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The tapered bore bearing can be directly installed on the tapered journal, or it can be installed on the cylindrical journal by using the adapter sleeve removal sleeve as an intermediary, but in any case, the interference of the inner ring of the tapered bore The amount can be determined based on the reduction in SKF bearing clearance.
The amount of radial clearance reduction is the difference between the radial clearance of SKF bearings before and after installation. Before installation, the original radial clearance of the SKF bearing should be measured, and the clearance should be measured frequently during installation until the reduction of the radial clearance corresponding to the ideal interference amount is reached.
diameter The measurement of the reduction in clearance can also be replaced by the measurement of the thrust of the SKF bearing on the tapered journal. For a standard taper of 1:12, the radial clearance reduction is about 1/15 of the axial thrust. Under this ratio, for a solid shaft, the interference of the mating surface is only 75% to 85%. Play the role of expanding the inner ring.
The radial clearance reduction of large spherical roller SKF bearings and cylindrical roller bearings is usually measured with a feeler gauge. Note that for spherical roller SKF bearings, two rows of rollers must be measured from two end faces respectively. The radial clearance at the inner ring and the outer ring can be guaranteed to be relatively positive only when the clearance values u200bu200bat the two rows of rollers are the same.
Small tapered bore SKF bearings cannot be measured with a feeler gauge because their radial clearance is too small. You can use a dial indicator to contact the shaft or the SKF bearing seat to measure the amount of lift during propulsion. It is the change in the radial clearance, and the elastic deformation of the rolling elements and raceways is not considered. The force used to push the SKF bearing or bearing seat should be roughly equivalent to their weight.
When the large SKF bearing is installed into the dismounting sleeve, it can not only greatly save labor, but also especially suitable for the occasions where the position is restricted and the large hook wrench cannot be used. The specific operation is: place the hardened gasket S on the end of the dismantling sleeve, gently tighten the nut M, and then evenly tighten the hardened bolts K evenly distributed along the circumference until the required clearance reduction is obtained. small amount. Since the dismantling sleeve is self-locked by the friction of its tapered surface, even if the pressing device is removed, it will not be loosened, so that the compression nut M can be safely removed, and the fixed nut is used instead, and the dismantling sleeve is pressed tightly .
A very thin layer of lubricating oil must be applied to the mating surface of the withdrawal sleeve during installation to reduce friction and facilitate installation. But be careful not to apply thick oil, otherwise, the dismantling sleeve will lose its self-locking ability. When the compression screw and nut are removed to replace the fixing nut, the dismantling sleeve will loosen and deviate from the set position, resulting in installation errors.
In addition, during the working process, the lubricant will gradually be squeezed out or escaped from the fitting gap, causing the original interference fit of the SKF bearing to become loose.
When removing the installed SKF bearing and then installing it on the journal, the nut cannot be screwed to the original position as it is, because the original fit of the SKF bearing system has become loose after a long time of operation. This is due to the gradual loosening of the thread, the permanent deformation of the mating surface under pressure, and the wear due to friction. In this case, the radial clearance reduction, axial advance or expansion must be re-measured during installation.
For large SKF bearings, if the hydraulic installation method is adopted, the installation is labor-saving and fast, and the disassembly is more convenient.
For all standard dismounting sleeves and threaded shaft ends, SKF bearings can also be mounted on tapered journals using piston-type hydraulic nuts, or the dismounting sleeves can be pressed into predetermined positions on cylindrical journals . The composition and working principle of the piston hydraulic nut are as follows: with the help of the manual oil pump, the pressure oil is pressed into the oil cylinder (nut) through the high-pressure hose, the oil cylinder is fixed on the threaded shaft end with its inner thread, and the overhanging end of the piston is pushed on. On the end face of the inner ring of the SKF bearing, the pressure oil drives the piston to push the SKF bearing forward along the tapered journal. According to the pressure of the oil pressure gauge in the pipeline, the propulsion amount of the SKF bearing can be roughly judged.
For experienced SKF bearing installers, try rotating the SKF bearing by hand to perceive its running flexibility, and can also control the interference of the SKF bearing without measuring it with an instrument, which is very important for small This is especially true for the installation of the tapered bore bearing, but it can only be implemented when it has been strictly tested and sure, and there must be no negligence in case.