Apparatus and a method for machining elements with non-circular cross section, in particular for axial couplings for mechanical connection, and coupling made applying said method and apparatus

Abstract

Described herein is an apparatus for machining elements for axial couplings for mechanical connection, with non-circular cross section, which comprises: a work spindle fitted on the shaft of appropriate means for actuation in rotation; a tool guided by appropriate means in the displacements both along the axis perpendicular to that of rotation of the spindle and along the axis parallel to that of rotation of the spindle; means for actuation of the displacements of said tool on said guide means; and a central control unit connected to said displacement means of said tool and to said means for actuation in rotation of said spindle, capable, via an appropriate program, of supervising turning of the side coupling surface of said elements for axial couplings for angular connection.

1 ) An apparatus for machining elements for axial couplings for mechanical connections, with non-circular cross section, comprising: a work spindle ( 1 ) fitted on the shaft ( 103 ) of appropriate means ( 3 ) for actuation in rotation; a tool ( 7 ) guided by appropriate means ( 5 ,  6 ) in the displacements both along the axis perpendicular to that of rotation of the spindle and along the axis parallel to that of rotation of the spindle; means ( 105 ,  106 ) for actuation of the displacements of said tool on said guide means ( 5 ,  6 ); and a central control unit ( 4 ) connected to said displacement means ( 105 ,  106 ) of said tool and to said means for actuation in rotation ( 3 ) of said spindle ( 1 ), capable, via an appropriate program, of supervising turning of the side coupling surface of said elements for axial couplings for angular connection.  
   
   
       2 ) The apparatus according to  claim 1 , further comprising means ( 203 ) for detection of the angular position and of the angular velocity of said shaft ( 103 ) of the means ( 3 ) for actuation of said spindle ( 1 ).  
   
   
       3 ) A method for the turning of elements for axial couplings with non-circular cross section in an apparatus according to  claim 1 , comprising it comprises the steps of: defining the profile of the cross section of each of said elements, on the basis of non-circular parametric curves; parameterizing the equation of the selected curve, by means of the appropriate dimensional parameters of said element; processing the datum of position of the tool for turning with respect to said element according to the angular position thereof, in relation to a given cross-sectional plane; synchronizing the rotation of the spindle for supporting said element with the displacements of said tool on said plane; and further synchronizing the displacements of said tool with respect to an axis perpendicular to said plane.  
   
   
       4 ) The method according to  claim 3 , wherein, simultaneously with the step of synchronization of rotation of the supporting spindle with the displacements of said tool on said cross-sectional plane, the data appropriately acquired corresponding to the angular position and to the angular velocity of said spindle are processed.  
   
   
       5 ) The method according to  claim 3 , wherein, simultaneously with the step of synchronization of the rotation of the supporting spindle with the displacements of said tool on said cross-sectional plane, the mechanical inertia of the actuation means used is compensated.  
   
   
       6 ) The method according to  claim 3 , wherein, simultaneously with the step of synchronization of the displacements of said tool with respect to an axis perpendicular to said cross-sectional plane, for each displacement of the tool in the direction perpendicular to the axis of rotation, a new processing of the datum of position of the tool for turning with respect to the new cross-sectional plane is executed, the displacement from one cross-sectional plane to the other being performed at each complete rotation of the spindle.  
   
   
       7 ) The method according to  claim 3 . wherein the non-circular parametric curves are trochoidal curves, and in particular are three-lobed curves.  
   
   
       8 ) A computer program, which can be directly loaded into the internal memory of a computer, comprising the appropriate software code designed to execute the steps of the method according to  claim 3 , when said program is run on a computer.  
   
   
       9 ) Elements ( 21 ,  22 ) for axial couplings for mechanical connection, having non-circular cross section, wherein the side walls of said elements ( 21 ,  22 ) are made by turning.  
   
   
       10 ) The elements ( 21 ,  22 ) for axial couplings for mechanical connection according to  claim 9 , wherein the peak-trough distance of their lobed profile is less than 1000 μm.  
   
   
       11 ) The elements ( 21 ,  22 ) for axial couplings for mechanical connection according to  claim 10 , wherein the peak-trough distance of their lobed profile is between 100 μm and 500 μm.  
   
   
       12 ) The elements ( 21 ,  22 ) for axial couplings for mechanical connection according to  claim 11 , wherein the peak-trough distance of their lobed profile is on average in the region of two μm.  
   
   
       13 ) The elements ( 21 ,  22 ) for axial couplings for mechanical connection according to  claim 9 , wherein a conicity (α) is between 0° and 15°.  
   
   
       14 ) The elements ( 21 ,  22 ) for axial couplings for mechanical connection according to  claim 9 , wherein a conicity (α) is between 5° and 10°.