Backlash-free ROBA-DS servo couplings with split clamping hubs

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High-performance ROBA-DS shaft couplings from Mayr Transmissions transmit torque backlash-free and with high torsional rigidity. They compensate for shaft misalignment, and are claimed to be both wear- and maintenance-free. In sizes up to 150 Newton metres, Mayr Power Transmission will extend its standard hubs for mounting the shafts by a radially divisible hub – for easy and fast installation, even in difficult conditions.

Along with short dimensions, small installation space requirements, reduced weight and low mass moments of inertia, the ROBA-DS servo couplings are expected to be popular due to their high performance density. They are able to transmit high torques even at a comparably small diameter, which makes them suitable for dynamic drive systems with high speeds. These couplings are made of steel and high-strength aluminium alloys, forming the basis for the compact design.

These couplings compensate for radial, axial and angular shaft misalignments by means of flexible disk packs. In this way, they protect the bearings from unwanted wear and tear and prevent unnecessary downtime and costs. In order to achieve backlash-free torque transmission, the disks in the fixing area are treated with a special blasting procedure. The ROBA-DS disk pack couplings are robust and reliable. They are described as temperature-resistant, wear- and maintenance-free and transmit the torque with very high torsional rigidity. Therefore, they are especially suited for applications in extreme conditions.

Application areas for servo couplings are growing. Therefore, Mayr Power Transmission has extended the standard hubs for shaft attachment by a radially divisible hub, a so-called split clamping hub, for sizes 3 to 15 also. At permitted speeds of 3000 rotations per minute, these sizes for shaft diameters of 45 to 79 millimeters cover torques from 35 to 150 Newton metres. The half-shells guarantee easy and fast coupling installation, even in difficult conditions. Therefore, the hubs are used preferably in applications, in which the drive aggregates such as the motor and the gearbox must not be moved after the positioning and aligning for coupling installation. These hubs are also recommended for large shaft distances, for example for cardan shafts in linear actuators, as in these cases the coupling is installed last and therefore has to be easy to install.

Installation is carried out radially. To do this, the coupling is brought to the shafts and pre-assembled with the axially moveable half-shells. Here, it is important that the markings on the half-shells and on the hub bodies overlap. Then, the cap screws must be tightened evenly and in sequence to the required tightening torque.

ROBA-DS servo couplings are available as double-jointed couplings with a connection plate or a variable-length sleeve. Their compact design, short installation times and high performance density make these couplings a particularly efficient and economic option. For further information please go to

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