What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the design of modern aviation and aerospace vehicles, in order to reduce weight and save space, the space of the fastening installation system is getting narrower and narrower, and blind hole installation is often required. In this case, single-sided riveting installation is usually used for fastening connection. At present, this kind of fastening connection products are mainly blind rivets. The riveting installation principle of blind rivets is to use the method of pulling, pulling the mandrel, and extruding the nail sleeve to deform it at the blind end to achieve the function of fastened connection. This kind of fastening connection method requires special riveting, generally imported riveting, the replacement of internal parts is expensive, the installation process is complicated, and the installation cost is high.
Stud bolts are manufactured in accordance with GB897-GB901 standards, the materials used are: Q235, 45#, 40Cr, 35CrMoA, Q345D, the specifications are: M3mm-M100mm, and the length can be customized according to user needs. High strength stud bolts, materials are 35#, 45#, 35CrMoA, 25Cr2MoV, 304, 316, 304L, 316L, 2H, 2HM, B7, B7M, B16, B8, 8, B8M, 8M, widely used in electric power, chemical industry , oil refining, valves, railways, bridges, steel structures, automobile and motorcycle accessories and other fields: generally used in mining machinery, bridges, automobiles, motorcycles, boiler steel structures, pendant towers, long-span steel structures and large buildings, etc. . Representation method of stud bolts: General stud bolts are expressed as: M12×100 GB 901-88 (standard) 35#/35# (material) 8.8 grade/8 grade (modulation grade) means: diameter = 12mm length = 100mm GB 901-88 adopts the national standard (of course, the industry standard can also be used as needed) stud bolt standard: GB 900-1988 Introduction to stud bolts Stud bolts save time and cost All stud bolt structures do not require drilling, Steps such as punching, threading, riveting, threading and finishing continue to expand the application potential of structural design, high current and small penetration. Therefore, welding to very thin sheets is possible. The workpiece for stud welding must be welded from one side. Can be soldered in all positions, with the help of extenders on vertical bulkheads that can be restricted. Since it is welded for a short time and there is little deformation after welding, no trimming is required. Because the welded structure does not require drilling, there is no leakage. The joint can achieve high strength, that is, the joint strength of stud welding is greater than the strength of the stud itself. How to install studs Good economy The advantage of other welding methods is the welding power. For mass-produced workpieces, standard studs are low cost. There are various types of equipment and welding torches, and the acquisition cost of equipment is relatively low. According to the product, it can be made into a multi-station automatic welding machine, or a high-precision gantry-type CNC automatic welding machine. Stud welding has high quality reproducibility and low rejection rate. However, in the application of stud welding, it should be noted that, like other fusion welding, there are certain restrictions on the carbon content in the steel. For structural steel studs, welding should be performed according to the recommended combination of stud material and base metal. There will be infusibility with the base metal. Combinations of stud material and base metal outside the recommended range shall be tested to determine the weldability and the product design requirements of the anchor bolt for the possibility of relevant inspection and evaluation.
In the prior art, the independent pocketed spring is to encapsulate the springs in bags independently, connect each independent pocketed spring side by side, and then cover it with a large non-woven fabric to form a Spring cushions. This spring mat structure has many disadvantages: 1. Uneven force and low hardness; 2. Easy to deform, pit, low flatness and unsightly; 3. The spring directly contacts the non-woven fabric, causing wear and tear, and the life of the spring mat relatively short.
In order to overcome the technical problem that the screws and nuts cannot be disassembled and assembled at the same time in the prior art, Guangdong Yueluo Hardware Industry Co., Ltd. provides a simple structure and can be quickly disassembled and assembled at the same time in a small space. screw and nut removal tool.
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