Coupling is also called the coupling. Its main role is to different institutions of the driving shaft and driven shaft firmly connected to rotate together, and deliver the movement and torque. Sometimes can be used for the connecting shaft and other parts. Sometimes as a safety device used to prevent the connection parts carry too much load, have the effect of overload protection. We would say under the rigid coupling. Rigid coupling for buffer and compensate the ability of two axes relative displacement, so the requirements of the two axis, at the same time this kind of coupling structure is simple, low manufacturing cost, convenient installation, maintenance, ensures the two axis have higher to neutral, and large transmission torque, wide application. Generally have flange coupling, coupling sleeve coupling and shell to choose from.