The invention relates to a rotary power head of a cosine tooth profile drilling
machine. A cosine tooth profile transmission and speed change device is composed of an input gear shaft, a large gear and an output shaft, a cover plate is fixed on a
machine seat, a
flange is fixed on the cover plate, the input gear shaft is supported on the cover plate and the
machine seat respectively together with a bearing A and a bearing B, a motor is fixed on the
flange and connected with the input gear shaft, the output shaft is supported on the machine seat and the cover plate respectively together with a bearing C and a bearing D, a joint type forced filling oil cup penetrates a small end cover at the
tail part of the input gear shaft and is connected with the input gear shaft, an air inlet hole is arranged on an
air chamber, the
air chamber is fixed on the machine seat, a seal A and a seal B are matched with the
air chamber and the output shaft, a radial hole on the output shaft is communicated with the air chamber, and an internal thread hole is arranged on the output shaft. The invention has the advantages of overcoming the shortcomings of a traditional speed
reducer and the rotary power head, providing a
universal series for the speed
reducer and providing a rock drilling mechanical rotary power head which is convenient to detach and
mount, small in radial size, large in transfer torque and applicable to
heavy load for the drilling machine.