The invention relates to a method for producing a drive unit device, in particular a fan device, which has at least one first modular unit (12) and at least one second modular unit (16), which concentrically accommodates at least a portion of the first modular unit (12), with the first and second modular units (12, 16) being intended to contribute mechanically to a change in torque, and the first modular unit (12) being secured in the second modular unit (16) in at least one method step (100, 110). To increase safety and reduce process costs, it is proposed that the first modular unit (12) be secured in the second modular unit (16) by means of at least one concentric pressing process step.