汽车离合器壳开裂的系统分析

Analysis of Bus Clutch Housing Cleavage

在台架条件下，通过静态应变仪的测试及对离合器壳断口的微观分析结果表明：ＳＹ６４７４轻型客车动力总成各分总成间的装配偏差使离合器壳拨叉孔处应力升高，达该车离合器壳材料持久疲劳强度极限的１８％；动力总成弹性悬置装配偏差使离合器壳下边筋的柱锥过渡处应力升高，达该车离合器壳材料持久疲劳强度极限的２３％。该离合器壳开裂为疲劳破坏，开裂源在离合器壳下部的缩孔处。由于断口中存在着气孔、夹杂物和疏松现象，这些缺陷使材料抗冲击性能变差，抗疲劳强度降低。

On the dais, the microscopic analysis of clutch housing nick was made through the test made by quiescent state defoemeter.The assembling deviation among some motive power in SY6474 mini-bus makes stress heighten in clutch housing shift yoke opening, by 18% of the clutch housing material endurance fatigue strength limit.The assembling deviation of motive power elastic suspension makes stress heighten in clutch housing lower boundary cylindro-conical transition, by 23% of the clutch housing material endurance fatigue strength limit.The clutch housing cleavage is fatigue breakdown. The cleavage source is in the draw of the clutch housing lower side casting defect.There are blowholes, occluded foreign substance and puff. These defects make material shock resistance bad, fatigue strength depression. These make early cleavage finally