Among the loads borne by ball screw, both radial load and axial load exist at the same time, which should be considered when selecting bearings. Common bearings that can bear the above load at the same time are angular contact bearing and tapered roller bearing. The former focuses on light load and high speed occasions, while the latter focuses on heavy load and low speed occasions. It should be noted that the above two kinds of bearings are generally used in pairs, and they are relatively installed (face to face or back to back), which can limit the axial movement of the lead screw.