【正文】 滑油；也可能是無(wú)意中引入的，例如在光滑的橡膠輪胎和潮濕的路面之間的水。潤(rùn)滑劑的分布也決定了系統(tǒng)的選擇。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。還有，它還需要更大的動(dòng)力來(lái)克服這種不斷增大的摩擦。 (b)hydrostatic。 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。 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。 關(guān) 于潤(rùn)滑，還有許多其他的系統(tǒng)，針對(duì)各種類型的潤(rùn)滑劑，對(duì)不同類型的運(yùn)動(dòng)零件是有效的。 處于無(wú)潤(rùn)滑滑動(dòng)和流體膜潤(rùn)滑之間的潤(rùn)滑被稱為邊界潤(rùn)滑。潤(rùn)滑劑通過(guò)潤(rùn)滑膜來(lái)增加滑動(dòng)面之間的距離，從而減輕磨料污染物和表面不平度造成的損傷，因此，10 減輕了磨損和由固體與固體之間接觸造成的磨損。為了獲得最高絕緣性能，潤(rùn)滑劑中不能含有任何雜質(zhì)和水分。 （ 3）干潤(rùn)滑。在一個(gè)自鎖的軸承裝置中， 這種相對(duì)運(yùn)動(dòng)就是轉(zhuǎn)動(dòng)。最近在軸承材料上的研究已有了一定的突破。從數(shù)學(xué)上的解釋就需要接觸壓力和流體機(jī)械的理論。這些表面通常是要發(fā)生相對(duì)滑動(dòng)。 傳遞動(dòng)力 。在邊界潤(rùn)滑狀態(tài)，潤(rùn)滑劑黏度對(duì)摩擦力的影響不象其化學(xué)性質(zhì)的影響那么顯著。 為了把零件隔離開(kāi)，潤(rùn)滑膜中的壓力必須和作用在滑動(dòng)面上的負(fù)荷保持平衡。這種系統(tǒng)用于草坪修剪機(jī)中發(fā)動(dòng)機(jī)的曲軸箱，對(duì)曲軸、連桿和活塞等零件進(jìn)行潤(rùn)滑。因?yàn)樗梢员ＷC運(yùn)動(dòng)部件的運(yùn)動(dòng)和克服摩擦力。而膨脹可以使得軸承或滑動(dòng)表面之間的配合更緊密。1 外文文獻(xiàn) 原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overe the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overe in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedgeshaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. 2 As a result ,heat is produced from the added energy required to keep the parts turning and overe friction. The friction caused by the wedging action of surface irregularities can be overe partly by the precision machining of the surfaces. However, even these smooth surfaces may require the use of a substance between them to reduce the friction still more. This substance is usually a lubricant which provides a fine, thin oil film. The film keeps the surfaces apart and prevents the cohesive forces of the surfaces from ing in close contact and producing heat . Another way to reduce friction is to use different mate