高强化柴油机铝活塞销孔开裂分析及改进

李倩^1,2，王志龙^1,2，张俊青^1,2，王世利^1,2，王君^1,2，刘世英^1,2

1.滨州渤海活塞有限公司，山东 滨州  256602；2.山东省发动机活塞摩擦副重点实验室，山东 滨州  256602

摘要：基于失效机理分析某国六高强化柴油机铝活塞耐久试验中销孔开裂问题，发现活塞失效的主要原因为活塞销椭圆变形过大，导致销孔部位水平方向受力较大，疲劳强度不足。通过将活塞销孔由圆柱孔改为椭圆孔、在活塞销孔部位预留空间、将活塞销内孔喇叭口改为通孔等措施对销孔结构进行改进，采用有限元分析软件对改进方案进行模拟计算，并结合销孔疲劳试验和耐久试验进行验证。结果表明：改进后的活塞销孔平均负载增加约6.5%，改进后未出现活塞销孔开裂问题。

关键词：铝活塞；销孔开裂；有限元；试验验证

Analysis of cracking of aluminum piston pin hole for high-strength diesel and its improvement

LI Qian^1,2, WANG Zhilong^1,2, ZHANG Junqing^1,2, WANG Shili^1,2, WANG Jun^1,2, LIU Shiying^1,2

1. Binzhou Bohai Piston Co., Ltd., Binzhou 256602, China;

2. Shandong Province Key Laboratory of Engine Piston Cylinder Kits, Binzhou 256602, China

Abstract：Based on the analysis of the failure mechanism on the problem of pin hole cracking in the endurance test of aluminum piston of high-strength diesel engine,the main reason of piston failure is that the elliptical deformation of piston pin is too large, which makes the horizontal force on the pin hole position greater, which brings insufficient fatigue strength.The optimize structure of the piston pin hole is improved by changing the cylindrical hole into the elliptical hole, reserving the space in the piston pin hole position, changing the piston pin inner hole bell mouth to the through hole, the finite element analysis software is then used to simulate and calculate the optimization scheme, and the results are verified by fatigue test and durability test. The results show that the average load of the piston pin hole increases by about 6.5%, and the piston pin hole does not crack.

Keywords: aluminum piston; pin bore cracking; finite element; test verification