“Milestone” achieved through collaboration between FST, Freudenberg corporate research department
Weinheim, Germany – Freudenberg Sealing Technologies (FST) has produced its first pressure seal developed through an “entirely simulation-based” process.
The project is a collaboration between FST and the central corporate research department Freudenberg Technology Innovation, the sealing specialist said in a 15 July statement.
The new approach has delivered design improvements to the Simmerring radial shaft seal compared to previous, conventionally developed versions.
As a result, the seals “easily surpass” the requirements of modern hydraulic systems in terms of service life and reliability, FST said.
This, it added, leads to longer maintenance intervals and lower maintenance costs.
The seals were developed with a new tool called FIRS³T, which stands for “Freudenberg integrated radial shaft seal simulation tool”.
The tool was programmed by the experts at Freudenberg Technology Innovation as “a fully coupled EHL (elastohydrodynamic lubrication) simulation model.”
Designing the tool, FST explained, was “a highly challenging task," due to factors such as the complex fluid dynamics when the shaft rotates relative to the sealing ring.
As part of the partnership, FST supplied the practical development parameters for the new pressure seal.
“The simulation model is a milestone in our development process and holds strong potential for future applications,” said Dr Daniel Froelich, technical director of the lead centre Simmerring Industry at FST.
It enables FST “to push physical boundaries and develop seals with even better performance parameters than ever before – and much faster.”
Specialists from both teams worked on the simulation model “for several years”, with the process now ready for series development and “proven” for its effectiveness.
The new pressure seal is designed for a wide range of hydraulic pump and motor applications operating at varying pressure levels.
“It has a redesigned sealing lip with an optimal contact width under all pressure conditions,” said Froelich.
This, he explained, ensures “excellent wear behaviour” at pressures of up to 5 bar while also providing robust sealing at lower pressures.
The ability to withstand dynamic pressure cycles makes the seal ideal for demanding fluid system applications, Froelich added.
While radial shaft seals are commonly used across industries, many aspects of their contact with the shaft remain unclear due to practical barriers.
FIRS³T, however, is claimed to offer “a new level of insight through simulation.”
The tool delivers “precise, traceable predictions of the sealing performance under varying loads and conditions, which makes it possible to develop the optimum design and functionality,” according to FST.
The tool, FST noted, contains "considerable and complex" knowledge, such as data about the surfaces in contact between the sealing ring and shaft as well as contact pressure distribution, the distortion of the seal in dynamic operation, and lubricant simulation with viscosity and flow factors on the surfaces.
All influencing variables can be adjusted flexibly in the calculation model, offering a simulated view inside the system.
The simulation technology also speeds up development, with the process reaching “design freeze” in days.
Furthermore, only one physical prototype is needed for validation, cutting time and cost compared to months of iterative prototyping.
“For the radial shaft seal, the results from FIRS³T closely matched the values actually measured with the prototype seal,” Froelich explained.
Freudenberg plans to use FIRS³T as a standard tool to develop large seals, such as those for wind turbines.
The company is continuing to refine the model with practical experience.