According to different working conditions, the coupling must have the following performance:
(1) Mobility. The mobility of the coupling refers to the ability to compensate for the relative displacement of the two rotating components. Factors such as manufacturing and installation errors between the connected components, temperature changes during operation and load deformation, etc., all put forward requirements for portability. The movable performance compensates or relieves the additional load between shafts, bearings, couplings and other parts caused by the relative displacement between the rotating components.
(2) Cushioning. For occasions where the load is frequently started or the working load changes, the coupling needs to have elastic elements that play a role in buffering and damping to protect the prime mover and the working machine from damage.
(3) Safe and reliable, with sufficient strength and service life.
(4) Simple structure, convenient assembly, disassembly and maintenance.

Selection of coupling type When selecting a coupling type, the following items should be considered.
①The size and nature of the torque to be transmitted, the requirements for buffering and damping functions, and whether resonance may occur.
②The relative displacement of the axis of the two shafts is caused by manufacturing and assembly errors, shaft load and thermal expansion deformation, and relative movement between components.
③Allowable dimensions and installation methods are the operating space necessary for ease of assembly, adjustment and maintenance. For large couplings, it should be possible to disassemble and assemble without axial movement of the shaft.
In addition, the working environment, service life, lubrication, sealing, and economy should also be considered, and then refer to the characteristics of various couplings to select a suitable coupling type.