Why use Rigid Couplings?

This article will take a closer look at rigid couplings in particular, noting the differences between them and flexible couplings, and explaining why using a rigid coupling is a better choice in certain situations.

What Are Rigid Couplings?

Rigid couplings are designed to connect two shafts together as you would expect, but their rigidness ensures that there is no relative motion occurring between the two shafts. You should use rigid couplings when your application requires precise alignment of the two shafts, especially when there will not be any significant radial or axial misalignment.

A rigid coupling consists of two flanges which are mounted on each shaft. Their installation and operation require exact alignment between the two shafts. Should the application produce significant misalignment, then a rigid coupling would suffer a high amount of stress which will likely lead to early coupling failure, with significant misalignment causing considerable wear on the bearings and seals. Thus, you should use flexible couplings in such instances where there will be a lot of misalignment, as they are specially designed to transmit torque while allowing for various levels of axial, radial and angular misalignment.

As a rigid couplings supplier, Yorkshire’s YB Components know that a good quality rigid coupling will not allow any axial or radial motion between both the driving and driven shafts. For this reason, rigid couplings are commonly used in vertical pump applications.

Using Rigid Couplings to Correct Misalignment

Although it sounds somewhat contradictory to the above section, rigid couplings can sometimes be used to correct shaft alignment in misaligned systems. To achieve this, the mounts of the driving and driven shafts should be relaxed to ensure free movement while the rigid couplings work to align the two shafts. This will also result in greater wear on the rigid couplings, but can bring a misaligned system into line in the process.

Once aligned, the shaft mounts should be fixed fast once again and the shafts should now be aligned.

Choosing a Rigid Coupling

There are not as many rigid coupling designs as there are flexible coupling designs as the purpose of a rigid coupling is pretty straightforward. There are also hybrid couplings which are notionally rigid but do contain a certain amount of flexibility. The manufacturer of your application should advise as to which type of coupling to use, although you can always check with your local rigid couplings supplier in Yorkshire.

Source: YBComponents