Patent ID: 6951501

Claim:
A method for dressing a grinding worm for forming a conical face gear having a plurality of face gear teeth, the method comprising: providing a dressing tool having a flat dressing surface; providing a theoretical conical involute pinion having a plurality of pinion teeth, one of the plurality of pinion teeth being a reference tooth with a pair of tooth flanks; and employing the conical face gear and the theoretical conical involute pinion to position the flat dressing surface of the dressing tool in tangent contact with a first one of the tooth flanks; rotating the theoretical conical involute pinion about a rotational axis of the conical face gear while the conical face gear is fixed and the teeth of the conical face gear and the teeth of the theoretical conical involute pinion maintain tangent contact, the conical face gear and the theoretical conical involute pinion obeying true relative conjugate action such that the theoretical conical involute pinion also rotates about a pinion rotational axis; and simultaneously with the rotation of the theoretical conical involute pinion, rotating the dressing tool and translating the dressing tool by a predetermined amount Δs in a direction normal to the flat surface of the dressing tool so that the flat surface of the dressing tool remains in tangent contact with the first one of the tooth flanks; wherein the step of employing the conical face gear and the theoretical conical involute pinion to position the flat dressing surface of the dressing tool includes: locating a plurality of straight generators on the first one of the tooth flanks; generating a vector d from a rotational axis Zp of the theoretical conical involute pinion to a rotational axis Zg of the conical face gear, the vector d being perpendicular to the rotational axis Zp and the rotational axis Zg; generating a plane A that is perpendicular to the vector d and passes through the rotational axis Zp; generating a line CC that is perpendicular to the rotational axis Zp and lies on the plane A; generating a vector {right arrow over (t)} that is attached to the reference tooth on the theoretical conical involute pinion; superimposing the theoretical involute pinion and the vector {right arrow over (t)} to the conical face gear such that the vector {right arrow over (t)} intersects the line CC at a point F 0 ; generating a vector {right arrow over (F)} that commences from the point F 0 and is parallel to the vector {right arrow over (t)}; and aligning the flat surface of the dressing tool to a first one of the plurality of straight generators such that a vector {right arrow over (n)} in the normal direction of the flat surface is aligned with the normal of the reference tooth at the first one of the straight generators.