Research And Trial Evaluation On Wheel Hub Bearing Grease

As the key parts of automotive, the wheel hub bearing plays a role of bearing the axialload and radial load, also guiding the direction precisely at the same time. Wheel hubbearing usually working in harsh condition, such as high temperature, heavy load and highspeed and so on, so it demands on the properties of lubricant is very high. The bearing lifeand driving safety depends on the grease of wheel hub bearing seriously. Therefore, carryout an in-depth research on the wheel hub bearing lubrication, has an important significancefor save energy, increase driving safety and bearing life.The main research works of this paper are the following several parts:Firstly, investigate the failure models and mechanisms of wheel hub bearings bytheoretical and experimental methods.1200sets of failure wheel hub bearing are counted,and summarized the typical failure model of wheel hub bearing. The grease of failure wheelhub bearing are analyzed by FITR and MOA II, and the surface of failure wheel hubbearings are analyzed by SEM and EDS, in order to research for the failure mechanism ofwheel hub bearings. Index that the performance parameters for grease of wheel hub bearingby working condition investigation and failure mechanism research.Secondly, a set of technology route for grease production is designed, which is aprotection method for grease in refining state of high temperature condition, enhancing theperformance of ant-oxidation and high temperature service for grease effectively, andenhancing the velocity of blending process by improve the blending technology. Accordingto the production process in this paper, a set of saponification, blending and filter process ofproduction equipment for grease is designed, and double jacketed reactor and the externalcirculation process piping are designed too, in addition, the prediction and integralseparation algorithm is used to control the temperature of reactor.Thirdly, according to the demands of performance parameters for grease of wheel hubbearings, production materials of grease is analyzed and selected, after an initial screening,four types of grease formula are manufactured. The new designed production process andequipment are used to research the grease of wheel hub bearing by experimental method,the Physical and chemical indicators are tested, the results show that the indicators of greasesatisfy the demand of wheel hub bearing lubrication. The structures of thickener of grease are researched by FTIR technology, and carry out the molecular models in two-dimensionaland three-dimensional space. The high temperature performance of grease is analyzed byTG-DSC, the results show that the thermal weight loss of grease under350°C is low, andhas a nice performance of anti-evaporation and anti-oxidation.Besides, in order to improve the performance of grease fatherly, three kinds of size fortungsten disulfide additive are selected to add in the grease, and prepare four types of newgrease. The micro morphology, composition, particle size and high temperature stability oftungsten disulfide additive are analyzed by SEM, EDS, XRD, laser particle size analyzer,TG-DSC technology and so on, the results show that layered tungsten disulfide powder witha good high temperature performance. The different size of tungsten disulfide powder addedto the grease according to the concentration of1%to5%respectively, and the droppingpoint, EP and anti-wear properties are tested. The results show that The EP and anti-wearproperties of grease are improved noticeable by mixed with solid additive of micro scale,but the effect on the dropping point slightly. Through the experiment results of four balltester rig, indicate that the friction coefficient and diameter of scar diameter are decreasednoticeable by add the solid additive into the grease. The flow model of the nano materialstreaming in the grease is carried out in this paper, and the mechanism of anti-wear andfriction reduction for grease is analyzed too. The effect of nano material on the thickenerstructure and high temperature performance are analyze by FTIR and TG-DSC technology,the results show that add the nano material into the grease has a tiny influence on thethickener structure and high temperature performance.Finally, comparison the four kinds of new grease (M-15, P-15, H-15, L-15) with theShell and Krupp wheel hub bearing grease, and general lithium grease for domestic motorsby test rig experiments, the results show that the performance of M-15and P-15wheelbearing grease has reached or better than the similar domestic products, and reached ornearly to the international advanced level.