Bergborrkrona och gängförband för slående bergborrning

摘要

A drill bit intended for percussive rock drilling is formed to reduce the occurrence of cavitation during percussive drilling. The drill bit includes an integral skirt and at least one channel for transport of flush medium, such as water. The drill bit has a front face provided with buttons, which define a greatest first external diameter (D 0 ). A recess with a female thread, such as a rope or trapezoid thread for percussive drilling, extends into the drill bit from a rear end face of the drill bit. The recess has an axial depth (L 0 ). The external surface of the skirt includes a conical portion having an axial extension that is greater than one-eighth of the depth (L 0 ) of the recess but smaller than the depth (L 0 ) of the recess.