Papers by Keyword: Lubrication Performance

Abstract: A lubricating oil additive for armored vehicle engine was synthesized by ultrasonic dispersion and physical blending with polyisobutylene and poly alpha olefin as polymer matrix, nanoBN and nanoALN as antifriction materials and polyisobutylene succinimide as surfactant. Polymer-based lubricating oil additive, hydroxyl magnesium silicate powder additive, commercial anti-wear repairing agent Goldway and commercial anti-wear protective agent Chief were dispersed into 10W-40 armored vehicle engine special lubricating oil according to a certain mass fraction. The dissolution stability of different lubricating oil additives in lubricating oil was investigated by standing test. The effects of ultrasonic time and temperature on the dispersion of different kinds of lubricating oil additives in lubricating oil are investigated by using ultrasonic disperser and particle size analyzer. The MDW-5G multifunctional end-face friction and wear tester is used to simulate the actual working process of cylinder liner-piston ring in armored vehicles during driving, and tribological tests were carried out under conventional working conditions to evaluate the tribological properties of different lubricating oil additives. Scanning electron microscope was used to measure and analyze the wear surface morphology and friction interface elements after tribological test, and the lubrication mechanism of lubricating oil additives is revealed. The results show that the polymer-based lubricating oil additive has good dissolution stability and dispersion in lubricating oil. Compared with pure lubricating oil, the average friction coefficient of lubricating oil containing 3wt% polymer-based additives is 0.085, and the friction coefficient decreases by 38.8%. During the friction process, polymer-based lubricating oil additives form a self-repairing oil film to cover the surface of the sample through a series of complex physical and chemical reactions, which reduces the friction and wear between the grinding pairs and improves the lubricating performance of lubricating oil.

Abstract: In this paper, using Nissan car engine oil as the research object, their main physical and chemical performances and three factors of oil carrying capacity such as the maximum non-seizure load P_B, sintering load P_D and the composite wear value ZMZ are experimental analyzed in different mileage. And decay law of the lubrication performances are discussed. It was found that, after used a certain time, the oils film strength reduced relatively fast, the limit ability to work reduced not obvious, and its anti-extrusion capability will gradually deteriorate with the increase in the running time.

Abstract: The water lubrication performance of spiral groove thrust bearings was affected by different groove molded lines. The pressure fields and the load capacity of water-lubricated spiral groove thrust bearings with different groove molded lines were simulated by computational fluid dynamics. The results show that the spiral groove which can produce the best loading capacity and steadier pressure field is appropriate to water-lubricated spiral groove thrust bearing. The line spiral groove can be used for decrease the process difficult when the loading capacity require is low.

Abstract: Water-lubricated thrust bearing is a key component of certain main pump motor. In this paper, the right structure of water-lubricated thrust graphite bearings is designed based on low viscosity hydrodynamic lubrication theory by combining the bearings running working condition, and the frictional accessory material is also determined by theoretical analysis and test. The factors influencing lubrication performances of water-lubricated thrust bearings are analyzed; the methods improving lubrication performances are put forward to guarantee that water-lubricated thrust graphite bearings have the good lubrication performances, good carrying capacity and longer work life.

Abstract: This paper reports a case of lubricating property test of bearing. In order to seize the performance and the reasonable work condition of Ф480mm elliptical bearing with groove on all pads for 1000MW steam turbine, an experimental method that load is on the rotor was adopted in this paper. And the test focused on the bearing characteristics which is most concerned by designers such as power loses, temperature, flow, and flow state, etc. The influence on power loses, temperature rise, flow by the temperature and pressure of inlet oil, load, speed was studied in this test. The results show that the flow state in this bearing is changed from laminar to turbulent in the speed range 2000rpm~2200rpm and in the Reynolds number range 1325.8~1556.5. The specific pressure for the bearing with groove on the down pad is proper between 1.57MPa and 1.96MPa.

Abstract: A new coupling numerical algorithm has been developed to integrate Finite Difference Method (FDM) with Boundary Element Method (BEM) to analyze shear performance of oil film by iteratively solving a series of equations such as the film flow velocity and shear stress equations for contact bodies in bearing system. With consideration of the variations of viscosity and density with pressure and temperature, the effects of shear stress of oil film layers on lubrication performance of contact surfaces under different loadcases were discussed. Moreover, Germany-made Anton Paar MRD (Magnetic Rheologic Device) was used to determine the relationship between the viscosity and shear stress of lubricating oil. The conclusions were verified to be beneficial to the further study on lubricating performance of heavy contact components and to prolong their service lives.