Angular contact ball bearing can bear radial load and axial load at the same time. It can work at high speed. The larger the contact angle is, the higher the axial bearing capacity is. The contact angle is the angle between the line of contact point between ball and raceway in radial plane and the vertical line of bearing axis. The contact angle of high precision and high speed bearings is usually 15 degrees. Under the action of axial force, the contact angle will increase.