| 摘要 |
<p>The present invention relates to a drill unit with a drill (1), having a cooling channel (2), and with a device for supplying cooling fluid to the cooling channel of the drill. According to the invention the drill (1) comprises three teeth (3, 4, 5), of which the first tooth (3) extends from the periphery of the drill to its centre, while the second and the third teeth (4, 5) extend inward from the periphery of the drill without reaching its centre thereof. Further the cooling channel axially extends in the centre through the drill and is deflected in the bit point of the drill so that it emerges in the space between the centre and the terminal points of the second and the third teeth (4, 5). The supply arrangement for the cooling fluid is applied to supply the fluid under high pressure.</p> |
