Apparatus for cooling machine components using phase-change material

The invention relates, on the one hand, to a machine element (6), for example a motor spindle or an electromechanical drive unit, with integrated, internal cooling system (8) and, on the other hand, to a closed cooling circuit (24) with corresponding machine element (6). According to the invention, the cooling takes place with a special coolant (4). The coolant (4) is a dispersion containing at least one Phase Change Material (PCM).