The Experts below are selected from a list of 1110 Experts worldwide ranked by ideXlab platform
Monika Ivantysynova - One of the best experts on this subject based on the ideXlab platform.
-
Slipper Surface Geometry Optimization of the Slipper/Swashplate Interface of Swashplate-Type Axial Piston Machines
International Journal of Fluid Power, 2019Co-Authors: Ashkan A. Darbani, Lizhi Shang, Jeremy R. Beale, Monika IvantysynovaAbstract:The slipper/Swashplate interface, as one of the three main lubricating interfaces in Swashplate type axial piston machine, serves both a sealing function and a bearing function while dissipating energy into heat due to viscous friction. The sealing function prevents the fluid in the displacement chamber from leaking out through the gap to the case, and the bearing function prevents the slipper from contacting to the Swashplate. The challenge of the conventional slipper/Swashplate lubricating interface design is to rely on the tribological pairing self-adaptive wearing process to find a slipper surface profile that fulfills the bearing function. However, the resulted slipper surface profile from uncontrollable wearing process is not necessarily able to achieve good energy efficiency. This article proposes a novel slipper design approach that overcomes this challenge by adding a quadratic spline curvature to the slipper running surface which eliminates the wear while keeping good efficiency. A fully-coupled fluid-structure and thermal interaction model is used to simulate the performance of the slipper/Swashplate interface. A computationally inexpensive optimization scheme is used to find the desired slipper design. This article presents the simulation methodology, the optimization scheme, the full factorial simulation study results, and the optimized slipper running surface.
-
slipper surface geometry optimization of the slipper Swashplate interface of Swashplate type axial piston machines
International journal of fluid power, 2019Co-Authors: Ashkan A. Darbani, Lizhi Shang, Jeremy R. Beale, Monika IvantysynovaAbstract:The slipper/Swashplate interface, as one of the three main lubricating interfaces in Swashplate type axial piston machine, serves both a sealing function and a bearing function while dissipating energy into heat due to viscous friction. The sealing function prevents the fluid in the displacement chamber from leaking out through the gap to the case, and the bearing function prevents the slipper from contacting to the Swashplate. The challenge of the conventional slipper/Swashplate lubricating interface design is to rely on the tribological pairing self-adaptive wearing process to find a slipper surface profile that fulfills the bearing function. However, the resulted slipper surface profile from uncontrollable wearing process is not necessarily able to achieve good energy efficiency. This article proposes a novel slipper design approach that overcomes this challenge by adding a quadratic spline curvature to the slipper running surface which eliminates the wear while keeping good efficiency. A fully-coupled fluid-structure and thermal interaction model is used to simulate the performance of the slipper/Swashplate interface. A computationally inexpensive optimization scheme is used to find the desired slipper design. This article presents the simulation methodology, the optimization scheme, the full factorial simulation study results, and the optimized slipper running surface.
-
A Transient Thermoelastohydrodynamic Lubrication Model for the Slipper/Swashplate in Axial Piston Machines
Journal of Tribology, 2015Co-Authors: Andrew Schenk, Monika IvantysynovaAbstract:A transient lubrication model has been developed for the sliding interface between the slipper and Swashplate in axial piston hydraulic pumps and motors. The model considers a nonisothermal fluid model, microdynamic motion of the slipper, as well as pressure and thermal deformations of the bounding solid bodies through a partitioned solution scheme. The separate contributions of elastohydrostatic and elastohydrodynamic lubrication are studied. Although hydrostatic deformation dominates, hydrodynamic effects are crucial for actual operation. Finally, the impact of transient deformation on lubricant pressure is explored, with its consideration necessary for accurate analysis.
J.-m. Perrochat - One of the best experts on this subject based on the ideXlab platform.
