Grinding machine and method for machining workpieces

Abstract

A grinding machine for machining workpieces comprises a machine bed; a workpiece holder comprising a workpiece spindle; at least one grinding spindle comprising a grinding tool for machining; a set of steady rests spaced apart from each other along an axial longitudinal extension of the workpiece, wherein the steady rests are operable in an engagement state and a disengagement state, and wherein the steady rests of the set of steady rests are arranged to engage in the engagement state a workpiece for support, the workpiece being mounted on the workpiece holder; and a control device that is configured to selectively set the steady rests into the engagement state or the disengagement state in such a way that a change between the engagement state and the disengagement state takes place during the machining of the workpiece.

What is claimed is: 
     
         1 . A grinding machine for machining workpieces, comprising:
 a machine bed,   a workpiece holder comprising a workpiece spindle,   at least one grinding spindle comprising a grinding tool for machining,   a set of steady rests spaced apart from each other along an axial longitudinal extension of the workpiece,   wherein the steady rests are operable in an engagement state and a disengagement state, and   wherein the steady rests of the set of steady rests are arranged to engage in the engagement state a workpiece for support,   the workpiece being mounted on the workpiece holder, and   a control device that is configured to selectively set the steady rests into the engagement state or the disengagement state in such a way that a change between the engagement state and the disengagement state takes place during the machining of the workpiece.   
     
     
         2 . The grinding machine as claimed in  claim 1 , wherein the set of steady rests comprises at least two steady rests that are individually controllable, wherein, during machining, a first steady rest of the two steady rests is at least temporarily in the engagement state while a second steady rest of the two steady rests is in the disengagement state, and wherein, during machining, the first steady rest is at least temporarily in the disengagement state while the second steady rest is in the engagement state. 
     
     
         3 . The grinding machine as claimed in  claim 2 , wherein the control device is further configured to selectively operate the at least two steady rests in the engagement state and in the disengagement state during the machining of the workpiece. 
     
     
         4 . The grinding machine as claimed in  claim 2 , wherein the control device is further configured to operate the at least two steady rests at least temporarily in the same state when the first steady rest is transferred from the engagement state into the disengagement state and the second steady rest is transferred from the disengagement state into the engagement state. 
     
     
         5 . The grinding machine as claimed in  claim 2 , wherein the control device is further configured to operate at least two steady rests of the set of steady rests simultaneously in the engagement state and in the disengagement state, and wherein the at least two steady rests are toggled between the engagement state and the disengagement state. 
     
     
         6 . The grinding machine as claimed in  claim 1 , wherein the control device is further configured to operate the steady rests in a transition state, the transition state indicating an imminent change between the engagement state and the disengagement state. 
     
     
         7 . The grinding machine as claimed in  claim 1 , wherein the control device is further configured to control an infeed drive of the grinding spindle to reduce an infeed force of the grinding tool to the workpiece during a transition of a steady rest between the engagement state and the disengagement state. 
     
     
         8 . The grinding machine as claimed in  claim 1 , wherein at least some of the steady rests of the set of steady rests are arranged as active steady rests and are provided with at least one steady rest drive or are arranged to be coupled therewith to selectively bring a respective steady rest into the engagement state or the disengagement state. 
     
     
         9 . The grinding machine as claimed in  claim 1 , wherein the control device is further configured to bring the steady rests into a transition state which is passed through upon a change between the engagement state and the disengagement state, and wherein in the transition state the grinding spindle is controlled to regulate the infeed force of the grinding tool on the workpiece. 
     
     
         10 . The grinding machine as claimed in  claim 1 , wherein the at least one grinding spindle comprises at least one grinding wheel that is arranged as a grinding wheel package, wherein the grinding wheel package comprises a core which is formed as a multi-part and which comprises various axial sections that are joined together, and wherein the grinding wheel package comprises a plurality of grinding segments that are associated with corresponding sections of the workpiece to be machined. 
     
     
         11 . The grinding machine as claimed in  claim 1 , comprising two or more spindle units, wherein at least one of the spindle units comprises a grinding spindle having a grinding wheel that is overhung mounted. 
     
     
         12 . The grinding machine as claimed in  claim 11 , wherein at least one of the two or more spindle units comprises two grinding spindles, wherein the two grinding spindles comprise a common travel drive, and wherein the two grinding spindles of the spindle unit are movable alternately into an active position or a passive position with respect to the workpiece. 
     
     
         13 . The grinding machine as claimed in  claim 12 , wherein the common travel drive is a rotary drive that is associated with the spindle unit. 
     
     
         14 . The grinding machine as claimed in  claim 1 , wherein the grinding machine is arranged as a cylindrical grinding machine. 
     
     
         15 . A method for grinding shaft-like workpieces using the grinding machine as claimed in  claim 1 , the method comprising the following steps:
 mounting a shaft-like workpiece on the workpiece spindle,   machining the workpiece, comprising:
 producing an infeed motion to bring the grinding tool into engagement with the workpiece, 
 producing a relative rotation between the grinding tool and the workpiece, and 
 controlling the set of steady rests by means of the control device to selectively bring the steady rests into the engagement state or the disengagement state, 
 wherein a change between the engagement state and the disengagement state takes place during machining. 
   
     
     
         16 . The method as claimed in  claim 15 , wherein an infeed force by means of which the grinding tool acts on the workpiece is reduced when one of the steady rests is switched between the engagement state and the disengagement state, and wherein the infeed force is reduced while the steady rest is in a transition state that initiates a change between the engagement state and the disengagement state. 
     
     
         17 . The method as claimed in  claim 15 , wherein at least some steady rests of the set of steady rests are toggled several times between the engagement state and the disengagement state during machining. 
     
     
         18 . The method as claimed in  claim 17 , wherein at least two steady rests of the set of steady rests are toggled alternately between the engagement state and the disengagement state. 
     
     
         19 . A method for machining shaft-like workpieces, comprising the following steps:
 mounting a shaft-like workpiece on a workpiece spindle,   providing a set of steady rests that are spaced apart from one another along an axial longitudinal extension of the workpiece, the steady rests being arranged to assume one of an engagement state and a disengagement state, the steady rests engaging the workpiece for support in the engagement state,   providing at least one grinding spindle comprising at least one grinding tool, and   machining the workpiece, comprising:
 producing an infeed motion to bring the grinding tool into engagement with the workpiece, 
 producing a relative rotation between the grinding tool and the workpiece, and 
 controlling the set of steady rests to selectively bring the steady rests into the engagement state or the disengagement state, 
 wherein a change between the engagement state and the disengagement state takes place during machining. 
   
     
     
         20 . The method as claimed in  claim 19 , wherein the set of steady rests comprises at least two steady rests that are individually controllable, wherein, during machining, a first steady rest of the at least two steady rests is at least temporarily in the engagement state while a second steady rest of the at least two steady rests is in the disengagement state, and wherein, during machining, the first steady rest is at least temporarily in the disengagement state while the second steady rest is in the engagement state.