What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The embedded nut proposed by Guangdong Yueluo Hardware Industry Co., Ltd. is used to be embedded in an injection molded part. The embedded nut is arranged in a column shape and has a screw hole inside. The embedded nut includes an outer peripheral surface and is formed in the inner nut. The upper end surface and the lower end surface of the two ends of the embedded nut are provided with knurling on the outer peripheral surface, and a guide surface is formed at the connection between the outer peripheral surface and the lower end surface.
Fasteners are a type of mechanical parts that are used for fastening connections and are widely used. All kinds of fasteners can be seen on all kinds of machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, meters and supplies. It is characterized by a wide variety of specifications, different performance uses, and a very high degree of standardization, serialization and generalization. Therefore, some people also refer to a type of fasteners with existing national standards as standard fasteners, or simply as standard parts. Fasteners are the most widely used mechanical foundations. With my country's entry into the WTO in 2001, it has entered the ranks of major international trade countries. my country's fastener products are exported to many countries in the world, and fastener products from all over the world are also pouring into the Chinese market. Fasteners, as one of the products with the largest import and export volume in my country, are in line with international standards, which have important practical significance and practical significance for promoting Chinese fastener enterprises to go to the world and promoting fastener enterprises to fully participate in international cooperation and competition. strategic significance. Due to the specifications, dimensions, tolerances, weights, properties, surface conditions, marking methods, and specific requirements of items such as acceptance inspection, marking and packaging for each specific fastener product.
The national standard for the size of the screws in the round head three-combination screw is GB818. The main technical requirements of various types are: iron and stainless steel for material requirements, low, medium and high carbon steel for iron, and stainless steel combination screws The materials are stainless steel 201, stainless steel 304 and stainless steel 316. The thread tolerance is 6G, and the mechanical properties of the iron combination screws are 4.8 and 8.8. The 4.8-level combination screws are ordinary steel, and the maximum allowable hardness is 255HV. The 8.8-level combination screws are generally made of wire rod 10B21. , and then undergo hardening treatment, and then dehydrogenation after hardening treatment. Hydrogen removal is to prevent hydrogen embrittlement of the spring washer in the combination screw. Prevent the spring pad from breaking. The tolerance class of the combination screws is A. The cross groove is H-shaped. The surface treatment of the combination screw has environmental protection and non-environmental protection. Such as, environmental protection blue zinc, environmental protection color zinc, black zinc, color zinc, white nickel and so on. The technical requirement of the combination screw for the spring washer is that the washer should be able to rotate automatically without falling off.
The technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. to solve its technical problems is: a waterproof rivet, including an integrally formed waterproof cap and a rivet rod for waterproofing, and the waterproof cap includes a lower part that is fixedly connected with the rivet rod. An end face, the lower end face includes a fixing portion arranged in order from the center position of the lower end face to the outside, a buffer portion arranged circumferentially with the fixing portion as the center, and a waterproof portion arranged circumferentially with the fixing portion as the center, the fixing portion and the rivet The rods are fixedly connected, and the section of the waterproof part is a figure-eight shape.
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