Coupling is mainly used to connect two shafts together. When the machine is running, the two shafts cannot be separated. Only when the machine stops and the joints are disassembled, the two shafts can be separated. With or without elastic elements, whether there is any ability to compensate for various relative displacements, that is, whether the coupling function can be maintained under relative displacement conditions and the use of the coupling, the couplings can be divided into rigid couplings, flexible couplings and safety couplings.
Among them, the rigid coupling can only transmit motion and torque, and does not have other functions, including flange coupling, sleeve coupling, and cage coupling. Flexible couplings can be divided into inelastic and elastic ones. Inelastic couplings can transmit motion and torque and the same time, they have different degrees of axial, radial, angular compensation, some of the products are gear couplings, cardan shafts, chain couplings, slider couplings, etc.
The flexible coupling with elastic elements can transmit motion and torque; it has different degrees of axial, radial and angular compensation; it also has different degrees of vibration damping and buffering to improve the performance of the transmission system. The structures of various elastic couplings are different and their roles in the transmission system also vary.
Other couplings are named after their unique features, such as pin , friction, magnetic powder, centrifugal, hydraulic and other safety couplings.