Effect of Facing Groove Design on Drag Torque of Automatic Transmission Wet Clutches

2018 ◽  
Author(s):  
Kazunari Asai ◽  
Takanobu Ito
Keyword(s):  
Automatic Transmission ◽  
Drag Torque ◽  
Groove Design

scholarly journals Prediction of Drag Torque in a Disengaged Wet Clutch of Automatic Transmission by Analytical Modeling

2016 ◽  
Vol 11 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Shahjada Ahmed Pahlovy ◽  
Syeda Faria Mahmud ◽  
Masamitsu Kubota ◽  
Makoto Ogawa ◽  
Norio Takakura
Keyword(s):  
Analytical Modeling ◽  
Automatic Transmission ◽  
Drag Torque ◽  
Wet Clutch

Combined Numerical and Experimental Study on Drag Torque in a Wet Clutch

2011 ◽  
Author(s):  
Youhei Takagi ◽  
Yasunori Okano ◽  
Masatoshi Miyagawa ◽  
Nobuyuki Katayama
Keyword(s):  
Experimental Study ◽  
Volume Fraction ◽  
Rotation Speed ◽  
Automatic Transmission ◽  
Rotating Disk ◽  
Open Boundary ◽  
Drag Torque ◽  
Two Phase ◽  
Frictional Material ◽  
Wet Clutch

The effect of flow field on drag torque in a wet clutch was examined through a combined numerical and experimental study. Three-dimensional hydrodynamic numerical simulations were carried out, and the drag torque was measured experimentally for a single wet clutch pack. Two-phase flow induced by aeration was visualized in the experiment. In the present drag torque test, the main section was consisted of two parallel circular plates. The plate with the frictional material was rotated. The frictional material was divided into some sections, and radial or circumferential grooves were made on the rotating disk. Automatic Transmission Fluid (ATF) was supplied from the axial center, and ejected into the surrounding open boundary. At low rotation speeds, it was found that the oil flow is of single-phase, and the drag torque is linearly proportional to the rotation speed since the shear stress on the clutch plate increased monotonically. In the single-flow regime, the slope of drag torque curve was controlled with the clearance between the clutch plates. The drag torque reached a peak value at a certain rotation speed, and it decreased gradually after the peak. These observed phenomena were due to the aeration from the inner gap on the disk, and the bubble volume fraction was directly related to the drag torque. The peak of drag torque was controlled by both the flow rate of supplied ATF and the arrangement of grooves on the frictional material. It also was found that the smooth ejection of ATF and the enhancement of aeration led to a reduction in the drag torque.

Model for Predicting Drag Torque in Open Multi-Disks Wet Clutches

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Shoaib Iqbal ◽  
Farid Al-Bender ◽  
Bert Pluymers ◽  
Wim Desmet
Keyword(s):  
Stokes Equations ◽  
Volume Fraction ◽  
Automatic Transmission ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Drag Torque ◽  
Navier Stokes Equations ◽  
Transmission Fluid ◽  
Flow Pressure ◽  
Air Film

A mathematical model based on continuity and Navier-Stokes equations, considering laminar flow in the gap between the disks, is presented to estimate the drag torque in open multidisks wet clutches. By taking into account the effects of Poiseuille and centrifugal forces, the flow pressure and velocity fields are investigated. The model quantifies the volume fraction of fluids and predicts the evolution of film shape. The drag torque estimated by the model is the sum of drag torque due to shearing of automatic transmission fluid (ATF) and the mist (suspension of ATF in air) film. In order to validate the model, experiments are performed on SAE# 2 test-setup under actual operating conditions of clutches. The model is capable of predicting the drag torque under conditions of variable flow rate and different disks rotational state for higher clutch speed range.

