What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
M4 grounding screw used to fix the grounding wire on household appliances and other equipment, the stud is cylindrical, and the thread is perpendicular to the end (section) surface. However, the screw holes on the equipment all have tapping guide grooves for sinking and guiding due to the manufacturing process requirements. When fixing the ground wire, if the screw is not positioned accurately (the screw is inclined), the screw is pressed down hard, which is easy to cause the screw and the screw. The screw hole bites the teeth, and after biting the teeth, it is easy to cause the screw to loosen or fall off, posing a safety hazard.
1. Material strain hardening When the material is cyclically loaded, the phenomenon of cyclic strain hardening or cyclic strain softening will occur, that is, under the condition of constant cyclic strain, the stress amplitude will increase or decrease with the increase of the number of cycles. . After several cycles, the stress amplitude enters a cyclic steady state. The low-cycle fatigue of the lock nut is carried out under the condition that the strain is constant, and the strain hardening or softening of the threaded piece will affect the size of its maximum unscrewing torque. The alloy steel used to make the lock nut is a cyclic strain hardening material, and the hardening of the material will increase the elastic restoring force FN of the threaded sheet and increase the unscrewing torque.
The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to overcome the above shortcomings and provide a limit screw. The technical scheme of Guangdong Yueluo Hardware Industry Co., Ltd. is realized in the following way. Its structure is composed of screws, hexagonal copper posts and limit necks. The left end of the limit neck is open, the hexagonal copper column is communicated with the inside of the limit neck, and the inside is provided with screw threads. The design length of the screw thread in the hexagonal copper column is 1/3-2/3 of its own length. The advantages of Guangdong Yueluo Hardware Industry Co., Ltd. are (10), which can effectively prevent the problem of poor memory contact caused by the increase of the deformation of the motherboard due to the warping and deformation of the motherboard during installation and fixation, and can effectively control the deformation. effect.
Blind rivets (blind rivets) --------- rivet body (rivet body) mandrel (rivet stem or rivet mandrel). It is a type of rivet for single-sided riveting, but it must be riveted with a special tool - a rivet gun (manual, electric, pneumatic). When riveting, the rivet core is pulled by a special rivet gun to expand the rivet body and play a riveting role. This type of rivet is especially suitable for riveting occasions where it is inconvenient to use ordinary rivets (riveting from both sides), so it is widely used in construction, automobiles , ships, aircraft, machinery, electrical appliances, furniture and other products. Among them, the open-type oblate head blind rivets are the most widely used, the countersunk head blind rivets are suitable for riveting occasions where the surface needs to be smooth, and the closed blind rivets are suitable for riveting occasions that require high load and certain sealing performance.
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