What are the different Flexible coupling types?

In the previous article, we have discussed the Functional requirement of coupling, coupling classification and Rigid Coupling types. In this article, we are going to discuss the different Flexible coupling types.

Flexible coupling types

Flexible couplings are used to connect two shafts having axial, radial and angular misalignment. Following are the different types of flexible couplings.

• Gear coupling
• Old-ham coupling
• Disc Coupling
• Grid Couplings
• Diaphragm coupling
• Fluid Couplings
• Torsional couplings
• Bushed pin type coupling
• Universal coupling

Gear coupling

Gear Couplings are usually torsionally rigid couplings. These can transmit the highest amount of torque from one end to the other end.

These gear couplings can be designed in a completely flexible model where it can accommodate the parallel misalignment and flexible-rigid model where it can not accommodate the parallel misalignment.

In a complete Flexible gear coupling model, both sides of the gear coupling come with a sleeve(Internal gear tooth) and hub with external gear tooth. Which will provide a double flexible engagement for all three misalignments(Axial Parallel, Angular).

In the Flexible- rigid gear coupling model, only one side will be having a sleeve with inner gear tooth and the hub with external gear tooth and on the other side with a rigid flange hub. Which will provide only single flexible engagement for the two misalignments(Axial, angular). Parallel misalignment is not possible in this model.

Gear Coupling Application: Industrial Applications, Turbomachinery

Old-ham coupling

Old-ham coupling usually provides a huge amount of parallel misalignment. It consists of three members. There is a floating member trapped in between the other to members by means of 90° grooves on both sides o the floating member. Check out the picture of the Old -ham coupling.

Old-ham coupling Application: Robotics, servo in addition to the printer and copy machines

Disc Coupling

The disc coupling is having a thin sheet of discs laminated as the main part of the coupling for the flexibility to accommodate the misalignments.

Check out the above disc coupling picture. it consists of two hubs on each side and a spacer at the middle joined by the discs on both sides.

Disc Coupling Application: Hydrostatic application (Gearbox to hydraulic pumps), Turbomachinery

Grid Couplings

Grid couplings are very good at dampening the vibrations. These Grid couplings have some quite similar components as the gear couplings except the gear meshing. the hubs will have the slots and these slots will mesh with the steel spring. Check the picture of a grid coupling.

These grid couplings cannot accommodate the parallel misalignments. Minimal angular misalignments can be provided and a good amount of axial misalignment can be accommodated. Grid coupling can transmit the high torques because of its all metallic design.

Grid Coupling Application: Industrial application where a coupling needs to absorb the shock loads.

Diaphragm coupling

Diaphragm coupling also uses thin sheets as a flexible element as like the disc coupling. On the outer diameter side of the diaphragm will be bolted with the hub and the inner side diameter portion of the diaphragm disc will be fitted into the slots of the spool portion. On the other end of the spool(spacer) will be again joined by a diaphragm disc with a hub.

Diaphragm couplings can accommodate all the three misalignments. It can accommodate more range of misalignment axially.

Diaphragm Coupling Application: Turbomachinery

Fluid Couplings

The fluid coupling also is known as the hydraulic couplings. There will be two turbines (Impellers) covered by housing to fill the fluid. One impeller will be installed on the drive shaft and the other will be on the driven shaft. These two impellers will be connected with the fluid supported by the housing. as the input shaft rotates the input impeller also rotates. as a result, the fluid will transmit the torque slowly into the driven impeller as the speed increases. This Fluid coupling will be used as the mechanical clutch.

Fluid Coupling Application: Automobiles, marine and industrial machine drives as a mechanical clutch.

Torsional couplings

Torsional couplings are mostly to accommodate the torsional vibration. Most of these are rubber coupling where it can dampen the vibrations and also accommodate the misalignments. Also, spring torsional couplings are also available as the torsional couplings.

Torsional couplings Applications: Diesel engine generators, marine application.

Bushed pin type coupling

It is a simple type of coupling with two flanges bolted with the help bolt and nut covered by bush made up of rubber. Check the Bushed pin type coupling picture. These couplings are torsionally rigid and also accommodate all three misalignments. Because of its simple design, these are less expensive.

Bushed pin type coupling Application: Industrial applications.

Universal coupling

Mostly known as the Universal joint and it is well known to us. It is a linkage consisting of two yokes connected by a spider.

Check out the gif image of a universal joint. As you can see it can accommodate massive angular misalignments. It is mainly used for the lengthy shaft linings supported by bearings.

Universal Coupling Applications: automobiles, Aircraft application, Driveshaft, Stone crushers, Control mechanisms, Belt conveyors, Metal forming machinery, Tool drivers

These are the different flexible coupling types and their application.

Conclusion

We have discussed the Flexible coupling types with its applications with the help of neat pictures. If you have any further thoughts on this topic, let us know in the comment section below.