The installation of precision NSK bearings

NSK bearings precision due to the requirement of matching parts precision accuracy of NSK bearings itself within the 1 mu m, therefore require matching parts ( Shaft, NSK bearing and end cover, collar, etc. ) Have high dimensional accuracy and shape accuracy, especially fitting surface accuracy to control within the NSK bearings with the same level, it is crucial, and also the most easily overlooked. NSK bearings must also pay attention to the precision of matching parts if not meet the above requirements, often makes precision NSK bearings after installation error times larger than the original NSK bearings, even more than 10 times error, NSK bearings completely to be precise, is not a simple reason is that the error of the matching parts often superimposed on the error of NSK bearings, but added in different multiples enlarged. Precision NSK bearing NSK bearings to cooperate in order to ensure that does not produce excessive deformation after installation, must do: ( 1) Shaft and hole of the roundness and shoulder roll perpendicularity to NSK bearings in accordance with the corresponding precision requirements. ( 2) Should not only precise calculation of rotating ring with the amount of interference, also to accurate calculation of the fixed ring with right quantity. The rotating ring burning interference quantity within may also should be made smaller. As long as to ensure that work under the temperature of thermal expansion effect, and under the maximum speed of centrifugal force effect, not cause peristalsis or sliding on the surface of the tight fit. NSK bearings fixed ring according to the working load size and size, select the smallest clearance fit or interference fit, too loose or too tight is unfavorable to keeping the original precise shape. ( 3) NSK bearings, such as under the condition of high speed operation and high working temperature, should pay special attention to the matching of the rotating ring is too loose, to prevent the eccentric vibration, and the matching of the fixed ring is a gap, in order to prevent the ferrule deformation and vibration under load. ( 4) Conditions for surplus with fixed circle take transgressions is suitable surface on both sides have high shape accuracy and smaller roughness, cause otherwise in installation and removal harder, in addition, also need to consider the influence of the spindle thermal elongation. ( 5) Using double in pairs NSK spindle bearings, angular contact ball mostly load lighter, its interference such as large amount, the amount of axial preload is its internal significantly larger, causing adverse effects. Using the double row short cylindrical roller bearing NSK spindle NSK bearings and tapered roller shaft, its load is opposite bigger, so its interference also relatively large. The methods of improving the precision for actual cooperate with NSK bearings in order to improve the actual coordination with the precision when installation, must not make NSK bearings deformation measuring method and measuring tools, NSK bearings on surface of the inner hole and cylindrical coordinate measure precision of the actual size, can be related to the inner diameter and outer diameter measuring project all be measured, and a comprehensive analysis of measured data, based on this, according to the precision with NSK bearings for shaft and hole of the parts of the size. In the actual measurement with a shaft and the corresponding size and shape of the hole, is to be the same with NSK bearings and measurement temperature conditions. In order to guarantee a higher actual cooperate effect, the surface of the shaft and hole and NSK bearings are suitable, the roughness should be small as possible. NSK bearings in the measurement of above, should be in the outer circle and inner hole, as well as the shaft and hole corresponding to the surface, near the sides of the assembly chamfering can separately in Ming direction of maximum deviation of two sets of tags, so that when the actual assembly, make suitable maximum deviation on the same position of the two parties, so after the assembly, the two sides to partially offset the deviation. Make directional signs, the purpose of the two groups is the deviation of the compensation can be considered, even if the rotation of supporting their precision is improved, and between the two bearing hole and trunnion coaxiality error to get part on both ends. To cooperate with the surface to surface strengthening measures, such as sandblasting processing, with a slightly larger diameter of column precision plug plug a hole, etc. , are beneficial to improve the fit precision.