For tapered bore SKF bearings, the inner ring is always mounted with an interference fit. Unlike cylindrical bore SKF bearings, the interference of tapered bore SKF bearings is not determined by the selected shaft fit tolerance, but by the advancing distance of the SKF bearing on the tapered journal, bushing or withdrawal sleeve. The radial internal clearance of the SKF bearing decreases as the SKF bearing advances on the tapered journal. By measuring the reduction, the degree of interference and the tightness of the fit can be determined. When installing self-aligning ball SKF bearings, CARB toroidal roller SKF bearings, spherical roller SKF bearings and high-precision cylindrical roller SKF bearings with tapered holes, it is necessary to determine the radial internal clearance reduction value or the tapered base. The axial advance distance is used as a measure of the amount of interference. Guidelines for clearance reduction and axial advance distance are found in the relevant product section. Small SKF Bearings Small SKF bearings can be pushed onto a tapered base using a nut. In the case of a bushing, a socket nut is used. Small withdrawal sleeves can be pushed into the SKF bearing bore with a nut. Nuts can be tightened with a hook wrench or an air wrench. Before starting installation, a little oil should be applied to the surfaces of the journal and sleeve. Medium and Large SKF Bearings Large SKF bearings require significantly increased mounting force and should use hydraulic nuts and/or oil injection. Both of the above methods can significantly simplify the installation process. The oil filling equipment required to operate the hydraulic nut and use the oil filling method is supplied. Detailed information on these products can be found in the relevant section in the online catalog 'Maintenance and Lubrication Products'. When using the hydraulic nut to install the SKF bearing, it must be positioned on the threaded part of the journal or the thread of the sleeve, so that the annular piston abuts the inner ring of the SKF bearing, the nut on the shaft or the retaining ring installed on the shaft end. The oil is pressed into the hydraulic nut by the oil pump to move the piston in the axial direction with the force required for safe and precise installation. Using the hydraulic nut, the spherical roller SKF bearing is installed in the oil injection method, the oil is injected between the SKF bearing and the journal under high pressure to form an oil film. This oil film separates the mating surfaces and significantly reduces the friction between the mating surfaces. This method is generally used when mounting SKF bearings directly onto tapered journals, but it is also used to mount SKF bearings on adapter and push sleeves specially prepared for the oil injection method. The oil pump or oil injector generates the necessary pressure to inject oil between the mating surfaces through the grooves and oil distribution channels on the shaft or sleeve. When designing an SKF bearing layout, consideration must be given to arranging the necessary grooves and races on the shaft. The spherical roller SKF bearing is installed on the withdrawal sleeve with oil groove. By injecting oil into the mating surface and tightening the screws in sequence, the withdrawal sleeve is pressed into the SKF bearing hole.