缸套表面复合织构润滑性能理论及试验研究

Theoretical and Experimental Study on Lubrication Performance of Composite Textures on Cylinder Liners

通过建立织构化缸套活塞环混合润滑理论计算模型,基于织构协同润滑机理模拟分析,设计、计算了槽腔及交叉沟槽2种复合织构,同时结合摩擦学性能试验,研究了复合织构对摩擦副润滑性能的影响。结果表明,复合织构润滑性能明显优于单一织构,较槽腔复合织构而言,交叉沟槽织构在改善润滑摩擦性能方面效果更好。复合织构改善润滑的原理是:在上止点处通过协同叠加形成局部高压油膜,从而缩小了混合润滑范围;在行程中部区域通过协同互补有效地弥补了空化区域的油膜压力衰减,从而延展了有效承载面积。相比单一凹腔织构,槽腔复合织构在各行程中部区域的最小膜厚比可增加34.3%左右,交叉沟槽织构可增加57.6%,槽腔复合织构的循环摩擦功耗可降低8.2%,交叉沟槽织构可降低19.7%。摩擦磨损试验结果显示,相对于未经织构试样,织构试样表面的润滑性能可得到显著改善,尤其是交叉沟槽织构,其摩擦系数最大可降低48.1%。

A mixed lubrication model for textured cylinder liner-piston ring friction pair is constructed.By simulating and analyzing the collaborative lubrication mechanism of textures,two composite texture schemes,dimple-groove and cross groove textures,are designed and calculated.The effects of composite textures on the lubrication performances of friction pair are studied associated with the tribological performance tests.It is found that the lubrication performances of composite textures are obviously better than that of single textures,and cross groove texture outperforms dimple-groove texture.The partial high film pressure is formed by collaborative overlying in TDC area to reduce mixed lubrication range,and the effective bearing area extends by collaborative complementation to increase film pressure in cavitated area at middle of the engine stroke,thus the composite textures greatly facilitate lubrication performance.Compared with the single dimple texture,in the regard of the minimum film thickness ratio in the middle of the engine stroke,the dimple-groove composite texture makes it increase by 34.3% while the cross groove texture makes it increase by 57.6%; as to the friction power loss in an engine cycle,the dimple-groove composite texture makes it decrease by 8.2% while the cross groove texture makes it decrease by 19.7%.The tribological performance tests reveal that the surface lubrication performance of textured samples can be modified more effectively than the sample without textures,especially the cross groove texture enables to reduce friction coefficient maximally by 48.1 %.