FIELD: manufacturing technology.
SUBSTANCE: invention relates to the geometry of the thread profile of a screw. Threaded fastener with male thread comprises a thread profile defined by three zones. Profile of the outer zone is defined as having thread profile surfaces constructed as a parabola. Central zone is defined as having profile surfaces constructed as sides of a trapezium. Inner zone is defined as having profile surfaces constructed as a hyperbola. Shape of the profile is constructed around the selected base mean thread diameter, wherein mean thread diameter is the selected nominal base mean thread diameter to which the selected absolute deviation is added, wherein the lateral sides of the trapezium in height are equally spaced above and below the mean diameter. Parabola of the outer zone is constructed from the upper position of the central trapezium to the larger, outer diameter of the screw/bolt thread, wherein the width of the vertex on which the parabola ends passes on the outer diameter, wherein the inner zone hyperbola is constructed from the inner position of the central trapezium and extends to the inner diameter of the thread. Inner hyperbola extends to the centre between the threads at the point where it touches the inner diameter of the thread.
EFFECT: higher reliability of the screw and nut connection when threading.
10 cl, 4 dwg
