Bushing is used in: packaging machinery, textile machinery, mining machinery, metallurgical machinery, printing machinery, tobacco machinery, forging machinery, all kinds of machine tools and interchangeable machinery. For example: pulley, sprocket, gear, propeller, large fan and other connections; Features: large torque, high precision, convenient and fast assembly and disassembly, simple operation, good positioning, reducing the scrap rate of matched shaft and hub, reusable and not damaging the matching surface. It is the most ideal and economical choice at present.
1. Installation: the expansion sleeve has been coated with lubricating oil before leaving the factory and can be directly installed and used. During installation, first screw three bolts into the screw holes of the flange of the other part, evenly distribute them along the circumference, and push the inner sleeve and outer sleeve apart. Then put the expansion sleeve into the hub hole at the design position, and tighten the bolts with a force measuring wrench. The tightening method is that each bolt is only tightened to 1 / 4 of the rated torque each time. The tightening sequence is bounded by the opening, and the left and right cross symmetrically tightened successively to ensure that the rated torque value is reached.
2. Disassembly: loosen all bolts for several turns before disassembly. Then screw in the bolt top loose sleeve in the disassembled screw hole crosswise. 3. Protection: prevent the expansion sleeve from being polluted during installation. On machines operating in the open air or with poor working environment, the exposed expansion sleeve end face and bolts shall be coated with anti rust grease regularly, and the expansion sleeve type with good anti rust property shall be selected. The expansion coupling sleeve is a new and advanced mechanical basic part in modern times. It is a new type of keyless connection device widely used in the world to realize the connection between parts and shafts, and realize load transmission by tightening grade 12.9 high-strength screws to make the pressure and friction between the inclusion surfaces.
In the moving parts, the parts are worn due to long-term friction. When the clearance between the shaft and the hole is worn to a certain extent, the parts must be replaced. Therefore, the designer selects the materials with low hardness and good wear resistance as the shaft sleeve or bushing in the design, which can reduce the wear of the shaft and seat. When the shaft sleeve or bushing is worn to a certain extent, it can be replaced, This can save the cost of replacing the shaft or seat.
Generally speaking, the bushing and seat adopt interference fit, while the bushing and shaft adopt clearance fit, because no matter how or can not avoid wear, it can only prolong the service life, and the shaft parts are relatively easy to process; Some new designers don't like this design and think that this is to increase the cost during manufacturing, but after a period of use, it is still necessary to transform according to this method during maintenance, but the transformation is easy to reduce the accuracy of the equipment.
The reason is very simple. The secondary processing can not guarantee the supplement of the position of the seat hole center. The shaft sleeve is used to replace the rolling bearing (in fact, the shaft sleeve is also a sliding bearing) in some places with low speed, high radial load and high clearance requirements (such as camshaft). The materials require low hardness and wear resistance. The inner hole of the shaft sleeve can achieve high matching accuracy after grinding and scraping, There must be an oil groove for lubricating oil on the inner wall. The lubrication of the shaft sleeve is very important. If it is dry ground, the shaft and shaft sleeve will soon be scrapped. It is recommended to scrape the inner hole wall of the shaft sleeve during installation, so as to leave many small pits. Enhance the lubrication. Different models of the bushing and shaft sleeve are selected according to different industrial and mining conditions. The most important conditions are: pressure, velocity, pressure velocity product, lubrication state and load property. The bushing is fast, easy and excellent, and the automatic selection is included. Wrapped around the valve stem, it is worn and can be replaced easily. If the bushing is not used, replace the parts after wear. Therefore, the bushing is replaced (in design, the hardness of the bushing is reduced to make it a wear part in the friction pair). Because of its convenient processing, low replacement cost and easy replacement. Of course, there are guiding functions, which are second.