misalignment, the outer diameter of the screw is determined to be a size smaller than the diameter of the transverse hole. If the aiming is not maintained within this small dimension value, the locking screw can pass through the transverse hole without difficulty despite the aiming error. Now, however, the locking screw has a certain clearance relative to the transverse hole due to the determination of a smaller size value.
The shaft and gear of financial self-service equipment are often connected by elastic straight groove cylindrical pins. When repairing, the traditional disassembly method is to use the shaft and gear as components. After disassembling together, align the punch with the elastic pin by hand, and use a hammer to remove the elastic pin. Pin out. With this disassembly method, the human hand is easily injured, and the disassembly efficiency is low.
In the prior art, the spring washer has a certain anti-loosening effect. However, due to the unreasonable design structure, the upper and lower pressing forces of the spring washer and the spring washer's anti-return force are poorly matched, resulting in the smooth surface and the bolt head. The friction between the nut and the connected parts is small. When the bolt or nut is subjected to strong vibration, the bolt or nut will still loosen. Therefore, the anti-loosening effect of the above spring washer still needs to be improved.
In the current plastic matrix, it is common to use self-tapping screws or add copper inserts during injection molding. The former has poor strength, and the threaded hole is easy to crack; the processing cost is high, the injection molding efficiency is low, the labor cost and manufacturing cost are increased, and the insert is easy to slip and crack on the plastic, and the thread strength of the copper insert is not as high as that of the iron nut.
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