-
Wear Mechanisms in Contacts Involving Slippers in Axial Piston Pumps: A Multi-Technical Analysis
Journal of Materials Engineering and Performance, 2018Co-Authors: G. Schuhler, A. Jourani, S. Bouvier, J.-m. PerrochatAbstract:Axial piston pumps are widely used in actuation as power conversion systems, especially in aeronautics. Even though they combine compactness and efficiency, wear of their parts reduces their lifespan. Studies on these pumps often consist in analytic or numerical analyses of lubricated contact between their components. Piston slippers are in tribological contacts with Swashplate, pistons and slipper retainer. This study aims to understand wear mechanisms in the contacts involving this central component. An experimental multi-technical analysis of helicopter pumps parts after several functioning times is presented. To determine wear mechanisms, worn surfaces are observed with SEM. 3D surface roughness measurements provide surface topography. Contact conditions and consequently wear severity and mechanisms differ from one contact to another. Detached coarse carbides from the Swashplate surface act as an abrading third-body against slippers and Swashplate. Debris generated in this contact is carried by the fluid to the other contacts. Although pistons are made of the same steel as Swashplate, there is no carbide detachment and wear comes from debris polluting the fluid. Slipper retainer is almost not worn, and debris causes abrasive wear and craters generation in the slippers.
-
Efficacy of coatings and thermochemical treatments to improve wear resistance of axial piston pumps
Tribology International, 2018Co-Authors: G. Schuhler, A. Jourani, Salima Bouvier, J.-m. PerrochatAbstract:Abstract A former study on wear in helicopter axial piston pumps showed the main wear mechanism in the contacts slipper/Swashplate is abrasion due to carbides removal. Resulting debris and particles pollute the lubricating fluid leading to abrasive wear in most contacts. Accordingly, surface treatments on the Swashplate steel are proposed to reduce slipper/Swashplate wear. This study consists in a multitechnical experimental analysis of these solutions in dry and lubricated conditions. With lubricant, steel without treatment suffers carbide removal. PTFE coating prevents it by diminishing the coefficient of friction but are less resistant in highly loaded contact. Nitriding results in higher wear resistance, especially when lubricated. (DLC + WC) coating is the most efficient in dry conditions by minimizing friction coefficient and wear rate.
Qian Zhi-bo - One of the best experts on this subject based on the ideXlab platform.
-
Simulation of Swashplate Engine Based on Virtual Prototyping Technology
Computer Simulation, 2012Co-Authors: Qian Zhi-boAbstract:Swashplate engine is the special engine used in the underwater vehicles.Theoretical analysis of the engine has much limitations,whereas virtual prototyping of engine has extensive advantages.In addition,it is necessary to do multi-body dynamics simulation analysis of engine for the sake of vibration damping and noise reduction.Based on the UG and ADAMS software platform,the virtual prototyping models were built.By the simulation analysis,the motion curves of the main components and the forces and torque curves among the main components were acquire.It was concluded that the impacts of piston to rod and piston to Swashplate,the forces between rollers and the Swashplate box,and the loads of the bearings between the Swashplate and the clino-axis,are the main sources of the vibration and noises.These simulation results provide an important basis for the vibration analysis,noise analysis,and finite element analysis of the Swashplate engine.
G. Goritschnig - One of the best experts on this subject based on the ideXlab platform.
-
The Dynamics of the Swashplate Mechanism of a VTOL Unmanned Aerial Vehicle
Multibody System Dynamics, 2001Co-Authors: C. Lange, F. Ranjbaran, J. Angeles, G. GoritschnigAbstract:The dynamics of the Swashplate mechanism of the CL-327, anUnmanned Aerial Vehicle (UAV) with a Vertical Take-Off-and-Landing(VTOL) ability is discussed in this paper, the underlying kinematicshaving been discussed in an earlier paper. The CL-327 ( Guardian )is currently under production by Bombardier Services-Defence, and isconsidered the world's most versatile and advanced VTOL system inproduction. The steering control mechanism used in all helicopters,including the CL-327, is a complex multiloop kinematic chain oftencalled the Swashplate mechanism. In this paper a dynamic analysis of theparticular design used for the Swashplate of the CL-327 is discussed.The Newton–Euler formulation is used in conjunction with the naturalorthogonal complement in order to derive the equations of motion of thesystem.
-
The Kinematics of the Swashplate Mechanism of a VTOL Unmanned Aerial Vehicle
Multibody System Dynamics, 1999Co-Authors: C. Lange, F. Ranjbaran, J. Angeles, G. GoritschnigAbstract:The kinematics of the Swashplate mechanism of an Unmanned Aerial Vehicle (UAV) is discussed in this paper. The UAV under study, known as the CL-327 Guardian, is currently under production by Bombardier Services, Defence. It is considered to be the world's most versatile and advanced UAV system capable of Vertical Take Off and Landing (VTOL). The steering control mechanism used in all helicopters, including the CL-327, is a complex closed kinematic chain often called the Swashplate mechanism. In this paper a detailed kinematic analysis of the particular design used for the Swashplate of the CL-327 is discussed.
