| There are friction and abrasion always in running machines. To reduce them, lubrication is needed. Radial-thrust floating-ring hybrid bearing, which can not only sustain the radial load but also the axial load, colligate the strongpoints of pure dynamic and static bearings. Since it was introduced in the 70s of 20th century, many studies have been performed. However, many of those studies focused on the structures of bearing itself. And few studies have been done on the gas cavity caused by the decrease of oil-pressure in the oiling system, which influences bearing. According to the papers by AN Qi or SHEN Xin-min, we know that gas cavity in the oil recess can influence the static characteristics of bearings.My paper attempts to attain some conclusions from this study of gas cavity, and these conclusions may be useful to controlling bearing operation.The oiling system is an important part of Radial-thrust floating-ring hybrid bearing.There are some factors that lead to the variation of oil-pressure in the oiling system. The oiling system consists of many components, so it is inevitable that the stabilization of oil-pressure will be distracted as some of them don't work properly as usual. For example, there might be a blockage in the filter as a result of oily soil; also there might be some leakage in the whole oil circuit. As oil pressure is higher, the center of journal is closer to the center of bearing, thus the eccentricity is decreased. On the other hand, as oil pressure is low, there is a deviation between them, thus the eccentricity is decreased. These will influence the characteristics of bearing indirectly.The static characteristic of bearing includes the distribution of oil pressure,frictional force, friction torque, friction power and oil temperature.Oil film is also a variable link in the whole system. The variation of oil pressure will influence the dynamic characteristics of oil film indirectly.In this paper, firstly, to discuss the effects caused by oiling system components under the variation of oil pressure. Secondly, to research the phenomena of gas cavity in the oil recess, which was caused by the low oil pressure and to analyze its influence on the dynamic and the static characteristics of bearing. Thirdly, to make an initial study of two phrase flow lubrication in the case of turbulent flow. Fourthly, to give an introduction about the static characteristics experiment, which has the plan, the devices and the methods of experiment and the metering equipment. Finally, to process data and make graphs, to contrast experimental results with calculation results and make certain explanations and to come to some conclusions.The contents are as followed:1. To make an analysis of how the components of bearing influence the stability of oil pressure.2. Firstly, to make new hypothesis hi the case of gas cavity existing hi oil recesses. Secondly, new mathematic model is made. Thirdly, the edge condition of oil recess was introduced. Fourthly, the function relationship was made between oil pressure and density of two phrase flow. Finally, the concerned calculation formulas of static and dynamic characteristics were deduced.3. By use of the Finite Element Method, the numerical computation methods of the pressure distribution, the dynamic characteristics and the static characteristics ofbearing are presented.4. Computation formulas of pressure distribution and dynamic and static characteristics of Radius-thrust float ring hybrid bearing are deduced. The two phrase flow Reynolds Equation in the case of turbulence is developed by adding the turbulent factors in the non-normal variable-density Reynolds Equation mentioned above.5. By the means of experiment, some data were measured. Then these data were processed and graphs were made and illustrated. Finally, a contrast was made between experimental result and computation result. The difference between them was analysed and some conclusions were attained. |
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