Installation coordination and adjustment of high-speed FAG bearings: 1. Fit and clearance of high-speed FAG bearings Since high-speed FAG bearings must meet the requirements of both high-precision FAG bearings and high-temperature FAG bearings, when considering their fit and clearance, The following two points should be taken into consideration: (1) dimensional change and hardness change from normal temperature to high temperature; (2) force system change and shape change caused by centrifugal force at high speed. In a word, under the conditions of high speed and high temperature, it is difficult to maintain the accuracy and working performance of FAG bearings from the selection of fit and clearance. In order to ensure the small deformation of the raceway after the FAG bearing is installed, the interference of the interference fit cannot be too large, and the centrifugal force at high speed and the thermal expansion at high temperature may offset the normal pressure on the mating surface. Or make the mating surface slack, so the interference must be calculated carefully under the premise of considering the above two factors. The effective interference at normal temperature and speed may be invalid for high-speed FAG bearings. If the contradiction in the calculation results is too large (usually only at ultra-high speed), only the dual lubrication measures of the under-ring lubrication method and the hydrostatic lubrication method are adopted, and this solution may make the dmn value of the FAG bearing. exceeded the 3 million mark. Thermal expansion at high temperatures, or normal pressure to counteract mating surfaces. Or make the mating surface slack, so the interference must be calculated carefully under the premise of considering the above two factors. The effective interference at normal temperature and speed may be invalid for high-speed FAG bearings. If the contradiction in the calculation results is too large (usually only at ultra-high speed), only the dual lubrication measures of the under-ring lubrication method and the hydrostatic lubrication method are adopted, and this solution may make the dmn value of the FAG bearing. exceeded the 3 million mark. When considering the clearance of high-speed FAG bearings, not only the above factors should be considered, but also the influence of thermal elongation of the shaft on the clearance should be considered. And this kind of clearance is formed when the center of the inner and outer ring ball grooves are precisely aligned. Since high-speed FAG bearings strive to reduce relative sliding and internal friction, it is best not to adjust the clearance of ball FAG bearings by displacing the inner and outer rings relative to each other in the axial direction. When considering the fit interference and clearance of FAG bearings, it is necessary to pay attention to the characteristics of the material becoming soft and easy to deform at high temperature, and the possibility of certain permanent deformation caused by repeated temperature changes from normal temperature to high temperature. 2. Requirements for the relevant parts of the main engine High-speed FAG bearings require that the rotary system where the FAG bearings are located must undergo precise dynamic balance, and the parts where the FAG bearings are installed on the shaft and the seat hole should have dimensional accuracy and shape and position accuracy higher than the general requirements, especially coaxial When considering these issues, it is also necessary to pay attention to the high-speed and high-temperature factors during the operation of FAG bearings. The shaft support system requires both high rigidity and light weight as much as possible. In order to overcome this contradiction, measures such as reducing the surface roughness and improving the surface strengthening can be taken to improve the support rigidity, and the hollow shaft can be used to reduce the system mass.