Due to the low friction and convenient maintenance of needle roller bearings, they are often used in mechanical applications. However, various problems often arise during operation, which require diagnostic techniques to help solve practical problems.

　　1. Vibration diagnosis technology. When diagnosing needle roller bearing faults, when fatigue peeling, indentation, or local corrosion occur on the working surface of its components, periodic pulse signals will appear during operation. This periodic signal can be received by sensors (speed type or acceleration type) installed on the bearing seat, and the fault of the needle roller bearing can be diagnosed by analyzing the vibration signal.

　　2. Ferrographic diagnostic technology. Wear particles are closely related to their working conditions. Lubricating oil with wear particles is subjected to a strong magnetic field, and under the action of the strong magnetic field, the wear particles precipitate on a ferrograph according to a certain pattern. The ferrograph can be qualitatively observed on a ferrograph microscope or tested on a quantitative instrument to determine the working condition of the needle roller bearing. The machine does not require disassembly; Low investment, good results; Early fatigue failure of needle roller bearings can be detected; Can conduct research on wear mechanism.

　　3. Oil film resistance diagnostic technology. The company introduces needle roller bearings with good lubrication. Due to the effect of oil film, there is a large resistance between the inner and outer rings. Therefore, by measuring the resistance of the inner and outer rings of the needle roller bearing, the abnormality of the needle roller bearing can be judged. The same evaluation standard can be used for different working conditions, but the diagnostic effect on surface peeling, indentation, cracks and other abnormalities is poor.