OUTER THREAD KNURLING METHOD Russian patent published in 2005 - IPC

FIELD: manufacturing processes in machine engineering, namely processes of forming outer threads by plastic deforming, particularly knurling outer threads of mean and large sizes in blanks of high-ductile materials.

SUBSTANCE: method is realized by plastic deforming of metal in roller type die. Thread profile is positively deformed at least by means of three rotating threading rollers that are rigidly kinematically joined one to other. Rollers have multi-start thread whose profile corresponds to that of knurled thread, Blank freely rotating by action of friction forces at rotation of rollers is deformed at end sides due to acting upon it by means of punches moving one towards other. One of said punches is floating stop that allows to compensate axial motion of blank. Diameter of thread knurling rollers is selected in such a way that rollers may impart to blank axial motion only in direction towards floating stop and it is normalized by means of mathematical expression. Method allows knurl relatively short threaded portions of stable size at relation length/diameter no more than 5 that it is difficult to form by other methods, for example rectangular and large-size trapezoidal threads.

EFFECT: enhanced efficiency of process, improved quality of thread surfaces.

2 dwg, 1 ex