Dressing tool for the grinding wheel of a gear grinding machine

Claim 1

A truing tool for the grinding wheel of a gear grinding machine for profile grinding helical spur gears, said truing tool when truing the grinding wheel being guided past the grinding wheel in the same manner as a workpiece gear when being ground, said truing tool comprising: a disc-shaped member (10') presenting opposed planar side surfaces, at least one tooth space (12') being provided on the circumference of said member with truing flanks (14', 16') having surfaces (40) in the form of a section of the workpiece gear, said member having defined therein the root and crown cylinders associated with the workpiece gear, said flanks lying at an angle to the planar surfaces of said member in accordance with the angle of skew of the helical spur gear, each of said flanks utilizing that portion of the surface (40) lying between the intersections (52, 50) with a pair of planes, one of said planes (54) being tangent to the root cylinder (42) at a point where said surface (40) intersects said root cylinder, the other of said planes (56) being tangent to the root cylinder (42) at a point angularly displaced from said first point of tangency through a rolling angle ρ so that said plane and said surface intersect the crown cylinder (44) at a common point, said flank surface portion being connected along its outer edge (50) to a uniaxially curved transition surface, the flanks of said tooth space opening into a bore located beneath the root cylinder, the diameter of which is larger than the closest distance between said flanks; a strip of abrasive applied to said flank surfaces, said strip having the ends thereof affixed to said disc on either side of said tooth space and a central portion extending into said bore; and tightening means mounted in said bore and engaging said central portion of said strip, said means being radially movable to establish said strip taut on said flank surfaces.