1、 Types and characteristics of common couplings

Rigid coupling: the rigid coupling does not have the ability to compensate the relative offset of the axes of the two connected shafts, nor does it have the performance of cushioning and shock absorption; however, the structure is simple and the price is cheap. Only when the load is stable and the rotation speed is stable, and the relative deviation of the axes of the two connected shafts is very small, can the rigid coupling be selected.

Flexible coupling without elastic element: it has large bearing capacity, but it also has no cushioning and shock absorption performance. It has impact noise when it is at high speed or unstable speed, or when it is often in forward or reverse rotation. It is suitable for low speed, heavy load and stable speed.

Safety coupling: the structural feature is that there is a safety link (such as pin movable connection), which can only bear limited load. When the actual load exceeds the pre-determined load, the safety link will change, cutting off the transmission of motion and power, so as to protect the rest of the machine from damage, that is, to play a role of safety protection.

2、 Function of coupling

The coupling is a component that connects the two shafts axially and transmits torque and motion, and has the ability to compensate the offset of the two shafts. In order to reduce the vibration of the mechanical transmission system and reduce the impact peak load, the coupling should also have a certain damping performance. Sometimes the coupling also has the function of overload safety protection.

3、 Selection of coupling

When selecting the coupling, the following requirements should be considered:

For neutral: for neutral, it is better to select rigid coupling, and flexible coupling when compensation is needed;

Assembly and disassembly: considering the convenience of assembly and disassembly, choose the coupling that can move radially directly;

Environment: if working under high temperature, coupling with non-metallic components is not optional;

Cost: under the same conditions, try to choose the coupling with low price and simple maintenance