What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Although there are many types of self-tapping screws, they all have the following common points: (1) They are generally made of carburized steel (accounting for 99% of the total output). Also available in stainless steel or non-ferrous metals. (2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. In order to make the self-tapping screw meet the mechanical properties and performance required by the standard. (3) The product has high surface hardness and good core toughness. That is, inner softness and outer rigidity. This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the toughness of the core is poor, it will break as soon as it is screwed, and it cannot be used. Therefore, inner soft outer steel is a very important requirement for self-tapping screws to meet the performance requirements. (4) The surface of the product needs surface protection treatment, generally electroplating treatment. The surface of some products must be treated with phosphate (phosphating), such as wallboard self-tapping screws are mostly phosphated. (5) Produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine for production. The emphasis here is on high speed to ensure product quality. Only self-tapping screws produced by high-speed machines have well-formed heads and high-quality threads.
The traditional dismantling of automobile girder rivets is mostly carried out manually, which has many defects such as long disassembly time, low disassembly efficiency, labor-intensive, time-consuming, labor-intensive, low operation safety, difficult protection, and easy injury.
In order to achieve the above purpose, Yueluo provides the following technical solutions: threaded rivets include a nail rod, an expansion piece, and a nail sleeve, one end of the nail rod is provided with a mounting piece, and the side of the mounting piece away from the nail rod is movably installed with a mounting piece. There is a driving mechanism. The driving mechanism includes a mounting cylinder and a movable rod. A cross groove is formed at one end of the mounting piece close to the driving mechanism. The rod is movably installed on the inner side of the installation cylinder, and one end of the movable rod close to the cross groove is fixedly provided with a cross connecting piece that matches the cross groove, the cross connecting piece is matched with the cross groove, and the movable rod is far away from the cross groove. One end of the cross connecting piece is fixedly provided with a fixing piece, the fixing piece and the installation cylinder are screwed together by threads, the expansion piece is sleeved on the outer side of the nail rod, and the nail sleeve is movably installed on the nail rod away from the driving mechanism The outer side of one end of the nail rod is movably installed with a fixing mechanism.
4. Manufacturing and assembly Due to the limitations of manufacturing technology and accuracy, there are sharp corners on the edge of the thread or the dimensional coordination between parts is not coordinated. During the initial assembly, the screw-in and screw-out torque may fluctuate or fluctuate to a certain extent. After a certain number of running-in, more accurate reusability characteristics of the lock nut can be obtained.
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