Gear machining apparatus and gear machining method

A gear machining apparatus configured to perform cutting work for a workpiece and generate a gear by performing a feed operation of a gear cutter relative to the workpiece along a direction of an axis of the workpiece while synchronously rotating the gear cutter and the workpiece in a state in which an axis of the gear cutter is inclined with respect to a line parallel to the axis of the workpiece,

• the gear having a plurality of teeth each having a face provided with a gear slip preventing portion including:
• a first tooth flank;
• and
• a second tooth flank formed continuous with the first tooth flank and having a helix angle different from a helix angle of the first tooth flank,
• the gear machining apparatus comprising a machining control unit configured to control rotation of the workpiece and rotation of the gear cutter, and control the feed operation of the gear cutter relative to the workpiece, wherein
• a position where the gear cutter cuts the face is defined as a cutting point, the cutting point when the cutting work is started is defined as a start point, and the cutting point when the gear cutter is fed by a predetermined feed amount from the start point is defined as a movement point,
• the cutting point when the gear cutter is fed by the predetermined feed amount from the start point while the workpiece and the gear cutter rotate in a predetermined reference synchronous rotation state is defined as a reference movement point,
• a phase shift angle to one side in a circumferential direction of the workpiece, which is set to shift a phase of the movement point from a phase of the reference movement point when the gear cutter is fed by the predetermined feed amount from the start point, is defined as a correction angle, and
• the machining control unit is configured to continuously perform the cutting work for the first tooth flank and the cutting work for the second tooth flank during the feed operation performed on a single occasion, and change the correction angle between the cutting work for the first tooth flank and the cutting work for the second tooth flank.