Rotary spindle head with gear reducer

A rotary spindle head with gear reducer, comprising:

• a rotary spindle unit, composed of a spindle having a cutting tool mounted thereon and a rotary seat;
• a fork-shaped spindle base, disposed to the machine tool and is rotatably connecting to the rotary spindle unit;
• and
• a driving unit, having a torque motor and a gear reducer coaxially coupled to the torque motor;
• wherein the structure of the coaxially disposed torque motor and the gear reducer is coupled to the fork-shaped spindle base while enabling the gear reducer to further couple to the rotary spindle unit for bringing along the rotary spindle unit to rotate inside the fork-shaped spindle base;
• and
• wherein the gear reducer is primarily composed of:
• a driving gear, at least one idle gear, a ring gear and an axle seat, in a manner that the driving gear is configured to be driven by the torque motor;
• the at least one idle gear is mesh respectively with the driving gear and the ring gear while being pivotally coupled to an axial part;
• the ring gear is disposed coaxially with the driving gear and is coupled to the rotary spindle unit by the use of an axis that is formed at a side of the ring gear for bringing along the rotary spindle unit to rotate accordingly.