Method and tool for producing a thread in a workpiece

A tool for producing a thread in a workpiece having the following features:

• a) the tool is rotatable about a tool axis,
• b) the tool has a number n≧1 of groove generating regions twisted about the tool axis for generating a respective groove in the workpiece and a number m≧1 of helical thread generating regions twisted about the tool axis for generating the thread in the workpiece,
• d) each of the m thread generating regions is arranged
• c) the twisting of the groove generating regions and the twisting of the thread generating regions are matched to one another,
• downstream of one of the n groove generating regions, following the twisting of this groove generating region,
• e) at least some of the thread generating regions of the thread generating tool have thread pressing lobes and/or thread-cutting teeth arranged on a helical line, which corresponds in terms of thread pitch and turning direction to the thread to be generated, about the tool axis, which thread pressing lobes and/or thread-cutting teeth project radially furthest outward within the thread generating region.

A method for producing a thread in a workpiece, said method comprising the following method steps:

• a) generating a number n≧1 of twisted grooves in a wall of the workpiece encircling a thread axis
• or
• generating a wall of the workpiece which has a number n≧1 of twisted grooves and encircles a thread axis,
• b) respectively inserting a thread generating region of a tool which is twisted to match the twisting of the twisted grooves into each of the twisted grooves in a twisted insertion movement matched to the twisting of the associated groove,
• c) generating a thread in each wall sub-region, adjoining the grooves, of the wall of the workpiece by rotating the tool about the thread axis and with a simultaneous axial feed motion of the tool coaxially with respect to the thread axis with an axial feed speed adapted to the rotational speed of the rotational movement and to the thread pitch, wherein, during the rotation and the simultaneous axial feed movement, each thread generating region engages into the associated wall sub-region and generates an associated part of a thread flight, and after the rotation projects into the same groove again or into another groove in the wall,
• d) wherein at least one groove is generated by a non-cutting process, using a groove generating tool or groove generating region of a tool which moves in the direction of the desired groove and operates by a non-cutting process,
• e) wherein at least one thread generating region is a thread forming region and generates its part of the thread flight by a forming and thus non-cutting process,
• f) moving each thread generating region of the tool out of the associated groove in a twisted removal movement matched to the twisting of the associated twisted groove.