Tool holder for the shrink-attachment of tools

Abstract

A tool holder comprising a coupling shaft, a shrink chuck and a central member. The shrink chuck has a head and a base, the head having a tensioning portion with a carrier comprising an axial internal bore. The central member is interposed between the coupling shaft and the base. A surface contour connecting the front and rear diameters of the shrink chuck has at least two portions substantially even relative to a diameter course of the contour at the at least two portions. A first portion is disposed on the head and a second portion is disposed on the base, and a transition is interposed between the head and the base. A chuck diameter of the shrink chuck increases in a substantially discontinuous manner at the transition from the first portion to the second portion so that the head is slimmer than the base.

1 . A tool holder for shrink-attachment of tools having preferably cylindrical tool shafts, comprising: 
 a coupling shaft for coupling to a machine tool;    a shrink chuck having a shrink chuck head and a shrink chuck base, the shrink chuck head having a tensioning portion with a carrier comprising an axial internal bore for gripping the tool shaft; and    a central member interposed between the coupling shaft and the shrink chuck base;    the shrink chuck having a front diameter at the shrink chuck head for facing towards the machine tool and a rear diameter at the shrink chuck base facing towards the central member;    wherein a surface contour connecting the front and rear diameters of the shrink chuck has at least two portions substantially even relative to a diameter course of the contour at the at least two portions, the at least two portions comprising a first portion and a second portion, the first portion being disposed on the shrink chuck head and the second portion being disposed on the shrink chuck base, and a transition being interposed between the shrink chuck head and the shrink chuck base, a chuck diameter of the shrink chuck increasing in a substantially discontinuous manner at the transition from the first portion to the second portion so that the shrink chuck head is slimmer than the shrink chuck base.    
   
   
       2 . A tool holder in accordance with  claim 1 , wherein: 
 the carrier has an axial limit stop for determining an axial position of the tool shaft within the carrier; and    the axial limit stop, when viewed axially, is located at a height or between the position of the transition and a front end of said shrink chuck head so that, in a gripped state relative to the central member, a lower end of the tool shaft, when viewed axially, is located before or at the height of the transition.    
   
   
       3 . A tool holder in accordance with  claim 2 , wherein: 
 the first portion runs between the front end of the shrink chuck head and the transition, and has a substantially conical periphery.    
   
   
       4 . A tool holder in accordance with  claim 3 , wherein: 
 a diameter of the periphery extending towards the transition at an angle relative to a longitudinal axis of the tool holder at about 1° to 20°.    
   
   
       5 . A tool holder in accordance with  claim 4 , wherein: 
 the angle is about 4.5°.    
   
   
       6 . A tool holder in accordance with  claim 3 , wherein: 
 the diameter of the surface contour of the shrink chuck extends at the transition from the first portion to the second portion towards the shrink chuck base at an angle perpendicular to the tool holder's longitudinal axis at about 0° to 50°.    
   
   
       7 . A tool holder in accordance with  claim 6 , wherein: 
 the angle is about 10° to 40°.    
   
   
       8 . A tool holder in accordance with  claim 7 , wherein: 
 the angle is about 30°.    
   
   
       9 . A tool holder in accordance with  claim 1 , wherein: 
 a third portion is interposed between the central member and the second portion, the third portion having a substantially cylindrical periphery and the diameter of a periphery of the second portion flaring out towards the central member at an angle relative to the tool holder's longitudinal axis at about 1° to 20°, a transition of the surface contour occurring substantially continuously between the second and third portions.    
   
   
       10 . A tool holder in accordance with  claim 9 , wherein: 
 the angle is about 6° if the tool holder has a hollow shaft coupling.    
   
   
       11 . A tool holder in accordance with  claim 9 , wherein: 
 the angle is about 8° if the tool holder has a tapered shaft coupling.    
   
   
       12 . A tool holder in accordance with  claim 1 , wherein: 
 a third portion is interposed between the central member and the second portion and a fourth portion is interposed between the third portion and the central member, the second portion and the fourth portion having substantially cylindrical peripheries and the third portion having a substantially conical periphery, a diameter of the periphery of the third portion extending towards the central member at an angle relative to the tool holder's longitudinal axis at about 1° to 20°, transitions of the surface contour occurring substantially continuously between the second and third portions and between the third and forth portions.    
   
   
       13 . A tool holder in accordance with  claim 12 , wherein: 
 the angle is about 6° if the tool holder has a hollow shaft coupling.    
   
   
       14 . A tool holder in accordance with  claim 12 , wherein: 
 the angle is about 8° if the tool holder has a tapered shaft coupling.    
   
   
       15 . A tool holder in accordance with  claim 1 , wherein: 
 bores for counter-balancing members are provided within the second portion.    
   
   
       16 . A tool holder in accordance with  claim 1 , wherein: 
 the tool holder includes an axial internal bore as a cooling fluid supply channel, the supply channel having a diameter of about 3 mm to 6 mm.