Analysis: the application of bearing clearance rate and matching instrument - bearing knowledge

One, must attach great importance to improve the bearing clearance rate the importance of form a complete set of bearing the radial clearance is one of main quality index. Radial clearance refers to the inner and outer channel and the roller diameter direction of the total clearance. Bearing clearance, therefore, is not only the identification of qualified after the finished parts matching is one of the main parameters of the qualified finished products bearing, and bearing can work normally one of the important factors. Clearance value is not in conformity with the technical standards, will influence the reasonable distribution of load between the rolling element bearing rotating accuracy, vibration value, life will be affected, therefore improve and guarantee the bearing clearance rate, doubtless is very important. Second, the analysis of the radial qualified rate of the causal relationship between the quality of the products in the process of formation, once found that the problem will be immediately look for reason. Use causal analysis form, let us to solve the problem of radial clearance partial qualified rate is low profile. Factors influencing the quality of bearing clearance has five. If not considering material and environmental factors, can be used to analyze the main testing instrument, process method and personnel quality on the quality of the bearing clearance, bearing inner and outer ring and ball past matching method is to inside, the diameter of the outer channel deviation separation with instrument is good, and according to the standard clearance to calculate an inner ring channel diameter size value and an outer ring channel diameter size, and then select the corresponding size of copper ball, after the three assembly, with the axial clearance tester to test the axial clearance upper and lower limit value, does not meet the technical requirements, selection again. As to the value of the radial clearance of bearing with axial clearance value, it is difficult to ensure accuracy. Because the measured axial clearance value is upper and lower limit value, while the upper and lower limit value of channel curvature size and each technique varies, so in this way, matching of bearing the radial qualified rate is not stable. High low, when the number of rework more frequently, don't really have to clearance of the product quality. Third, application supporting device, improve the radial clearance rate in order to ensure the quality of bearing parts processing and guarantee the accuracy of the test instrument in value under the premise of using the bearing inner and outer ring form a complete set of special instrument to reasonable matching of bearing inner and outer ring, is one of the effective methods to improve the bearing radial clearance rate: 1, the necessary instrument supporting principle in the process of bearing assembly, bearing clearance must comply with the provisions of the standard, the centripetal ball bearing radial clearance error formula is: U = X - Y- 2 z and X - Y = U + 2 Z type U = centripetal ball bearings in the radial clearance without load, X = ditch outside diameter deviation, Y = inside groove diameter deviation, Z = ball diameter deviation, the U value in the formula can consult from the national standard, the Z values have been marked in the steel ball check. With matching instrument matching task is after the bearing inner and outer ring size separation, with matching instrument one-off measure ( x - y) Value, and then selecting the appropriate size of the steel ball after assembling, the radial clearance value with radial clearance gauge to inspect again. 2, the necessary method first with the bearing inner and outer groove diameter size standard calibration instrument. Because matching instrument is to use two comparison measurement, so checking instrument need two standard parts namely, inner ring and outer ring groove diameter standard parts. Supporting apparatus is equipped with three dial gauge, around two dial indicator reflects the internal and external channel diameter deviation, in the middle of a dial indicator one-time reflects ( x - y） The numerical values. For example: the outer ring the actual diameter deviation of standard channel + 8 um, inner ring the actual diameter deviation of standard channel - 5 um, X-ray y = + 8 - ( - - - - - - 5) =13um。 Calibration, aim the channel inside and outside diameter standard parts with respective measuring points, form a complete set of instrument in the middle a dial gauge pointer should be to point to in + 13 um position, prove the instrument has been calibrated. Conversely, + 13 um dial gauge pointer is not refers to the position, you need to readjust the equipment. Because before matching has good internal and external channel diameter size separation, so matching instrument dial gauge could save on the left and need not, simply reflect a dial gauge (middle x - y) Values can be equipped with a certain size of steel ball. This matches the bearing radial clearance values conform to the requirements of the standards. Is important to remind that in the process of form a complete set of inner, outer ring, to stick to frequently use standard calibration instruments, prevent the stopwatch, otherwise, the measure of ( X - Y value is not accurate, with the bearing clearance value will be wrong. On the application effect, to promote the use of form a complete set of apparatus, percent of pass is 98 - 100%.