The rigid coupling has a simple structure and a low price, which is suitable for two shafts with good concentricity.

   The structure of the elastic coupling is relatively complicated and the price is relatively high. It is suitable for the situation where the concentricity of the two shafts is not very good, and is suitable for the situation with torsional vibration (vibration reduction).

　　Coupling is a mechanical part used to connect two shafts (driving shaft and driven shaft) in different mechanisms so that they can rotate together to transmit torque.The two shafts cannot be separated when the machine is running. The two shafts can only be separated after the machine is parked and the connection is disconnected.In high-speed and heavy-load power transmission, some couplings also have the function of buffering, damping and improving the dynamic performance of the shafting.The coupling is composed of two halves, which are respectively connected with the driving shaft and the driven shaft.The general power machine is mostly connected with the working machine by means of a coupling.