Tailored to high-speed testing technology

Drive axles in high-speed applications require reliable couplings – both for overload protection and for compensating shaft misalignment. Based on the proven Roba-DS steel disc coupling, Mayr Power Transmission has developed a weight-optimized aluminum version with the same power density. This is tailored for high-speed applications, for example, in test bench technology. Mayr will present its new developments at the Automotive Testing Expo 2025 in Stuttgart.

Compared to the steel version, the outer diameter of this new coupling is reduced by up to 10 mm, and the mass and inertia are 40% to 60% of the steel version, depending on the design and size. The power density, however, remains unchanged.

Shaft compensation couplings are a crucial accessory in test benches. They minimize the disturbances acting on the measuring flange. These disturbances, or so-called parasitic forces, often arise from misalignment in the drive train. Misalignments between the input and output sides therefore occur in almost all applications. Shaft compensation couplings are therefore used in conjunction with the measuring flange. It is important that the geometric basis is correct and that the couplings are already designed for measuring flanges and high speeds in their standard version. The key is to find the balance between stiffness and elasticity to avoid restoring forces on the system.

A crucial criterion for Mayr couplings is that the couplings are compact and power-dense. Even steel versions must be characterized by low mass and inertia while achieving high speeds of up to 30,000 rpm. In addition, precise manufacturing with few interfaces as well as high running smoothness and balancing quality are required. In general, it is therefore important that customers always consider the application when selecting the coupling and material. Here, it is important to balance material properties, such as weight, stiffness, or fatigue strength, with the final customer application, i.e., the actual speeds, load changes, load cycles, bearing spacing, and bore diameters. Ultimately, of course, the price-performance ratio also counts.

Reliable overload protection at high speeds

If the torque in a test bench exceeds the limit set on the safety coupling, the coupling disengages and separates the input and output within fractions of a second. In the worst case scenario, after an overload, the measuring shaft must be recalibrated, but the safety coupling reliably prevents expensive damage to the drive train or test object.

Mayr's EAS HSE safety couplings transmit torques backlash-free and with high torsional stiffness. They are also compact and feature a low moment of inertia with high power density. The compact, power-dense design of the couplings is achieved through a small outer diameter and a relatively large bore diameter. The integrated elements through which torque is transmitted in the couplings are also specially selected and symmetrically arranged. Ultimately, the following applies to the design: bore diameter, outer diameter and element size must harmonize to achieve a low-vibration system that functions precisely in the event of a trigger.