What Should Be Noted in the Installation of Precision Bearings?
Precision bearings are mainly used in high-speed rotating applications with light loads, requiring high precision, high rotational speed, low temperature rise, low vibration, and a certain service life. They are often installed in pairs as supporting components for high-speed motorized spindles, and are key supporting parts for high-speed motorized spindles in internal grinding machines.
Installation Precautions
1. Bearing installation shall be carried out in a dust-free and clean room. Bearings shall be carefully selected, and bearing spacers shall be ground. While keeping the inner and outer spacers at equal height, the parallelism of the spacers shall be controlled below 1 μm.
2. Bearings shall be thoroughly cleaned before installation. During cleaning, the inner ring slope shall face upward, and the bearing should rotate flexibly without stagnation. After drying, apply a specified amount of grease. For oil mist lubrication, add a small amount of oil mist oil.
3. Special tools shall be used for bearing installation, with even force applied; striking or hammering is strictly prohibited.
4. Bearings shall be stored in a clean, ventilated environment free of corrosive gases, with relative humidity not exceeding 65%. Regular rust prevention treatment is required for long-term storage.
Precision Bearing Installation Measurement
To improve the actual fitting accuracy during precision bearing installation, it is necessary to use measuring methods and tools that do not deform the bearings to accurately measure the fitting surface dimensions of the inner bore and outer circle of the precision bearing. All relevant measurement items of inner and outer diameters can be measured, and the measured data can be comprehensively analyzed. Based on this, the dimensions of the shaft and housing bore at the bearing mounting positions can be precisely machined. The actual measurement of the corresponding dimensions and geometric forms of the matched shaft and housing bore shall be conducted under the same temperature conditions as those used for measuring the precision bearing.
Fitting Effect
To ensure a high actual fitting effect, the surface roughness of the shaft and housing bore surfaces matched with precision bearings should be as low as possible.
During the above measurement, two sets of marks indicating the direction of maximum deviation shall be made on both sides near the assembly chamfer on the outer circle and inner bore of the precision bearing, as well as on the corresponding surfaces of the shaft and housing bore. During actual assembly, the maximum deviations of both mating parts shall be aligned in the same direction, so that the deviations of both parts can be partially offset after assembly.
The purpose of making two sets of directional marks is to comprehensively consider the compensation of deviations, which not only improves the rotation accuracy of the supports at both ends, but also partially eliminates the coaxiality error between the housing bore and the shaft journals at both ends. Surface strengthening measures on the fitting surfaces, such as sandblasting or plugging the inner bore once with a slightly larger precision plug, are beneficial to improving fitting accuracy.
Source: Sichuan Juneng Bearing Official WeChat Account