裝載機(jī)動(dòng)臂間歇下降是怎么回事？

裝載機(jī)在動(dòng)臂操作手柄扳到動(dòng)臂下降位置時(shí)，動(dòng)臂不是平穩(wěn)下降，而是間歇下降，造成整機(jī)前后搖晃，動(dòng)臂起升過(guò)慢，出現(xiàn)這種現(xiàn)象是怎么回事呢？

引起這種現(xiàn)象的原因可能是裝載機(jī)起升滑閥卡滯，在動(dòng)臂下降過(guò)程中，閥芯滑動(dòng)不暢，油口不能完全打開(kāi)，使動(dòng)臂缸有桿腔進(jìn)油不足，而當(dāng)翻斗加載時(shí)，動(dòng)臂在自重的作用下，有桿腔的容積增大速度大于進(jìn)油速度，出現(xiàn)負(fù)壓。這時(shí)在無(wú)桿腔產(chǎn)生一個(gè)反作用力，阻止液壓缸活塞向無(wú)桿腔滑動(dòng)，當(dāng)作用力與反作用力達(dá)到平衡時(shí)，就會(huì)造成動(dòng)臂停止下降。而這時(shí)有桿腔仍然在進(jìn)油，負(fù)壓逐漸減小，液壓缸兩腔又需要達(dá)成新的平衡，這樣就造成了動(dòng)臂斷續(xù)下降，并引起整機(jī)的劇烈搖晃。當(dāng)山東裝載機(jī)空載時(shí)，由于自重減小，下降速度減慢，故障現(xiàn)象不明顯。當(dāng)動(dòng)臂起升時(shí)，因?yàn)樾枰蛪簩?dòng)臂頂起，不會(huì)產(chǎn)生負(fù)壓，但因閥芯打開(kāi)不完全而造成動(dòng)作緩慢。
The reason for this phenomenon is probably caused by Shandong loader lifting spool valve sticking, in the boom-down process, the valve slide poor port can not be completely open, so that the boom cylinder rod chamber into the lack of

oil, and when when the dump load, boom under the action of gravity, there is an increase in the volume of the rod chamber faster than the inlet velocity, appear negative. Then in the rod chamber to generate a reaction force to prevent hydraulic cylinder piston rod chamber slide, when the action and reaction equilibrium, it will cause a boom stopped falling. And then there is still the rod into the oil chamber, the negative pressure decreases, the hydraulic cylinder two chambers and the need to reach a new equilibrium, thus causing intermittent boom down and cause violent shaking machine. When Shandong loaders load, due to the weight decreases, the rate of decline slowed, the fault is not obvious.When lifting the boom when the boom because of the need hydraulic jacking, will not produce negative pressure, but not completely open the valve and cause slow.

這時(shí)應(yīng)該拆檢裝載機(jī)主控閥，閥芯有些卡滯，清洗后試驗(yàn)，仍有卡滯，再用卡尺測(cè)量，發(fā)現(xiàn)閥芯失圓，更換新閥后，故障解除。
At this point it should be overhauled Shandong loader master valve spool some catching, after cleaning the test, there are still catching, then caliper, found the spool out of round, after valve replacement, the fault is removed.