Romax Concept

Part of the Romax toolset, Romax Concept is an easy-to-use environment for designing drivetrain layouts. Create and simulate drivetrain models rapidly to predict life, efficiency, vibration, cost, size, weight and more to assess trade-offs and choose the right design early.

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Romax: Integrated powertrain simulation

Romax Concept is part of the Romax portfolio, an integrated toolset for ePowertrain engineering from concept exploration to virtual product sign-off.

Romax ConceptThe challenge

60% of project costs are committed after just 15% of the timescale has elapsed.

This means that early decisions are vital for success. With little data available in the early stages, how can you ensure your design concept meets requirements?

Traditional methods like spreadsheets, hand calculations, and CAD are slow to edit, error prone, and unsuitable for communicating complex kinematic systems.

Graphic showing different design aspects that Concept supports e.g. performance, weight, cost, sizing, efficiency, gear ratio
The solution

With the right tools, the concept design stage can be an opportunity to analyse ideas, gather insights and even validate requirements. Romax Concept empowers experts and non-experts to get the most out of the initial phases of a design project.

Draw powertrain layouts in minutes with drag-and-drop modelling. The Romax model is parametric – design changes are pain-free with a click or two. System analysis is fast. 
Gain insights in seconds. Assess a multitude of drivetrain attributes in one model and assess their relationship. The easiest and cheapest time to make a change to your design 
is as-early-as-possible.




Romax Concept is a CAE tool built to make designing rotating machinery both user-friendly and easy to learn. Anyone can learn how to use its drag-and-drop interface in no time at all.
Opening up the initial design to less experienced engineers allows more people to contribute to powertrain architecture selection, so that the best concept can be identified and taken forwards.

Bring ideas to life with a tool that’s as easy to use as pen and paper, and then analyse and optimize the model to learn if it’s feasible.

Find the optimum drive system for your application with holistic system simulation, powerful optimisation tools, and ready-made reports.

Understand the pros and cons of any full drive system in minutes.

Import existing drivetrain models via REXS, export to CAD to save time tweaking 3D geometry after each design change, export to ADAMS for multi-body dynamics simulation, and export to other Romax products for further analysis and detailed component design.

Rapid design 

Romax Concept is the true starting point for model creation, with an incredibly easy to use interface that anyone can learn in a few hours. Build parametric models of any full drive system rapidly (in minutes), with a drag-and-drop 2D modelling interface and a live reflection of the model in 3D visualisation.


Looking for inspiration?

A database of design templates is available in Romax Concept. Create a new model from any template to save time. Templates can be scaled up and down to match your application. Users can save custom templates for common layouts to save modelling time and to re-use designs in other drivetrain engineering projects.

Are your drivetrain designs in another software package?

Romax Concept supports the REXS file format for importing and exporting models. Bring your gear geometry or gearbox design into Romax Concept to analyse straight away without re-modeling. Then, convert to Adams for multi-body dynamics simulation with ease.

Are you spending a lot of time tweaking a drivetrain CAD model?

To facilitate using Romax Concept alongside CAD, transferring 2D and 3D geometry between CAD and Romax Concept could not be easier. Automatically generate CAD geometry from your Romax Concept model in seconds, eliminating the need to tweak CAD following a design change. With Romax CAD Fusion, models can be imported into Romax Concept from all major CAD packages. Import structures such as housings, mounting points, controls and more as reference geometry for packaging studies in Romax Concept.

Romax Concept offers a range of analyses suited to the early design stage, so you can get rapid insights on your design concepts and make well-informed engineering decisions. Analyses run in seconds and key results can be reported in simple, sharable formats.

As with the rest of the Romax portfolio, the simulation considers the full system holistically, including the cumulative effect of the complex interactions between all components, deflections, loads, stresses and misalignments.

Romax Concept offers:

  • Bearing stiffness calculation: rolling element bearing stiffness is non-linear and inherently difficult to calculate. Romax Spin’s advanced method of calculating bearing stiffness is world-class and has been validated with FEA and with physical testing. Romax Concept uses the same bearing model under-the-hood as part of its system simulation for accurate system loads and results.
  • Durability rating calculations: component rating methods such as ISO 6336 for spur and helical gear load capacity, ISO 281 for rolling element bearing life, and more, are all included as standard in Romax Concept. These rating methods are embedded in bearing selection, gear design and modelling tools to give designers the information they need to optimise their design.
  • Noise, vibration and harshness: early identification of potential issues including common factors of gear pairs, excitation orders, and planetary NVH assessment. Avoid late-stage excitation issues before detailed component design.
  • Efficiency assessment: component efficiency including gear and bearing loss prediction considering component design, operating conditions and lubricant, as well as vehicle efficiency simulation and fuel consumption over a driving cycle.
  • Cost calculations: cost estimations for each design, sub-assembly and component, based on either material cost per kg or user-defined cost. Compare with other analysis to learn the trade-off between cost, weight, durability, material and more.

