Tribological Behavior of Hydraulic Cylinder Coaxial Sealing Systems Made from PTFE and PTFE Compounds

Deaconescu, Andrea; Deaconescu, Tudor

doi:10.3390/polym12010155

Cited by 7 publications

(16 citation statements)

References 16 publications

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“…A greater velocity causes a thicker fluid film, and the consequent fluid type friction ensures a high level of energy efficiency. This is, however, conflicting in relation to the sealing process, as the hydrodynamic separation of seal and cylinder surface leads to an increased loss of fluid that flows towards the lower pressure side [4].…”

Section: Coaxial Sealing Systemmentioning

confidence: 99%

“…The pre-stressing rings of coaxial sealing systems are generally made from elastomers of various types: nitrile (NBR), hydrogenated nitrile butadiene rubber (HNBR), silicone rubber (Q), fluorocarbon (FKM), ethylene propylene diene monomer (EPDM) and fluorosilicone (FVMQ). For high temperature working situations, up to 325 • C, the material recommended for these rings is perfluoroelastomer (FFKM), while for very low temperatures, as low as −75 • C, the recommended material is VMQ [4,18].…”

Section: Coaxial Sealing Systemmentioning

confidence: 99%

“…With the onset of motion two wedge-shaped fluid films are formed, one for each piston, in the contact area of the respective seals with the cylinder barrel. The average thicknesses of the fluid films are not identical (g 01 and g 02 , respectively) and the method for computing these is described in [4]. The fluid film thicknesses, being unequal, yields the conclusion that the kinematic friction forces generated by the two seals are not equal either.…”

Section: Determination Of the Kinetic Friction Coefficientmentioning

confidence: 99%

“…Hydraulic cylinder sealing system performance is influenced by numerous variables that cannot be simultaneously taken into consideration for obtaining generalized mathematical relationships. Speeds or properties of the sealing system components materials, roughness of the contacting surfaces, and temperature of the sealed fluid are only a few such quantities that affect the operational behavior of sealing systems [4][5][6]. The importance of an optimum sealing system design follows also from the conclusion of the study published by Oprean et al [7], which asserts that 44% of the operational malfunctioning of hydraulic cylinders is due to flawed sealing.…”

Section: Introductionmentioning

confidence: 99%

“…0.1) and is also nearly completely chemically inert to the substances it comes into contact with. These characteristics render PTFE eligible for tribological applications designed to reduce energy consumption in friction-intensive machinery, as well as for reactive and corrosive applications [4]. Another polymer material is polyurethane, which, when combined with certain solid lubricants, ensures small friction coefficients.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities

Deaconescu

2022

Polymers

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Reducing friction in the coaxial sealing systems of hydraulic cylinders is one of the solutions for increasing the energy efficiency of industrial actuations. This is a requirement, particularly in the case of small velocities that carry the risk of eigen-vibrations and/or stick-slip. The authors discuss the experimental research conducted on three coaxial sealing systems made from thermoplastic polymer and polyurethane type materials. The paper presents the equipment and method used for the experimental determination of static and kinematic friction coefficients and discusses the subsequent results obtained to test different working parameters. The experimentally determined friction coefficients yielded a range of materials recommended for coaxial seals such as to minimize the occurrence of jerky operation.

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Section: Coaxial Sealing Systemmentioning

confidence: 99%

Section: Coaxial Sealing Systemmentioning

confidence: 99%

Section: Determination Of the Kinetic Friction Coefficientmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities

Deaconescu

2022

Polymers

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Impact Response of the Tail Beam Jack Based on Bidirectional Fluid-Structure Coupling Simulation

et al. 2023

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In top coal caving mining, the coal rock collapse will cause an irregular impact on the tail beam jack of the caving control mechanism. The severe impact will lead to jack failure. The bidirectional fluid-structure coupling model is built on Fluent and Mechanical software to study the impact response of the tail beam jack. The dynamic flow velocity streamlines, hydraulic pressure distribution, stress field, and strain field of the jack under impact load are extracted. The response characteristics of the jack in the stationary state and motion state are analyzed. The conclusions are as follows: the stress and strain of the rodless cavity are much larger than those of the rod cavity, which is more likely to be damaged. The hydraulic pressure in the jack cavity is in vertical layered distribution. The flow velocity streamlines present spiral shapes. The response degree of the hydraulic pressure signal in the rodless cavity is stronger than that in the rod cavity, and the response degree of the flow velocity signal in the rod cavity is stronger than that in the rodless cavity. The impact response of the jack in the motion state is more sensitive and stronger than that in the stationary state. The coal rock collapse situation can be most effectively identified only by comprehensively analyzing the rodless cavity’s pressure signal and the rod cavity’s velocity signal. This paper innovatively visualizes the flow velocity streamlines and pressure distribution together. The bidirectional fluid-structure coupling method is innovatively applied to the tail beam jack. The findings of this study can help for better understanding of the tail beam jack’s structural design and failure prevention. This study provides a certain research basis for the intelligent coal rock identification technology in mining coal based on jack vibration signals.

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Effect of different molding pressures on the properties of glass fiber / molybdenum disulfide / Polytetrafluoroethylene composites

Yang

2023

High Performance Polymers

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Both glass fiber (GF) and molybdenum disulfide (MoS2) can enhance the comprehensive properties of PTFE (polytetrafluoroethylene)-based composites, however the properties of the composites are significantly influenced by the molding pressure utilized. In this study, GF/MoS2/PTFE composites were produced under varied molding pressures (50–70 MPa), and the composites’ mechanical and tribological properties were evaluated. The results showed that the tribological parameters (such as friction coefficient and volumetric wear rate) and mechanical parameters (such as density, hardness, tensile strength, and elongation at break) varied depending on the molding pressure. When the molding pressure was 50 MPa, the GF/MoS2/PTFE composites displayed their finest mechanical properties. The composite had the best wear resistance with the lowest wear rate of only of 2.135 × 10−6 mm3/Nm at a molding pressure of 60 MPa and the lowest friction coefficient of 0.166 at a molding pressure of 70 MPa. The increased molding pressure that was employed to make the samples, as predicted by SEM analysis, would lead to greater residual stresses inside the specimens, which would ultimately result in cracking and peeling. In the friction test, specimens with a lower forming pressure are more likely to have surface furrows that are deeper and wider, as well as to shed their filler. Due to the increased molding pressure, the depth of furrows and filler shedding on the composite surface are also more apparent.

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Tribological Behavior of Hydraulic Cylinder Coaxial Sealing Systems Made from PTFE and PTFE Compounds

Cited by 7 publications

References 16 publications

Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities

Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities

Impact Response of the Tail Beam Jack Based on Bidirectional Fluid-Structure Coupling Simulation

Effect of different molding pressures on the properties of glass fiber / molybdenum disulfide / Polytetrafluoroethylene composites

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