Gear coupling are just flexible coupling, gear coupling is the same number of teeth with tooth ring gear and the flange-band semi-coupling components, such as spare parts. Outside the tooth is divided into straight-tooth and two tooth crown gear, the so-called crown gear teeth is to be made outside the sphere, spherical center axis in the gear, the gear side of space than the average gear, and drum gear coupling can be allow greater angular displacement (as opposed to straight-tooth coupling), can improve the tooth contact conditions, the ability to improve the transmission of torque to extend the service life. There are angular displacement along the tooth width at the contact state. With the radial, axial and angular deviation to the axis of compensation, such as capacity, with compact structure, small radius of gyration, the carrying capacity of large, high transmission efficiency, low noise and maintenance of long-term advantages, especially for low-speed heavy load operating conditions, such as metallurgy, mining, lifting and transportation industry, also apply to oil, chemicals, general machinery, such as various types of mechanical transmission shaft ...