| 发明名称 | Drill bit | ||
| 摘要 | Provided is a step-shaped drill bit including at least two stepped cutting edges that are axially provided. A cutting edge of a first step from a tip is formed so as to satisfy at least one of the following conditions. That is, a number of blades is smaller, a point angle of the cutting edge is larger, or a clearance angle of the cutting edge is larger than that of cutting edges of a second and subsequent step(s). As a result, a thrust resistance during a perforation can be reduced compared with a case in which the first step cutting edge is formed such that the number of blades, the point angle of the cutting edge and the clearance angle of the cutting edge are the same as those of the second and subsequent step(s). | ||
| 申请公布号 | US9409239(B2) | 申请公布日期 | 2016.08.09 |
| 申请号 | US201213489938 | 申请日期 | 2012.06.06 |
| 申请人 | MAKOTOLOY CO., LTD.;FUJI JUKOGYO KABUSHIKI KAISHA | 发明人 | Higashiwaki Hirofumi;Hashimoto Eiji;Saito Manabu;Watanabe Masao;Nakahata Tatsuo |
| 分类号 | B23B51/02;B23B51/00 | 主分类号 | B23B51/02 |
| 代理机构 | Smith, Gambrell & Russell, LLP | 代理人 | Smith, Gambrell & Russell, LLP |
| 主权项 | 1. A step-shaped drill bit comprising at least two stepped sections that are axially provided, wherein a cutting edge of a first stepped section from a tip has a point angle that is larger than a point angle of a cutting edge of a second stepped section, and a cutting edge of the first stepped section has a circumferential clearance angle that is larger than a circumferential clearance angle of a cutting edge of the second stepped section. | ||
| 地址 | Osaka JP | ||