scholarly journals Study on the Characteristics of Wet Clutch Drag Torque According to Phase of Oil Groove Patterns on Double Side Friction Plate

2021 ◽  
Vol 29 (12) ◽  
pp. 1073-1082
Author(s):  
Youngtaek Oh ◽  
Siyoul Jang
Keyword(s):  
Drag Torque ◽  
Wet Clutch ◽  
Friction Plate ◽  
Side Friction

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.

Experimental Research on Drag Torque for Single-plate Wet Clutch

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Hu Jibin ◽  
Peng Zengxiong ◽  
Wei Chao
Keyword(s):  
Contact Angle ◽  
Surface Tension Force ◽  
Transmission Efficiency ◽  
Viscous Drag ◽  
Drag Torque ◽  
Two Phase ◽  
Rotating Speed ◽  
Single Plate ◽  
Wet Clutch ◽  
Set Up

The relative motion between the friction and separate plates in a disengaged wet clutch causes viscous drag torque when the lubrication fluid flows through the clearance. Reduction of the drag torque is one of the important potentials for the improvement of transmission efficiency. The objective of this study is to set up an experimental rig to measure drag torque for a single-plate wet clutch. Visualization of the flow pattern in the clearance through transparent quartz was presented. Design factors and lubrication conditions were tested to evaluate the effects on drag torque. A comparison between the nongrooved plate and grooved plate was made. Plates made up of different materials were also tested to reveal the effects caused by the contact angle. Drag torque increases linearly at low rotating speeds and gradually decreases at high rotating speeds. It is confirmed that fluid completely covers the plate surface at a low rotating speed and air mixes with the fluid at a high rotating speed. A low feeding flow rate is useful to reduce drag torque. The reduction of the drag torque benefits from radial and deep grooves compared to a flat plate. A small contact angle near the stationary plate plays an important role in maintaining the oil film, however, it has little effect on the drag torque at the rotating side because the hydrodynamic force becomes dominant compared to the surface tension force. The test results help to build an accurate mathematical model based on two-phase flow lubrication.

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.

Sign in / Sign up

Export Citation Format

Share Document