What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Flat washers are frequently used in mechanical connections. They are usually placed between the nut or screw head and the connected parts to prevent the screw or nut from loosening during use. The upper and lower end faces of conventional flat gaskets are mostly smooth planes, with a single structure and poor compressive capacity. When assembled with a nut or screw, the pressure on the flat washer is increased, and when it is closely rubbed with the nut or screw, it is prone to breakage, which greatly affects the quality of the product.
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.
At present, the commonly used fastener loosening prevention methods generally include non-removable anti-loosening solutions and friction-increasing anti-loosening solutions. The non-removable anti-loosening scheme uses welding, bonding or punch point riveting to change the detachable threaded connection into a non-detachable threaded connection. In the non-removable anti-loosening scheme, the threaded fasteners cannot be reused and the operation is troublesome. It is often used in some important occasions that require high anti-loosening performance without disassembly. The anti-loosening scheme that increases the frictional force uses the method of increasing the frictional force of the bolt (screw) head and the end face of the nut to achieve the purpose of anti-loosening. The anti-loosening solution that increases friction is not limited by space and can be disassembled repeatedly, but the reliability is poor. After a certain period of work, the anti-loosening effect will be reduced due to vibration and other reasons.
In the prior art, the screw suction device can be implemented in the following two ways. One is to use a magnet to magnetize the electric bit head, and the electric bit head is used to approach the screw, and the screw is stuck by the electric bit head, so that the function of picking up the screw can be realized; The vacuum generator is used to form a negative pressure in the screw guide groove, and the screw is sucked into the tube to realize the screw pickup. The disadvantage of this solution is that in the process of picking up the screws, the grooves of the screws cannot be aligned, which leads to the deviation or leakage of the screws. The disadvantage of this solution is that the screw with an aspect ratio of less than 1.8 is prone to suction and skew, and the stability is not high. It can be seen that the existing technology still needs to be improved and developed.
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