scholarly journals Wear investigation of wet clutch friction material

2010 ◽  
Vol 1 (1) ◽  
pp. 46-49
Author(s):  
Bart Genbrugge ◽  
Patrick De Baets ◽  
Wouter Ost
Keyword(s):  
Applied Pressure ◽  
Friction Material ◽  
Sliding Velocity ◽  
Operational Parameters ◽  
Wear Model ◽  
Thickness Change ◽  
Wet Clutch ◽  
Drive Chain ◽  
Friction Plate ◽  
Wear Law

Wear of friction plates for wet clutch applications can result in a decreasing transmittable torque and the occurrence of vibrations throughout the entire drive chain causing loss of performance and discomfort. The need for a simple wear model exists to predict the lifetime of the clutch and to give an insight in the combined influence of the operational parameters such as pressure and speed. In this paper wear of paper-based friction material is investigated on a simplified SAE#2 test-rig using only one friction plate and one spacer plate. During engagement torque, applied pressure and sliding velocity are continuously monitored. After a set number of engagement cycles the thickness change of the friction plate is measured and surface topography of the spacer plate is registered. Based on Archard’s wear law a specific wear rate is derived.

scholarly journals Prediction the wear of sliding bearings

2018 ◽  
Vol 7 (2.23) ◽  
pp. 4 ◽  
Author(s):  
Dykha Aleksandr ◽  
Marchenko Dmitry
Keyword(s):  
Wear Resistance ◽  
Experimental Method ◽  
Wear Test ◽  
Design Stage ◽  
Linear Wear ◽  
Sliding Velocity ◽  
Operational Parameters ◽  
Wear Model ◽  
Sliding Bearings ◽  
Sliding Bearing

The problem of developing a calculation-experimental method for calculating wear of a sliding bearing based on a two-factor wear model (contact pressure - sliding velocity) with identification of wear resistance parameters was considered. On the basis of the proposed wear model, the wear-contact problem for a cylindrical sliding bearing was solved. The equation of equilibrium for medium pressures and the approximating function of linear wear from the arc of contact between the shaft and the bushing were used as the determining equations. To identify parameters of wear resistance in the wear model, a calculation-experimental method for determining calculated dependences of wear resistance parameters was developed on the basis of the wear test by the «cone – three balls» scheme. The results of wear tests of bronze conical specimens with a variable wear spot and two values of sliding velocity were taken as a base. The obtained results were recommended for predicting wear of sliding bearings at the design stage and optimizing their design and operational parameters.  

scholarly journals Effects of operating and material parameters on the thermal characteristics of a wet clutch

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110341
Author(s):  
Zhigang Zhang ◽  
Ling Zou ◽  
Hang Liu ◽  
Yonglong Chen ◽  
Benzhu Zhang
Keyword(s):  
Heat Flux ◽  
Applied Pressure ◽  
Thermal Characteristics ◽  
Thermal Models ◽  
Material Parameters ◽  
Heat Transfer Theory ◽  
Friction Disk ◽  
Viscous Shear ◽  
Wet Clutch ◽  
Transient Thermal

Based on the frictional mechanism of a wet clutch, frictional models of wet clutch engagement were established using the modified Reynolds equation and the elastic contact model between frictional pairs. Then, the heat flux models for the viscous shear and asperity friction were built, and the two-dimensional transient thermal models for the separator plate, friction disk, and ATF heat convection model were deduced based on the heat transfer theory and conservation law of energy. Finally, the Runge–Kutta numerical method was used to solve the frictional and thermal models. The average temperature of the separator plate, friction disk, and ATF were calculated. The effects of operating and material parameters, such as applied pressure, initial angular velocity, friction lining permeability, surface combined roughness RMS, equivalent elastic modulus, and ATF flow, on the thermal characteristics of friction pairs and ATF during engagement, were studied. The simulation results show that the temperature characteristics of the separator plate, friction disk, and ATF depend mainly on the viscous shear and asperity friction heat flux, and that the operating and material parameters of the wet clutch also have significant impacts on the overall variation trend of the thermal characteristics of the separator plate, friction disk, and ATF.

Experimental study on the friction stability of paper-based clutches concerning groove patterns

2019 ◽  
Vol 72 (4) ◽  
pp. 541-548 ◽  
Author(s):  
Liang Yu ◽  
Biao Ma ◽  
Man Chen ◽  
He Yan Li ◽  
Jikai Liu
Keyword(s):  
Experimental Study ◽  
Surface Temperature ◽  
Design Methodology ◽  
Automatic Transmission ◽  
Applied Pressure ◽  
Friction Torque ◽  
Content Type ◽  
Rotating Speed ◽  
Wet Clutch ◽  
Transmission Fluid

Purpose This paper aims to study and compare the friction stability of wet paper-based clutches with regard to the radial grooves (RG) and waffle grooves (WG). Design/methodology/approach This paper presents an experimental study of a wet clutch concerning the effect of groove patterns on the friction torque and surface temperature. The friction stabilities of RG and WG are investigated with the applied pressure, rotating speed and automatic transmission fluid (ATF) temperature taken into consideration. Findings The friction torque and surface temperature of WG are larger than those of RG under the same operating condition. The friction torque difference between RG and WG grows with the increase of applied pressure and narrows with the increase of ATF temperature. Additionally, their temperature difference expands via increasing the rotating speed and ATF temperature or reducing the applied pressure; in this way, not only the variable coefficient difference between RG and WG can be narrowed, but also the friction stability of the clutch can be improved dramatically. Originality/value This paper explains the thermodynamic differences between RG and WG; moreover, it is verified experimentally that WG has a better friction stability than RG.

