Engagement of Oil Immersed Multi-Disc Clutches

1992 ◽  
Author(s):  
Bengt Jacobson
Keyword(s):  
Simple Model ◽  
Dry Friction ◽  
Friction Surface ◽  
Friction Torque ◽  
Oil Film ◽  
Return Spring ◽  
Simulation Results ◽  
Friction Surfaces

Abstract Oil immersed clutches are often treated without respect to the oil being present, i.e. the torque is assumed to be a pure dry friction torque, directly controlled by the actuating force. However, during the engagement this is sometimes not enough. The oil film acts in two ways: Firstly, the oil has to be squeezed out before dry friction can be developed. Secondly, before the friction surfaces have reached contact, the torque is viscous. This work proposes equations that take these phenomena into account. A simple model for the transition from viscous to dry friction is used. Compensation for grooves in the friction surface is made. Also the hydraulic actuating equipment (piston, return spring, orifice etc.) is modelled. Simulation results are verified by experiments.

scholarly journals Analysis of surface structure of zirconia crystals in case of friction against steel

2020 ◽  
Vol 329 ◽  
pp. 02008
Author(s):  
Valery Alisin ◽  
Mikhail Borik ◽  
Alexey Kulebyakin ◽  
Elena Lomonova ◽  
Irina Suvorova
Keyword(s):  
Dry Friction ◽  
Friction Surface ◽  
Friction Pair ◽  
Base Material ◽  
Electron Microscopic Examination ◽  
Third Body ◽  
Electron Microscopic ◽  
The Third ◽  
Transfer Films ◽  
Friction Surfaces

The article considers the formation of the third body during dry friction of the nanostructured zirconia crystals partially stabilized with yttria against steel. The assumption is substantiated that the tribological properties of the studied friction pair are determined by the properties of the films formed on the surface of the crystals. Friction tests under sliding conditions were performed according to the “disk-finger” scheme. The results of electron microscopic examination of the friction surfaces of crystals are presented. The elemental composition was determined, and the phase composition of the transfer films of various sections of the crystal friction surface was calculated. At high magnifications, it was found that the friction surface of samples with 2-4 mol.% of Y2O3 has the sufficiently homogeneous structure of the films with traces of boundaries of smaller particles of the transferred material. Destruction of the friction surface of a sample with a Y2O3 content of 8 mol.% occurs at a deeper level and affects not only the layer of secondary structures, but also the underlying layers of the base material.

Investigation of Changing of Chemical and Phase Composition of the Friction Surface Fe-Mn-C-B-Si-Ni-Cr

2018 ◽  
Vol 759 ◽  
pp. 65-68
Author(s):  
Mykhaylo Paszeczko ◽  
Klaudiusz Lenik ◽  
Krzysztof Dziedzic ◽  
Marcin Barszcz
Keyword(s):  
Phase Composition ◽  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Dry Friction ◽  
Friction Surface ◽  
X Ray ◽  
Pin On Disc ◽  
Xps Study ◽  
Friction Surfaces ◽  
Scanning Electron

The paper presents the results of a SEM/EDS and XPS study of changing of chemical and phase composition of the friction surfaces Fe-Mn-C-B-Si-Ni-Cr hardfacing coatings depend on depth. The tribological examination was conducted in a pin-on disc system with unitary pressure of 10 MPa under dry friction conditions. A scanning electron microscope SEM/EDS as well as X-Ray photoelectron spectroscopy (XPS) were used to examine the structures on the friction surface and depend on depth 5, 10, 15, 20, 50, 100, 200, 6000 nm. The presence of compounds such as oxides (B2O3, SiO2, Cr2O3), carbides (Fe3C, Cr7C3), borides (FeB, Fe2B).

