Lubricant have 3 kinds of state: Complete film is lubricant, attrib border lubricant, mixture lubracation. They are 3 kinds of different position, but rely on lube to lubricate fight grind.
Lubricating is the problem that often encounters in equipment care and maintenance, but after all what is lubricant? Respecting is lubricant, the setting that appears in our brain perhaps is an oil only or grease besmear chafes to machinery face, reduce attrition. Although this idea is right, but a respect that just lubricates.
A lot of material can slip with Yu Run, the commonnest is lube (liquid state is oily) with grease (it is to cream commonly below normal temperature shape) , grease and lube photograph are stiffer, because grease was used on the foundation of lube,be stiff change an agent. The oil that slips with Yu Run kind can be to take from petrolic mineral oil, also can be artificialize learns complex oil kind, still vegetable oil, animal oil also can serve as lube.
The lubricating oil that uses now, grease basically is to come from Yu Shi oil to perhaps synthesize oil, joining additive and stiff we call the oil before changing an agent base oil, it is the bases of lube. Base oil itself has had lubricity, but the overall performance to optimize base oil, we add a few additive again. Mineral oil can satisfy common industry lubricant requirement, because this current oil tastes 90% above,be to be based on mineral oil. The performance that synthesizes oil is better, use vegetable oil basically stems from environmental protection consideration.
Additive can optimize the function of base oil, undertake inhibition to bad property, enhance favorable performance, gift even base oil a few new property. But additive is not more better, because additive belongs to chemical material, tie-in on category and scale reasonable ability wants to have anticipated result between all sorts of additive. In addition, the amount of additive considers use occasion even, for example the lube of car engine (engine oil) the kosher and dispersive function with better need, in cleared engine accumulate carbon and cigarette ash, may join in the lubricating oil that heavy load machinery uses extremely press additive, fight in order to increase grind ability.
Lubricant action
Reducing attrition is one of main purposes of lube, but besides decrease grind, lube still has other action, for example lube film is OK and antirust, prevent a metal to be corroded. Lube still can have clean effect, the impurity of equipment interior resembles the toxin in our body same, carrying course filter core to get rid of from oil. Cooling action: Heat build-up of the attrition between the metal, lube sheds classics metal surface to take away quantity of heat.
3 kinds of lubricant condition
Lubricant have 3 kinds of state: Complete film is lubricant, attrib border lubricant, mixture lubracation. They are 3 kinds of different position, but rely on lube to lubricate fight grind.
(1) complete film is lubricant (Full-film Lubrication)
Complete film is lubricant, divide again lubricate for motivation of two kinds of fluids (Hydrodynamic Lubrication) lubricate with stretch fluid motivation (Elastohydrodynamic Lubrication) . Fluid motivation lubricates is to point to: Two make the sliding friction range of opposite motion, the lubricating film of body of one laminar flow that produces at relative speed with have the aid of chafes two the face is separated completely, avoid them direct contact happens work to chafe and wear away. Stretch fluid motivation lubricates and fluid motivation is lubricant and similar, also be to rely on lubricating film of body of one laminar flow to open interface space. Different point depends on the opposite motion between interface is scroll, pressure of formation susceptive of complete film lubricating film lubricates at fluid motivation greatly, what more lubricant than fluid motivation condition leaves the lubricant space film of generation is a few thinner.
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Even if machine the metal with very tall precision, pure zero dioptre does not slip the surface, below microscope, we can see metallic surface is bumpy actually. Burr is us what naked eye can have discovered is protuberant, and those taller metals below microscope are raised the part is dot of a few peaks, naked eye sees hard, but very important however to lubricating. Lubricate to achieve complete film, the ply of lubricating film must want to exceed the height that these peaks nod, divide them completely separate, ability avoids the peak point contact between two interface. Can realize complete film to lubricate, it is best lubricant condition, can realize the most effective protection to mechanical interface.
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(2) attrib border and lubricant (Boundary Lubrication)
Although complete film is lubricant very ideal, but some circumstances can not form complete lubricating film certainly however, for example the machine is opened often stop, factor of concussion sex bear, speed, load can’t form complete film to lubricate wait for a circumstance, these circumstances can cause border to lubricate. It is admittedly good to can form complete lubricating film, but when the condition insufficient, cannot form complete lubricating film or lube film attenuates (fall in high temperature) , produce liquid attrition to transfer to dry attrition (contact directly between attrition face) the critical condition before the process, it is attrib border and lubricant. Accordingly, construct and the case is used mechanically in union, some equipment are used with respect to the requirement extremely profiling lube, contain inside extremely press additive (EP: Extreme-pressure Additives) , perhaps fight wear a lotion (AW: Anti-wear Additives) , when cannot realize complete film to lubricate, when occurrence border is lubricant, these additive develop action to protect mechanical face. This kind of additive can be adsorptive in metallic surface, form a covering layer, achieve avoid metallic tatty end. When producing border to lubricate, lean completely extremely press additive to protect metallic face. Lubricate compared with complete film, the lubricating film attrition of the generation when border is lubricant is bigger, the quantity of heat of generation is more also, but avoided complete dry friction.
The action of attrib border film, it is actually by the active of oily agent part base physisorption and chemical adsorption arise in metallic surface, form firm oily film, assure to lubricate thereby. If chafe pair of negative charge that go up is bigger, in the meantime, because the surface is rough,return, pressure of protruding summit office is very great, when velar intensity is less than the attrition force that sliding contact manages, can cause the rupture of attrib border film, generation metal is contacted directly.
Generally speaking, the lubricant condition of mechanical and slip face, form oily film on odd plane not merely, the fluid that makes ideal is lubricant condition, still can see tiny poor oily film condition even. And good the treatment precision that considers mechanical surface, exterior knaggy is affected, still have the actual state that contacts directly partly, its contact the intensity of pressure with place extremely high happening, this part metal sends plasticity flow. At this moment, lube is placed between two metals surface, the oily film of lube can attenuate, be in the place with very high pressure to produce phenomenon of oily film cracked, from the fluid as a result lubricant condition turns into lubricant condition becomes stretch fluid mixture lubracation condition. Turn to border to lubricate further.
Typical film thick 1-50nm, lubricant action reduces the fluid of lubricant, do not act well completely even, load passes the attrib border lubricating film that the interaction between small protruding body and lubricant and surface makes to bear entirely almost.
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(3) mixture lubracation (Mixed Lubrication)
Mixture lubracation condition is to point to confuse the case that complete film lubricates with border. We are mentioned in front, if the peak dot of metallic surface is taller, prep above lube when film, with respect to can mutual contact. In mixture lubracation, although major area is in complete film to lubricate, when these peak point contact, can appear local border is lubricant.