Deep groove ball bearing is the most common type of rolling bearing. The basic deep groove ball bearing consists of a outer ring, an inner ring, a group of steel balls and a group of retaining structures. There are two types of deep groove ball bearing: single row and double row. The deep groove ball structure is divided into sealed and open type. Open type refers to the bearing without sealing structure. The sealed deep groove ball is divided into dust-proof seal and oil proof seal. The material of dust-proof cover is steel plate stamping, which can only prevent dust from entering the bearing raceway. The anti oil type is contact oil seal, which can effectively prevent the grease in the bearing from overflowing. Single row deep groove ball bearing type code is 6, double row deep groove ball bearing code is 4. Its structure is simple, easy to use, is the most common production, the most widely used class of bearings.