Active water cooling of gear mechanisms by means of a geometrically specially formed insert in diamond drilling devices

A drive shaft of a machine tool that is connectable to a drilling tool, comprising:

• a cavity, wherein the cavity extends substantially over an entire length of the drive shaft and along an axis of rotation and wherein the cavity contains an inflow opening through which water is feedable along the drive shaft into the drilling tool;
• and
• an insert device disposed in the cavity through which the water is guidable first in a first direction and then in a second direction, wherein the insert device contains a first curved guide element and a second curved guide element for separating water which is guided in the first direction from water which is guided in the second direction, wherein a cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to a cross-sectional area of the second curved guide element, and wherein the first curved guide element and the second curved guide element extend along an entire length of the insert device;
• wherein the machine tool is a core drilling machine.