The self-aligning ball bearing has two structures: cylindrical hole and conical hole, and the material of the cage includes steel plate, synthetic resin, etc. Its characteristic is that the outer ring raceway is spherical in shape and has automatic centering, which can compensate for errors caused by different centricity and shaft deflection. However, the relative inclination of the inner and outer rings should not exceed 3 degrees. It mainly bears radial loads and can also withstand small axial loads. The axial displacement of the shaft (shell) is limited within the clearance limit, with automatic centering performance, allowing normal operation under conditions of relatively small internal and external inclination. It is suitable for components where the support seat hole cannot strictly guarantee coaxiality.