The influences on the precision of the measuring instrument for ball bearings contact angle caused by the dynamic characteristic of the instrument

test speed and test load were taken into consideration

then the calculation model of the instruments dynamic uncertainty was established. Based on the measuring results of the small sample

the grey theory was applied to calculate the uncertainty of the measurement. The principle of the influence on the uncertainty of the measurement caused by the instrument's dynamic characteristic

test speed and test load was separated based on the uncertainty separation principle

and then the calculation model of the instruments dynamic uncertainty was established. After that

the calculation model was verified by the actual examples. The calculation model of the instruments dynamic uncertainty established could be used to predict the uncertainty of the measurement for contact angle under different conditions. With this help

the corresponding calibration could be done on the measuring instrument in time to raise the precision of the measurement for ball bearings contact angle.