Q: Will the radial clearance of imported bearings is the smaller the better? A: Not necessarily! Not all imported bearings require the minimum working clearance, you must select the appropriate clearance according to the conditions. For example, the national standard 4604-93, the radial clearance of the rolling bearing is divided into five groups - 2 groups, 0 groups, 3 groups, 4 groups, 5 groups, followed by clearance values ​​from small to large, of which 0 group standard clearance. The basic radial clearance group for general operating conditions, conventional temperature and commonly used interference fit; in high temperature, high speed, low noise, low friction and other special conditions of the bearing should choose a large radial clearance; Precision spindle, spindle bearings, etc. should choose a smaller radial clearance; for roller bearings can maintain a small amount of work clearance. In addition, the separation of the bearing is indifferent clearance; Finally, the bearing installed after the working clearance than before the original clearance is small, because the bearing to withstand a certain load rotation, but also the need to import bearings and loads generated The amount of elastic deformation. Therefore, the radial clearance of imported bearings is not necessarily the smaller the better. Q: What is the bearing steel imported bearings? What is the material composition? How to classify? A: The bearings inside and outside the ring, the ball of steel for the bearing material (vacuum heat treatment). Most of the imported bearings, the use of JIS steel type SUJ2, which is the domestic chromium steel (GCr15). SUJ2 chemical composition, in all countries in the world, as bearing materials have been standardized. For example: with AISL52100 (USA), DIN100Cr6 (West Germany), BS535A99 (UK) are the same kind of steel. The use of the material, effectively improve the bearing torque performance, reduce noise and extend life expectancy. However, in humid or hot environment, the use of martensitic stainless steel material. Q: Does the phenomenon of regular tone bearings imported what is the reason? A: The regular tone phenomenon of imported bearings may be caused by the following two reasons: 1, foreign body caused by channel corrosion, indentation, scars. The solution is: cleaning related parts, the use of clean grease 2, the channel spalling, fatigue wear. The solution is: replace the bearing. Q: Will the imported bearings must be cleaned before installation? A: Yes. Because imported bearings coated with anti-rust oil, so not only need cleaning, but also must be carefully cleaned with clean gasoline or kerosene, and then coated with clean high-quality or high-speed high-temperature grease can be installed before use. The impact of cleanliness on bearing life and vibration noise is very large. But we want to remind you is: fully enclosed bearings do not need cleaning and refueling.