Detailed Program of the 22nd ISC 2024
Pneumatic Seals: A Review of Experimental Measurement and Theoretical Modeling of Sealing Friction
Summary
Pneumatic components perform mechanical work by pressured air. Seals in pneumatic components enable the functionally relevant pressure build-up and are thus crucial parts of their respective component. Dynamic seals in pneumatic cylinders and valves are subject to a motion relative to their counterface, which in turn causes a friction force acting between the seal and the counterface. This friction force reduces the dynamics of the component, leads to additional losses and can negatively affect the control behavior.
In the past decades, several attempts have been made to understand the friction behavior of pneumatic seals both by experiments and simulation models. This includes measurements of the friction force for different pneumatic pressures, velocities, grease types or grease film heights. However, even for basic questions like the velocity dependence of the friction force there is no clear consensus amongst different authors up to this day. While some authors found an increase of the friction force with increasing velocity, others authors have described a decrease of friction force instead. Furthermore, some sources even found no relevant influence of the velocity on the friction force at all. This unclear state of research makes modeling, constructing and dimensioning pneumatic sealing systems a difficult task during the development process.
This paper aims to give a comprehensive overview of the state of research regarding pneumatic sealing friction. For that, this paper presents a literature review of friction force measurements with special regard to the influence of the parameters of the sealing system. In addition, different modeling concepts are compared regarding their capability to calculate and understand the behavior of pneumatic seals. Finally, the paper highlights the challenges in modeling pneumatic sealing friction and proposes a new simulation framework based on the findings from the presented literature.