Method and apparatus for circular grinding

1. A method for a circular grinding of a workpiece which has a workpiece axis and, while the method is being carried out, rotates about the workpiece axis, whilst at the same time a grinding wheel rotating about a grinding-wheel axis and the workpiece are advanced towards one another, in order to grind a first workpiece face which is designed to be rotationally symmetrical with respect to the workpiece axis the workpiece further having a second workpiece face which is designed to be rotationally symmetrical with respect to the workpiece axis and which is defined by a rectilinear generatrix, and the two workpiece faces being arranged adjacently to one another in such a way that a circular transition edge is formed between them, wherein, during grinding, an auxiliary abrasive tool, which rotates about an auxiliary-tool axis and has a plane abrasive surface arranged at right angles to the auxiliary-tool axis, is pressed against the workpiece in such a way that the abrasive surface is arranged in a tangential plane to the second workpiece face and touches the second workpiece face along a contact line the abrasive surface projecting in the direction of the contact line away from the second workpiece face beyond the transition edge.

2. The method according to claim 1 , wherein the pressing of the auxiliary abrasive tool against the workpiece and the grinding of the first workpiece face are terminated at the same time.

3. An apparatus for a circular grinding of a workpiece, comprising:

a workpiece spindle which rotates about a workpiece-spindle axis and provided with a workpiece holder designed for receiving the workpiece;

a grinding wheel rotating about a grinding-wheel axis;

a first advancing device in order to advance the grinding wheel and the workpiece towards one another;

an auxiliary abrasive tool which rotates about an auxiliary-tool axis and which has a plane abrasive surface arranged at right angles to the auxiliary-tool axis;

a second advancing device for advancing the auxiliary abrasive tool towards the workpiece; and

a control device for controlling the apparatus in such a way that, by means of the first advancing device, the grinding wheel and the workpiece are advanced towards one another, in order to grind a first workpiece face in one grinding operation, and in that, during the grinding operation, the auxiliary abrasive tool is advanced towards the workpiece by means of the second advancing device in such a way that the auxiliary abrasive tool presses with its abrasive surface against a second workpiece face, the two workpiece faces being designed to be rotationally symmetrical with respect to the workpiece-spindle axis, and the second workpiece face being defined by a rectilinear generatrix, and the two workpiece faces being arranged adjacently to one another in such a way that a circular transition edge is formed between them, and the abrasive surface being arranged in a tangential plane to the second workpiece face and touching the second workpiece face along a contact line, and the abrasive surface projecting in the direction of the contact line away from the second workpiece face beyond the transition edge.

4. The apparatus according to claim 3 , wherein a portion of the auxiliary abrasive tool is of cylindrical design, the abrasive surface being the cylinder base area.

5. The apparatus according to claim 3 wherein the auxiliary abrasive tool is designed in such a way and, while being pressed against the second workpiece face, is arranged in such a way that the contact line on the abrasive surface extends as an uninterrupted line from an outer margin of the abrasive surface, along a diameter leading through the auxiliary-tool axis, beyond the auxiliary-tool axis as far as the transition edge.

6. The apparatus according to claim 5 , wherein, while the auxiliary abrasive tool is being pressed against the second workpiece face, the workpiece is made to rotate about the workpiece-spindle axis in such a way and the auxiliary abrasive tool is made to rotate about the auxiliary-tool axis in such a way that the auxiliary abrasive tool has, in the region of the intersection point of the contact line with the transition edge, a speed component opposite to the direction of the speed of the workpiece in this region.

7. The apparatus according to claim 3 , wherein the auxiliary abrasive tool includes a honing pin or a precision-grinding stone.

8. The apparatus according to claim 3 , further comprising:

a conditioning tool for the conditioning of the abrasive surface.

9. The apparatus according to claim 3 , further comprising:

means for selectively setting of force with which the auxiliary abrasive tool presses against the second workpiece face.

10. The apparatus according to claim 3 , wherein the auxiliary abrasive tool, while being pressed with the abrasive surface against the second workpiece face, machines the second workpiece face with a substantially lower grinding power than the grinding power with which the grinding wheel at the same time machines the first workpiece face.

11. The apparatus according to claim 3 , wherein the auxiliary abrasive tool is arranged on a platform which is movable with respect to the workpiece spindle and which is equipped with at least one measuring instrument.

12. The apparatus according to claim 3 , wherein the auxiliary abrasive tool, while being pressed against the second workpiece face, is arranged on a side of the workpiece which faces away from the grinding wheel.