What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The main purpose of the screw is to make the industrial product form a fixed one. In use, it often happens that the teeth cannot be closely attached, the screw head will be broken if the screw is locked too hard, or the tooth pattern is not properly locked, etc., and the use conditions are not met, all of which are quality. the problem of accuracy. Screws are mass products, not handmade works of art. In mass production, the purpose is to achieve high-precision and stable quality and popular prices to supply consumers. The accuracy of screws is usually 6g, and the rough screws used in construction projects are 10g. The value of screws is very important. In the world, there are examples of automobile factories going bankrupt because of poor screw quality; there are also examples of planes falling and vehicles being overturned because of poor screw quality.
The existing structure is found in the practical application experience that there are still the following problems and drawbacks: the screw structure and the screw space are combined with each other in a complementary manner, so they can provide a higher torque value, however, not every workpiece. The combination requires a high torque value, so it often results in excess quality. Although the price of the screw is low, if it can change the unchanging structure of the traditional screw, it can provide a technical means to simplify (change) the process. The effect of improving production capacity and convenience of use is indeed a technical bottleneck that the relevant industry should break through.
Electrical contact element is a kind of low-voltage electrical products and household electrical products widely used in switches, relays, thermostats, circuit breakers, contactors, controllers, timers, etc. There are mainly three types of electrical contact elements. 1. Riveting parts , riveting the rivet on the copper piece; 2. Welding piece, welding the sheet contact on the copper piece; 3. Stamping piece, punching the composite tape into components. Existing rivet contacts on the market at present are usually all made of precious metals, such as a simple metal matrix such as gold or silver. Its electrical contact performance is limited by a single metal material, and its electrical contact performance is poor; and due to certain requirements for metal purity in production, production efficiency is low, and production costs are high, resulting in the production of products that cannot be sold on a large scale in the market. and application.
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.
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