Motor shaft coupler is the common part of motor system. Generally, customer will choose encoder coupling according to motor shaft size. But in fact, encoder couplings are of different types for different applications. Flexible coupling and rigid coupling are the two main type. Flexible coupling means there is one part flexible in coupling. The flexible part connects the two hubs and ensures some variant in some range when coupling working. When using this type of motor shaft flexible coupling, it can reduce the accuracy requirement for alignment, facilitate testing, and have good damping function when the speed is not stable.

Flexible coupling is used between encoder and motor. Sometimes, it is called encoder coupling or motor coupling. Encoder coupling is a mechanical part used to couple two shafts (driving shaft and driven shaft) in different mechanisms to rotate together in order to transmit torque are used to transmit torque from one shaft to another when the two shafts are slightly misaligned. Motor coupling can adapt to different degrees of misalignment up to 3°. The high speed encoder coupling and low speed large torque motor coupling are widely applied to universal mechanical devices, like paper making machinery, ventilating device.