What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The technical scheme adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is: a pin pressure riveting structure, including a pin, a cavity and a pressure riveting fixture, the pin is a columnar structure, an annular groove is arranged on the surface of the pin, and the cavity is The body is provided with a light hole, the depth of the light hole is greater than the height of the annular groove relative to the bottom of the pin, the lower end of the pin is inserted into the light hole, the pressure riveting fixture includes a pressure riveting part and a pressure-bearing part located on the top of the pressure riveting part, so The riveting part and the pressure-bearing part are provided with coaxial and penetrating connecting holes, and the upper ends of the pins are sleeved in the connecting holes.
In the switchgear of high and low voltage power equipment, the surface of many switchgear shells is painted or sprayed with plastic, and the installation beams and other parts of the switchgear and the entire cabinet must be continuously grounded according to the requirements of switchgear standards to improve the safe use of equipment. Because the common screw, spring washer, flat washer and nut type structural connection between the surface of the shell and the metal mounting beam cannot meet the requirements of grounding continuity, in order to meet the requirements, the surface of the shell is painted or Before spraying, special grounding studs must be welded. With the increase of installation beams, the number of welded studs must also increase, which increases the complexity of the product processing technology, wastes man-hours and increases costs.
nut is a connecting nut, a part that is screwed together with a bolt or connecting screw for fastening, and a component that must be used in all production and manufacturing machinery. There are many kinds of nuts, we commonly have standard, German standard, British standard, American standard, Japanese standard nuts. According to different materials, nuts are divided into carbon steel, high strength, stainless steel, plastic steel and other types. According to the product attributes, the corresponding standard numbers are divided into ordinary, non-standard, standard, new standard, American system, British system, and German standard. Different sizes, unequal threads are divided into different specifications. The general standard and German standard are represented by M, and the American system and the British system are represented by fractions or #. The specification nut is a part that tightly connects the mechanical equipment. Only through the inner thread, the same specification nut and screw can be connected together. The anti-loosening of the screw has always been the intersection of people's attention. The anti-loosening of the nut is of great significance to the current life, because it directly affects the service life of the machine. Therefore, it is also very important for people's life safety. Technicians can achieve the anti-feeding of the nut by changing the material of the nut and increasing the method of tightening the nut, but these methods cannot fundamentally solve the problem, and increase the tightening nut while taking up more space.
Bolt material: 18Cr2Ni4W, 25Cr2MoV steel; bolt specification: M27～M48. Because this kind of steel is easy to form a passivation film on the surface, and this passivation film will make the bolt unable to obtain a good adhesion chemical nickel phosphorus layer, so special pretreatment measures must be taken to remove the film first, and measures should be taken To prevent its regeneration, it is possible to ensure a good bonding force between the plated coating and the substrate. At the same time, due to the large geometric size of the bolt, it increases the difficulty of nickel-phosphorus plating treatment and quality inspection of the process.
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