Clearance and Dry Friction Study in a Nonlinear Torsional Vibration of a Rotating Machinery

1999 ◽  
Author(s):  
Kazuki Mizutani ◽  
Hossain Md. Zahid
Keyword(s):  
Torsional Vibration ◽  
Dry Friction ◽  
Friction Torque ◽  
Frictional Property ◽  
Behavioral Characteristics ◽  
Spring Stiffness ◽  
Response Curves ◽  
Friction Models ◽  
The Difference ◽  
Friction Study

Abstract Clearance problem in coupling is often experienced in a rotary torsional vibration system. We tried to analyze the qualitative and quantitative characteristics of torsional vibration by modeling the bilinear spring stiffness with changing friction torque. Symmetric and asymmetric spring stiffness with friction models are developed to investigate the behavioral characteristics of the system for simulations and experiments. The frequency response curves and time response curves with external sinusoidal excitation are observed by several non-dimensional numerical simulations. The thoroughly experiments are done to understand the actual phenomena of torsional vibration, verification of models and adjustability of simulations. The frictional property considered as dry friction in coupling is found very significant parameter to reduce the vibration within a tolerable range in both of the simulations and experiments. The difference between the results getting from simulations and experiments are also demonstrated in this paper elaborately.

Tribometer for Dry Friction Measurement

1999 ◽  
Author(s):  
Marc Brandl ◽  
Friedrich Pfeiffer
Keyword(s):  
Coefficient Of Friction ◽  
Dry Friction ◽  
Stribeck Curve ◽  
Body System ◽  
Friction Measurement ◽  
Detailed Model ◽  
The Coefficient Of Friction ◽  
Simulation Results ◽  
Multi Body

Abstract This paper deals with the measurement of dry friction. A tribometer was developed in order to identify both the sticking and the sliding coefficient of friction. The aim was to determine the so called Stribeck-curve of any material in contact. The design of the plant is presented. Avoiding errors in recalculating the coefficient of friction, a detailed model of the plant as a multi body system with motor feedback was generated. Advantages of the tribometer are shown in simulations. Some results of measurements in comparison with simulation results are presented.

Investigation of the formation of friction surface microgeometry of a wear-resistant coating during friction with a metal counterbody

2021 ◽  
pp. 147-152
Author(s):  
N.F. Struchkov ◽  
G.G. Vinokurov ◽  
O.N. Popov
Keyword(s):  
Statistical Model ◽  
Binomial Distribution ◽  
Friction Surface ◽  
Sliding Friction ◽  
Wear Particles ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Frictional Interaction ◽  
Surface Microgeometry ◽  
Friction Surfaces

Were is researched the friction surfaces of wear-resistant coatings with modifying additives Al2O3 and metal counterbody made of ShH15 steel, and also reveals the factors that influence the formation of coating microgeometry of surface during sliding friction. A statistical model has been developed based on the binomial distribution of removed wear particles to describe the frictional interaction during friction of the coating with a metal counterbody.

In situ monitoring of friction surfaces and their sequence pattern analysis

2007 ◽  
Vol 366 (1865) ◽  
pp. 665-671 ◽  
Author(s):  
S Kano ◽  
H Homma ◽  
S Sasaki ◽  
H Shimura
Keyword(s):  
Laser Pulse ◽  
Friction Surface ◽  
Optical Microscope ◽  
Carbon Steels ◽  
In Situ Monitoring ◽  
Plate Motion ◽  
Surface Pattern ◽  
Size And Shape ◽  
Motion Speed ◽  
Friction Surfaces

Friction occurs between solid surfaces, and even sometimes on lubricated surfaces. To understand tribological subjects, it is important to know the changes that occur in friction surfaces. In this study, a laser strobe technique is applied to a friction surface observation. The recorded surface images were analysed using pattern-matching methods and their correlations are discussed. A test using pin-on-plate methods with carbon steels was performed using a reciprocating motion speed of 10 Hz for 4.9 N. A pulsed laser light (Nd:YAG SHG=532 nm, 5 ns per pulse) was irradiated onto the friction surface. It was induced using an optical microscope that was located just to the side of the pin. The laser pulse was synchronized with the plate motion, which was a trigger of the laser pulse. The surface image was stored for every cycle. These sequences were calculated and their correlations were analysed as a function of the surface pattern and the friction track size and shape. Analysis revealed that some groups were distinguishable as parameters of the damage size and shape.

