圆上泽文大华 OUTLINE Power Screw Introduction @ Basic Terminology ©Torque Loading ©Other issues 圆上海夫通大学 Self-Locking Condition in which the screw cannot be turned by any magnitude of force applied axially(not as a torque)to the nut ▣For this to happen >Torque to lower the load has to be positive and non-zero T=Fd nfd seca-l >0 2πdn+fseca >For this expression to be positive,then πfd sec a-l>0 2525 OUTLINE Power Screw Introduction Basic Terminology Torque Loading Other issues Self-Locking  Condition in which the screw cannot be turned by any magnitude of force applied axially (not as a torque) to the nut  For this to happen Torque to lower the load has to be positive and non-zero For this expression to be positive, then 0 sec sec 2               d fl Fd fd l T m m m － sec － 0 m   fd l 