Parametric analysis of the drag torque model of wet multi-plate friction clutch with groove consideration

2018 ◽  
Vol 70 (7) ◽  
pp. 1268-1281 ◽  
Author(s):  
Peng-hui Wu ◽  
Xiaojun Zhou ◽  
Chenlong Yang ◽  
Haoliang Lv ◽  
Tianhao Lin ◽  
...  
Keyword(s):  
Parametric Analysis ◽  
Multigrid Method ◽  
Automatic Transmission ◽  
Solution Process ◽  
Operating Conditions ◽  
Distribution Model ◽  
Drag Torque ◽  
Content Type ◽  
Wet Clutch ◽  
Friction Clutch

Purpose The purpose of this paper is to reduce the drag loss and study the effects of operating conditions and groove parameters such as flow rate and temperature of automatic transmission fluid, clearance between plates, groove depth and groove ratio on the drag torque of a wet clutch for vehicles, parametric analysis of the drag torque model of wet multi-plate friction clutch with groove consideration. Design/methodology/approach Both experimental and numerical research was carried out in this work. Parametric groove models, full film lubrication flow model and pressure distribution model are established to investigate the effects of the grooves on drag torque of a wet clutch. Multigrid method is used to simplify the solution. Findings In this paper, a drag torque model of a wet multi-plate friction clutch based on the basic theory of viscous fluid dynamics is examined through experimental and numerical methods that take grooves into account, and the change trend of drag torque with operating conditions and groove parameters is analyzed. Originality/value Multigrid method is used to solve the governing equations, which simplifies the solution process because of the restrictions and interpolation operations between the adjacent layers of coarser and fine grids. These works provide insight into the effect regularity of operating conditions and groove parameters on drag torque of a wet multi-plate friction clutch. Furthermore, variable test conditions and sufficient experimental data are the main functions in the experimental research.

scholarly journals Mathematical Model and Experimental Evaluation of Drag Torque in Disengaged Wet Clutches

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Shoaib Iqbal ◽  
Farid Al-Bender ◽  
Bert Pluymers ◽  
Wim Desmet
Keyword(s):  
Flow Rate ◽  
Stokes Equations ◽  
Automatic Transmission ◽  
Experimental Results ◽  
Navier Stokes ◽  
Drag Torque ◽  
Navier Stokes Equations ◽  
Rotational States ◽  
Disk Size ◽  
Transmission Fluid

When the clutch is in disengaged condition, ideally no torque should be transmitted. However, in reality, the relative motion between the disks causes viscous shearing of fluids in the gap. This results in a drag torque which is considered as a loss. The objective of the present study is to formulate a drag torque model as well as to experimentally evaluate the effect of several parameters on the drag torque. A model based on continuity and Navier-Stokes equations, considering laminar flow, is deduced. The drag torque estimated by the model is the sum of drag torque due to shearing of the automatic transmission fluid (ATF) and mist (suspension of ATF in air) film. In order to validate the model and characterize the drag torque, experiments are performed using an SAE no. 2 test setup under real conditions of variable ATF flow rate and disks' rotational states for higher clutch speed range. The drag torque predicted by the model is in good agreement with the experimental results obtained by varying the flow properties and disks' rotational states. By analyzing the experimental results, a factor by which, the variation in parameters such as ATF flow rate, ATF temperature, disk size, and disk rotational state influencing the drag torque is determined.

Computational Simulation Study on the Viscous Drag of the Automotive Wet Clutch for Prediction and Control

2015 ◽  
Author(s):  
In-Ha Sung ◽  
Jin Seok Ryu
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Automatic Transmission ◽  
Computational Simulation ◽  
Viscous Drag ◽  
Drag Torque ◽  
Wet Clutch ◽  
Pattern Shape ◽  
Friction Plate ◽  
Groove Pattern

The reduction of drag torque is an important issue in terms of improving transmission efficiency. Drag torque in a wet clutch occurs because viscous automatic transmission fluid flow narrow gap between friction plate and separate plate. The main purpose of this study is to observe the effects of the various parameters on the drag torque using finite element simulation. In this study, the simulation analysis reveals that as the rotational speed increases, the drag torque generally increases to a critical point and then decreases sharply at a high speed regime. Depth of groove on the friction plate plays an important role in controlling drag torque peak. An increase in the depth of groove causes a decrease in shear stress; thus, the drag torque also decreases according to Newton’s law of viscosity. Also, an observation of the effect of the angle of groove pattern shape shows that the drag torque changes with groove pattern shape. Therefore, the optimum angle of the groove pattern should be determined carefully, considering both the clutch performance and drag reduction. It is expected that the results from this study can be very useful as a database for clutch design and to predict the drag torque for the initial design with respect to various clutch parameters.

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