Apparatus and method for precision grinding of face gears

A precision grinding apparatus, comprising:

• a case-hardened face gear adapted for meshing with a spur-pinion surface of a spur pinion, a curvilinear line being defined as a line along the spur-pinion surface that is generally parallel to a rotational axis of the spur pinion;
• a grinding worm disposed in a substantially normal orientation to the case-hardened face gear, the grinding worm having a grinding worm-surface adapted for contacting and grinding the case-hardened face gear;
• and
• a dressing tool having a flat surface, which is adapted to contact and move along the grinding-worm surface and which, at the same time, is adapted to pass along but not intersect the curvilinear line, the dressing tool being adanced to move in a feed direction that is always substantially perpendicular to a plane formed by the flat surface.

A precision grinding apparatus, comprising:

• a case-hardened face gear adapted for meshing with spur-pinion teeth disposed on a spur-pinion surface, a curvilinear line being defined as a line along the spur-pinion surface that is generally transverse to the spur pinion teeth;
• a grinding worm having a grinding worm rotational axis and adapted for being disposed in a substantially normal orientation to the case-hardened face gear, the grinding worm having a grinding-worm surface adapted for contacting and grinding the case-hardened face gear;
• and
• a dressing tool having a truncated cone shape and a planar grinding-worm contacting surface, the dressing tool being adapted for defining the curvilinear line on the surface of the grinding worm as the grinding worm rotates about the grinding worm rotational axis, the dressing tool being adapted to move in a feed direction that is always substantially perpendicular to a plane formed by the planar grinding-worm contacting surface.