Browsing by Author "Bauer, Frank"
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Item Open Access Abschätzverfahren für die Kontakttemperatur bei Radial-Wellendichtungen(2016) Feldmeth, Simon; Bauer, Frank; Haas, WernerItem Open Access Assessment of the Lubricity of Grease‐Sealing Rotary Shaft Seals Based on Grease Properties(2022) Hahn, Susanne; Feldmeth, Simon; Bauer, FrankGrease‐lubricated sealing systems have an increased risk of starved lubrication. For this work, the lubricity of 23 greases in a rotary shaft sealing system was evaluated with a new test and evaluation method. The lubricity was then correlated with rheological and other grease properties. These grease properties are either available by the data sheet or can be measured with low effort. The results of the correlation allow a preselection of greases which are expected to lubricate rotary shaft seals well. This can support manufacturers and users in considering the lubrication of the sealing system early in the development process.Item Open Access Bewertung von Radial-Wellendichtungen anhand des Förderwerts(2014) Remppis, Marco; Bauer, Frank; Haas, WernerItem Open Access Bidirectional PTFE lip seals - superior to elastomeric seals?(2014) Gölz, Jan; Bauer, Frank; Haas, WernerItem Open Access Blasen auf Radial-Wellendichtringen : eine immer häufigere Schadensursache(2018) Bauer, Frank; Haas, WernerItem Open Access Computational fluid dynamics of the lubricant flow in the sealing gap of rotary shaft seals(2022) Grün, Jeremias; Feldmeth, Simon; Bauer, FrankThe lubricant flow in the sealing gap significantly affects the sealing behavior of rotary shaft seals. Computational fluid dynamics (CFD) are applied here to analyze these fluid flows. A decisive input parameter is the sealing gap height respectively the lubricant film thickness. The film thickness is estimated on the basis of several analytical elastohydrodynamic lubrication (EHL) equations. The results for sealing characteristics such as the pumping rate and the friction torque derived from the numerical analyses are compared and discussed with the results obtained from test rig studies. This allows the validity of the applied methods to be verified.Item Open Access Einfluss supergefinishter Dichtungsgegenlaufflächen auf die Funktion von Radial-Wellendichtungen(2016) Schulz, Markus; Bauer, Frank; Haas, WernerItem Open Access Einfluss von Drehzahlwechseln in Lastkollektiven auf das System Radial-Wellendichtung(2016) Eipper, Axel; Bauer, Frank; Haas, WernerItem Open Access Einflüsse praxisrelevanter Systemparameter auf das Förderverhalten von Radial-Wellendichtungen(2018) Bekgulyan, Sumbat; Simon, Feldmeth; Bauer, FrankItem Open Access Elastohydrodynamic simulation of pneumatic sealing friction considering 3D surface topography(2022) Bauer, Niklas; Baumann, Matthias; Feldmeth, Simon; Bauer, Frank; Schmitz, KatharinaThis contribution presents an elastohydrodynamic lubrication (EHL) model for pneumatic spool valves. For an accurate estimation of the transient friction of this tribological sealing system, the surface topography of the cylindrical sealing counterfaces of the valve housings are measured and analyzed with an optical surface measurement instrument. Based on the surface topography data, tribological properties and flow factors of the system are derived. It has been found that the consideration of the surface topography has a significant influence on the simulation results of the EHL model, lowering the calculated friction force by up to 20 %.Item Open Access An empirical study on the friction of reciprocating rod seals at predefined lubrication conditions and shear rates(2022) Feuchtmüller, Oliver; Hörl, Lothar; Bauer, FrankA key factor influencing the friction of rod seals is a thin oil film, which is dragged into the sealing gap at outstroke and instroke. Accurate determination of oil film thickness in the sealing gap of rod seals is a challenging task since it is only in the range of a few nanometers. A novel measurement procedure to analyze the friction of common reciprocating sealing systems in direct relation to the shear rate and film thickness is introduced in this paper. Results from a first empirical study with film thicknesses in the range of a few nanometers