Single-tooth gearing

A single-tooth gearing, suitable for use e.g. in a hydrodynamic torque converter, is disclosed. The gearing includes a reciprocating rod having a tooth gap and a gear wheel having a tooth for engaging the tooth gap. The flanks of the tooth gap are precisely perpendicular to the path of motion of the rod, while the corresponding flanks of the tooth are curved, preferably having the shape of circular cylinders. The front flank of the tooth has a radius of curvature larger than that of the rear flank of the tooth. At the point of the rod's motion at which the force between the front edge of the tooth and the corresponding flank of the tooth gap is a maximum, the point of contact between the front edge of the tooth and the corresponding tooth gap flank is located on a plane containing the axis of rotation of the gear wheel and perpendicular to the path of the rod's motion. The length of the tooth gap is preferably equal to the sum of the radii of curvature of the two flanks of the tooth. As a result of this design, the force between the rod and the tooth is essentially entirely parallel to the directon of the rod's motion, reducing wear on the gearing.