Parametric analysis of wear factors of a wet clutch friction material with different groove patterns

The experimentally observed, two-stage wear in the wet clutch friction material is directly related to temperature and engagement load. To gain insight into the durability of the friction lining, an extensive parametric analysis of the factors is performed that takes into account different groove patterns (waffle shape, radial, and spiral), internal structure and material properties. The temperature field is predicted using a thermohydrodynamic analysis with the consideration of the asperity contact stress during the engagement process. The results should be useful to facilitate the industrial design of friction lining by avoiding costly wear test.

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Numerical Simulation of Engagement of Paper Based Wet Clutch Facing

Journal of Tribology ◽

10.1115/1.2927201 ◽

1994 ◽

Vol 116 (2) ◽

pp. 232-237 ◽

Cited By ~ 83

Author(s):

Shinichi Natsumeda ◽

Tatsuro Miyoshi

Keyword(s):

Hydrodynamic Lubrication ◽

Compressive Strain ◽

Viscosity Reduction ◽

Frictional Heat ◽

Asperity Contact ◽

Wet Clutch ◽

Engagement Process ◽

Torque Curve ◽

The Many ◽

Made In

Theoretical analysis was carried out on the engagement process of a paper based wet clutch. The annular multidisk clutch in a SAE#2 tester was chosen as an example. The average flow model on partial hydrodynamic lubrication proposed by Patir and Cheng was employed for the analysis of squeeze motion taking the permeability, the compressive strain, and the asperity contact of paper facing into account. Simultaneously, the equations of heat conduction were solved to calculate the viscosity reduction due to frictional heat generation. The theoretical torque curve agreed qualitatively with the experimental one in spite of the many assumptions made in this analysis.

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Research on the Wet Clutch Engagement Torque

Volume 7: 2nd Biennial International Conference on Dynamics for Design; 26th International Conference on Design Theory and Methodology ◽

10.1115/detc2014-34179 ◽

2014 ◽

Author(s):

Yingying Zhang ◽

Changle Xiang

Keyword(s):

Rough Surface ◽

Automatic Transmission ◽

Squeeze Film ◽

Real Contact Area ◽

Asperity Contact ◽

Time Flow ◽

Clutch Engagement ◽

Wet Clutch ◽

Lubrication Oil ◽

Engagement Process

The driving performance of the vehicle with automatic transmission is influenced by the performance of the wet clutch directly. But at present it is still a challenge to build a reliable predictable model for the torque of the engagement process of the wet clutch. Focusing on the wet clutch of vehicle, this paper starts from mechanism analysis, and a modified Reynolds equation with the consideration of the centrifugal force of the squeeze-film is established. In the model, we can consider the speeds of the friction and separator plates independently. At the same time, flow factors have been used to research the impacts of rough surface on the flow of the lubrication oil. In the three-dimensional solution domain, the circumferential pressure gradient of lubrication oil is considered. The model is solved with the finite volume method. The simulation of the torque of the asperity contact calculates the real contact area changed with the engagement process, and the microscopic texture direction of rough surface is considered. Subsequently, the squeeze-film flow model is combined with the asperity contact model to create an integrated clutch engagement model. Finally, the influence of applied force, viscosity of lubrication oil, friction material, the depth of grooves and the width of the grooves are investigated. Based on the comparison with the experimental data, the performance of the proposed model is found satisfactory. Because in this model more detail properties of material and geometric features of the friction plate are include, the wet clutch model developed in this research can become a baseline model for the prediction of the engagement behavior of a real wet clutch. The present model may become an efficient alternative to laboratory testing and lead to designs that can not be envisioned by other approaches.

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Response Characteristics of Dynamic Torque for Wet Clutch Engagement: A Numerical and Experimental Study

Shock and Vibration ◽

10.1155/2021/5522998 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Zhigang Zhang ◽

Ling Zou ◽

Hang Liu ◽

Jin Feng ◽

Zhige Chen

Keyword(s):

Elastic Modulus ◽

Applied Pressure ◽

Asperity Contact ◽

Oil Film ◽

Response Characteristics ◽

Clutch Engagement ◽

Torque Response ◽

Wet Clutch ◽

Friction Lining ◽

Lubricant Viscosity

To determine the factors affecting the dynamic transmitted torque response characteristics of the wet clutch, the oil film pressure, the asperity contact pressure, the applied pressure, and the dynamic transmitted torque model were established, using the fourth-order Runge–Kutta numerical method to couple the oil film thickness and the speed difference to obtain the change curve of the joint pressure and the transmitted torque. The established model was used to study the influence of the pressure hysteresis time, lubricant viscosity, friction lining permeability, friction pair equivalent elastic modulus, and surface combined roughness RMS on the dynamic transmitted torque response during the wet clutch engagement. The results indicate that the longer the pressure hysteresis time, the smaller the permeability of the friction lining, the smaller the equivalent elastic modulus, the greater surface combined roughness RMS, the more delayed the response of the transmitted torque, and the smaller the level of jerk of the wet clutch engagement. Also, the lower the lubricant viscosity, the greater the permeability of the friction lining, and the smaller the equivalent elastic modulus is and the greater surface combined roughness RMS is, the more sensitive the transmitted torque response is to pressure response changes.

