Abstract: A spindle unit for a machine tool includes a drive unit having a drive shaft and a spindle head assembly constructed for receiving a tool and having a hollow spindle head shaft driven by the drive unit. Arranged for axial displacement in the hollow spindle head shaft is a tie rod which is mechanically coupled with the drive shaft so as to transmit an axial movement of the drive shaft to the tie rod.

Abstract: A system and a method are described that facilitate gear switching of a motor-driven spindle. A spindle head shaft is driven by a drive shaft via a gear mechanism in a first gear position. The drive shaft, including a rotor, can be switched from the first gear position to a second gear position where the spindle head shaft is connected by interference fit directly with the drive shaft without the interposed gear mechanism. The spindle head shaft can then be directly driven by the drive shaft in the second gear position. This eliminates the need to dismantle an anterior spindle from the drive unit.

Abstract: A spindle unit for a machine tool includes a drive unit having a drive shaft and a spindle head assembly constructed for receiving a tool and having a hollow spindle head shaft driven by the drive unit. Arranged for axial displacement in the hollow spindle head shaft is a tie rod which is mechanically coupled with the drive shaft so as to transmit an axial movement of the drive shaft to the tie rod.

Abstract: A system and a method are described that facilitate gear switching of a motor-driven spindle. A spindle head shaft is driven by a drive shaft via a gear mechanism in a first gear position. The drive shaft, including a rotor, can be switched from the first gear position to a second gear position where the spindle head shaft is connected by interference fit directly with the drive shaft without the interposed gear mechanism. The spindle head shaft can then be directly driven by the drive shaft in the second gear position. This eliminates the need to dismantle an anterior spindle from the drive unit.

Abstract: A boring spindle unit with automatic tool liftoff, especially for the finish boring of a workpiece with an oxide-ceramic boring tool carried by the spindle shaft. The spindle shaft is journaled in at least two main bearings and at least a further bearing is disposed proximal to the main bearing at the tool end of the shaft. During the spindle retraction movement, the additional bearing takes up the journaling of the shaft and has an axis which is offset by a distance from the axis of the main bearings and in a direction opposite that from which the tool projects from the shaft so that the tool does not groove the workpiece during the retraction operation. While the main bearings are effected, the auxiliary bearing receives the shaft with radial play and, while the auxiliary bearing is effective, at least the main bearing proximal to the tool end receives the shaft with radial play.