Abstract: A tool arrangement, including a tool spindle having a fixed first part and a second part rotatably mounted relative to the first part. The second part carries a tool. A drive motor having a stator and a rotor rotates the second part relative to the first part. The first part is formed by the stator and the second part is formed by the rotor. The stator includes a first bearing that supports the rotor at a first axial position and a second bearing that supports the rotor at a second axial position. The first bearing has an inner ring arranged on the outer circumference of the stator, and an outer ring arranged on an inner cylindrical surface of the rotor. The second bearing has an outer ring arranged on an inner cylindrical surface of the stator and an inner ring arranged on an outer cylindrical surface of a cover that is connected to the rotor.

Abstract: A method for clamping a tool on a tool spindle in a hard finishing machine that includes: the tool spindle connected to a drive motor, with a cylindrical receiving seat and a thread, and the tool. The receiving seat is limited at one axial position of the tool spindle by a abutment flange for axial abutment of the tool. A clamping nut can be screwed onto the thread and is designed for axial abutment on the tool. The clamping nut is temporarily held in a rotationally fixed manner when the tool spindle is rotated by the drive motor. The method includes: placing the tool on the receiving seat and screwing the clamping nut onto the thread; blocking the clamping nut against rotation during the rotation of the tool spindle with the drive motor; and actuating the drive motor to tighten the clamping nut so it presses axially against the tool.

Abstract: A grinding machine including an electric drive with a drive wheel, wherein the electric drive is arranged on a base unit of the grinding machine, a grinding spindle unit constructed as a grinding arm arranged removable on the base unit and which includes a grinding tool and a gear element which transmits the rotational movement of the drive wheel to the grinding tool. To facilitate the change of the grinding arm, the gear element includes: a driver which is supported on the grinding spindle unit and which is directly or indirectly in rotary union with the grinding tool, two guide wheels which are supported on the grinding spindle unit and a belt which is guided around the driver and the guide wheels, wherein in the mounted state of the grinding spindle unit at the base unit the drive wheel contacts the belt between the two guide wheels and hereby drives the same.

Abstract: A grinding machine including an electric drive with a drive wheel, wherein the drive is arranged at a base unit of the grinding machine, a grinding spindle unit arranged removable at the base unit and which includes a grinding tool and a gear element which transmits the rotational movement of the drive wheel to the grinding tool. To facilitate the change of the grinding arm the gear element includes: a driver which is supported in the grinding spindle unit and which is directly or indirectly in rotary union with the grinding tool, two guide wheels which are supported in the grinding spindle unit and a belt which is guided around the driver and the guide wheels, wherein in the mounted state of the grinding spindle unit at the base unit the drive wheel contacts the belt between the two guide wheels and hereby drives the same.