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Three-Dimensional Thermohydrodynamic Analysis of a Wet Clutch With Consideration of Grooved Friction Surfaces

Journal of Tribology ◽

10.1115/1.4003019 ◽

2010 ◽

Vol 133 (1) ◽

Cited By ~ 25

Author(s):

J. Y. Jang ◽

M. M. Khonsari ◽

Rikard Maki

Keyword(s):

Heat Dissipation ◽

Three Dimensional ◽

Groove Depth ◽

Friction Material ◽

Temperature Fields ◽

Torque Response ◽

Viscous Heat ◽

Wet Clutch ◽

Engagement Process ◽

Energy Equations

A model is developed to investigate the effect of radial grooves and waffle-shape grooves on the performance of a wet clutch. Three-dimensional formulation of the governing equations, boundary conditions, and numerical solution scheme are presented for modeling the thermal aspects of the engagement process in a wet clutch. The thermal model includes full consideration of the viscous heat dissipation in the fluid as well as heat transfer into the separator, the friction material, and the core disk. The convective terms in the energy equations for the oil as well as the heat conduction equations in the bounding solids are properly formulated to determine the temperature fields corresponding to the domains between grooves. Roughness, centrifugal force, deformability, and permeability of the friction material with grooves are taken into account. The effects of groove geometry such as groove depth, grooved area, and number of grooves on the engagement characteristic of a wet clutch are investigated. It is also shown that the thermal effects in a wet clutch influence the engagement time and the torque response and should be included in the analytical studies.

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Thermal Characteristics of a Wet Clutch

Journal of Tribology ◽

10.1115/1.2834111 ◽

1999 ◽

Vol 121 (3) ◽

pp. 610-617 ◽

Cited By ~ 66

Author(s):

J. Y. Jang ◽

M. M. Khonsari

Keyword(s):

Thermal Effects ◽

Heat Dissipation ◽

Thermal Characteristics ◽

Friction Material ◽

Solution Technique ◽

Governing Equations ◽

Viscous Heat ◽

Wet Clutch ◽

Engagement Process ◽

Full Consideration

A comprehensive formulation of the governing equations, boundary conditions, and numerical solution technique is presented for modeling the thermal aspects of the engagement process in a wet clutch. The thermal model includes full consideration of the viscous heat dissipation in the fluid as well as heat transfer into the separator, friction material, and the core disk. Roughness, waviness, deformability and permeability of the friction material are taken into account. It is shown that very large temperatures develop in the fluid during the engagement process which takes place on the time scale of one second. It is also shown that thermal effects influence the engagement time and the torque behavior of a clutch and should be included in the analytical studies.

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A Review on Non-Asbestos Friction Materials: Material Composition and Manufacturing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1150.22 ◽

2018 ◽

Vol 1150 ◽

pp. 22-42

Author(s):

Dinesh Shinde ◽

Kishore N. Mistry ◽

Suyog Jhavar ◽

Sunil Pathak

Keyword(s):

Composite Materials ◽

Material Properties ◽

Single Phase ◽

Friction Material ◽

Material Surface ◽

Surface Wear ◽

Friction Modifier ◽

Friction Materials ◽

Morphological Studies ◽

The Impact

The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.

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Modeling and experimental research on engaging characteristics of wet clutch

Industrial Lubrication and Tribology ◽

10.1108/ilt-12-2017-0383 ◽

2019 ◽

Vol 71 (1) ◽

pp. 94-101 ◽

Cited By ~ 1

Author(s):

Yanzhong Wang ◽

Yuan Li ◽

Yang Liu ◽

Wei Zhang

Keyword(s):

Contact Surface ◽

Hydrodynamic Lubrication ◽

Load Capacity ◽

Lubricating Oil ◽

Centrifugal Effect ◽

Element Analysis ◽

Content Type ◽

Clutch Engagement ◽

Wet Clutch ◽

Engagement Process

PurposeTo gain in-depth understandings of engaging characteristics, the purpose of this paper is to improve the model of wet clutches to predict the transmitted torque during the engagement process.Design/methodology/approachThe model of wet clutch during the engagement process took main factors into account, such as the centrifugal effect of lubricant, permeability of friction material, slippage factor of lubricant on contact surface and roughness of contact surface. Reynolds’ equation was derived to describe the hydrodynamic lubrication characteristics of lubricant film between the friction plate and the separated plate, and an elastic-plastic model of the rough surfaces contact based on the finite element analysis was used to indicate the loading force and friction torque of the contact surface.FindingsThe dynamic characteristics of wet clutch engagement time, relative speed, hydrodynamic lubrication of lubricating oil, rough surface contact load capacity and transfer torque can be obtained by the wet clutch engagement model. And the influence of the groove shape and depth on the engaging characteristics is also analyzed.Originality/valueThe mathematical model of the wet clutch during the engagement process can be used to predict the engaging characteristics of the wet clutch which could be useful to the design of the wet clutch.

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