Cooled control unit of a motorized belt retractor

The present invention relates to a control unit (1) of a motorized belt retractor comprising a magnetic wheel (11), which is arranged and adapted to be driven by the motor (3) of the belt retractor, and a Hall sensor (13) arranged and configured to detect the rotational speed of the magnetic wheel (11), wherein the magnetic wheel (11) is a fan providing an air flow for cooling electronic components of the control unit (1).