Magnetic Flux Leakage Detection Method And System For Bearing Ring Cracks

As an important basic part of machines, the quality level of bearing rings directly decides the performance, quality and reliability of machines. According to the statistics, about 30% of rotating machinery faults are resulted from bearing rings' defects. Thus it's very significant to improve the detection ability of bearing rings.Firstly, this article takes the GCr15 tapered roller bearing rings, which are one of the most widely used bearing rings in our country, and cracks on their surface as the research object. The related research method can be easily applied to other types bearing rings after being accommodated.Further, this paper proposes a bearing ring crack MFL detection method. The results of the ANSYS finite element analysis and other research methods show the influence of magnetization and liftoff control for bearing ring cracks inspection. On the basis of comprehensive analysis and experimental contrast for hall sensor, coil and MR sensor, we choose the coil as the magnetic sensitive element of this system. This thesis illustrates the similarity between the playback process of the magnetic ring head and crack detection process and summarizes the key points of crack detection sensor from the analysis for the playback process influence factors of magnetic ring head. Then, we have designed array sensor and conducted experimental verification. On the basis of a comprehensive comparison of the current bearing rings circumferential magnetization method, this paper has designed the U-shaped yoke circumferential magnetic devices and performed experimental verification.Taking these findings and the characteristics of automated production lines into account, this easy has proposed the detection mode of bearing rings rotating in place while probe fitting and designed multi-size bearing rings MFL(magnetic flux leakage) detection devices, signal conditioning and acquisition system and high-speed automated testing process.At last, field tests show that the bearing rings cracks MFL testing system can efficiently and reliably accomplish automated detection. This system has been accepted by the customer and will be put into use in the near future.