The influence of thread screw parameters on the efficiency of threaded joints

Non-movable threaded joints (bolted connections) and movable threaded joints (power screws) are subassemblies that have a large field of application in the mechanical industry. With these subassemblies, a part of the input energy in the form of torque is spent on overcoming friction on the contact sliding surfaces. These energy losses mostly depend on the geometric and tribological characteristics of the threaded joint. Compared to bolted joints, power screws consume significantly more energy to perform their elementary function. Bolted joints have a much larger field of application in the mechanical industry. In the case of bolted joints metric thread is the most common, and in power screws, threaded joints with a trapezoidal thread. Accordingly, this paper analyses the effects of the coefficient of friction and geometric and kinematic parameters on the energy efficiency of trapezoidal and metric threaded joints. The performed analysis can be used to select the optimal parameters of the threaded joints from the aspect of energy efficiency during the design of new or reconstruction of existing machine structures.