High speed precision NSK Bearings are mainly used in high-speed rotating occasions with light load. NSK Bearings are required to have high precision, high speed, low temperature rise, low vibration and certain service life. It is often used as the support of high-speed motorized spindle. It is the key kit of high-speed motorized spindle of internal surface grinder.
1. NSK bearing accuracy index: exceeding grade P4 accuracy in GB / 307.1-94
2. High speed performance index: DMN value 1.3 ~ 1.8×106/min
3. Service life (average): > 1500h
1. NSK Bearings shall be installed in a clean room without dust. NSK Bearings shall be carefully selected and matched. Spacer rings for NSK Bearings shall be ground. On the premise of maintaining the equal height of inner and outer spacer rings, the parallelism of spacer rings shall be controlled below 1um;
2. NSK bearing shall be cleaned before installation. During cleaning, the inner ring slope shall be upward, and the hand shall be flexible without stagnation. After drying, put the specified amount of grease. If it is oil mist lubrication, put a small amount of oil mist oil;
3. Special tools shall be used for NSK bearing installation, with uniform stress and no knocking;
4. NSK Bearings shall be stored clean and ventilated without corrosive gas, and the relative humidity shall not exceed 65%. Long term storage shall be regularly rustproof.
In order to improve the actual fitting accuracy of NSK bearing during installation, the measurement methods and tools that do not deform NSK bearing must be used to accurately measure the fitting surface dimensions of inner hole and outer circle of NSK bearing. All the measurement items related to inner diameter and outer diameter can be measured, and the measured data can be comprehensively analyzed,
Size of NSK bearing installation position precisely matched with shaft and seat hole. When actually measuring the corresponding size and geometry of the matched shaft and seat hole, it shall be carried out under the same temperature conditions as when measuring NSK bearing.
In order to ensure a high actual matching effect, the roughness of the surface matching the shaft and seat hole with NSK bearing shall be as small as possible.
During the above measurement, two groups of marks indicating the direction of large deviation shall be made on the outer circle and inner hole of NSK bearing and the corresponding surface of shaft and seat hole on both sides close to the assembly chamfer, so that the large deviation of matching two sides can be aligned in the same direction during actual assembly, so that the deviation of both sides can be partially offset after assembly.
The purpose of making two groups of orientation marks is to comprehensively consider the compensation of deviation, not only improve the rotation accuracy of the supports at both ends, but also partially eliminate the coaxiality error of the seat hole between the two supports and the journal at both ends.
The surface strengthening measures for the mating surface, such as sand blasting and plugging the primary inner hole with a slightly larger diameter precision plug column, are conducive to improving the mating accuracy.
It is necessary to accurately calculate both the interference of the rotating ferrule and the appropriate fit of the fixed ferrule.
The burning interference of rotating ferrule should also be small within the possible range. As long as the effect of thermal expansion at working temperature and centrifugal force at high speed are ensured, the creep or sliding of tight fitting surface will not be caused.
According to the working load and NSK bearing size, the fixed ring selects a very small clearance fit or interference fit. Too loose or too tight is not conducive to maintaining the original accurate shape.