explained earlier the crown tip relief u03b4 r serves to reject the pawl during ratcheting according to the invention the contour 13 a between points a and b is in the form of a circular arc with outer radius r ar about a mid point m kr thus the tooth crown surface 13 a is a circular cylindrical surface with constant curvature with m kr as the mid point of the curvature and r k the radius of the curvature the width of the wheel tooth 13 is indicated by a sector u03c6 zr the tooth width u03c6 zr is decisive for calculating the crown tip relief u03b4 r fig9 represents schematically a pawl tooth 15 of a locking pawl not shown the pawl tooth 15 has a concavely shaped tooth crown surface 15 a also called the contour 15 a in what follows which extends in the rotational direction d of the parking lock gearwheel not shown here from a forward point a to a rear point b a tooth flank at the front relative to the rotational direction d is indexed 15 b and called the forward tooth flank and a tooth flank at the back relative to the rotational direction d is indexed 15 c and called the rear tooth flank referring to fig8 the point a of the wheel tooth 13 therefore.