Precision bearings are mainly used in high-speed rotation situations with light loads, which require high precision, high speed, low temperature rise and low vibration, and a certain service life. They are often used as supports for high-speed electric spindles and are installed in pairs. They are hub accessories for high-speed electric spindles of internal surface grinders. So what should we pay attention to when installing precision bearings?
The service life of high-speed precision bearings has a great relationship with installation. The following matters should be paid attention to:
1. The bearing installation should be carried out in a dust-free and clean room. The bearings should be carefully selected and the spacers for the bearings should be ground. Under the condition of maintaining the same height of the inner and outer ring spacers, the parallelism of the spacers should be controlled at 1um. the following;
2. The bearing should be cleaned before installation. During cleaning, the inner ring should be sloped upward, and it should feel flexible in the hand without any sense of stagnation. After drying, put in a specified amount of grease. If it is oil mist lubrication, a small amount of oil mist oil should be put in;
3. Special tools should be used for bearing installation, the force should be even, and knocking is strictly prohibited;
4. The bearings should be stored in a clean and ventilated place, without corrosive gases, and the relative humidity should not exceed 65%. For long-term storage, they should be rust-proofed on schedule.
In order to improve the actual fitting accuracy when installing precision bearings, it is necessary to use measurement methods and measuring tools that do not deform the precision bearings to carry out actual precision measurements of the mating surface dimensions of the inner hole and outer circle of the precision bearings. The relevant inner diameter and outer diameter can be All diameter measurement items are measured, and the measured data are comprehensively analyzed. Based on this, the dimensions of the precision bearing installation parts of the shaft and seat hole are precisely matched. When actually measuring the corresponding dimensions and geometry of the matched shaft and seat hole, it should be carried out under the same temperature conditions as when measuring precision bearings.
In order to ensure a high actual matching effect, the roughness of the surfaces of the shaft and seat hole that match the precision bearing should be as small as possible.
When making the above measurements, two sets of marks indicating the direction of the maximum deviation should be made on the outer circle and inner hole of the precision bearing, as well as on the corresponding surfaces of the shaft and seat hole, on both sides close to the assembly chamfer. In order to align the maximum deviations of the two matching parties in the same direction during actual assembly, the deviations of both parties can be partially offset after assembly.
The purpose of making two sets of orientation marks is to comprehensively consider the compensation of deviations. Even if the rotation accuracy of the supports at both ends is improved, the coaxiality error of the seat holes between the two supports and the journals at both ends can be partially eliminated. . Implementing surface strengthening measures on the mating surface, such as sandblasting and using a precision plunger with a slightly larger diameter to plug the primary inner hole, will help improve the mating accuracy.
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