The influence of repeated high-energy engagements on the permeability of a paper-based wet clutch friction material

2017 ◽  
Vol 231 (12) ◽  
pp. 1574-1582
Author(s):  
Niklas Lingesten ◽  
Pär Marklund ◽  
Erik Höglund
Keyword(s):  
High Energy ◽  
Friction Material ◽  
Sliding Surface ◽  
Steel Core ◽  
Interface Surface ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Oil Flow ◽  
Contradictory Behavior ◽  
Test Cells

The behavior of a wet clutch during engagement is of great importance to the durability of the clutch and the drivability of a vehicle. While many different factors influence the engagement behavior, the focus of this paper is to investigate only one factor, the permeability of the wet clutch friction material. Two test cells for measuring the permeability of friction material mounted on clutch discs have been developed. The test cells were then used to examine the effect of clutch material ageing through clutch engagement on the permeability of the material. The tests were performed on full size friction discs including the steel core prior and subsequent to testing in a wet clutch engagement test rig. The ability of the friction material to allow for oil flow both through the sliding surface layer and the bulk of the material was measured. The results indicate that repeated clutch engagements will increase the bulk permeability. However, the repeated engagements will decrease the ability to pass fluid through the friction material sliding surface. This contradictory behavior could be explained by a combination of an increase in pore size through repeated compression and the surface glaze clogging of the friction interface surface pores.

Widening Classical Wear Laws to the Concept of Third Body

2005 ◽  
Author(s):  
N. Fillot ◽  
I. Iordanoff ◽  
Y. Berthier
Keyword(s):  
Twentieth Century ◽  
Wear Rate ◽  
Applied Pressure ◽  
Third Body ◽  
Sliding Speed ◽  
Wear Law

During the second part of the twentieth century, many efforts have been done to model wear. Particularly, Archard proposes in 1953 [1] one of the first wear law, which is often written on the following form: dW/dt=K.P.V(1) with dW/dt the mass of detached particles from the rubbing materials per unit time, P the applied pressure, V the sliding speed and K the “wear rate”.

On the Formation of Hot Spots in Wet Clutch Systems

2001 ◽  
Vol 124 (2) ◽  
pp. 336-345 ◽  
Author(s):  
J. Y. Jang ◽  
M. M. Khonsari
Keyword(s):  
Hot Spots ◽  
Friction Material ◽  
Mechanical Seal ◽  
Comprehensive Model ◽  
Governing Equations ◽  
Thermoelastic Instability ◽  
Wet Clutch ◽  
Special Case

A comprehensive model is developed for analyzing the onset of thermoelastic instability in a wet clutch. For this purpose, appropriate governing equations are derived that take into account the porosity and deformability of the friction material. The effect of the thickness of the separator disk and that of the friction material are also included. The model is general and can be used to describe TEI in a variety of other systems such as in a mechanical seal, as a special case. A series of simulations are presented that predict the thermoelastic behavior of a wet clutch from an instability viewpoint.

A Continuum Model for Fiber-Reinforced Soft Robot Actuators

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Audrey Sedal ◽  
Daniel Bruder ◽  
Joshua Bishop-Moser ◽  
Ram Vasudevan ◽  
Sridhar Kota
Keyword(s):  
Continuum Model ◽  
Applied Pressure ◽  
Experimental Parameter ◽  
Building Blocks ◽  
Axial Rotation ◽  
Parameter Determination ◽  
Fiber Reinforced ◽  
Operational Parameters ◽  
Computationally Efficient ◽  
Design Synthesis

Fiber-reinforced elastomeric enclosures (FREEs) generate sophisticated motions, when pressurized, including axial rotation, extension, and compression, and serve as fundamental building blocks for soft robots in a variety of applications. However, most modeling techniques employed by researchers do not capture the key characteristics of FREEs to enable development of robust design and control schemes. Accurate and computationally efficient models that capture the nonlinearity of fibers and elastomeric components are needed. This paper presents a continuum model that captures the nonlinearities of the fiber and elastomer components as well as nonlinear relationship between applied pressure, deformation, and output forces and torque. One of the key attributes of this model is that it captures the behavior of FREEs in a computationally tractable manner with a minimum burden on experimental parameter determination. Without losing generality of the model, we validate it for a FREE with one fiber family, which is the simplest system exhibiting a combination of elongation and twist when pressurized. Experimental data in multiple kinematic configurations show agreement between our model prediction and the moments that the actuators generate. The model can be used to not only determine operational parameters but also to solve inverse problems, i.e., in design synthesis.

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.

NUMERICAL AND FINITE ELEMENT CONTACT TEMPERATURE ANALYSIS OF FRICTION MATERIAL ’S TYPE EFFECT ON A THERMAL TRANSIENT BEHAVIOR OF A SINGLE-DISC DRY CLUTCH

Tribologia ◽  
2018 ◽  
Vol 271 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Majid Habeb FAIDH-ALLAH
Keyword(s):  
Finite Element ◽  
Transient Behavior ◽  
Friction Material ◽  
Sliding Velocity ◽  
Friction Materials ◽  
Clutch System ◽  
Friction Clutch ◽  
Dry Clutch ◽  
Element Technique ◽  
Contact Temperature Analysis

The sliding period is considered a critical period in the lifetime of friction clutches, because most failures occur during this period. High temperatures due to sliding velocity will appear on the contacting surfaces of the friction clutch system (e.g., in single -disc clutch are pressure plate, clutch discs and flywheel). The finite element technique has been developed to investigate the effect of the type of friction material (material properties) on the transient thermoelastic behaviour of a single-disc dry clutch. Two types of friction materials are used in this work: organic and sintered friction materials. Axisymmetric models are developed to simulate a friction clutch system (single disc with two effective sides). The results represent the comparisons between organic and sintered friction discs, behaviours during slipping periods in clutches.

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