一台铁牛-55型拖拉机在作业中,发生离合器摩擦片折断故障,更换了从动盘总成后工作不久,故障又重新出现。检查发现从动盘上的钢片也折断了,而且钢片与花键轮毂连接的铆钉松动。后在清洗离合器壳体内油污时,看到壳体外有清洗油渗出,发现离合器壳体已开裂,且裂缝长度已达壳体圆周长的一半,这才发现摩擦片折断的原因。离合器正常工作时,离合器轴中心线应与曲轴中心线重合, A tractor in the operation of a tractor -55, the occurrence of clutch friction plate broken fault, replace the driven plate assembly work shortly after the fault re-emerged. The inspection revealed that the steel plate on the driven plate was also broken, and that the rivet connecting the steel plate to the splined hub was loosened. After cleaning the oil in the clutch housing, it was found that there was a leakage of cleaning oil outside the housing. The clutch housing was cracked and the length of the crack reached half of the circumference of the housing, which showed that the friction plate was broken. Clutch normal work, the clutch shaft centerline should coincide with the centerline of the crankshaft,