Optimized steel bellows design combines high peripheral speeds, high torsional
stiffness, and low moment of inertia.

Wörth am Main, September 2026 – As rotational speeds increase, so do the demands
placed on powertrain components. There is a need for couplings that reliably transmit
high circumferential speeds while operating with precision and smoothness. R+W has
further developed its welded steel bellows coupling specifically for this purpose. The
new version achieves circumferential speeds of up to 200 m/s, which is approximately
15 percent higher than standard high-speed solutions on the market. It combines a
low moment of inertia with high torsional stiffness and a design built for long-term
durability.

Low Weight Meets High Stiffness

Weight plays a crucial role in high-speed couplings. Lightweight materials such as aluminum
reduce rotating mass but come with limitations in terms of stiffness and fatigue strength.
R+W therefore employs a different design approach. The metal bellows are welded directly to
the coupling and compensate for misalignments without additional fasteners. Its hollow
structure and FEM-optimized components keep the weight low. As a result, the steel
construction achieves a moment of inertia on par with standard lightweight solutions. Fewer
interfaces and screw connections simultaneously increase torsional stiffness and
smoothness of operation.

High Manufacturing Quality for Maximum Smoothness

High manufacturing precision forms the basis for operation at high circumferential speeds. All
fit and position tolerances are therefore specified to IT6. In addition, the balancing grade is
G2.5 or better, in accordance with ISO 21940-11. The very low residual unbalances minimize
vibrations and bearing loads, contributing to low-vibration operation. The external geometry
has also been optimized for airflow. Countersunk screw heads reduce air turbulence and
thus minimize aerodynamic losses and noise generation.

Flexibly adaptable and precisely balanceable

The direct flange connection facilitates integration into various drive systems. Standardized
bellows bodies can be combined with customer-specific connection geometries. For the most
demanding requirements regarding smooth operation, optional trim threads are available,
which enable fine balancing while the unit is installed and thereby achieve the highest
concentricity.

Designed for dynamic high-speed applications

The coupling is particularly suitable for use in test benches, high-speed spindles, and
applications in e-mobility and drone drives. Especially in compact drive systems with high
rotational speeds, the combination of low moment of inertia and high stiffness, precise manufacturing and high balancing quality,
as well as a fatigue-resistant design is crucial. R+W has consistently designed the new highspeed
coupling with this in mind.