What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
With the rapid development of China's automobile industry, the requirements of body assembly process are constantly improving. Riveting has the characteristics of short process cycle, low noise and low energy consumption, and is widely used in automobile bodies. In the automobile industry, due to the complexity of the body sheet metal structure, there are many cavities, and the riveting tools in some positions will interfere with the structure. Many assembly points cannot use the traditional two-way loading riveting technology, so single-sided riveting is used instead. craft.
The maximum unscrewing torque of the lock nut is affected by many factors. For the research on the low-cycle fatigue performance of the lock nut, the pitch diameter of the thread, the helix angle and the bevel angle of the thread remain unchanged. Only the maximum elastic restoring force FNmax and the equivalent friction angle ρe of the thread piece will appear to a certain extent after repeated use. Change. Therefore, it is only necessary to analyze the variation law of the maximum unscrewing moment when the lock nut is subjected to cyclic load from these two aspects.
Semi-round head plastic screws have high-quality characteristics such as insulation, non-magnetic, corrosion resistance, beautiful appearance, and never rust, and modified engineering plastics, its strength and impact resistance are comparable to those of metals. The plastic screws we often say are commonly known as nylon. After adding 30% glass fiber to the screw, its mechanical properties are far superior to ordinary nylon. The materials used for the dome head plastic screws are becoming more and more diverse, the performance is constantly improving, and the application fields are becoming wider and wider. 1. Medical equipment industry (insulation, non-magnetic, environmental protection, anti-interference, make medical equipment safer to use) 2. Wind power industry (isolation and insulation of chassis circuit PCB boards) 3. Aerospace industry (electronic equipment Insulation, anti-interference) 4. Office equipment industry (never rust, beautiful and practical) 5. Petrochemical industry (high temperature resistance, chemical resistance, corrosion resistance, prolong equipment life) 6. Electronics industry (insulation, anti-interference) , light weight) 7. Communication industry (insulation, non-magnetic, safety) 8. Ship industry (acid resistance, alkali resistance, corrosion resistance, extended service life), etc... .
The existing open-type blind rivets are widely used, usually composed of an iron rivet shell and an iron or stainless steel mandrel. During the riveting process, the open-type rivets are often unstable and biased due to the unsteady breaking force of the mandrel. When the foam is riveted, the nail head is directly pulled into the foam layer to damage the product structure. And there may be safety hazards such as scratching the operator during the installation process due to the exposed nail core. At the same time, due to the expansion of the rivet shell hole, the nail head will be loose inside.
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