Cavitation damage of cylinder block and cylinder liner of small loader will cause cracks and even through holes, resulting in cooling water entering the cylinder and engine oil, and then significantly reduce the service life and working reliability of diesel engine. The main cause of cavitation is the vibration of cylinder liner.

當(dāng)活塞到達(dá)上止點的時候，側(cè)壓力的作用方向發(fā)生另外變化，活塞從缸套的一面橫擺到另外對面，就出現(xiàn)了活塞擺的現(xiàn)象。由于活塞跟缸套之間留有熱間隙，所以活塞的擺動還是有沖擊性的。這種沖擊引起缸套的強(qiáng)烈振動。

When the piston reaches the top dead center, the action direction of the side pressure changes. The piston swings from one side of the cylinder liner to the other side. Because there is a thermal gap between the piston and the cylinder liner, the swing of the piston is still impulsive. This impact causes strong vibration of the cylinder liner.

當(dāng)缸套壁振動時，水腔中發(fā)生交替的拉伸和壓縮，從而使外壁附近的水域中產(chǎn)生局部的高壓和真空泡。在高真空的作用下，冷卻水蒸發(fā)成氣泡，有的真空泡和氣泡發(fā)生在氣缸套外壁微小的針孔中，或者是在振動的作用下被擠入針孔。

When the cylinder liner wall vibrates, alternating tension and compression occur in the water chamber, resulting in local high pressure and vacuum bubbles in the water near the outer wall. Under the action of high vacuum, the cooling water evaporates into bubbles. Some vacuum bubbles and bubbles occur in the tiny pinholes on the outer wall of the cylinder liner, or are squeezed into the pinholes under the action of vibration.

當(dāng)真空泡或氣泡受到高壓沖擊而破裂時，就在破裂區(qū)附近產(chǎn)生壓力沖擊波，其壓力可達(dá)數(shù)十大氣壓并沖擊氣缸外壁，這樣頻繁的反復(fù)沖擊，就使缸套表面急劇損壞。我們?yōu)榱朔乐寡ㄎg，目前常用的方法是：減小氣缸與活塞之間的間隙，從而減小缸套的振動；采用長的活塞裙部；加大冷卻水流速，改進(jìn)水流方向及冷卻系的結(jié)構(gòu)；增加氣缸套的支承剛度；改進(jìn)氣缸套的材料及工藝，以提高其抗穴蝕能力等等。

When the real bubble or bubble is broken by high-pressure impact, a pressure shock wave will be generated near the fracture area, and its pressure can reach tens of atmospheres and impact the outer wall of the cylinder. Such frequent repeated impact will sharply damage the surface of the cylinder liner. In order to prevent cavitation, the commonly used methods are: reduce the gap between cylinder and piston, so as to reduce the vibration of cylinder liner; Adopt long piston skirt; Increase the flow rate of cooling water, improve the flow direction and the structure of cooling system; Increase the support stiffness of cylinder liner; Improve the material and process of cylinder liner to improve its cavitation resistance, etc.

小型裝載機(jī)的氣缸套穴蝕的原因就是上面介紹的這些，再出現(xiàn)了這種現(xiàn)象之后一定要及時修理，但是預(yù)防也是關(guān)鍵。

The reasons for the cavitation of cylinder liner of small loader are those described above. After this phenomenon occurs again, it must be repaired in time, but prevention is also the key.