Research on the stabilization of friction torque of precision ball screw

Taking into account the influence of the error in the contact points of balls and the groove on the contact force, the influence of manufacturing errors of grooves on friction torque was analyzed. The view that the manufacturing errors of groove in ball screw mechanism affect the value of the friction torque averagely was brought forward. The characteristic of fiction torque of three type ball screws included inner-return type, return pipe type and end cap type was investigated through the friction torque test. The influence of lubrication on the stabilization of fiction torque of ball screw was also investigated through the tests. It was found that the fluctuation of the friction torque at the normal frequency of 1 Hz could be eliminated completely when the ball screw mechanism is lubricated by grease. Analysis indicates that the fluctuation of the friction torque at the normal frequency of 1 Hz is resulted from the jam and fall off of balls because of poor lubrication.