Method and Machine for Finishing a Spherically Curved Surface Portion of a Workpiece by Means of a Finishing Tool and a Dressing Tool for the Finishing Tool

Abstract

A method for finishing a spherically curved surface portion of a workpiece with a finishing tool having a machining surface includes the steps of finishing the surface portion of the workpiece, whereby the finishing tool, with at least one part of the machining surface, is brought into contact with at least one part of the surface portion of the workpiece. The workpiece and the finishing tool are rotatably driven; and dressing the finishing tool with a dressing tool having a curved dressing surface, whereby the dressing tool, with at least one part of the dressing surface, is brought into contact with at least one part of the finishing surface of the finishing tool. The finishing tool and/or the dressing tool are rotatably driven, whereby the dressing surface of the dressing tool has a different curvature than the spherically curved surface portion of the workpiece.

We claim: 
     
         1 . A method for finishing a spherically curved surface portion of a workpiece with a finishing tool ( 1 ) having a finishing surface ( 2 ), including at least the following steps:
 finishing the surface portion of the workpiece, wherein the finishing tool ( 1 ), with at least with one part of the finishing surface ( 2 ), is brought into contact with at least one part of the surface portion of the workpiece, wherein the workpiece and the finishing tool ( 1 ) are rotatably driven;   dressing the finishing tool ( 1 ) with a dressing tool ( 3 ) having a curved dressing surface ( 4 ), wherein the dressing tool ( 3 ), with at least one part of the dressing surface ( 4 ), is brought into contact with at least one part of the finishing surface ( 2 ) of the finishing tool ( 1 ), and wherein the finishing tool ( 1 ) and/or the dressing tool ( 3 ) are rotatably driven,   wherein the dressing surface ( 4 ) of the dressing tool ( 3 ) has a different curvature than the spherically curved surface portion of the workpiece.   
     
     
         2 . The method according to  claim 1 , wherein the finishing tool ( 1 ) and/or the dressing tool ( 3 ) is substantially rotatably driven during dressing. 
     
     
         3 . The method according to  claim 1 , wherein the dressing surface ( 4 ) of the dressing tool ( 3 ) is formed rotationally symmetrical to an axis of rotation ( 5 ) and has an aspherical curvature, wherein the dressing surface ( 4 ), has a hyperbolic or parabolic curvature running along the axis of rotation ( 5 ). 
     
     
         4 . The method according to  claim 1 , wherein the dressing surface ( 4 ) has a spherical curvature, wherein a radius of curvature of the spherical curvature differs from the radius of curvature of the spherical surface portion of the workpiece. 
     
     
         5 . The method according to  claim 1 , wherein an axial face ( 6 ) of the finishing tool ( 1 ) is dressed simultaneously with the finishing surface ( 2 ) of the finishing tool ( 1 ). 
     
     
         6 . The method according to  claim 1 , wherein a dressing tool ( 3 ) is used for dressing different finishing tools ( 1 ), wherein the different finishing tools are configured to finish spherical surface portions of workpieces with different radii of curvature. 
     
     
         7 . A machine for finishing a spherically curved surface portion of a workpiece, comprising:
 at least one rotatably driven workpiece holder in which the workpiece is arranged;   at least one rotatably driven finishing workpiece holder, wherein a finishing tool ( 1 ) having a finishing surface is held in the finishing workpiece holder; and   a dressing tool ( 3 ) having a curved dressing surface ( 4 ), wherein the dressing tool ( 3 ) with the curved dressing surface ( 4 ) is configured to be brought into contact with the finishing surface ( 2 ) of the finishing workpiece ( 1 ),   wherein the dressing surface ( 4 ) of the dressing tool ( 3 ) has a different curvature than the spherical surface portion of the workpiece.   
     
     
         8 . The machine according to  claim 7 , wherein the finishing tool holder and a dressing tool holder that holds the dressing tool ( 3 ) are radially and axially adjustable relative to one another. 
     
     
         9 . The machine according to  claim 7 , wherein the dressing tool ( 3 ) is arranged in a workpiece holder and the workpiece holder thereby forms the dressing tool holder. 
     
     
         10 . The machine according to  claim 7 , wherein an setting angle between the finishing tool holder and the dressing tool holder is adjustable. 
     
     
         11 . A dressing tool ( 3 ) for dressing a finishing tool ( 1 ), comprising:
 a curved dressing surface ( 4 ) having a cutting ability and a rotationally symmetrical curvature along an axis of rotation ( 5 ), wherein the dressing surface ( 4 ) is brought into contact with a finishing surface ( 2 ) of the finishing tool ( 1 ), wherein the curved dressing surface ( 4 ) has an aspherical shape.   
     
     
         12 . The dressing tool ( 3 ) according to  claim 11 , wherein a planar, circular, and axially aligned dressing surface ( 7 ) contacts the curved dressing surface ( 4 ) for dressing a face ( 6 ) of the finishing tool ( 1 ). 
     
     
         13 . The dressing tool ( 3 ) according to  claim 11 , wherein the curved dressing surface ( 4 ) has a continuously changing curvature along the axis of rotation ( 5 ). 
     
     
         14 . The dressing tool ( 3 ) according to  claim 11 , wherein the curved dressing surface ( 4 ) has a hyperbolic or parabolic progression. 
     
     
         15 . The dressing tool ( 3 ) according to  claim 11 , wherein the curved dressing surface ( 4 ) has multiple, spherically shaped sections, wherein the sections have different radii of curvature.