Specificationsciclz type drum shape gear coupling m shaped tooth type coupling drum shaped tooth surface make within, and outside tooth of contact conditions are improve, avoid has in corner displacement conditions xia straight tooth tooth end edges side extrusion, stress concentrated of disadvantages, while improve has tooth surface friction, and wear situation, reduced has noise, maintenance cycle long. 4, outside the drum shape teeth-formula shaft coupling gear teeth is trumpet shaped, inner and outer gear assembly and disassembly is easy. 5, drum shape teeth-formula shaft coupling transmission efficiency as high as 99.7%. Scripture-based features, now widely at home and abroad to drum gear replace gear type coupling. For request