1. Preload lifting accuracy method
After the grooved roller bearings are installed in the server, if the axial vibration of the main shaft grooved roller bearings is accurately measured, it can be found that the measured value of each rotation has a certain change; when the precise measurement is continued, it can be found that after a certain rotation speed, this transition will be repeated similarly. 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 similar repeated occurrence of the transition means the "quasi-cycle time" of the rotation accuracy of the circulatory system. System rotation accuracy is poor. For example, a moderate preload is applied to the spindle grooved roller bearings in various aspects, and the speed ratio is gradually increased to be close to the speed ratio in the working process, to implement the "run-in period" effect of the grooved roller bearings, which can improve the rotation accuracy of the circulation system of the spindle grooved roller bearings.
2. Steel balls are all over the distance to improve the accuracy of grooved roller bearings
A factory developed instruments and meters, the main shaft grooved roller bearings used 6202/P2 grooved roller bearings, but the accuracy still could not meet the requirements, the motor shaft was thickened and the dovetail guide was made on it to replace the inner hole, and the steel ball Carry out high-precision and precise measurement, with each group of three steel balls in the specification and size, and each group of steel balls is separated at a distance of close to 120°, because the production and processing surface is reduced by one layer, and the mating surface is reduced by one layer. The bending stiffness of the imported grooved roller bearings system software, and the close and fixed distance of the big three steel balls and the small three steel balls are distributed, which improves the rotation accuracy of the shaft, so it meets the precision requirements of the equipment.
3. Comprehensive calibration method of installation accuracy
After installing the grooved roller bearings into the spindle grooved roller bearings, the inspection sequence of the installation accuracy is as follows (taking a CNC lathe with a journal of 60Ф100 mm as an example):
(1) Accurately measure the specifications of the shaft and the hole of the grooved roller bearings to clarify the mutual matching accuracy of the grooved roller bearings. The cooperation is stipulated as follows: The inner hole and the shaft adopt transition fit, and the interference is 0～+4μm (in light load, 0 for high precision); transition fit is adopted between the outer side and the hole of the grooved roller bearing, and the gap is 0～+6μm (but the gap can be enlarged when the angle touch ball grooved roller bearing is applied to the grooved roller bearing at the free end); The concentricity error of the surface of the seat hole is below 2μm, the flatness of the inner hole of the commonly used spacer for imported grooved roller bearings is below 2μm, and the vibration of the inner hole of the shaft ring is below 2μm. The vibration of the line is below 4μm; the inner end of the front cover of the main shaft grooved roller bearing should be below 4μm for the vibration of the center line.
(2) Installation of grooved roller bearings on the shaft before the fixed end
Clean the grooved roller bearings with clean cleaning gasoline. For grease lubrication, first, introduce a solvent with 3% to 5% lubricating grease into the grooved roller bearings for degreasing and cleaning, and then use an edible oil gun to quantitatively analyze the lubricating grease. Fill in the grooved roller bearings (accounting for 10%～15% of the indoor space capacity of the grooved roller bearings); heat the grooved roller bearings to raise the temperature to 20～30℃, and install the grooved roller bearings into the grooved roller bearings end cap with a hydraulic press; The fixed sleeve is pressed on the shaft and pressed against the inner hole of the grooved roller bearings with a suitable working pressure to make it radially accurately positioned; the strap of the spring scale is wound on the outside of the grooved roller bearings, and the required running torque is accurately measured to check the requirements Does the preload change significantly (even if the grooved roller bearings are appropriate, the preload is likely to change due to mutual fit or deformation of the ball grooved roller bearings).
(3) Install the grooved roller bearings shaft assembly into the seat hole
Heat the seat hole to raise the temperature by 20~30℃, and install the grooved roller bearings. 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. The outer and inner hole of the bearing seat is the standard, the head of the micrometer is repelled on the surface of the motor shaft, and the vibration of the shaft is accurately measured by rotating the shaft, and the specified error is below 10 μm; the micrometer is accurately positioned on the shaft, and the head is repelled from the inner surface of the rear seat hole, turn the shaft to accurately measure the parallelism of the front and rear left and right seat holes of the grooved roller bearing seat.
(4) Optionally place the grooved roller bearings at the free end at the position that is likely to offset the error, install it to the rear support part of the grooved roller bearing seat, and try to offset the concentricity error and parallelism error between each other.
4. Installation of cone hole double row short cylindrical roller grooved roller bearing grooved roller bearings
When installing NN3000K series products with cone holes, double row, short cylindrical roller, and grooved roller bearings, it is necessary to pay attention to the proper conformity between the inner diameter of imported grooved roller bearings and the smoothness of the shaft. In the case of low total output, the coloring method can be used. Carry out touch inspection, but when manufacturing large quantities, use high-precision finish card gauges for inspection. When installing the imported grooved roller bearings 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.