and shear rates up to γ˙=107 s−1 were used to compare the friction of practically relevant polyurethane U-cups. The U-cups differ in their geometry and surface roughness. It is seen that even at such thin films, the measured friction of those seals can be approximated by Newtonian fluid friction (speed, film thickness, viscosity, contact area). In general, the novel measurement procedure is useful in a scientific and technical context, since it offers a new perspective on tribological mechanisms at thin film lubrication conditions.Item Open Access An empirical study on the wear of reciprocating hydraulic rod seals using 15 different oils(2022) Feuchtmüller, Oliver; Hörl, Lothar; Bauer, FrankHydraulic oils differ in their chemical composition and viscosity substantially. Their influence on the wear of rod seals is neither fully understood nor can be predicted precisely. The primary objective of this study was to evaluate the influence of various oils and their wetting properties on the wear of rod seals. In an empirical study, the wear of 30 commercially available polyurethane U‐cups was investigated with 15 different oils using a recently built test rig. The wear of rod seals increased with lower viscosity and higher polarity of the oil. Both oil properties are combined in a new parameter which helps to assess the lubricity of oil and the wear of rod seals.Item Open Access Empirische Modellierung der Drall-induzierten Fluidförderwirkung von Dichtungsgegenlaufflächen - Sind Grenzwerte möglich?(2016) Baumann, Matthias; Bauer, Frank; Haas, WernerItem Open Access Erweiterung der Einsatzgrenzen von PTFE-Manschettendichtungen mit Spiralrille(2006) Bauer, Frank; Haas, WernerItem Open Access Estimating the contact temperature and the pumping rate of rotary shaft seals : new possibilities with a web application(2023) Feldmeth, Simon; Bekgulyan, Sumbat; Bauer, FrankItem Open Access Förderwirkung von Fehlstellen im Dichtsystem Radial-Wellendichtung(2018) Totz, Jan; Baumann, Matthias; Bauer, FrankItem Open Access Functional behaviour of different back structures for PTFE shaft seals(2018) Stoll, Mario; Dakov, Nino; Hörl, Lothar; Bauer, FrankItem Open Access How wetting properties influence the wear of radial lip sealing systems(2022) Fricker, Philipp; Baumann, Matthias; Bauer, FrankIncreased wear on radial lip seal systems is observed when sealing modern lubricants, such as polyglycols and esters. This can impair the function of the sealing system and ultimately lead to leakage. This work, carried out within the AiF research project “Welleneinlauf” (wear of counter faces) [1], shows methods to identify and predict excessive wear of radial lip sealing systems based on their wetting properties and pumping rate. The knowledge gained will support users by providing faster and more cost‐effective testing methods early in the design process, thus enables a significant increase in the service life of radial lip sealing systems.Item Open Access Improving a gear box sealing system - individual test design based on given application parameters and failure analysis(2021) Merkle, Lukas; Baumann, Matthias; Bauer, FrankItem Open Access Influence of protection lips on the frictional torque of rotary shaft seals(2024) Olbrich, Christoph; Feldmeth, Simon; Bauer, FrankRotary shaft seals are used to seal rotating machine parts. In most cases one single sealing lip (main lip) contacts the shaft and separates the fluid on one side from the environment on the other side. To prevent the entry of other fluids and or particles, seals with additional protection lips are used (two lips), especially in heavily contaminated environments. When the protection lip contacts the shaft, a vacuum can form between the main lip and the protection lip, leading to increased contact pressure and friction. The increased frictional torque generates more heat and leads to overheating in the contact area between the lip and the shaft. Test runs conducted on a friction torque test bench with various seal configurations confirm that the two lips influence each other. Higher frictional torques and contact temperatures occur, when the volume between the lips isn't vented. This shows the importance of venting.
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