| 摘要 |
PROBLEM TO BE SOLVED: To soften a shock applied to a press metal mold at the time of gear pressing by providing a gear part with a tooth surface meshed with the tip of one face screw driver, and making a tooth forming part thick. SOLUTION: A screw shaft part 2 and a gear part 3 of a screw 1 with a gear are integrally subjected to cold working. A straight part which has a diameter a little larger than that of the screw shaft part and in which a screw groove is not formed is formed between the screw shaft part 2 and the gear part 3. The gear part 3 is disc-like, and a tooth flank 7 having an engagement tooth 6 is formed in an area outside of the central part of the screw shaft part 2 side surface thereof. The tooth flank forming part 8 is tilted backward to the central part 9. The back face 8a of the tooth flank forming part 8 is a surface parallel to the tooth bottom face 8b of the tooth flank 7. Further the basic thickness A of the tooth flank forming part 8 is made larger than the basic thickness B of the central part 9. A hexagonal head part 10 is projected on the central part of the back of the gear part 3. |
