When choosing coupling type, the following items should be considered:

1. Considering the working environment, service life, smoothness, sealing and economy, and referring to the characteristics of various types of couplings, a combined type of couplings should be selected.

2. The size and nature of the required transfer torque, the requirements for cushioning and vibration reduction functions, and the possibility of resonance, etc.

3. Relative displacement of axes of two axes is caused by fabrication and device errors, axle load and thermal expansion deformation, and relative motion between components.

4. The allowable dimensions and installation methods, in order to facilitate the installation, adjustment and maintenance of the necessary operating space. For large coupling, it should be able to disassemble and assemble without axially moving the shaft.