Ensuring thorough lubrication in a gearbox is a complex problem that is hard to cover on a test bed. Glass boxes enable the visibility of oil distribution but influence the oil’s behavior. For higher rotational velocities, even when using high speed cameras, the information that can be extracted from the gearbox test bed is minimal.
The simulation of a gearbox is also a demanding challenge for most numerical CFD methods, due to the complexity of the geometries and the kinematics.
Using PreonLab for gearbox simulations will boost the pace of your gearbox development. The time you spend setting up the simulation is reduced to a minimum. PreonLab can import your STL files in seconds, and no meshing is required. Kinematics even for complex setups, e.g. planetary gearboxes, can be defined in a few minutes. Because PreonLab’s simulations are so quick, you will be able to simulate many different design variants. Because PreonLab’s post-processing and visualization tools are so complete and easy to use, you’ll be able to rapidly iterate towards a final gearbox design.
The Schaeffler Group is developing electric axle systems for hybrid- and fully electric cars. Gearbox lubrication and cooling poses a major challenge for the developers of e-axle systems. When Schaeffler Technologies needed to understand and optimize oil distribution in their electric axle gearbox, they chose PreonLab, our Computational Fluid Dynamics (CFD) simulation tool. PreonLab supports Schaeffler in analyzing and optimizing the oil distribution in its gearboxes.
Single phase simulations are an efficient method to deliver accurate results for many cases involving more than one fluid, such as gearboxes with low rotational speeds, where the behavior of one fluid is not significantly affected by the presence of the second.
It is also generally possible to model the second, less-significant fluid phase as a boundary condition (for example drag force for air) if required. However, this situation changes when the second fluid phase becomes more influential and introduces additional effects which are not captured in basic single-phase simulations.
For cases like gearbox simulations with high rotational speeds, multiphase simulations are the most accurate method to achieve realistic results.
Normally, it can be computationally challenging to perform multiphase simulations, especially, when the density ratio between the two fluids is high.
With this in mind, PreonLab 5.1 has made it possible to perform such multiphase simulations in an efficient way. This has proven to be highly advantageous in order to achieve more realistic simulation results for large gearboxes and for cases where high rotational speeds are involved.
PreonLab 5.2 takes the benefits of multiphase simulations even further with a new time-stepping feature. Results obtained using this newly introduced feature are more comparable with the experimental data, such as torque loss values, than those obtained by utilizing single phase simulations.
Another new feature in PreonLab 5.2 allows the usage of real bulk modulus values, which enhances the quality and accuracy of the simulation and improves the workflow by eliminating the need to fine-tune setup parameters.
Video runs at 0.25x playback speed. Real time simulation = 2 seconds.
Our particle-based rigid body solver can handle concave and very detailed geometries, is multithreaded and optimized for integration with the PREON fluid solver.
In this case, only the blue gear is keyframed while the others are simulated. This further simplifies the model setup for gearbox simulations.
Merkle & Partner GbR sees a decisive advantage for their CFD simulations in PreonLab. In the German journal Konstruktion & Entwicklung, Merkle & Partner qualifies our software, PreonLab, as an evolutionary leap compared to regular CFD methods and states that the gridless calculation method accelerates the geometry preparation and meshing significantly:
“Einer der entscheidenden Vorteile liegt in der Erweiterung unseres M&P Öl-Sim Simulationsbaukastens durch die Simulationssoftware PreonLab. Hierdurch konnte ein Evolutionssprung gegenüber herkömmlicher CFD-Verfahren erzielt werden. Damit nutzen wir ein gitterloses Berechnungsverfahren, wodurch die Geometrievorbereitung und Vernetzung erheblich beschleunigt werden kann.”
Merkle & Partner favors PreonLab for transmission oiling as for them:
“PreonLab offers an enormous time advantage over conventional CFD methods (..) only a small amount of manpower and time has to be invested in geometry preparation and cross-linking. (…) Photorealistic representations as well as effective postprocessing possibilities are further advantages of PreonLab.”
The aim of a good engine housing design is to ensure a sufficient oil supply to the oil pump, even during extreme driving maneuvers. If this is not the case, the engine parts are lubricated unevenly which might lead to insufficient lubrication in certain areas and to increased friction in others. The former could lead to structural changes in the long run and ultimate failure of the engine, the latter reduces the efficiency of the engine. PreonLab predicts the oil distribution for arbitrary test scenarios before a first engine prototype is even built. In the following case, you can see the effect on the oil distribution caused by an acceleration and a subsequent braking maneuver in travel direction.