機(jī)械類畢業(yè)設(shè)計(jì)外文翻譯---軸承的摩擦與潤(rùn)滑-免費(fèi)閱讀
【正文】 需要很少的甚至是12 不需要 潤(rùn)滑劑。齒輪的齒嚙合是轉(zhuǎn)動(dòng)與相對(duì)滑動(dòng)的合成。 第三種潤(rùn)滑方式是一種現(xiàn)象，這種現(xiàn)象是，一種潤(rùn)滑劑是用在發(fā)生相對(duì)轉(zhuǎn)動(dòng)的工作表面之間。 （ 5） 固體潤(rùn)滑。在 潤(rùn)滑劑和潤(rùn)滑表面之間這種化學(xué)的和物質(zhì)的相互滲入作用，就是為了提供給機(jī)器一個(gè)良好的工作狀態(tài)。 在象減振器這樣的能量傳遞裝置中 和在承受很高的間隙載荷的齒輪這樣的機(jī)器零件的周圍，潤(rùn)滑劑被作為減振液使用。 其他作用 除了減小摩擦外，潤(rùn)滑劑還經(jīng)常有其他的用途。 潤(rùn)滑劑通過減小摩擦和將產(chǎn)生的熱量帶走來降低溫度。在流體潤(rùn)滑狀況時(shí)，摩擦力與流體黏度成正比。邊界潤(rùn)滑包括大部分潤(rùn)滑現(xiàn)象，通常在機(jī)器的啟動(dòng)和停止時(shí)出現(xiàn)。盡管流體通常是油、水和其他很多種類的液體，它可以是氣體。 盡管潤(rùn)滑的主要目的之一是為了減小摩擦力，任何可以控制兩個(gè)滑動(dòng)表面之間摩擦和磨損的物質(zhì)，不管是液體還是固體或氣體，都可以歸類于潤(rùn)滑劑。 在低速度運(yùn)動(dòng)的部件，一個(gè)油溝足以將所需要的數(shù)量的潤(rùn)滑劑送到相互運(yùn)動(dòng)的表面。也就是說用軟的或硬的金屬組成表面?？梢允狗肿舆\(yùn)動(dòng)。這些靜止部件的凹谷和尖峰必須整理光滑，而且能相互抵消。熱能是有破壞性的。 (e)solid film. Hydrodynamic lubrication means that the loadcarrying surfaces of the bearing are separated by a relatively thick film of lubricant, so as to prevent metal contact, and that the stability thus obtained can be explained by the laws of the lubricant under pressure ,though it may be。 even some metals monly serve as sliding surfaces in some sophisticated machines. Function of lubricants 4 Although a lubricant primarily controls friction and ordinarily does perform numerous other functions, which vary with the application and usually are interrelated . Friction control. The amount and character of the lubricant made available to sliding surfaces have a profound effect upon the friction that is encountered. For example, disregarding such related factors as heat and wear but considering friction alone between the same surfaces with on lubricant. Under fluidfilm conditions, friction is encountered. In a great range of viscosities and thus can satisfy a broad spectrum of functional requirements. Under boundary lubrication conditions , the effect of viscosity on friction bees less significant than the chemical nature of the lubricant. Wear control. wear occurs on lubricated surfaces by abrasion, corrosion ,and solidtosolid contact wear by providing a film that increases the distance between the sliding surfaces ,thereby lessening the damage by abrasive contaminants and surface asperities. Temperature control. Lubricants assist in controlling corrosion of the surfaces themselves is twofold. When machinery is idle, the lubricant acts as a preservative. When machinery is in use, the lubricant controls corrosion by coating lubricated parts with a protective film that may contain additives to neutralize corrosive materials. The ability of a lubricant to control corrosion is directly relatly to the thickness of the lubricant film remaining on the metal surfaces and the chermical position of the lubricant. Other functions Lubrication are frequently used for purposes other than the reduction of friction. Some of these applications are described below. Power transmission. Lubricants are widely employed as hydraulic fluids in fluid transmission devices. Insulation. In specialized applications such as transformers and switchgear , lubricants with high dielectric constants acts as electrical insulators. For maximum insulating properties, a lubricant must be kept free of contaminants and water. 5 Shock dampening. Lubricants act as shockdampening fluids in energy transferring devices such as shock absorbers and around machine parts such as gears that are subjected to high intermittent loads. Sealing. Lubricating grease frequently performs the special function of forming a seal to retain lubricants or to exclude contaminants. The object of lubrication is to reduce friction ,wear , and heating of machine pars which move relative to each other. A lubricant is any substance which, when inserted between the moving surfaces, acplishes these purposes. Most lubric
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