| 摘要 |
PROBLEM TO BE SOLVED: To provide a thread shape more stable in threading than in the case of a metric coarse screw thread, excellent in strength, and also excellent in loosening torque after vibration is applied thereto in such a sheet and a thin-wall part that the current metric coarse screw thread can secure the number of threaded threads equal to three threads. SOLUTION: In this thread shape for fastening the sheet or the thin-wall part, the value of the ratio (P/D) of the pitch (P) to the nominal diameter (D) of each of the coarse screw threads is reduced more than those of the coarse screw threads in various screw standards, and the number of threads is set to 2 or more lines. COPYRIGHT: (C)2006,JPO&NCIPI
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