Grinding machine for bearing rings and method for moving a bearing ring in such a machine

Abstract

A grinding machine for bearing rings, the machine includes a frame, a rotating grinding wheel movable in rotation around a first rotation axis, and a working station where a bearing ring stands during a grinding operation of one of its surfaces. The grinding machine also includes a holding subsystem for holding a bearing ring in the working station and transfer subsystem for transferring bearing rings to and from the working station. The transfer subsystem includes at least a multi-axis robot and a ring moving arm provided with a gripping subsystem for temporarily gripping a bearing ring, the ring moving arm being rotatable around a second rotation axis, parallel to the first rotation axis, and movable in translation along the second rotation axis.

1 . A grinding machine for bearing rings, the machine comprising:
 a frame;   a rotating grinding wheel movable in rotation around a first rotation axis;   a working station where a bearing ring stands during a grinding operation of one of its surfaces;   a holding subsystem for holding one bearing ring in the working station; and   a transfer element for transferring the bearing rings to the working station and from the working station, wherein the transfer element includes:
 a multi-axis robot, and 
 a ring moving arm provided with a gripping feature for temporarily gripping a bearing ring, the ring moving arm being rotatable around a second rotation axis, parallel to the first rotation axis, and movable in translation along the second rotation axis. 
   
     
     
         2 . The grinding machine according to  claim 1 , further comprising a driving subsystem for automatically driving the moving arm in rotation around and in translation along the second rotation axis. 
     
     
         3 . The grinding machine according to  claim 2 , the driving subsystem further comprising:
 a first pneumatic jack dedicated to driving the moving arm in rotation; and   a second pneumatic jack dedicated to driving the moving arm in translation along the second rotation axis.   
     
     
         4 . The grinding machine according to  claim 3 , wherein the first pneumatic cylinder is rotatable around a third rotation axis parallel to the first rotation axis. 
     
     
         5 . The grinding machine according to  claim 1 , further comprising a releaser for separating from the gripping feature, a ring born by the moving arm, via a translation movement of the moving arm parallel to the second rotation axis. 
     
     
         6 . The grinding machine according to  claim 1 , further comprising:
 a loading station and an unloading station;   wherein the multi-axis robot is configured to carry one bearing ring from the loading station to the working station, and   the moving arm is configured and driven to carry one bearing ring from the working station to the unloading station.   
     
     
         7 . The grinding machine according to  claim 6 , the unloading station further comprising an outlet chute whose width is adjustable, depending on an axial thickness of the bearing rings. 
     
     
         8 . The grinding machine according to  claim 1 , the gripping feature further comprising a nose part adapted to be one of:
 engaged into a central bore of the bearing ring, or   taken out of the central bore of the bearing ring, depending on an axial position of the moving arm along the second rotation axis.   
     
     
         9 . The grinding machine according to  claim 1 , further comprising a sensor system for sensing the angular position of the moving arm around the second rotation axis. 
     
     
         10 . The grinding machine according to  claim 9 , further comprising several proximity sensors adapted to detect a part fast in rotation, around the second rotation axis, with the moving arm. 
     
     
         11 . The grinding machine according to  claim 2 , further comprising a sensor system for sensing the angular position of the moving arm around the second rotation axis,
 wherein actuation of the driving subsystem to drive the moving arm in translation along the second rotation axis depends on an output signal of the sensor system.   
     
     
         12 . The grinding machine according to  claim 1 , wherein the moving arm is movable in rotation around the second rotation axis between:
 a first position where the gripping feature are aligned, along a fourth axis parallel to the first rotation axis, with an unloading station of bearing rings; and   a second position where the gripping feature are aligned, along a fifth axis parallel to the first rotation axis, with the working station,   
     
     
         13 . The grinding machine according to  claim 3 , wherein the second pneumatic jack is operable to drive the moving arm in translation along the second rotation axis only when the sensor system detects that the moving arm is one of:
 in the first angular position, or   in the second angular position.   
     
     
         14 . The grinding machine according to  claim 11 , wherein the second pneumatic jack is operable to drive the moving arm in translation along the second rotation axis only when the sensor system detects that the moving arm is one of:
 in the first angular position, or   in the second angular position.   
     
     
         15 . The grinding machine according to  claim 12 , wherein the second pneumatic jack is operable to drive the moving arm in translation along the second rotation axis only when the sensor system detects that the moving arm is one of:
 in the first angular position, or   in the second angular position.   
     
     
         16 . The grinding machine according to  claim 1 , wherein the holding subsystem includes a magnetic clutch, and
 wherein the multi-axis robot is configured to introduce the bearing ring in the working station via a translation along an axis parallel to the first rotation axis.   
     
     
         17 . A method for moving a bearing ring between a loading station and an unloading station in a grinding machine provided with a grinding wheel rotatable around a first rotation axis, the method comprising steps of:
 a) picking the bearing ring with a multi-axis robot;   b) moving the bearing ring with the multi-axis robot into a working station of the grinding machine;   c) actuating holding subsystem for holding the bearing ring in the working station during grinding of a surface of the bearing ring;   d) gripping the bearing ring in the working station via gripping feature provided on a moving arm using a translation movement of the arm along a second rotation axis parallel to the first rotation axis;   e) deactivating the holding subsystem;   f) rotating the moving arm around the second rotation axis in a direction that brings the bearing ring close to the unloading station;   g) translating the moving arm along the second axis of rotation in a direction that frees the bearing ring from the gripping feature.