Angular contact bearing is a type of rolling bearing where the contact point between the steel ball and the inner and outer rings forms an angle with the radial direction. The contact angle is divided into 15 ° (C type), 30 ° (A type), and 40 ° (B type), with the A5 type produced by NSK corresponding to a contact angle of 25 °. The forming method adopts stamping or turning, and the materials are mainly steel plate and brass. The retaining frame can be made of engineering plastic. This bearing can withstand both radial and axial loads at the same time, and the larger the contact angle, the stronger the axial bearing capacity. High precision and high-speed bearings often use a 15 ° contact angle. Single row angular contact bearings can only withstand unidirectional axial loads and are often installed in pairs to eliminate additional axial forces. The types include single row (70XX series), double row (52XX/53XX series), four point contact (QJ2XX series) and other structures. The locking port is usually located on the outer ring and the inner and outer rings cannot be separated