Bearings in the host after installation, such as measuring spindle run out, Qingdao Swiss precision bearings Mechanical and Electrical Equipment Co., Ltd. Main Products can be found in each transfer of measured value with a slight variation; continuous measurements, can be found after a certain number of revolutions, this change will be approximately repeated. Indicators measure the extent of this change cycle rotation accuracy, the approximate change recurring "quasi-periodic cyclic rotation accuracy of the representatives of the required number of revolutions, the magnitude of change in the quasi-periodic amplitude is in cycle rotation accuracy.
Proper pre load, such as the spindle speed is gradually increased to close to the speed of work, in order to implement the "run-in" effect of the bearing, the cycle of rotation of the spindle accuracy.
2. Improve the accuracy of a bearing
Factory trial precision instruments, the spindle with 6202/P2 bearings and precision still can not meet the requirements, lubricant or lubrication method is appropriate or not will greatly affect the life of imports bearing bold journal on production raceway to instead of the inner ring and the ball waxy density measurement, separated from the size of a group of three, each ball to take close to 120 ° intervals, due to the reduction of a re-machined surface, but also reduce the weight of the mating surface, and at the same time improve the stiffness of the shaft bearing system, the largest three minimum three ball nearly equally spaced, but also improves the accuracy of shaft rotation, so to meet the accuracy requirements of the instrument.
Mounting accuracy check
Angular contact ball bearing into the spindle mounting accuracy check in the following order (shaft diameter 60-100mm ordinary lathe, for example):
(1) Measuring shaft and housing bore size, to determine with precision of the bearing with the requirements are as follows:
The inner ring and the shaft to take an interference fit, SKF bearing mating surfaces to each other unfavorable axial sliding interference 0 ~ +4 μm (at light load, high-precision, 0); outer ring and bearing hole to take a clearance fit, the amount of backlash from 0 to +6 m (but free end bearings angular contact ball bearings, but also increase the gap); surface of the shaft and housing bore roundness error of less than 2 uM bearing spacer Parallelism 2 uM external face of the shaft shoulder face beat in 2 uM; the bearing hole shoulder block axis beating 4μm; spindle inside the front cover side facing the axis of the beating in the 4μm.
(2) The installation of the fixed end of the front bearing on the shaft
After the organic solvent was injected into the bearing thoroughly cleaned with a clean cleaning kerosene, grease, the first containing 3% to 5% of the grease bearings for degreasing, then the grease gun fill in the bearing grease of the quantitative (% the bearing space volume of 10% to 15%); the heated bearings make the temperature 20 to 30 ° C, a hydraulic press bearing onto the shaft; adapter sleeve pressure and to the right pressure on the shaft against the bearing face its axial positioning; spring balance tape volumes on the outer ring of the bearing pre-load the required measurement method of starting torque check whether there is a substantial change (even if the bearings are correct, but the fit or the deformation of the cage, preload also may change).
(3) Into the bore bearings - shaft combination
Heated seat hole to make the temperature 20 to 30 ° C, with continuous gentle pressure will be loaded into the bore bearings - shaft combination; NSK bearings coated with anti-rust oil with good lubricating properties to adjust the front cover, the front cover tight The solid content of 0.02 to 0.05, as a reference to the bearing seat face, inconsistent with the header of the dial gauge on the journal surface, rotate the shaft to measure the beating, requiring error dial gauge positioned on the axis 10μm; on the header conflict with the rear hole surface, rotate the shaft to measure the bearing front and rear seat hole concentricity.
(4) The free end of the bearing selectively placed on the deviation of the position may be offset mounted to the bearing block support position offset between roundness and concentricity deviation as much as possible.
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