| 摘要 |
In a drilling tool for drilling in solid metal material, in particular for drilling in plate stacks (plate drill), two geometrically similar reversible carbide tips (2, 3) are arranged at different radial distances at the end of the shank (1) and offset from each other by 180 DEG in the circumferential direction, whose working ranges overlap, and each of which comprises several cutting edges (2a, 2b, 3a, 3b) of equal length. Of the cutting edges (2a, 2b, 3a, 3b), respectively two adjacent cutting edges at an obtuse angle ( alpha ) to each other are simultaneously in contact, wherein the radially inner, first reversible carbide tip (2) extends by its cutting edge (2b) which is in contact slightly beyond the drill axis (A), and the radially outer, second reversible carbide tip (3) is axially set back from the first reversible carbide tip (2), and its two operative cutting edges (3a, 3b) form acute angles ( beta 1, beta 2) of different size with the drill axis (A). The first reversible carbide tip (2) is smaller than the second reversible carbide tip (3). On the same radius as the first reversible carbide tip (2) is arranged a third reversible carbide tip (4) which is also smaller than the second reversible carbide tip (3), in such a way that its operative cuting edge (4a) works approximately on the same working cone and on the same maximum radius (R) as the radially outer cutting edge (3a) of the second reversible carbide tip (3). |
