Rock drill tool, rock drill bit and production method

Abstract

A rock drill tool, which comprises a rock drill bit as well as a drill rod detachably connected with the rock drill bit, where the joint between the rock drill bit and the drill rod is effected by means of a conical connection. The rock drill bit has a generally conical cavity, and the drill rod has a generally conical portion. The conical cavity is provided with a crest-shaped projection, which has a rectilinear extension along the envelope surface of the conical cavity, that the conical portion has a groove, which has a generally rectilinear extension along the envelope surface of the conical portion, and that the crest-shaped projection is received in the groove. A rock drill bit and a production method are also disclosed.

1 . A rock drill tool, comprising: 
 a rock drill bit; and    a drill rod detachably connected to the rock drill bit, the joint between the rock drill bit and the drill rod being effected by means of a conical connection,    wherein the rock drill bit has an, at least partly, conical cavity,    wherein the drill rod has a generally conical portion, the conical portion having a driver member that is positioned within an envelope surface of the conical portion, one end of said driver member situated closer to an end of the conical portion than is a second end of the driver member,    wherein the conical cavity is provided with a projection, said driver member overlapping the projection, and    wherein the projection is in the shape of a ridge.    
   
   
       2 . The rock drill tool according to  claim 1 , wherein the driver member has rectilinear first side bordering edges, and the first side bordering edges are situated in planes extending through a second centre axis of the drill rod.  
   
   
       3 . The rock drill tool according to  claim 1 , wherein the radially inner part of the projection is rectilinear, and the radially inner part lies in a plane that extends through a first centre axis of the rock drill bit.  
   
   
       4 . The rock drill tool according to  claim 1 , wherein the projection has a length that constitutes a major part of the length of the generatrix that defines the conical part of the cavity.  
   
   
       5 . The rock drill tool according to  claim 1 , wherein the projection has a length that is less than half of the length of the generatrix that defines the conical part of the cavity.  
   
   
       6 . A rock drill bit to be included in a conical connection, the rock drill bit comprising an, at least partly, conical cavity, the conical cavity being provided with a projection, an end of the projection being situated closer to a bottom of the cavity than is the other end of the projection, wherein the projection has a shape of a rectilinear ridge.  
   
   
       7 . The rock drill bit according to  claim 6 , wherein a radially inner part is rectilinear, and wherein the radially inner part lies in a plane that extends through a first centre axis of the rock drill bit.  
   
   
       8 . The rock drill bit according to  claim 6 , wherein the projection has a length that represents a major part of the length of the generatrix that defines the conical part of the cavity.  
   
   
       9 . The rock drill bit according to  claim 6 , wherein the projection has a length that is less than half of the length of the generatrix that defines the conical part of the cavity.  
   
   
       10 . A method for the production of an, at least partly, conical cavity of a rock drill bit, which is intended to be included in a conical connection, the method comprising: 
 reaming by means of an end milling cutter at least a portion of the conical cavity,    wherein a relative motion between the rock drill bit and the end milling cutter during reaming is around a first centre axis of the rock drill bit, and    wherein the relative motion is 80-90% of a full revolution around the centre axis.