<p>Gear wheel (10) has around a common central axis or central shaft two wheel parts (11,12) with spur gears. Both the wheel parts rotate against each other fractionally by spring force working in axial direction along an axial bracing distance (V). Guiding movement (18) is provided at inner area of one of the two wheel parts along the axial bracing distance. The guiding movement has a spiral angle (alpha ) across from a parallel direction to the common central axis or central waves (13).</p>