-
The Kinematics of the Swashplate Mechanism of a VTOL Unmanned Aerial Vehicle
Multibody System Dynamics, 1999Co-Authors: C. Lange, F. Ranjbaran, J. Angeles, G. GoritschnigAbstract:The dynamics of the Swashplate mechanism of the CL-327, anUnmanned Aerial Vehicle (UAV) with a Vertical Take-Off-and-Landing(VTOL) ability is discussed in this paper, the underlying kinematicshaving been discussed in an earlier paper. The CL-327 (Guardian)is currently under production by Bombardier Services-Defence, and isconsidered the world's most versatile and advanced VTOL system inproduction. The steering control mechanism used in all helicopters,including the CL-327, is a complex multiloop kinematic chain oftencalled the Swashplate mechanism. In this paper a dynamic analysis of theparticular design used for the Swashplate of the CL-327 is discussed.The Newton–Euler formulation is used in conjunction with the naturalorthogonal complement in order to derive the equations of motion of thesystem.
Zebo Wang - One of the best experts on this subject based on the ideXlab platform.
-
Optimization and Influence of Micro-Chamfering on Oil Film Lubrication Characteristics of Slipper/Swashplate Interface within Axial Piston Pump
Energies, 2021Co-Authors: Jihai Jiang, Zebo WangAbstract:The overturning and eccentric abrasion of the slipper worsens the lubrication characteristics and increases the friction power loss and kinetic energy consumption of the slipper/Swashplate interface to reduce the axial piston pump efficiency. A coupling lubrication numerical model and algorithm and a micro-chamfering structure are developed and proposed to predict more precisely and improve the lubrication characteristics of the slipper/Swashplate interface. The simulation results reveal that the slipper without micro-chamfering overturns and contacts with the Swashplate, while the one with micro-chamfering forms a certain oil film thickness to prevent this contact effectively. The minimum total power loss of the slipper/Swashplate interface has to be effectively ensured under the worst working conditions, such as the high pressure, the low speed, the maximum Swashplate inclination angle and the minimum house pressure. The optimal micro-chamfering width and depth are 1.2 mm and 3.5 μm or C1.2-3.5, the simulation average oil film thickness of which is approximately equal to the optimal analytical value. The experimental friction power loss of the slipper/Swashplate interface is basically consistent with the simulation one, confirming the correctness and effectiveness of the coupling lubrication numerical model, and the optimization method and providing the further design direction of axial piston pumps.
-
The Impact of Slipper Microstructure on Slipper-Swashplate Lubrication Interface in Axial Piston Pump
IEEE Access, 2020Co-Authors: Jihai Jiang, Zebo WangAbstract:In order to decrease the tilt and eccentric abrasion of a slipper and improve the lubrication performance of the slipper-Swashplate interface in an axial piston pump, this paper proposes a comprehensive numerical simulation method to predict the lubrication performance and designs three types of slipper microstructures such as micro-chamfering, micro-filleting and micro-stepping to improve the lubrication performance. The lumped-parameter numerical pressure-flow model of the axial piston pump and the lubrication model of the slipper-Swashplate interface have been developed. These models consider the pressure of slipper’s center oil pool, hydrostatic lubrication, hydrodynamic lubrication, slipper microstructures, slipper’s micro motion and dynamic equilibrium. The influence of slipper microstructures on the lubrication performance of the slipper-Swashplate interface has been profoundly studied. Simulation results demonstrate that the slipper without a microstructure leans forward and finally touches the swashpate leading to wear-out and that all the three types of slipper microstructures improve the lubrication performance, where the effects of micro-chamfering and micro-filleting are better than the effect of the micro-stepping. With the increase of the micro-chamfering depth, the leakage decreases and the friction power loss increases, while with the increase of the micro-chamfering depth, the leakage increases and the friction power loss decreases. The experimental results are essentially consistent with the simulation results, which confirms the numerical models feasible and effective. The current work is significant for further designs and the structural optimization of the slipper-Swashplate interface.
