What are bellows couplings?

A bellows coupling is a type of coupling design which consists of a thin walled, flexible corrugation (bellows) that is connected between two clamping hubs.  They are traditionally used for servo motion control applications that have high positioning accuracy, speed, and torque requirements.

Cross Section View of Bellows Coupling

What makes bellows couplings unique?
Bellows couplings are unique because of the construction of the bellows which can flex and compensate for minor shaft misalignments (axial, lateral, radial), while still providing a zero backlash and torsionally rigid connection.  They are a unique blend of rigidity and flexibility.

How to specify bellows couplings
To specify a bellows coupling, the first parameters we typically look at are the torque and connecting shaft sizes which will help to give a general sense of the coupling size.  The nominal torque rating (continuous torque transmission)  of the coupling should be greater than the peak torque of the application to ensure a secure connection.  We then check the connecting shaft sizes which  must also be within the acceptable range of the coupling.  If the shaft diameter is smaller than the specified range on the coupling, the torque transmission value of the coupling can decrease.  From there, we check other application specific parameters which include the speed, shaft alignment, temperature, and drive resonance.  We need to make sure they are within the coupling specifications, if not, we look to apply a safety factor when applicable; otherwise we select a different coupling size, or design. 


Bellows couplings applications examples
When introduced, bellows couplings were first widely accepted in the Machine Tool industry for spindle drives.  Since then usage has expanded to a vast number of industries including Automotive, General Automation & Assembly, Material Handling, Medical, Packaging, Robotics, to name a few.


For more information about couplings, visit www.gamweb.com

Introducing the EDC Elastomer Drive Shaft Coupling

The EDC is designed, machined, and assembled to order in Mt. Prospect, IL.  CAD models are online and easily configurable for download in minutes.  The EDC is available in four sizes based on the torque rating: 25Nm, 35Nm, 80Nm, and 110Nm. Derived from the design of GAM's EKC elastomer coupling, the EDC is a quality drive shaft solution at an economical price for this torque segment.

Split Hub Design

The EDC has a split hub construction for easy installation.  This design feature allows the coupling to be installed by placing it directly over the shafts that need to be connected.  The shafts can remain fixed and do not need to be retracted during installation to get proper shaft engagement.

GAM's Drive Shaft Lineup

The EDC is the latest addition to GAM's family of drive shaft coupling solutions. GAM now has three options to cover various motion applications and torque requirements.

Option 1 - EDC
The EDC is rated up to 110Nm of torque and was designed to be an economical drive shaft option, suitable for general motion / lower torque applications.

Option 2 - EKZ
The EKZ is rated up to 700Nm of torque and is the next progression in GAM's drive shaft coupling range.  While still an elastomer style drive shaft coupling, the EKZ is suitable for higher torque applications.

Option 3 - WDS
The WDS is rated up to 1600Nm of torque and is GAM's highest performing drive shaft coupling, intended for dynamic applications that require high positioning accuracies.  It features a torsionally rigid bellows design which yields a 1208% increase in torsional rigidity over an elastomer style drive shaft coupling of a comparable torque rating.

Video Shoot at GAM