Dressing device, gear grinding machine, and dressing method for grinding wheel

A dressing device comprising:

• a dressing portion that is relatively movable in a first direction orthogonal to a grinding wheel rotation axis and is capable of dressing a thread of grinding wheel, with respect to a grinding wheel including the thread of grinding wheel spirally continuous around the grinding wheel rotation axis;
• and
• a controller configured or programmed to control an operation of the dressing portion;
• wherein
• the dressing portion includes:
• a disk-shaped dressing tool that is rotationally drivable around a tool rotation axis extending along the grinding wheel rotation axis and includes, at a distal end, a pair of dressing surfaces capable of dressing with respect to two grinding surfaces that are surfaces defining the thread of grinding wheel and adjacent in a groove width direction;
• and
• a tool swivel assembly to turn the dressing tool around a tool turning axis orthogonal to the tool rotation axis and the first direction;
• and
• the controller is configured or programmed to rotate the grinding wheel around the grinding wheel rotation axis and rotate the dressing tool around the tool rotation axis to dress the two grinding surfaces adjacent in the groove width direction with the pair of dressing surfaces, and turn the dressing tool around the tool turning axis by the tool swivel assembly to change an angle of the pair of dressing surfaces with respect to the two grinding surfaces.