A flexible, or elastic coupling, includes both rigid and fully elastic parts. These couplings are designed less to correct misalignment than to regulate torque variations (damping of shocks and vibrations in the transmission, when the torque is pulsating, for example).

  • Among the flexible couplings are found elastomeric bonding couplings, jaw couplings , tire couplings, tapes couplings , etc.
  • Finally, the last step in classifying flexible couplings is the technology used. There are many, they are used in particular in the following applications: conveyors, mixers, pumps, etc.
  • Choosing a flexible torque depends on a number of factors such as available mounting space, expected life and drivetrain performance. The operating temperature is an important parameter for the choice of a coupling (a temperature range is then provided).
  • Given the dimensional errors inherent in any mechanical assembly, the axes corresponding to the shafts to be joined present “misalignments” which complicate the transmission of movement. These misalignments can be axial, radial or angular.

Misalignments also cause fatigue or wear to the union. Consequently, for the choice of the union, you will have to take into account the speed of rotation, reducing the maximum admissible misalignments appearing in the tables provided for each model.

For measuring systems, the transmission is irrelevant on the couplings. For power drives, you must check that the torque to be transmitted is much lower than the nominal torque shown in the performance tables, taking a margin proportional to the foreseeable misalignment. The speed of rotation of such a flexible coupling is limited. Thus, flexible coupling models are not suitable for high speed axles, especially if there are large misalignments. For the rest of the unions, you will have to take into account that the useful life of the latter will depend on fatigue and, therefore, on the speed of operation.

Look for the Right Limits

Regarding shocks and vibrations, this coupling can generate vibrations if it takes play with wear. The unions can be supplied with fixing by set screw (2 to 90º) or by integral clamping collar. Fixing by clamp has the advantage of not producing any mark on the axes, thus better resisting sudden reversals and vibrations. Fixing by pressure screw is more economical and allows the use of pins with larger diameters for the same coupling. The downside of set screws is that they can cause axle cracks.

Choice of a torsionally rigid coupling.

The mechanical coupling malaysia torsionally rigid consists of rigid parts. They compensate for misalignment and transmit high torque. Torque transmission is accomplished here in rigid mode, using welded components. The damping of torsional vibrations at torsional stiffness is the decisive factor in the choice of this coupling. Increase on one side and decrease on the other. Generally described as the torque per unit of bending, the torsional stiffness is very important in positioning systems, it describes the resistance of the coupling to the bending force in torsion. 


Conversely, to torsional stiffness, there is torsional bending, which is defined by the bending per unit of torque. When used in closed loop or underspeed control systems, the torsional stiffness of the coupling becomes much more critical and is a variable in the calculation of dynamic performance and the upper limit of stability. Therefore, the upper limit will be the main selection criterion. Regarding the stiffness of the coupling, the torsional resonant frequency should exceed 300 to 600 Hz, depending on the dynamics.