Tool holder with built-in cavities

A tool holder for chucking a tool shaft by frictional engagement, comprising:

• a main body for coupling the tool holder to a spindle of a machine tool;
• a clamping surface joined to the main body, or a tube part joined to the main body, for fixation of a tool shaft by frictional engagement;
• and
• at least one portion of the clamping surface or tube part is shaped in one piece by primary shaping, in which an outer connecting channel extends into an interior of the portion and there, on a side of the clamping surface or tube part facing away from a mouth of the tool holder, widens, forming a plurality of interconnected ring-like cavities that are each circumferential around a tool shaft with a first ring-like cavity connected directly to the outer connecting channel and connected to at least one second ring-like cavity positioned in a direction toward an opening of the mouth of the tool holder, wherein the first ring-like cavity and each of the at least one second ring-like cavities are connected to one another via an inner connecting channel having a smaller inside cross-section than an inside cross-section of the first ring-like cavity and each of the at least one second ring-like cavities, and wherein the plurality of interconnected cavities are substantially closed on all sides with the exception of the inner connecting channels, and are spatially distributed and located entirely in the interior of the portion shaped in one piece by primary shaping, and wherein the inner connecting channels are not circumferential around the tool shaft,
• wherein the plurality of interconnected ring-like cavities are tight on their own even at extremely high internal pressures since the plurality of interconnected ring-like cavities are embodied entirely inside the one-piece portion, and
• wherein the plurality of interconnected ring-like cavities are filled with a fluid, and a pressure producer, actuated from outside, is built into the outer connecting channel, and the fluid can be subjected to pressure by the producer.