The bearing adopts a small outer diameter steel ball design to reduce friction torque and improve rotational accuracy, and achieves lightweight and wiring space optimization through a hollow shaft structure [1] [7]. Sealing forms are divided into two categories: contact type and non-contact type [1] [10]. The raceway of a four point contact ball bearing has a Gothic arc shape, and the ball and raceway form a four point contact, which can simultaneously withstand radial, axial, and torque loads [2] [5]. The materials include stainless steel, ceramics, etc., providing open and sealed structures, with a cross-sectional size range covering metric and imperial series [4] [8] [11]. Some models use electric permanent magnet suction cup processing technology to reduce thin-walled deformation and meet high-precision geometric tolerance requirements
