【正文】 by the moving surface to creat the pressure necessary to separate the surfaces against the load on the bearing . hydrodynamic lubrication is also called full film ,or fluid lubrication . 6 Hydrostatic lubrication is obtained by introducing the lubricant ,which is sometime air or water ,into the loadbearing area at a pressure high enough to separate the surface with a relatively thick film of lubricant. So ,unlike hydrodynanmic lubrication, motion of one surface relative to another is not required . Elasohydrodynamic lubrication is the phenomenon that occurs when a lubricant is introduced between surfaces which are in rolling contact, such as mating gears or rolling bearings. The mathematical explanation requires the hertzian theory of contact stress and fluid mechanics. When bearing must be operated at exetreme temperatures, a solid film lubricant such as graphite or molybdenum disulfide must be use used because the ordinary mineral oils are not satisfactory. Must research is currently being carried out in an effort, too, to find posite bearing materials with low wear rates as well as small frictional coefficients. In a journal bearing, a shaft rotates or oscillates within the bearing , and the relative motion is sliding . in an antifriction bearing, the main relative motion is rolling . a follower may either roll or slide on the cam. Gear teeth mate with each other by a bination of rolling and sliding . pistions slide within their cylinders. All these applications require lubrication to reduce friction ,wear, and heating. The field of application for journal bearing s is immense. The crankshaft and connecting rod bearings of an automotive engine must poerate for thousands of miles at high temperatures and under varying load conditions . the journal bearings used in the steam turbines of power generating station is said to have reliabilities approaching 100 percent. At the other extreme there are thousands of applications in which the loads are light and the service relatively unimportant. a simple ,easily installed bearing is required ,suing little or no lubrication. In such cases an antifriction bearing might be a poor answer because because of the cost, the close ,the radial space required ,or the increased inertial effects. Recent metallurgy developments in bearing materials , bined with increased knowledge of the lubrication process, now make it possible to design journal bearings with satisfactory lives and very good reliabilities. 7 中文譯文： 軸承的摩擦與潤(rùn)滑 現(xiàn)在看來(lái)，有很多這種情況，許多學(xué)生在被問(wèn)到關(guān)于摩擦的問(wèn)題時(shí)，往往都沒(méi)引起足夠的重視，甚至是忽視它。實(shí)際上，摩擦從某種程度上說(shuō)，存在于任何兩個(gè)相接觸并有相對(duì)運(yùn)動(dòng)趨勢(shì)的部件之間。而摩擦這個(gè)詞，本身就意味著，兩個(gè)或 兩個(gè)以上部件的阻止相對(duì)運(yùn)動(dòng)趨勢(shì)。 在一個(gè)機(jī)器中，運(yùn)動(dòng)部件的摩擦是有害的，因?yàn)樗档土藱C(jī)械對(duì)能量的充分利用。由它引起的熱能是一種浪費(fèi)的能量。因?yàn)椴荒苡盟鋈魏问虑椤＿€有，它還需要更大的動(dòng)力來(lái)克服這種不斷增大的摩擦。熱能是有破壞性的。因?yàn)樗a(chǎn)生了膨脹。而膨脹可以使得軸承或滑動(dòng)表面之間的配合更緊密。如果因?yàn)榕蛎泴?dǎo)致了一個(gè)足夠大的積壓力，那么，這個(gè)軸承就可能會(huì)卡死或密封死。另外，隨著溫度的升高，如果不是耐高溫材料制造的軸承，就可能會(huì)損壞甚至融化。 在運(yùn)動(dòng)部件之間會(huì)發(fā)生很多摩擦，如 動(dòng)摩擦。 啟動(dòng)摩擦是兩個(gè)固體之間產(chǎn)生的傾向于組織其相對(duì)運(yùn)動(dòng)趨勢(shì)的摩擦。當(dāng)兩個(gè)固體處于靜止?fàn)顟B(tài)時(shí)，這兩個(gè)零件表面的不平度傾向于相互嵌入，形成楔入作用，為了使這些部件“動(dòng)”起來(lái)。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。這兩個(gè)表面之間越不光滑，由運(yùn)動(dòng)造成的啟動(dòng)摩擦（最大靜摩擦力）就會(huì)越大。 因?yàn)?，通常?lái)說(shuō)，在兩個(gè)相互配合的部件之間，其表面不平度沒(méi)有固定的圖形。一旦運(yùn)動(dòng)部件運(yùn)動(dòng)起來(lái)，便有了規(guī)律可循，滑動(dòng)就可以實(shí)現(xiàn)這一點(diǎn)。兩個(gè)運(yùn)動(dòng)部件之間的摩擦就叫做滑動(dòng)摩擦。啟動(dòng)摩擦通常都稍大于滑動(dòng)摩擦。 轉(zhuǎn)動(dòng)摩擦一般 發(fā)生在轉(zhuǎn)動(dòng)部件和設(shè)備上，這些設(shè)備“抵觸”極大的外作用力，當(dāng)然這種外力會(huì)導(dǎo)致部件的變形和性能的改變。在這種情況下，轉(zhuǎn)動(dòng)件的材料趨向于堆積并且強(qiáng)迫運(yùn)動(dòng)部件緩慢運(yùn)動(dòng)，這種改變就是通常所說(shuō)的形變?？梢允狗肿舆\(yùn)動(dòng)。當(dāng)然，最終的結(jié)果是，這種額外的能量產(chǎn)生了熱能，這是必需的。因?yàn)樗梢员ＷC運(yùn)動(dòng)部件的運(yùn)動(dòng)和克服摩擦力。 8 由運(yùn)動(dòng)部件的表面不平度的楔入作用引起的摩擦可以被部分的克服，那就需要靠?jī)杀砻嬷g的潤(rùn)滑。但是，即使是非常光滑的兩個(gè)表面之間也可能需要一種物質(zhì)，這種物質(zhì)就是通常所說(shuō)的潤(rùn)滑劑，它可以提供一個(gè)比較好的、比較薄的油 膜。這個(gè)油膜使兩個(gè)表面分離，并且組織運(yùn)動(dòng)部件的兩個(gè)表面的相互潛入，以免產(chǎn)生熱量使兩表面膨脹，又引起更近的接觸。 減小摩擦的另一種方式是用不同的材料制造軸承和轉(zhuǎn)動(dòng)零件。可以拿黃銅軸承、鋁合金和含油軸承合金做例子進(jìn)行解釋。也就是說(shuō)用軟的或硬的金屬組成表