The installation of precision bearing

Precision bearing because of the precision bearing itself to the requirement of matching parts within 1 mu m accuracy, therefore require matching parts ( Shaft, bearing and end cover, collar, etc. ) Have high dimensional accuracy and shape accuracy, especially fitting surface accuracy to control inside and bearing the same level, it is crucial, and also the most easily overlooked. Must also pay attention to the matching precision bearing parts if not meet the above requirements, often makes precision bearing in times larger than the original bearing error occurred after installation, even more than 10 times error, completely not be precision bearing, the reason is that the error of the matching part is often not simply by adding up the error of the bearing, but added in different multiples enlarged. Precision bearing to cooperate in order to ensure that do not produce too large deformation of the bearings after installation, must do: ( 1) Shaft and hole of the roundness and block shoulder perpendicularity to according to the corresponding precision of bearing 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. Fixed ring according to the size of the working load and bearing size, choose the smallest clearance fit or interference fit, too loose or too tight is unfavorable to keeping the original precise shape. ( 3) Bearing 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 angular contact ball bearing of the spindle in pairs, for the most part load lighter, its interference such as large amount, the amount of axial preload is its internal significantly larger, causing adverse effects. Using double row short cylindrical roller bearing of the spindle and spindle taper roller bearings, the load is opposite bigger, so its interference also relatively large. The methods of improving the precision for actual cooperate in order to improve the actual coordination accuracy of bearing installation, must not make bearing deformation measuring method and measuring tools, the bearing 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 make a comprehensive analysis of measured data, based on this, according to the precision with a shaft with a hole the size of the bearing installation site. In the actual measurement with a shaft and the corresponding size and shape of the hole, should be the same as the measured bearing temperature conditions. In order to guarantee a higher actual cooperate effect, the surface of the shaft and hole and bearing are suitable, the roughness should be small as possible. When measuring above, should be on the bearing outer circle and inner hole, as well as the shaft and hole corresponding to the surface, near the sides of the assembly chamfering can respond 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.