R+W’s Bellows Coupling with Fully Split Clamping Hubs – Model BKH

March 1, 2022

The BKH series is a high precision coupling with fully split clamping hubs that allow for easy lateral installation and removal without the need to move or re-align connected components. It features a stainless-steel bellows with very high torsional stiffness and low moment of inertia, making it ideal for high precision and highly dynamic machines.

The bellows coupling can be used in a variety of applications where positional accuracy is of utmost importance, performance data is being measured, or fast reversals are a common occurrence. The high stiffness allows for high frequency tuning of motors and ensuring that even the smallest changes in torque or rotation can be transmitted and measured. Aluminum hubs are used for smaller sizes to reduce inertia, while steel hubs are used for sizes above 150Nm in order to increase torque capacity. The hubs are bonded to the bellows on a common mandrel in order to ensure the highest level of concentricity from one bore to the other. This removes the potential of vibration or additional misalignment loading being added into the system.  Welded connections are also available upon request if the coupling will be exposed to high temperatures or corrosive materials.

The BKH fully split hubs have two locking screws per side, which helps to prevent shaft slippage even for undersized shafts and generally increases torque capacity per coupling size. The hubs provide ample clamping pressure on the drive shafts without the need to use keys, however, keyways are available upon request when required. Multiple length options also allow users to find the best option depending on their shaft spacing. A special long length bellows has become available as well that compensates for up to 1mm of lateral offset between the drive shafts. This bellows has a greater wall thickness that provides very high torsional stiffness while being more flexible due to its longer length. This can be a great option when shaft misalignment cannot be mitigated.

Sizing in this series ranges from 15Nm to 4000Nm and can accommodate both metric and imperial bore sizes and keyways, which can be mixed and matched. The inner diameter range of 8mm to 90mm (3/8 inch to 3 5/8 inch) allows this unit to be used in a variety of situations where easy installation is desired. Many custom features can also be requested for the bellows coupling including custom hub materials such as steel or stainless steel, special surface treatments, special mounting hardware, and precision balancing. Custom bore designs can be integrated into the hubs upon request, including splines, dual keyways, and D profiles. 

Many BKH models are available for expedited delivery from our Illinois shop and warehouse. For more information, please reach out to one of R+W’s application specialists for more information or visit their product page here