扭矩对试验机转轴微动损伤特性的影响

Investigation on Effect of Torque on Fretting Damage of Test Facility Shaft

为了探索扭矩作用下转动轴的微动损伤特性,利用JD-1轮轨模拟试验机,通过改变载荷大小,研究了制动力矩对转轴与轴承内圈过盈配合面微动损伤特性的影响,并借助激光扫描共聚焦显微镜和扫描电子显微镜观察损伤表面的磨痕和剖面微观组织,分析了不同扭矩载荷下转轴表面的微动损伤机理.结果表明:在垂向试验载荷和制动力矩的作用下,试验机转轴在与左右两端轴承内圈过盈配合面处出现了微动损伤,磨损形式主要表现为磨粒磨损和粘着磨损;随着制动力矩的增加,转轴配合面的表面磨损加剧,塑性变形层变厚约75%,微动损伤变得更严重;左端配合面的磨损和塑性变形均比右端严重,两端配合面处的塑性变形层厚度分布不均;转轴配合面处产生了微裂纹,且左端产生的裂纹多于右端,微裂纹的数量随着制动力矩的增加而增多了约6倍,裂纹扩展角度也变大约50%.

The effect of torque on the fretting damage of an interface fit between the shaft and inner surface of bearings was investigated on the JD-1 wheel/rail simulation test facility with different loads. The fretting damage mechanism of the shaft surface was analyzed by observing the wear scar and microstructure of the cross-section of specimens by using a laser scanning confocal microscope and scanning electronic microscopy. The results indicate that the fretting damage appears on the interface fit between the shaft and inner surface of bearings under vertical load and braking torque, the wear is in the form of adhesive wear and abrasive wear. With an increase in braking torque, the wear on the surfaces of shaft is more serious, the plastic deformation layer is thicker by approximately 75% , the fretting damage becomes more severe. Moreover, the wear and plastic deformation on the left surface are more severe than those on the right, and the plastic layer is uneven. Micro cracks appear on the interface fit, and there are more cracks on the left interface fit than those on the right, the number of micro cracks increase by approximately six times with the increase of the braking torque, and the crack propagation angle also increases by approximately 50% .