| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw structure capable of remarkably reducing a contact area in respect to a mating member 8 as compared with that of the prior art, its process of manufacture, a rolling die used for its manufacture, a screw component having such a screw structure, a screw cutting tap and a driving rivet.SOLUTION: There are provided the first and second helical valley grooves 2, 3 crossing to each other to form several ridges 4 surrounded by these two valley grooves 2, 3, these ridges 4 are discontinuous from each other, but constitute a common screw thread to make a screw structure and these ridges 4 form a sharp-pointed shape toward an advancing direction of the screw thread. The rolling die has the first rolling die with the first protrusion corresponding to the first valley groove 2 and the second rolling die with the second protrusion corresponding to the second valley groove 3. |
