Thread forming screw has recesses on thread crests with volume of individual recesses reducing from start of thread to end so that reduction takes place continuously at least over part of length of thread

摘要

The thread forming screw has recesses (4) on the thread crests, with the volume of the individual recesses reducing from the start (5) of the thread to the end so that the reduction takes place continuously at least over part of the length of the thread, and in the region towards the thread end the recesses change into a volume value of 0. Before the part of the length with continuous volume reduction, the recesses over one or more thread turns follow each other with the same volume.