Study on the Lubrication and Anti-Friction Characteristics of the Textured Raceway of the Ball Screws Based on Elastohydrodynamic Lubrication

The surface texture technology has been applied to ball screws. However, the rough grinding surface of ball screws is not considered, and the elastohydrodynamic lubrication (EHL) characteristics and anti-friction and anti-wear mechanisms are not comprehensive and in-depth. Theoretical simulation and experimental measurement of the ground surface topography of the screw raceways are conducted to take into account the impact of the grinding surface on the EHL interaction between the ball and the raceway. The EHL model and friction torque model of ball screws have been established simultaneously, considering the ground surface topography of the raceway and the geometric features of the textures manufactured on the raceway surface. The friction reduction mechanism of the textured raceway of ball screws is elucidated in detail from the microscopic point of view, and the influence of the geometric features of the textures on the anti-friction characteristics of ball screws under different axial loads and rotation speeds is further analyzed and discussed. The proof-of-principle experiments of the friction-reducing performances of the textured raceways of the ball screws are conducted. The textured raceway of the ball screws provides an effective anti-friction effect that reduces the friction coefficient of the contact system of the ball screws by 15.2% at a normal contact force of 60.23 N, an entrainment speed of 167.5 m/s, a texture diameter of 40 μm, a texture depth of 10 μm and a texture areal density of 10%.