Increasing demands for high quality motion transfer in compact and efficient machinery require that every component be evaluated, including connecting elements.  When optimizing for highly dynamic motion, balance, and positioning accuracy, many mechanical designers are moving away from traditional shafted connections – opting instead for a more direct method of attachment for flexible joints.


R+W has seen a significant increase in demand for its high-performance bellows couplings to be configured for a direct match to component flanges for just these reasons.  While many standard and special flange hub designs already exist in the R+W design portfolio, new custom flange designs are being continuously developed and offered for direct attachment to a variety of torque transducer, motor, and gearbox flanges.


An example of a fully standardized version would be the model BK8, which is designed to fit directly to the most commonly used ISO flange outputs of high precision servo gearboxes.  While by no means representing the limits of the available configurations for flange mounted bellows couplings, the BK8 is a catalog item which can be immediately incorporated into machine designs and delivered quickly.


BK8 flange mount bellows couplings at a glance

·         Reduced assembly length and moment of inertia

·         Higher overall system stiffness

·         Improved concentricity and balance

·         5 standard sizes available

·         Torque capacity from 15 to 2,600 Nm

·         Inch and metric bore diameters from 12mm to 3.125”

·         Readily available


Bellows couplings stand out among flexible coupling designs for their ability to drive with zero backlash and a high level of torsional stiffness, while also being great for high speed and acceleration due to their light weight and continuous symmetry.   This makes them an ideal candidate for configuration into direct mounting for critical applications as a further performance enhancement.  Not only does direct flange mounting reduce assembly length, and in turn reduce inertia and increase overall stiffness, but it also improves concentricity and balance by eliminating additional centering pilots and clamping mechanisms.


Given a few days to configure the design, R+W can adapt its full range of bellows couplings to just about any flange pattern, and for application torques of up to 100,000 Nm and speeds of up to 100,000 rpm, depending on the size.

To get the most efficient high performance coupling system for your application through direct flange mounting, check out the BK8 product page or contact one of or our coupling experts for a custom solution!