销孔结构设计对活塞可靠性影响的研究

不同销孔结构参数对活塞可靠性的影响不同。对汽油机活塞,采用5种方案进行了机械负荷与热机械耦合负荷下的应力对比及液压疲劳试验下的循环寿命对比,其中相对于销孔中心设计的非对称减压弧结构更为明显地降低了应力集中现象;稳定的热负荷降低了机械负荷作用于销座部位的应力。柴油机活塞异形销孔降低销座部位应力的作用与汽油机活塞类似。分析与试验表明:柴油机活塞异形销孔与圆柱形销孔相比,提高了燃烧室喉口的拉伸应力幅值;销孔的优化设计可提高顶部的可靠性。

Piston Durability Research Based on the Pin-bore Profile Design

The different durability performances of a piston may be caused by the different parameters of the piston pin bore profile.For a gasoline engine piston,5 kinds of pin bore shapes were analyzed and compared by FEA under mechanical load and thermo-mechanical load.The hydrodynamic tests were performed to evaluate the pistons cycle life.The asymmetry relief hole relative to the gudgeon pin center appeared the best ability among them for lessening the stress concentration.The steady thermal load benefited to diminish the mechanical stress concentrated on the top of the pin boss,the stresses distribution of the pin bore circumference were uniformity under the thermo-mechanical loads.The pin boss stress of diesel engine piston had the similar characteristic with the relief bores,but the relief bores increased the tensile stress on the combustion chamber lip compared with the normal round profile,and the expected life could be achieved by the pin bore profile optimized.