How to install high speed bearings

High-speed bearing installation and adjustment:

    1. Coordination and play of high-speed bearings As high-speed bearings are required to meet high-precision bearings and high-temperature bearings, when considering the cooperation and clearance, the following two points must be taken into account:

    (1) Change in size and hardness from normal temperature to high temperature;

    (2) Force changes and shape changes caused by centrifugal forces at high speeds.

    In short, under the condition of high speed and high temperature, it is difficult to maintain the precision and performance of the bearing from the choice of fit and clearance.

    In order to ensure that the raceway after installation of the bearing is deformed little, the interference of the interference fit cannot be made too large, while the centrifugal force at high speed and the thermal expansion at high temperature can offset the normal pressure of the mating surface. Or make the mating surface loose, so the amount of interference must be carefully calculated under the premise of considering the above two factors. The effective amount of interference at normal temperature and normal speed may not be effective for high-speed bearings.

    If the result of the calculation is too contradictory (usually only at ultra-high speeds), only the dual lubrication measures of the ring-lubrication method and the hydrostatic lubrication method are used, and this solution may break the dmn value of the bearing. 3 million mark.

    Thermal expansion at high temperatures, or counteract normal pressure on the mating surface. Or make the mating surface loose, so the amount of interference must be carefully calculated under the premise of considering the above two factors. The effective amount of interference at normal temperature and normal speed may not be effective for high-speed bearings.

    If the result of the calculation is too contradictory (usually only at ultra-high speeds), only the dual lubrication measures of the ring-lubrication method and the hydrostatic lubrication method are used, and this solution may break the dmn value of the bearing. 3 million mark.

    When considering the high-speed bearing clearance, it is necessary not only to consider the above-mentioned factors, but also to consider the influence of the thermal elongation of the shaft on the clearance, and to require the bearing to have the best clearance in the working state, that is, at the operating temperature. This kind of clearance is formed in the state where the center of the ball groove in the inner ring and the outer ring is accurately aligned. Because high-speed bearings strive to reduce the relative slip and internal friction, it is best not to adjust the clearance of the ball bearings by using the relative dislocation of the inner and outer rings in the axial direction.

    When considering the fit and clearance of the bearing, it is necessary to notice that the material becomes soft and easily deformed at high temperatures, and the possibility of a certain permanent deformation caused by temperature changes from room temperature to high temperature for many times.

    2. Requirements for host-related parts

    High-speed bearings require that the bearing is located in the rotating system through precise dynamic balance, and the shaft and the mounting hole of the bearing hole should have higher dimensional precision and position accuracy than the general requirements, especially the coaxiality and the shoulder to the seat hole or journal. Verticality, and in considering these issues, it must also pay attention to the high-speed and high-temperature factors of the bearing operation.

    The shaft support system requires both high rigidity and lightweight as much as possible. To overcome this contradiction, measures such as reducing the surface roughness and improving the surface strengthening can be adopted to increase the support stiffness, and the hollow shaft can be used to reduce the system quality.