Installation, disassembly and maintenance instruct

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Installation, disassembly and maintenance instructions for beginners to install bearings

the fit between the bearing and the shaft is generally a transitional fit, and the fit between the race and the bearing seat hole is generally a clearance fit. The middle shaft ring of the two-way bearing should be fixed on the shaft to prevent rotation relative to the shaft. The installation method of bearing is generally shaft rotation, so the fit between inner ring and shaft is win-win fit, and the fit between outer ring and bearing chamber is clearance fit

when installing the bearing, the verticality of the shaft ring and the shaft centerline should be checked. The method is to fix the dial indicator on the end face of the housing so that the contact of the dial indicator is against the raceway of the bearing ring. While rotating the bearing, observe the pointer of the dial indicator. If the pointer is biased, it indicates that the axis ring and the axis centerline are not vertical. When the shell hole is deep, it can also be inspected with an extended dial indicator. When the bearing is installed correctly, its race can automatically adapt to the rolling of the rolling element, ensuring that the rolling element is located in the upper and lower race raceways. If installed reversely, not only the bearing will not work normally, but also the mating surfaces will be seriously worn. Since the difference between the shaft ring and the seat ring is not very obvious, extra care should be taken during assembly to avoid mistakes. In addition, a gap of 0.2-0.5mm should be left between the bearing race and the bearing seat hole to compensate for the error caused by the inaccurate processing and installation of parts. When the center of the bearing race is offset during operation, this gap can ensure its automatic adjustment, avoid contact friction, and make it operate normally. Otherwise, the bearing will be severely damaged

I. how to choose lubricating grease

lubrication has a very important impact on the operation and service life of bearings. Here is a brief introduction to the general principles of choosing grease. Lubricating grease is made of base oil, thickener and additives. The performance of different kinds of greases and different brands of the same kind varies greatly, and the allowable rotation limit is different. Be sure to pay attention to it when selecting. The performance of lubricating grease is mainly determined by the base oil. Generally, the base oil with low viscosity is suitable for low temperature and high speed, and the base oil with high viscosity is suitable for high temperature and high load. Thickener is also related to lubricating performance. The water resistance of thickener determines the water resistance of lubricating grease. In principle, greases of different brands cannot be mixed, and even greases with the same thickener, the smoothness of the film is mainly achieved by adding a lubricant, which will also have a bad impact on each other due to different additives

II. Must the bearing be cleaned before installation

the bearing surface is coated with antirust oil. You must carefully clean it with clean gasoline or kerosene, and then apply clean, high-quality or high-speed and high-temperature lubricating grease before installation and use. It cannot fluctuate back and forth too much, and the cleanliness has a great impact on the service life and vibration noise of rolling bearings. However, we would like to remind you that totally enclosed bearings do not need cleaning and oiling

III. how to install and disassemble

during installation, do not directly hammer the bearing end face and non stress surface, but use pressure block, sleeve or other installation tools (Tooling) to make the bearing evenly stressed, and do not drive the installation through the rolling element. If the installation surface is coated with lubricating oil, the installation will be more smooth. If the fit interference is large, put the bearing into mineral oil and heat it to 80~90 ℃ and install it as soon as possible. Strictly control the oil temperature not more than 100 ℃ to prevent tempering effect, hardness reduction and size recovery. When it is difficult to disassemble, it is recommended that you use the disassembly tool to pull outward and carefully pour hot oil on the inner ring. The heat will expand the inner ring of the rolling bearing, making it easier to fall off

Fourth, is it necessary to develop high-performance special materials such as photosensitive resin for 3D printing, high molecular powder and silk on the installation surface, as well as molding technology and installation site requirements

yes. If iron filings, burrs, dust and other foreign matters enter the bearing, the bearing will produce noise and vibration during operation, and even damage the raceway and rolling element. Therefore, before installing the bearing, you must ensure that the installation surface and installation environment are clean

V. When lubricating bearings, should the more grease be applied, the better

when lubricating bearings, the more grease you apply, the better. This is a common misconception. Too much grease in the bearing and bearing chamber will cause excessive mixing of grease, resulting in extremely high temperature. The amount of lubricant filled in the rolling bearing should be 1/2 ~ 1/3 of the internal space of the bearing, and should be reduced to 1/3 at high speed

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