Study On The Static And Dynamic Characteristics For The Ladder Recesses Hybrid Bearings With Capillary Throttle

With the large-scale, high precision, high speed, etc development of the modern mechanical equipments , the liquid lubrication hybrid journal bearings become more and more widely used in rotating machinery. Liquid lubrication hybrid bearings have large load capacity, stable and reliable operation. Lubricate capability will directly influence the credibility and life-span of the whole machine tool. At present, many domestic and abroadresearchers are progressing about the research for hybrid bearings. but for hybrid bearings, mature theory still haven't be formed. The difficulty of researching the hydrody bearing exists on the complexity of the oil flow, which coupled with the formation of static and dynamic pressure. Their work mechanism can't be explained by the solution of dynamic pressure or static pressure method. The throttles are used as regulate elements, on the entrance to hydrostatic oil recesses. This paper adopts the most commonly used capillary as hybrid bearings throttling components. In order to utilize hybrid bearings more effectively, and research hybrid bearings'internal operation mechanism and characteristic, it's necessary to optimize the design of hybrid bearings.This paper mainly study the characteristics of hybrid bearings based on capillary throttles, the main research contents and achievements are as follows:Analyzing the composition and work principle of the hybrid bearings based on capillary throttles. And illustrates that ladder hybrid bearings are superiority than hybrid bearings with no ladder .And establishing the Reynolds equation of the mechanical properties of the hybrid bearings.Based on MATLAB software, the ladder hybrid bearings'static performance was solved with finite element method, oil film bearing pressure field was calculated. And research the oil film pressure distribution when changing the depth of the ladder of the hybrid bearing.The formation mechanism of the dynamic coefficients of hybrid bearings (rigidity coefficient and damping coefficient of the oil film) was discussed and explained. Eight dynamic coefficients were calculated by the finite difference method. Finally, the stability of the bearings was judged according to the dynamic coefficients. The results were that hybrid bearings were in a stable state when the eccentricity was less than 0.5. The model and boundary conditions of hybrid bearings was established to simulating hybrid bearings'internal three-dimensional flow in the GAMBIT software. And in FLUENT software, laminar model and separate solver was chosen, pressure distribution and temperature distribution were computed. The results calculated by Fluent software was close to the results calculated by numerical method, and similar to the actual operating conditions. When bearing eccentricity was changed, the results of the maximum temperature, maximum pressure, bearing capacity and the deviation angle were analyzed.The study methods and the results of the ladder hybrid bearings with three recesses based on capillary throttling in the thesis would provide important reference value for the new kind of hybrid bearings. It would play an important role in the theory of bearing designing and researching in the operation condition.