Method and apparatus for supporting and rotating a workpiece

For the centreless precision machining, in particular grinding or lapping, of rotary bodies (1), the workpiece (1) bears on radial and axial supports (2, 3). Serving to rotate the workpiece (1) is a rotating friction element (5) which is pressed against the workpiece and presses it against its supports (2, 3). The greater this applied pressure, the greater the frictional resistance at the supports (2, 3). In order to avoid this, ultrasonic vibrations are fed to at least one of the supports in order to reduce the friction between this support and the workpiece moving relative to it. The supports (2, 3) are not connected to one another so that different directions of the ultrasonic vibrations can be selected. In this way, the vibrations can be optimally distributed so that the friction is only reduced at the desired locations. For this, the ultrasonic vibration is fed to the respective support (2, 3) in a direction which is at an angle ( alpha ) not exceeding 10 DEG to the generating line of the common contact surface or surfaces of this support (2, 3) with the workpiece (1).