Friction And Wear Behavior Of Bionic Coupling On Gear Material Under Starved Lubrication Conditions

Gear as one of the important parts in transmission, are widely used in aerospace,machinery manufacturing and other engineering fields. To investigate the lubricationand wear properties will help to improve the transmission performance of gears,reduce the power consumption and decrease the mechanical maintenance costs.Especially，due to the lack of lubricant makes the oil film thickness decreased, thebalance of transmission temperature field destroyed, and the temperature of the gearsurface increased rapidly, resulting in failure of the gears, and unnecessary economiclosses. Therefore, to study the friction and wear behavior of gear surface understarved lubrication has a high theoretical and practical value.The creatures live in the soil and sand in the millions of years of evolutionevolved an excellent wear-resistant ability. The wear-resistant parts of these creaturesin addition to distribute special non-smooth morphology, also has a special structureand material properties, Synergy of these factors, forming a “rigid and white”coupling system with excellent abrasion characteristics. We applied this couplingproperty of biological to the transmission gear surface, it helps to provide a news ideato improve the tribological properties of gear to its transmission efficiency andprolong service life.In this thesis, the basic theory is based on the coupling of bionics, using the lasertechnology prepared the morphology and structure dual coupled bionic unit on thetransmission gear surface. We compared the effect of different coupling elementcharacteristics (morphology and structure) on the friction and wear properties ofbionic coupling gear surface under starved lubrication, and study the effect ofdifferent operating conditions (load and rotating speed) on the friction and wearproperties of bionic coupling gear surface under starved lubrication. We have drawnthe following conclusions:1) Using the laser technology, we prepared the bionic surfaces with dual coupling element characteristics of morphology and structure. Thegrains were refined and accompanied by solid solution strengthen, the highestmicrohardness value of the bionic unit reached to786HV.2) To the specimens withdifferent surface morphology, the deep concave specimen has the lowest frictioncoefficient, and finally stable at0.041, the weight loss is about40%of the smoothspecimens; With the increasing of the coupling area density, the weight loss isgradually decreased, but then began to rise when the area density reached to a certainvalue, indicating that exist a most suitable area density range to make the gearcoupling surfaces’ friction and wear properties optimal.3). With the increasing of theload from50N to300N, the friction coefficient decreased and then increased, theweight loss increased and the property of wear-resistant decreased; with the increasingof the rotating speed, the friction coefficient decreased and the weight loss becomesmaller.4) Through the FEM analysis shows that the wear-resistance property ofbionic coupling surface comes from the improvement of the surface contactconditions, the non-smooth morphology and area density for interface stress andtemperature distribution have a significant effect.5) Under the starved lubricationconditions, the wear-resistant mechanism of the bionic coupling surfaces mainlyinclude improve the lubricant environment, release the abrasive wear, stop theexpansion of wear scars, disperse the stress concentration and dissipative surfacetemperature.