Coupled Analysis And Experimental Research Of Marine Wet Multi-plate Friction Clutch

Slipping friction and overheating caused by shearing of oil film were common problems when wet multi-plate friction clutches were disengagement in high speed. The causes of these problems were about not only inner temperature of the clutch and displacement of the disks, but also the flow field of the lubricant. A method based on two-equation turbulence model to analyze the complex flow field of the clutch was proposed, associating with the analysis of temperature field of disks, which was based on the energy conservation of the flow field, the numerical simulation and experimental study of the flow field of lubricant, together with the thermal fluid and thermal structure of the disks in disengaged operation and the thermal structure of the friction disks in engaging process were carried out. After research the influence of the structure of the oil way, the shape of the oil groove and operating conditions on the heating problems of the disks were summarized. Therefore, it has great theory significance and important engineering values to design clutches with low-heat, long-life and high-reliability.The topic of this thesis was drawn from scientific and technological project --- key technologies and industrialization of high-performance marine gearbox of Chongqing (CSTC: 2007AB3030) and key technologies and industrialization of marine wet multi-plate friction clutch (CSTC: 2008AC3102). The research work of numerical analysis and experimental study of the coupled of the wet multi-plate friction clutches could be summarized as follows:(1) With comprehensive consideration of the structure and operating conditions of the clutch, the parameterized finite model of original oil way was established and the influence of the structure of oil way on the lubricant pressure distribution in the clearances of the disks was studied, five modified structures were presented, and then the flow field analysis with different import velocity and oil temperature of lubricant in different operating conditions were analyzed.(2) The thermal analysis of lubricant of clutch was analyzed based on the energy conservation of flow. The influence of disengagement speed, inlet flow rate, type of oil grooves and width of the clearances between the disks on the lubricant temperature and after that the deformation of the disks was presented.(3) According to the structure of pressure-regulating vale in marine wet multi-plate friction clutch and the shape of its ellipsoidal spool, the oil way model of pressure-regulating valve was established and analyzed. Then after numerical simulation of the oil way, the pressure isograms at three different opening positions, the velocity vector diagram and lubricant pressure in the inlet of the vale could be displayed, and the influence of different lubricant temperature on the flow field were specified.(4) The friction plate solid and transient heat transfer finite model with spiral and radial oil groove was established, and the transient thermal field in the engaging process of single clutch was analyzed. The temperature contour and the curves of maximum temperature-time history of friction plate were displayed. After comparison the influence of groove width on the temperature distribution was specified. Considering the friction factor on the spline of the friction disks and disk blocks, the steel disks and clutch gear, the friction force distribution between the disks and the gears of spline could be analyzed. According to the establishment the thermal-elastic model of all disks and transient analysis of thermal structure of the disks, the temperature contour and distribution between the disks in engaging process was displayed, together with the thermal-elastic deformation and contact pressure.(5) The general performance test bench of gearbox was established, and the experiment of the two-stage pressure-regulating valve was done, the lubricant pressure curves at different opening positions were recorded. According to the original structure and five modified structures, width of the clearances between the disks and parameter of oil grooves, the experimental study was carried out, and the influences of different oil structure, clearances between the disks, parameter of oil grooves, inlet flow rate and temperature on inlet pressure and outlet temperature were got. The result of test and analysis show good agreement.