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前言柴油机曲轴在极高的压力下高速运动,由于承受复杂的交变应力,往往出现早期疲劳断裂或磨损失效。我国小功率柴油机曲轴多采用球墨铸铁制造,曲轴的断裂和早期磨损比较突出。据统计,曲轴断裂并不发生在使用初期,断裂位置基本上是在连杆轴颈过渡圆角对角线上,裂纹多数起源于连杆轴颈圆角。从曲轴断裂的宏观形貌,可以划分为裂纹的延伸区和瞬时断裂区。断口特征属于比较典型的疲劳断裂。曲轴的早期磨损主要表现在轴颈尺寸减小,与轴瓦的配合间隙增大甚至松动,导致柴油机不能正常运转。为提高曲轴疲劳强度和耐磨性,我们进行了一些试验研究工作。
Foreword Diesel crankshaft at high pressure under high-speed movement, due to bear the complex alternating stress, often appear early fatigue fracture or wear failure. China’s low-power diesel engine crankshaft multi-use ductile iron manufacturing, crankshaft fracture and early wear more prominent. According to statistics, crankshaft fracture does not occur in the early use, the fracture location is basically in the corner of the connecting rod journal fillet, the majority of cracks originated in the connecting rod fillet. From the crankshaft fracture macroscopic morphology, can be divided into crack extension and instantaneous fracture zone. Fracture characteristics belong to the typical fatigue fracture. Early crankshaft wear mainly in the journal size decreases, with the bush with the gap to increase or even loose, resulting in diesel engine can not be normal operation. To improve crankshaft fatigue strength and wear resistance, we conducted some experimental research.