变速箱齿轮低载强化微观机理的初步研究

疲劳试验表明工艺强化后的高强度变速箱齿轮经过低载强化,其单齿弯曲疲劳强度和疲劳寿命还能够得到一定程度的提高,而且疲劳寿命提高的幅度远大于疲劳后强度的提高幅度。本文参考未经过工艺处理的低强度前梁的低载强化微观分析结果,利用SEM和TEM对某汽车变速箱齿轮低载强化微观机理进行了初步研究,力图从微观上揭示工艺强化后高强度齿轮低载强化的成因和机理。结果表明,适当的强化载荷能够使高强度齿轮的疲劳扩展区域增加、裂纹扩展间距下降,低载强化使齿轮的微观组织得到进一步的锻炼、强度和硬度有所下降,但微观组织的整体机械性能得到提高。

Microcosmic Mechanism for Strengthening Low-amplitude Load for Automobile Transmission Gear

Fatigue experiments show that the single tooth bending fatigue strength and fatigue life of the high-strength transmission of an automobile gear can be increased after it is strengthened with low-amplitude load,but the increase of its fatigue life is far greater than that of its fatigue strength.Taking as reference the microcosmic analysis results of the low-strength front axle of an automobile,which has not strengthened with low-amplitude load,we study the microcosmic mechanism for strengthening the low-amplitude load for the transmission gear of an automobile using the scanning electronic microscope and the transverse electromagnetic microscope.The study results show that the high-strength transmission gear after appropriate strengthening with lowamplitude load has wider fatigue propagation area and lower interval of fatigue crack propagation.The strength and hardness of its microstructure decrease somewhat,but its whole mechanical performance increases.