What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The assembly of hollow rivets and flat head screws riveted on the cover plate is assembled in the product. Compared with the method of connecting with bolts, the loading and unloading speed can improve the efficiency by about 80% to 90%, and is widely used. The assembly needs to riveted hollow rivets and flat head screws on the cover plate, and ensure that the riveted flat head screws can rotate flexibly. When riveting, it is necessary to use special tools to riveted the hollow rivets, flat head screws and cover plates together for riveting. In the existing riveting process, the oval head screw is often damaged due to the action of external force. The positioning process is cumbersome and the work efficiency is low.
In order to solve this technical problem, Yueluo Company provides an adjusting nut, which includes a bearing unit, a thrust washer, an adjusting nut and a snap ring. The inside of the adjusting nut is an internal thread structure, and one end of the internal thread structure is provided with Ring groove, the snap ring is pressed into the ring groove with interference, and is rigidly connected with the adjusting nut without relative movement; the bearing unit is supported on the shaft, and the thrust washer is in plane fit with the bearing unit; the adjusting nut and the shaft are threadedly connected , Fit with the thrust washer plane, the inner diameter of the snap ring and the thread of the shaft are in interference fit.
The spring screw is a tool that uses the physical and mathematical principles of the oblique circular rotation of the object and the frictional force to fasten the machine parts step by step; the screw is a common invention in people's production and life for thousands of years. According to the application field, Screws have a wide range of applications.
When the countersunk head screws and hexagon socket head bolts are produced by the cold heading process, the original structure of the steel will directly affect the forming ability of the cold heading process. In the process of cold heading, the plastic deformation of the local area can reach 60%-80%, so the steel must have good plasticity. When the chemical composition of the steel is constant, the metallographic structure is the key factor to determine the plasticity. It is generally believed that the coarse flaky pearlite is not conducive to cold heading forming, while the fine spherical pearlite can significantly improve the plastic deformation ability of the steel. For medium carbon steel and medium carbon alloy steel with a large amount of high-strength bolts, spheroidizing (softening) annealing is performed before cold heading, so as to obtain uniform and fine spheroidized pearlite to better meet the actual production needs. For the softening annealing of medium carbon steel wire rods, the heating temperature should be kept above and below the critical point of the steel, and the heating temperature should not be too high, otherwise tertiary cementite will precipitate along the grain boundary, resulting in cold heading cracking. The wire rod of medium carbon alloy steel is annealed by isothermal spheroidization. After heating at AC1+ (20-30%), the furnace is cooled to slightly lower than Ar1, the temperature is about 700 degrees Celsius for an isothermal period, and then the furnace is cooled to about 500 degrees Celsius and air-cooled. The metallographic structure of the steel changes from coarse to fine, from flake to spherical, and the cracking rate of cold heading will be greatly reduced. The general area of softening annealing temperature for 35\45\ML35\SWRCH35K steel is 715-735 degrees Celsius; while the general heating temperature for spheroidizing annealing of SCM435\40Cr\SCR435 steel is 740-770 degrees Celsius, and the isothermal temperature is 680-700 degrees Celsius.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