Enhancement of the Accuracy of the Modified (P–ω) Method Through the Implementation of a Nonlinear Robust Observer

2005 ◽  
Author(s):  
G. A. Kfoury ◽  
N. G. Chalhoub ◽  
N. A. Henein ◽  
W. Bryzik
Keyword(s):  
Internal Combustion Engines ◽  
Sliding Mode ◽  
Angular Displacement ◽  
Digital Simulation ◽  
Friction Torque ◽  
Original Version ◽  
State Variables ◽  
Connecting Rod ◽  
Simulation Results ◽  
Elastic Modes

The original version of the (P–ω) method is a model-based approach developed for determining the instantaneous friction torque in internal combustion engines. This scheme requires measurements of the cylinder gas pressure, the engine load torque, the crankshaft angular displacement and its time derivatives. The effects of the higher order dynamics of the crank-slider mechanism on the measured angular motion of the crankshaft have caused the (P–ω) method to yield erroneous results, especially, at high engine speeds. To alleviate this problem, a nonlinear sliding mode observer has been developed herein to accurately estimate the rigid and flexible motions of the piston-assembly/connecting-rod/crankshaft mechanism of a single cylinder engine. The observer has been designed to yield a robust performance in the presence of disturbances and modeling imprecision. The digital simulation results, generated under transient conditions that represent a decrease in the engine speed, have illustrated the rapid convergence of the estimated state variables to the actual ones in the presence of both structured and unstructured uncertainties. Moreover, this study has proven that the use of the estimated rather than the measured angular displacement of the crankshaft and its time derivatives can significantly improve the accuracy of the (P–ω) method in determining the instantaneous engine friction torque. However, the effects of structural deformations of the crank-slider mechanism have rendered the original version of the (P–ω) method to be inapplicable at high engine speeds. This problem has been addressed herein by modifying the formulation of the (P–ω) method in order to account for the first two elastic modes of the crankshaft torsional vibration. The simulation results confirm the good performance of the modified (P–ω) method in determining the instantaneous friction torque at high engine speeds.

scholarly journals Analysis of Dynamic Engaged Characteristics of Wet Clutch in Variable Speed Transmission of a Helicopter

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1474
Author(s):  
Heyun Bao ◽  
Tongjing Xu ◽  
Guanghu Jin ◽  
Wei Huang
Keyword(s):  
Film Thickness ◽  
Bearing Capacity ◽  
Friction Torque ◽  
Rate Of Change ◽  
Lubricating Oil ◽  
Oil Film ◽  
Capacity Model ◽  
Wet Clutch ◽  
Friction Plate

The working principle and motion process of an aviation wet clutch are analyzed. The initial velocity before the friction pair engaged is solved. The transient Reynolds equation is modified, and an oil film bearing capacity model and a micro-convex bearing capacity model are derived. The film thickness equation between N friction pairs and a pressure-plate is derived. A dynamic engaged model of springs, pistons, friction pairs, and pressure plates are established. The torque balance equation is established of two pairs of friction pairs. The friction torque, rate of change in the oil film, and law of relative change in speed are obtained. The results demonstrate that the spring preload and the viscosity of the lubricating oil have a significant influence on the engagement characteristics. Increasing the quality of the friction plate will reduce the time of engagement, whereas the quality of the friction plate has slight effect on the friction torque characteristics and oil film thickness. The initial speed generated by the collision process will reduce the output speed, sharply increase the torque peak at the lock, and increase the shift shock.

Study of Fluid-Solid Simulation on the Large-Scale Hydrostatic Bearing of Hollow Coaxial

2009 ◽  
Vol 628-629 ◽  
pp. 281-286 ◽  
Author(s):  
Xiang Jun Yu ◽  
Ji Xin Wang ◽  
Yong Li
Keyword(s):  
Film Thickness ◽  
Large Scale ◽  
Maximum Stress ◽  
Impact Factors ◽  
Oil Film ◽  
Hydrostatic Bearing ◽  
Simulation Results ◽  
Stress And Deformation

In order to investigate the changing law of the film thickness caused by the deformation of hollow coaxial and drum-shaped lining and accurately calculate the stress of hollow coaxial and rum-shaped lining, the fluid-solid numerical simulatied model of a large-scale hydrostatic bearing was established. The stress and deformation of hollow coaxial and drum-shaped lining was obtained by indirect coupled methods. The typical impact factors and the deformation laws of the thinnest film were discussed. The simulation results indicate that the maximum stress locatioes on the drum-shaped lining and hollow coaxial; and the deformation of the hollow coaxial is 60.47 times that of the drum-shaped lining, and the oil film thinnest thickness decreases by 12.1% due to the deformation of the hollow coaxial and drum-shaped lining; and the stiffness of the hollow coaxial makes greatest impact on oil film deformation.

Sign in / Sign up

Export Citation Format

Share Document