Tubular blank for the production of drilling tools, method for the production of a blank and method for the production of drilling tools

Abstract

The invention relates to a tubular blank ( 22 ) for the production of drilling tools, wherein said blank has a forming part ( 26 ) that can be formed in a chipless manner by forming clamping grooves ( 12 ) and coolant channels. The finished drilling tool is fitted with a shaft for clamping in a machine tool and a drilling bit ( 20 ) having cutting edges. In order to adequately meet the requirements of strength and formability, the tubular blank ( 22 ) has a clamping part ( 16 ) integral therewith which is arranged on the end of the shaft side of the forming part ( 26 ), the thickness of the tubular wall of said clamping part being bigger than in the area of the forming part ( 26 ). The invention also relates to a method for the production of the tubular blank and to a method for the production of drilling tools.

1 . A method for the production of a drilling tool, which can be fitted with a shaft for clamping in a machine tool and with a drill tip ( 20 ) provided with cutting edges, by using a tubular blank ( 22 ), the tubular blank having a forming part ( 26 ) and a clamping part ( 16 ) which is arranged at the end of the forming part ( 26 ), is integrally connected to the latter and the tubular wall thickness of which is greater than in the region of the forming part ( 26 ), the forming part ( 26 ) being formed in a non-cutting manner while thereby forming chip grooves ( 12 ) and coolant channels ( 27 ).  
   
   
       2 . The method for the production of a drilling tool as claimed in  claim 1 , the outside tube diameter of the tubular blank being greater in the region of the clamping part ( 16 ) than in the region of the forming part ( 26 ).  
   
   
       3 . The method for the production of a drilling tool as claimed in  claim 1 , the inside tube diameter of the tubular blank being equal in the region of the clamping part ( 16 ) and the forming part ( 26 ).  
   
   
       4 . The method for the production of a drilling tool as claimed in  claim 1 , the inside tube diameter of the tubular blank ( 22 ) being smaller or greater in the region of the clamping part ( 16 ) than in the region of the forming part ( 26 ).  
   
   
       5 . The method for the production of a drilling tool as claimed in  claim 1 , a preferably planar clamping area ( 17 ) being arranged by a metal-cutting or non-cutting process on the outer side of the clamping part ( 16 ) of the tubular blank.  
   
   
       6 . The method for the production of a drilling tool as claimed in  claim 5 , the inside tube diameter of the tubular blank ( 22 ) being constant over the length of the clamping part ( 16 ).  
   
   
       7 . The method for the production of a drilling tool as claimed in  claim 5 , the inside tube diameter of the tubular blank ( 22 ) varying over the length of the clamping part ( 16 ) and being smaller in the region of the clamping area ( 17 ) than outside the clamping area ( 17 ).  
   
   
       8 . The method for the production of a drilling tool as claimed in  claim 5 , the clamping area ( 17 ) running parallel to the tube axis of the tubular blank ( 22 ).  
   
   
       9 . The method for the production of a drilling tool as claimed in  claim 5 , the clamping area ( 17 ) being aligned obliquely with respect to the tube axis of the tubular blank.  
   
   
       10 . The method for the production of a drilling tool as claimed in  claim 1 , the tubular blank ( 22 ) having a central channel ( 24 ), which has an oval or elliptical outline at least over the length of the clamping part ( 16 ).  
   
   
       11 . The method for the production of a drilling tool as claimed in  claim 10 , the clamping area ( 17 ) being arranged in the region of the smaller inside tube diameter of the clamping part ( 16 ).  
   
   
       12 . The method for the production of a drilling tool as claimed in  claim 1 , the tubular blank ( 22 ) having a central channel which, with a constant outside tube diameter, conically diverges at least over part of the length of the forming part ( 26 ) toward the free end.  
   
   
       13 . The method for the production of a drilling tool as claimed in  claim 1 , a transitional portion ( 32 ) running conically on the outside between the clamping part ( 16 ) and the forming part ( 26 ) of the tubular blank.  
   
   
       14 . The method for the production of a drilling tool as claimed in  claim 13 , the transitional portion ( 32 ) running conically on the inside between the clamping part ( 16 ) and the forming part ( 26 ) in the same direction as on the outer side.  
   
   
       15 . The method for the production of a drilling tool as claimed in  claim 1 , a step-shaped transitional portion ( 32 ) being arranged between the clamping part ( 16 ) and the forming part ( 26 ) of the tubular blank ( 22 ).  
   
   
       16 . The method for the production of a drilling tool as claimed in  claim 13 , the transitional portion ( 32 ) being formed and dimensioned in such a way that at least one bit seat for receiving a cutting bit can be formed in it there.  
   
   
       17 . The method for the production of a drilling tool as claimed in  claim 1 , the tubular blank consisting of a case hardening steel with a phase transition point of from 480 to 650° C.  
   
   
       18 . The method for the production of a drilling tool as claimed in  claim 1 , the tubular blank ( 22 ) consisting of a case hardening steel with a chromium content of less than 2%, preferably of a 16MnCr5 steel.  
   
   
       19 . The method for the production of a drilling tool as claimed in  claim 17 , the tubular blank ( 22 ) being hardened, preferably carburized or nitrided, at least on its outer surface, after the forming operation.  
   
   
       20 . The method for the production of a drilling tool as claimed in  claim 1 , the forming part ( 26 ) being formed by the swaging method.  
   
   
       21 . The method for the production of a drilling tool as claimed in  claim 1 , the coolant channels ( 27 ) being formed from the central channel of the clamping part ( 16 ) steplessly and seamlessly into the forming part ( 26 ).  
   
   
       22 . The method for the production of a drilling tool as claimed  claim 1 , a clamping shaft for clamping into a machine tool being clamped or shrink-fitted on in the region of the clamping part ( 16 ).  
   
   
       23 . The method for the production of a drilling tool as claimed in  claim 1 , an inflow chamber ( 34 ) which widens with respect to the inside tube diameter of the clamping part ( 16 ) and communicates with the coolant channels ( 27 ) of the forming part ( 26 ) being formed into a transitional portion ( 32 ) of the tubular blank ( 22 ) that adjoins the clamping part ( 16 ) in the direction of the forming part ( 26 ) having a smaller tubular wall thickness.  
   
   
       24 . A method for the production of a drilling tool as claimed in  claim 1 , a piece of tube with a constant inside and outside diameter being used to form the tubular blank, which is subjected to a metal-cutting operation, preferably drilled or turned on a lathe, on its inner and/or outer surface, while thereby forming the forming part ( 26 ) that has a thinner wall than the clamping part ( 16 ).  
   
   
       25 . A method for the production of a drilling tool as claimed in  claim 1 , a piece of tube with a constant inside and outside diameter being used to form the tubular blank ( 22 ), which is formed, preferably swaged, at least partially over a mandrel from the outside while thereby forming the forming part ( 26 ) that has a thinner wall than the clamping part ( 16 ).