What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In industrial production, some products need to remove the fixing screws; or in the assembly line, the screws that fix the product on the fixture also need to be removed when the product is unloaded. At present, the dismantling of the screws is mainly completed by the manual operation of the operator. However, this method of manually dismantling the screws has low work efficiency and high production cost.
The machinery industry is one of the main users of fasteners. Due to China's late understanding of the important position of mechanical basic parts in the machinery industry and a long-term lack of investment, the entire industry has a poor foundation, weak foundation and weak strength. Especially with the improvement of the level of the main engine in China, the bottleneck phenomenon that the mechanical basic parts lag behind the main engine has become increasingly apparent. Today, although the state has given certain support in technology introduction, technological transformation, scientific research and development, etc., there is still a big gap compared with the current market demand and foreign levels. Unstable quality, high early failure rate and poor reliability. Fasteners are the main basic products in the machinery industry, and the development of the machinery industry also puts forward higher requirements for fastener products. Domestic ordinary standard fasteners have always been in oversupply, while high-end fasteners (high temperature, special-shaped, titanium-plastic composite, special performance and other fasteners) are in short supply, and they also rely on imports. The State Machinery Bureau lists ordinary standard fasteners as restricted development products, and high-strength special-shaped fasteners as currently encouraged development products. With the improvement of the country's industrialization level and technological progress, the use of high-strength fasteners has gradually increased.
The purpose of Yueluo is to provide a stamping process for screws. Before stamping, a sticky protective layer is coated on the pressure surface of the screw blank. The sticky protective layer can play a buffering role during stamping and prevent the screw head from being damaged. In order to achieve the above purpose, the technical solution of Yueluo is to design a screw stamping process, which uses a stamping die to stamp the screw blank and punch out the screw head; and before stamping, the pressure surface of the screw blank is coated with adhesive protection. layer.
In order to tighten the fastener, the holding element of the tightening tool can hold the washer in engagement with the bolt to prevent the washer from rotating while allowing the rotating element of the tightening tool to rotate the nut. Such tools are disclosed, for example, in Application Serial Nos. 0/010377 and 10/120343. In this structure, since the same size washer cannot be arranged on the driving part and the fixing part, the driving part is made into the inner socket of the nut, and the fixing part is made into the outer socket of the washer, so , regular hexagonal nuts cannot be used. This is because, when just tightening the nut, the outer cavity cannot be removed since the hexagonal surface of the nut will not align with the hexagonal surface of the washer. Due to the larger diameter of the fastener formed as the outer cavity, side clearance problems may arise, thus increasing the cross-sectional profile of the hexagonal surface of the washer, which is undesirable.
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