A model-based local fault size measurement method of rolling bearing considering load influence

Rolling bearing local fault vibration mechanism research is the theoretical basis of advanced bearing fault diagnosis and size measurement technology. In this paper, the additional displacement and impact force excitation of inner and outer ring local faults under low speed and heavy load condition are analysed, and rolling bearing local fault vibration model is established. The simulated dual impulse characteristics have higher accuracy under low speed and heavy load condition compared with other traditional local fault models. The outer and inner ring fault simulated dual impulse interval errors are 6.7% and 1.1%, respectively. Then the local fault vibration mechanism is analysed, and the influence of heavy load condition on dual impulse characteristic is not negligible. Finally, a size measurement method of bearing local fault based on vibration model is proposed. Two sizes of outer ring fault bearing are tested in four different working conditions, and the average measurement error is 3.78%. The results show that the proposed method can overcome the influence of different working conditions and accurately measure different local fault sizes.