Medical or dentistry handpiece having at least one rotating part

There is a ball bearing (6) and a ball bearing unit, especially for high-speed devices such as dental turbines, Dental angle handpieces, turbomolecular pumps or the like, with balls (4) interposed between an inner Race (7) and an outer race (8) are arranged, proposed that or the rotating operation, especially during a start-up phase, significantly has better running characteristics, while providing a Overloading of the ball bearing and the bearing unit by the Bias or due to deviations in geometry and / or Inaccuracies in assembly is prevented. this will According to the invention achieved in that a device (4) dependent for generating one of a speed (n) Clamping force is provided.