Multi Disc Wet Clutch with Oil Spatter Cooling System in Main Manual Shift Transmission for Tractors 2012-01-2004
The scope of tractor usages are widely expanding to various non-agricultural and construction/earthmoving applications like loaders, dozers etc. The tractors with manual transmission driveline subjected to such heavy duty cycles are having conventional dry type clutches in general. These types of dry clutch when operated in such heavy application generate large amount of heat within shorter period of time on the surfaces of friction discs. This increase in disc surface temperature determines not only the level of the friction but also the rate of wear and durability. Number of clutch operation per minute for this application is also increasing to meet the improved productivity requirements.
Analysis shows that the rate of heat removal from the friction disc through oil flow system is higher compared to oil immersion type. In this work, an oil spatter concept is designed to provide active circulation of oil to the multi disc clutch during engaged conditions. The system is designed in such a way to cut-off the oil flow in to the clutch unit while clutch disengagement. This arrangement provides improved heat removal rate and significantly reduces the drag torque which in turn will increases the clutch life by 6 to 7 times more than that of the conventional dry clutch.
A mathematical model is developed to predict the interfacial surface temperature on the friction discs during the engagement. A complimentary numerical model is also made to determine the cooling oil flow rate based on the clutch slip relation and interface temperature. The effects of drag torque and thermal properties on the performance behavior of the clutch system are investigated to facilitate the conceptual design of oil spatter wet clutch system. An experimental setup is built. The result of analytical model is validated with that of experimental setup.