根据某发动机气门弹簧的服役环境和结构特征,设计了高频弹簧疲劳试验系统,同时对喷丸和未喷丸弹簧进行疲劳试验,测试了不同循环次数条件下气门全开和预压缩两种状态下弹簧的松弛率。结果表明:喷丸可提高弹簧气门全开和预压缩状态的松弛率,分别为68.1%和23.9%。并在99%置信度条件下采用统计分析发现:喷丸可提高气门弹簧气门全开和预压缩状态的松弛率,分别为69.8%和34.2%。同时分析了弹簧在一个循环周期内,预压缩和气门全开时松弛率没有对应关系的原因。

According to the service environment and structure features of an engine valve spring, the high frequency spring fatigue test system was designed. The fatigue tests were carried out for the engine valve springs with shot peening and without shot peening, and the relaxation rates of spring were tested at the valve fully open and pre-compression under the condition of different cycle times. The results showed that shot peening could increase the relaxation rates of spring, which were 68.1% and 23.9% at the valve fully open and pre-compression, respectively. After shot peening the relaxation rates of spring were increased by 69.8% and 34.2% respectively under the condition of 99% degree by the means of statistic analysis. And the reasons that no corresponding relation of the relaxation rate of spring in a cycle were analyzed.