李杰1，姜明文2
1.潍柴动力扬州柴油机有限责任公司技术中心，江苏扬州225000；2.扬州中远海运重工有限公司技术中心，江苏扬州225000
摘要：为解决某型柴油机高压油管漏油率较高问题，分析故障油管断裂部位、断口形貌特征、金相组织、振动测试结果及受力，确定高压油管断裂的主要原因为墩头及过渡区域设计不合理，导致其疲劳破坏而发生脆性断裂；优化高压油管结构与管型，改进管夹布置方式，增加油管稳定性；改进油管镦头尾部结构，增大锁紧螺母与镦头贴合面装配应力。振动及耐久试验证结果表明：改进后的高压油管平均破坏循环次数提高70.94%，满足疲劳寿命要求，改进方案有效，并成功应用于市场。
关键词：柴油机；高压油管；断裂
Abstract:In order to solve the problem of a high fuel leakage rate of the high pressure pipe of a diesel engine, fracture location,fracture surface morphology and metallographic, the vibration and the stress are investigated. The results show that the fracture is caused by unreasonable design of the pipe heading joint which leads to fatigue failure and brittle fracture. The structure and pipe type of highpressure tubing are optimized, the arrangement of pipe clips is improved, and the stability of tubing is increased;the structure of upsetting head tail is improved, and the assembly stress between locking nut and upsetting head is increased.The results of vibration and durability test show the average number of failure cycles of the improved high pressure tubing is increased by 70.94%, which meets the requirements of fatigue life,and the improved scheme is effective and the pipe is successfully applied to the market.
Keywords:diesel engine; high pressure fuel pipe;fracture
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