What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Countersunk rivet is a kind of part that uses its own deformation or interference connection to connect and position two objects in riveting. It is widely used in automobiles, vehicles, electromechanical products, aerospace products and other fields. When the countersunk head rivet is used, the head of the rivet sinks into the connected parts in whole or in part. This structure is mostly used for parts that require a smooth and smooth appearance. The standard structure of countersunk head rivets is specified in the national aviation standard, national standard and national standard, and the countersunk head rivets involved in these standards are all standard rotary structures.
Classification broadcast product series Product detailed classification Hexagon bolts (1) Hexagon bolts (1) Hexagon full teeth: GB5783/DIN933 (2) Hexagon half teeth; GB5782/DIN931 (3) Class B flange hexagon bolts: GB5787 (4) Joint bolts: GB798/DIN444 (5) Welding bolts for manual welding: GB902 square neck bolts (1) Half round head square neck bolts: GB14/DIN603 (2) Small half round head square neck bolts: GB12 (3) Half round head low square neck bolts: GB801 Remarks: Square neck bolts and carriage bolts Hexagon socket head cap screws (1) Hexagon socket head cap screws: GB70/DIN912 (2) Hexagon socket flat end set screws: BG70/DIN913 (3) Hexagon socket head set screws: GB78/DIN914 ( 4) Countersunk head socket head socket head set screw: GB79/DIN915 (5) Hexagon socket socket head set screw: GB80/DIN916 (6) Hexagon socket head countersunk head screw: DIN7991 (7) Hexagon socket head thin head screw: DIN7984 ( 8) Plug screw: ISO7379 machine screw (1) Slotted cylinder head screw: GB65/DIN84 (2) Slotted pan head screw: GB67/DIN85 (3) Slotted countersunk head screw: GB68/DIN963 (4) Slotted Large flat head screw (5) Cross recessed small pan head screw: GB823 (6) Cross recessed large flat head screw (7) Cross recessed pan head screw: GB818/DIN7985 (8) Cross recessed countersunk head screw: GB819/DIN965 (9 ) Cross recessed countersunk head screw: GB820/DIN966 thread and stud (2) Stud bolt-bm=1d: GB897/DIN938 (3) Stud bolt-bm=1.25d: GB898/DIN939 (4) Stud head Bolt-bm=1.5d: GB899 (5) Stud bolt-bm=2d: GB900 (1) Tooth bar: GB15389/DIN976 (6) Equal length stud: GB901/DIN976
Due to manufacturing and installation errors, the lamp head and its connecting part of the shadowless lamp will drift, which cannot be positioned at any position. Therefore, in the shadowless lamp, the damping force is usually provided by the damping screw to realize the positioning of the lamp cap and its connecting part. The damping screw needs to be able to provide a suitable damping force. The damping force should not be too small to meet the positioning requirements; at the same time, the damping force should not be too large to make the user feel comfortable when moving the lamp head and its connecting parts. In addition, within the normal life range, after the damping screw is worn, it should also be able to provide sufficient damping force to satisfy the positioning of the lamp cap and its connecting part. The damping screw is tightened by the thread, the top pressure disc spring is deformed, and the disc spring presses the friction end to generate frictional force, thereby providing an effective and lasting damping force. The damping force can be realized by adjusting the screw tightness. For the friction ends, there are certain requirements for wear resistance, certain self-lubrication, certain strength, hardness and toughness. At present, the friction end materials in the industry mainly include metals such as brass and tin bronze; non-metals such as nylon and POM. At present, the main disadvantage of the friction end of the damping screw is that it is easy to produce abnormal noise during the friction process for metal materials. For non-metallic materials, deformation is easy to occur and the strength is insufficient.
Among them, the pneumatic riveting machine is more commonly used. The pneumatic riveting machine is also equipped with a clamp for assembling the rivet. The existing clamp usually uses two rotating clamps for fastening and assembly, but the rotation easily causes the two clamps to buckle. Misalignment, thus affecting the assembly of the rivet.
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