1. precision improving method
Bearing after installation in the host, such as measurement of spindle runout, found its spin measured value has a certain amount of change during continuous measurement, after can be found after a certain speed, this change is approximately repeats. Measure of the change indicator for cyclic running accuracy, changes needed to approximate repeats to a few representative cyclic running accuracy of "cycles", in the quasi-periodic changes of amplitude, cyclic running accuracy is poor.
As to appropriate the spindle preload speed gradually increased to close to the speed, to achieve a bearing "break-in" effect, you can increase the cycles of spindle running accuracy.
2. a method for improving the accuracy of bearing
A factory trial precision instruments, spindle with 6202/P2 type bearing and its precision still cannot meet requirements, Hou plus rough axis neck and in its Shang produced roll road to instead of within ring, and will steel ball for waxy key measurement, to size size each three grain a group, each group steel ball take close to 120 ° of interval separate, due to reduced has a heavy processing surface, and reduced has a heavy tie surface, while and improve has axis a bearing system of stiffness, and maximum three grain and minimum three grain steel ball of close to raster distribution, and improve has axis of Rotary precision, Meet the accuracy requirements for the instrument.
3. installation accuracy and comprehensive method of verification
Angular contact ball bearing spindle was mounted, installed accuracy calibration sequence is as follows (an example of shaft diameter for lathe 60-100mm):
(1) measuring dimensions of the shaft and housing bore holes to determine the fitting accuracy of the bearing to meet requirements are as follows,
Take inner ring and shaft fits, interference 0~+4 μ m (at light load, high precision to 0);
Outer ring and housing bore clearance fit, gap 0~+6 μ m (in free-end bearing of angular contact ball bearings, can also increase the gap);
Shaft and hole 2 μ m below surface roundness,
Bearing with intermediate ring ends parallel 2 μ m below,
The shaft-side facing face beat in 2 μ m;
Bearing bore abutments on their beats in 4 μ m;
Front end facing the axis of spindle runout 4 μ m,
(2) locating bearing on the shaft before installation.
Bearing thorough cleaning of the wash with clean kerosene,
For grease lubrication, first with 3%~5% after degreasing cleaning organic solvents of grease into the bearing, and quantification of oil gun grease filled bearing (bearing space volume of 10%~15%);
Heating bearings make warming 20~30℃, hydraulic machines bearing mounted shaft ends;
Press the adapter sleeve on the shaft and at the right pressure against the bearing end its axial position;
The spring scale tape volumes on the bearing outer ring, with starting torque measurement method verifies that the required preload is a dramatic change (even though the bearing is correct, but combined with deformation or a cage, preload may also change).
(3) Insert the bearing-shaft assemblies seat holes.
Heating hole make warming 20~30℃, continuous gentle pressure to assemble the bearing-shaft Assembly seat hole;
Adjust the front cover, front cover fasten 0.02~0.05 μ m,
Bearing housing face as a benchmark, indicator table headers on the subject in the journal surface, rotate the measurement of its beats, requirements errors below 10 μ m;
The dial is positioned on the axis, headers after the conflict bore inner surface, axis to measure concentricity of the bearing seat hole before and after.
(4) the free-end bearing selectively placed in locations that might offset the bias, after installing the housing supporting position, as far as possible to offset the mutual deviation of roundness and concentricity deviation.
4. taper Kong Shuang row short cylindrical roller bearing installation
Install NN3000K series cone when Kong Shuang-row cylindrical roller bearings, care must be taken to correct fit of the bearing bore and shaft tapers, in the production of less available touch painting method in the case of parity, but in production volume is large, the best precision taper gauges calibration.
When the bearings are mounted on a tapered shaft, along an axis to the inner ring should be moved to the appropriate location, its radial internal clearance is close to zero.

 



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