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高速柴油机曲轴轴承的工况是相当恶劣的,最大油膜压力处的载荷高达350MPa,工作表面的滑油温度达160℃。为使轴承不至于因此降低抗失效的能力,在轴瓦表面电镀一层厚约0.025mm的铅锡或铅锡铜来改善轴承性能。但是镀层中的锡将随工作时间的延续而向减摩层扩散,即使在镀层与减摩层之间加入镍栅层来抑制扩散,但也不能完全杜绝这种现象,镀层中的锡含量仍会逐渐减少。久而久之,镀层的抗腐蚀能力、硬度和强度下降,在酸性滑油中镀层表面将出现腐蚀,在轴心运动剧烈变化区域,滑油产生的真空气泡会使局部表面发生气蚀。
High-speed diesel crankshaft bearings operating conditions are quite poor, the maximum film pressure at the load up to 350MPa, the working surface of the lubricating oil temperature of 160 ℃. In order to prevent the bearing from reducing the ability of anti-failure, the bearing surface is plated with a layer of 0.025mm thick tin or lead tin copper to improve bearing performance. However, the tin in the coating will diffuse to the anti-friction layer as the working time continues. Even if a nickel grid is added between the coating and the anti-friction layer to suppress the diffusion, this phenomenon can not be completely eliminated. The tin content in the coating Will gradually reduce. As time passes, the corrosion resistance, hardness and strength of the coating decrease, and the surface of the coating will appear corrosive in the acidic lubricant. In the area where the axial movement is drastically changed, the vacuum bubble generated by the lubricant will cause cavitation on the partial surface.