REXS – Standardised Gearbox Model...

...for the Simple Exchange of Gearbox Data. The first version of the REXS interface (Reusable Engineering EXchange Standard) is freely available under Creative Commons License (CC-BY-SA). REXS defines an industry-wide uniform modelling and nomenclature for the gearbox and its components based on the detailed terminology of 25 of FVA's project committees.


At a time when connectedness is becoming more and more important at all levels of society and industry, the software landscape in the field of gearbox development, simulation, and production is extremely heterogeneous. Although these programs perform different tasks, the data they use is largely identical. However, up to the present date, no industry-wide standard has been established for the exchange of gearbox data. This leads to high-cost, high-maintenance custom solutions and duplication of work that can be avoided.

The Solution: REXS - Standardised Interface for the Exchange of Gearbox Data

"The goal is to be able to efficiently and effectively use different systems with their own computational focuses, such as Bearinx, SIMPACK, and FVA Workbench," explains Dr. Heinrich Bolz, Head of Calculation and Simulation in Gearbox Development for SEW-Eurodrive GmbH & Co KG.

The history of German mechanical engineering, which began the standardisation of machine elements as early as 1918, has proven that consistent standardisation contributes significantly to success. What began with the standardisation of tapered pins more than 100 years ago must continue with software in the age of digitisation and Industry 4.0.

FVA e.V., the German Research Institute for Drive Technology, is committed to the goal of developing an industry-wide standard for the exchange of gearbox data. The interface will be developed in close cooperation with industry and research under the name REXS (Reusable Engineering EXchange Standard). REXS defines an industry-wide uniform modelling and nomenclature for the gearbox and its components based on the detailed terminology of 25 of FVA's project committees. With many years of experience and broad roots in industry and research, FVA is in a unique position to develop an industry-wide standard.For FVA partners SEW Eurodrive and Schaeffler, the focus is primarily on the exchange of gearbox data related to bearing calculation. However, instead of developing another specialised solution, both companies became involved in the FVA "Standardisation of Gearbox Modelling" research project, thus laying the foundation for the interface.Their many years of experience with gearbox software will ensure that the developed concept is applicable for the industrial environment. "For this purpose, we made a deliberate decision to develop a common standard with FVA, as this approach holds tremendous potential for the future," continued Dr. Heinrich Bolz and Stephan Evert, Leader of CAE Application Development for R&D Processes, Methods, and Tools for Schaeffler Technologies AG & Co. KG.

Stronger Together: Industry and Research are the Key to the Successful Establishment of REXS

The first practical implementation of the REXS interface was the exchange of data between the FVA Workbench, Shaeffler's BEARINX, and SEW's WESILAB software.

The New Interface Increases Efficiency and Quality

The advantages of the REXS interface are clear: it reduces errors during the exchange of data and minimises the effort required for communication between different programs. Development of a new interface is very labour intensive. Therefore, the barriers to creating new links between existing software tools are high. A uniform interface can be used to efficiently implement such links, and to accelerate and improve the product development cycle. "With REXS, gearbox data can be transferred quickly and reliably. Thus, the interface helps us to optimise our innovation processes," stated Dr. Heinrich Bolz. "With REXS, we can greatly reduce the effort for the technical coupling of CAD software tools, and at the same time simplify the IT architecture," added Stephan Evert.

Universal Schema for the Definition of a Gearbox and its Structure

In REXS, the components of a gearbox are defined based on common parameters. The REXS specification includes everything necessary to define a gearbox model. Essentially, this includes the machine elements, their attributes, and the relations which are used to define the relationships between machine elements. The simple and generic structure of REXS makes it possible to depict individual components, assemblies, and complex gearbox structures.

Open Architecture Enables Custom Solutions

The interface has an open architecture, so companies can define their own extensions without affecting the standard. Thus, the interface is suitable for exchanging data between standard programs as well for internal use with custom software solutions.

The First Version of the Interface is Available Now

The first version of the REXS interface was released at the annual FVA Information Conference on 29 November, 2017, and is freely available under Creative Commons License (CC-BY-SA) at Anyone who is interested can learn more about the interface as well as how they can contribute to its future development. Schaeffler and FVA demonstrated the simple transfer of data between their BEARINX and FVA Workbench software packages using the REXS 1.0 interface live at their stand at the FVA Information Conference.

"REXS defines a very simple, extensible data structure that was created from its conception as a standard to be distributed via free licensing," states Stephan Evert.

Future Development of the Interface

Although the current version of the interface is focused on the definition of gearboxes for calculation programs, the possibilities for future development are broad. According to the motto "if you want to achieve great things, you have to set high goals," FVA's vision for REXS is to develop an interface that can be used for all CAE powertrain applications.

"REXS is a real step toward new business models based on digital services, and can be used as a standardised data container for digital twins," explains Stephan Evert. Hartmut Rauen, Managing Director of FVA, also sees the great significance of the interface for digitisation: "An important milestone for Industry 4.0 is the establishment and propagation of standards. The REXS format has the potential to achieve this goal." 

REXS in the FVA Workbench 5.0

The FVA Workbench is a platform in which new concepts for the further development of REXS are already being implemented and tested for practical suitability. From version 5.0, the FVA Workbench will always support the latest version of the REXS interface. This will make an important contribution to the efficient exchange of data and provide users with reference software for the implementation of the interface."In order to take advantage of digitisation, it is essential that data can be exchanged beyond system boundaries. Proprietary data formats do not help, as they increase complexity in the digital world. That is why we see the FVA Workbench not just as a calculation platform for the community, but also as a common data hub and enabler for digitisation in drive technology," explains Norbert Haefke, Managing Director of FVA GmbH.