Gear machining apparatus and gear machining condition setting device

A gear machining condition setting device for outputting a machining condition in cutting a gear workpiece using a hob, the gear machining condition setting device comprising:

• a parameter receiving unit configured to receive
• a feeding amount determining parameter containing a specification of the hob and a specification of the gear workpiece, and
• a target temperature of a cutting edge of the hob during machining;
• a first storage unit configured to store a cutting-in amount calculation formula representing a relation between a computed cutting-in amount per a cutting blade of the hob and a characteristic value determined by the feeding amount determining parameter and a relative feeding amount of the hob with respect to the gear workpiece;
• a second storage unit configured to store a cutting-in amount upper limit per the cutting blade of the hob preliminarily set by the specification and a material of the gear workpiece;
• a feeding amount computing unit configured to compute a feeding amount of the hob using the cutting-in amount calculation formula based on a selected cutting-in amount, the selected cutting-in amount being selected as one of the computed cutting-in amount obtained from the cutting-in amount calculation formula and the cutting-in amount upper limit;
• a third storage unit configured to store data of a constant temperature curve representing a relation between the cutting-in amount and a cutting speed where the temperature of the cutting edge of the hob is set to be a predetermined temperature;
• and
• a cutting speed computing unit configured to compute the cutting speed corresponding to the selected cutting-in amount by referring to a curve of the target temperature of the cutting edge of the hob in the constant temperature curve.