Mining machinery and engineering machinery, mostly works mountains and desert mining site where away from the ordinary human life, and sometimes even work in the 2000 meters underground. There is a wide range of such machinery, milling machinery, cutting machines, screening machinery, loading machinery, transportation machinery, all these equipments are 24 hours per day continuously operation. These machines regardless of what kind of mechanical failure, will be a great impact to the production of the mining scene, under this environment, bearings with heavy load + impact load, light load + high-speed rotation, the heavy load+ low-speed rotation " are very harsh conditions. Therefore, customers’ desires to bearings have the robustness, durability and high reliability of the product resistant to harsh conditions.