1. Preload lifting accuracy method

After the roller bearings is installed in the server, if the axial vibration of the spindle bearing is accurately measured, it can be found that the measured value of each rotation has a certain change; when the accurate measurement is continued, it can be found that after a certain speed, this change will be Similar recurring. The index value to consider the level of this kind of transition is the rotation accuracy of the circulatory system. The rotation speed required for the transformation to occur repeatedly means the "quasi-cycle time" of the rotation accuracy of the circulatory system. System rotation accuracy is poor. For example, the spindle bearing is properly preloaded in various aspects, and the speed ratio is gradually increased to the speed ratio close to the working speed ratio, so as to promote the "run-in period" effect of the bearing, which can improve the rotation accuracy of the circulatory system of the spindle bearing.

2. Steel balls are distributed throughout to improve bearing accuracy

A factory developed instruments and meters. The main shaft bearing uses 6202/P2 type bearings, but its accuracy still cannot meet the requirements. The motor shaft is thickened and a dovetail guide is made on it to replace the inner hole, and the steel ball is developed with high precision and precision. The measurement is based on the size of each group of three balls, and each group of steel balls is separated by a distance of close to 120°, because the production and processing surface is reduced by one layer, and the mutual mating surface is reduced by one layer. In addition, the shaft-one imported bearing system software has been improved. The bending stiffness of the big three and the small three steel balls is close to the fixed distance, which improves the rotation accuracy of the shaft, so it reaches the precision requirements of the equipment.

3. Comprehensive calibration method of installation accuracy

After the bearing is installed into the spindle bearing, the inspection sequence of the installation accuracy is as follows (taking a CNC lathe with a journal of 60Ф100 mm as an example):

a. Accurately measure the specifications of the shaft and the bearing seat hole to clarify the mutual matching accuracy of the bearings. The mutual matching is stipulated as follows: The inner hole and the shaft adopt a transition fit, and the interference is 0～+4μm (0 for light load and high precision) ); Transition fit is adopted between the outer side and the bearing seat hole, and the clearance is 0～+6μm (but the gap can be enlarged when the angular contact ball bearing is used in the free end bearing); the concentricity error between the shaft and the seat hole surface is below 2μm, the imported The flatness of the inner hole of the common spacer of the bearing is below 2μm, the vibration of the inner hole of the collar is below 2μm; the vibration of the shoulder of the bearing seat hole to the center line is below 4μm; the inner end of the front cover of the main shaft bearing corresponds to the center The flutter of the wire is below 4 μm.

b. The installation of the front bearing of the fixed end on the shaft

Clean the bearing with clean cleaning gasoline. For grease lubrication, first introduce a solvent with 3% to 5% lubricating grease into the bearing for degreasing and cleaning, and then use an oil gun to fill in the quantitatively analyzed lubricating grease in the bearing ( (accounting for 10% to 15% of the space capacity of the bearing chamber); heat the bearing to raise the temperature to 20 to 30 °C, and install the bearing into the bearing end cover with a hydraulic press; press the adapter sleeve on the shaft and press it against the shaft with a suitable working pressure The inner hole of the bearing enables it to be accurately positioned radially; wrap the strap of the spring balance on the outer side of the bearing, and check whether the required preload changes greatly by accurately measuring the running torque (even if the bearing is very suitable, but because of mutual The deformation of the fit or ball bearing, the preload is also likely to change).

c. Install the bearing shaft assembly into the seat hole

Heat the seat hole to raise the temperature by 20~30℃, and install the bearing-shaft assembly into the seat hole with continuous and brisk working pressure; adjust the front cover so that the tightening amount of the front cover is 0.02~0.05μm, and the outer and inner parts of the bearing seat The hole is the standard, the head of the micrometer is repelled on the surface of the motor shaft, and the shaft is rotated to accurately measure the vibration, and the specified error is below 10 μm; In order to accurately measure the parallelism of the front and rear, left and right seat holes of the bearing seat.

d. The free end bearing can be selectively placed in the position where the offset error is likely to be installed, and installed on the rear support part of the bearing seat to offset the concentricity error and parallelism error between each other as much as possible.

4. Installation of Tapered Hole Double Row Short Cylindrical Roller Bearing Bearings

When installing NN3000K series tapered hole double row short cylindrical roller bearing bearings, it is necessary to pay attention to the proper conformity between the inner diameter of the imported bearing and the smoothness of the shaft. In the case of a small total output, the coloring method can be used to carry out touch inspection. , but in the production of large quantities, use a high-precision finish card gauge for calibration. When installing the imported bearing on the tapered shaft, the inner hole should be adjusted to a moderate position in the radial direction, so that the axial backlash is close to zero.