DF pairing (P0, P6, P5 levels)

DF pairing is one of the three classic paired installation methods for angular contact ball bearings, with the full name Double Face to Face and code DF. The core is to install two angular contact ball bearings of the same specification with the narrow outer edge facing each other and the wide inner edge facing each other, with the contact angle centerline converging towards the inside of the bearing to form an "inner eight" layout. It is suitable for radial loads and bidirectional axial loads, with small shaft span and high concentricity requirements. It is a commonly used choice for compact shaft systems such as pump valves, motor end caps, and small spindles, and can be adapted to a full range of angular contact ball bearings such as 7000C/AC/B and AC7000 full ceramic types.