Once you have got the answers you need from Romax Concept, and have completed the design iteration process, you can move it into the rest of the Romax portfolio for more in-depth assessment of durability, NVH and efficiency performance.

Creating models in Romax Concept is perfect for initial assessment of shaft centre distancing, gear sizing, packaging space, gear selection and simultaneous ratio optimization of individual gearsets. Users can iterate these activities to meet a number of different competing requirements.

Designing gears in Romax Concept is easy with its intelligent set of design tools. The staged gear design process in Romax Concept guides gear definition from simple speed ratios, to basic gear teeth/module, to fully defined gear set geometry.

For ratio selection, the saw profile diagram helps to achieve equally spaced gear ratios for a more continuous vehicle acceleration and better fuel economy at all speeds. The ratio optimisero ptimises the gearbox ratios and required gear size, according to targets specified, which can be either user-inputs or automatically generated.

For gear sizing, the K factor sizing method intelligently sizes parallel and planetary gears for a given application based on benchmarked data. Toothless gears can be used to set up load cases and estimate packaging concerns.

For gear rating, Romax Concept can automatically estimate your gear geometry based on size, ratio, and module to allow for preliminary rating. International rating standards are included in Romax Concept for assessing damage/life, power losses and more.

For gear geometry, the gear set designer is a powerful, automated multi-attribute gear macro geometry optimisation tool. Specify design criteria, generate gear designs, rank geometries by analysing and scoring their safety factors, transmission error and more.

Gear design

Select from a wide range of motor templates and perform an initial sizing in seconds with just a small number of parameters such as rated power, maximum torque, and speed, instantly evaluate the motor and see the calculated torque and efficiency. Import the motor geometry into Romax Concept with a single-click to analyse side-by-side with the gearbox.

Calculate the electromagnetic losses and generate a motor efficiency map for your chosen design. This can be imported into Romax Concept for a complete electro-mechanical efficiency map of the gearbox and motor together.

Go further and refine your motor design with ‘what-if’ studies to increase the performance of the machine:

  • is it worth reducing the air gap length to increase performance at the cost of manufacturing?
  • should we change the magnet material to improve torque capacity of the machine?
  • if the maximum torque was 50Nm larger, how would this affect machine size, gearbox size, overall packaging?

Through quick sizing studies like this, a motor designer can get an improved understanding of the performance, torque density, cost and efficiency of the motor. Electric motor design is easy and integrated into Romax Concept with JMAG-Express Online, and through integration with major electromagnetic packages for motor geometry import.

Capture and analyse the performance of the whole electromechanical system at the concept stage. Features include:

  • Motor selection and sizing
  • Full driveline performance simulation with motor torque-speed curve
  • Efficiency prediction of full driveline to a drive cycle, including energy consumption for range
  • Bearing selection and evaluation of different motor-bearing arrangements
  • Gear and motor excitation orders on the same plot for early NVH analysis
  • Materials’ cost and weight evaluation
  • Romax Concept can set a 2D freeform shape in the end view 

Drive systems are inherently complex, with many moving parts and many interconnected parameters.

To select the optimum drive system for your application, engineers have to get the balance right between size versus safety factor, efficiency versus complexity, cost versus durability, and many more trade-offs.

Romax Concept allows full driveline performance and efficiency predictions to be easily performed on electric powertrain designs using vehicle, transmission and electric machine data. This enables the efficiency and performance of different powertrain concepts to be assessed whilst considering the most important tradeoffs when selecting the optimum motor/transmission combination.

Romax Concept contains a set of analyses from the entire Romax suite, offering drivetrain simulation insights in a range of areas such as durability, NVH, efficiency, packaging, cost, weight and more.

The combination of a parametric model and fast system simulation gives designers the power to see the effect of design changes on transmission performance, even in the concept design phase.

Use Romax Concept to ensure your transmission design meets requirements and avoid costly late-stage design changes when information comes to light later on.

Efficiency drive cycle report from Romax, showing overall efficiency for a particular ratio condition

Integrated ePowertrain design 

Romax Concept is part of the Romax portfolio, which means you can use the same model in common file formats for multi-attribute, multi-fidelity, full system design, simulation and optimization. Our product range starts with Romax Concept, the perfect platform for early stage investigation and design space exploration, and extends through Romax Enduro, Romax Spectrum and Romax Energy for analysis and optimization of durability, NVH and efficiency within a single model. Romax Spin adds world-leading bearing design and analysis capabilities, while Romax Evolve provides the perfect tool for electric machine designers looking to test out the structural and NVH performance of their motor. 

Exploded view of ePowertrain

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