GⅡCLZ drum gear coupling is composed of internal gear ring with the same number of teeth and flange half coupling with external teeth.The external teeth are divided into straight teeth and drum teeth. The so-called drum teeth means that the external teeth are made into a spherical surface. The center of the spherical surface is on the gear axis. The tooth side clearance is larger than that of ordinary gears. Allows a larger angular displacement (compared to the straight tooth coupling), which can improve the contact conditions of the teeth, increase the torque transmission capacity, and prolong the service life.