Couplings save energy and steel

Edited by the Engineeringtalk editorial team Feb 27, 2008

If Roba-DS disk pack couplings were to be used consistently in all relevant applications, approximately 600 tonnes less steel would be used in Germany every year.

While shaft couplings are purely mechanical parts that use no energy they do influence the energy balance of the machine.

Compact, high-performance density couplings such as the backlash-free Roba-DS all-steel coupling have a very low mass moment of inertia.

They can make a contribution towards reducing the drive power required.

The Roba-DS allows higher torques to be transmitted within a smaller construction space.

Smaller construction space means less material consumption when manufacturing the coupling.

A 40 to 70% reduction in materials consumed can be achieved, depending on the coupling size and design.

If Roba-DS disk pack couplings were to be used consistently in all relevant applications, approximately 600 tonnes less steel would be used in Germany every year.

The energy consumption for producing that steel would be sufficient to supply 1028 houses.

According to the term definitions in the EuP directive, shaft couplings do not count as "energy using products".

However a mechanical component can play an important role in saving energy and reducing CO2 emissions when considering the entire production chain.

The Roba-DS backlash-free shaft couplings made by Mayr power transmission are torsionally rigid but bendable and can compensate for axial, angular and radial shaft misalignments.

At present, Roba-DS couplings are offered for nominal torques of up to 24,000Nm.

Disk pack couplings robust and reliable in extreme conditions.

Many disk pack couplings which are available on the market transmit the nominal torque defined in the catalogue only partially (50 to 80%) via frictional locking.

The remainder is transmitted via positive locking using fitting bolts.

Due to loads above the backlash-free frictional locking torque, tiny displacements occur in the area of the disk pack connection.

Dependent on the amount of load and the direction of the load, the individual components change position.

This leads to an unstable balance condition on the coupling.

The constant relative movement in the area of the disk pack screw connection means that the screw pre-tension force drops.

The bending components to be absorbed by the screw begin to increase, leading to broken screws.

In order to avoid these disadvantages, such couplings have to be limited by the manufacturers with reference to alternating torques or to the application of service factors.

All in all, a coupling often has to be selected which is one or even two sizes larger.

In order to unite high-performance density with absolute backlash-free function Mayr Power Transmission Roba-DS disks are treated in a special blasting procedure.

Specially-formed collar bushings are used for further backlash-free torque transmission from the disk pack onto the hubs or onto the intermediate part.

These collar bushings guarantee completely backlash-free connection to the hubs via the available screw pre-tension forces.

In this way, a backlash-free flow of force with excellent force flow density can be produced between the input and output of a shaft coupling.

Comparatively small screws can be applied and limitation of the misalignment compensation capability due to short free bending lengths can be avoided.

The nominal torques defined in the catalogue can be used without any limitations and a reduction due to misalignment, overall load configuration or balance demands remains unnecessary.