1. Coupling function
　　 is used to connect the two shafts together. The two shafts cannot be separated when the machine is running. The two shafts can be separated only after the machine is stopped and the connection is disconnected.
　　2, the type of coupling
　　 The two shafts connected by the coupling will change the relative position of the two shafts due to manufacturing and installation errors, deformation after loading, and the influence of temperature changes. Strict alignment is often not guaranteed. According to whether the coupling has elastic elements, whether it has the ability to compensate various relative displacements, that is, whether it can maintain the connection function and the purpose of the coupling under the condition of relative displacement, the coupling can be divided into rigid couplings, Flexible coupling and safety coupling. The main types and characteristics of the coupling and its role in the category of the role in the transmission system Remarks
　　 Rigid coupling can only transmit motion and torque, without other functions, including flange coupling, sleeve coupling, clamp coupling, etc.
Flexible couplings Flexible couplings without elastic elements can not only transmit motion and torque, but also have different degrees of axial, radial and angular compensation performance, including gear couplings, universal couplings , Chain coupling, slider coupling, etc.
The flexible coupling with elastic elements can transmit motion and torque; it has different degrees of axial, radial, and angular compensation performance; it also has different degrees of vibration reduction and buffering, improving the working performance of the transmission system including Various flexible couplings with non-metal elastic elements and flexible couplings with metal elastic elements. The structure of various elastic couplings is different, the difference is large, and the role in the transmission system is also different.