There is a contact angle between the ferrule and the ball. The standard contact angle is 15°, 30° and 40°. The larger the contact angle is, the greater the axial load capacity is. The smaller the contact angle is, the more favorable it is for high-speed rotation. Single row bearings can Bear radial load and one-way axial load. Structurally, two single row angular contact ball bearings combined on the back share the inner ring and outer ring, which can bear radial load and bidirectional axial load.