The invention discloses a main shaft device for a numerical controlled gear
hobbing machine. The main shaft device comprises a cutter bar
assembly, a cutter bar
assembly clamping mechanism and a cutter changing mechanism, wherein the cutter bar
assembly comprises a cutter bar, a
hobbing cutter, a cutter regulating pad, an axle sleeve, a locking nut and a cutter bar blind
rivet; the cutter bar assembly clamping mechanism consists of a square key and a claw assembly; and the cutter changing mechanism consists of a pull rod, a
piston rod, a disc-shaped spring, a hydro-cylinder body, a
flange plate, a bracket, a rotary joint and a spacing switch. The main shaft device has the advantages that: a hydrostatic bearing is arranged in the main shaft structure of the high-accuracy numerical controlled gear
hobbing machine, so the main shaft device can constantly work under a heavy-load
cutting condition; a main shaft has high accuracy and good accuracy retaining ability; and the cutter bar assembly with the hobbing cutter is arranged and set outside a
machine in a cutter workshop; the cutter bar assembly is subjected to whole cutter changing on the gear hobbing machine; and the setting assisting time of the hobbing cutter does not occupy the total part
machining time of a
machine tool, so the whole
machine tool has high working efficiency.