Bernát Rastislav, Žarnovský Jozef, Kováč Ivan, Mikuš Rastislav, Fries Jiří, Csintalan Radoslav
Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia.
Faculty of Mechanical Engineering, Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic.
Materials (Basel). 2021 Dec 26;15(1):158. doi: 10.3390/ma15010158.
The present paper analyzes the damage of surfaces at spots of frictional contact, namely, the friction nodes on a camshaft and the connecting rod pins of a crankshaft. The resulting wear of the monitored friction nodes reduces the technical life of the machines, which can lead to the decommissioning of the machine. Wear was assessed by measuring roughness and microhardness and by observing the microstructures of the materials. The results of the experiments show that the rotating parts displayed visible wear on the cams, as well as on the connecting rod pins. The experiments revealed that wear was caused by the heating of the material to a high temperature during the operation of the machine and that there was a gradual cooling and tempering of the material, which led to a reduction in the microhardness of the monitored object. Lower microhardness values can be a cause of greater wear of the monitored objects. When comparing the microhardness of the used and the new camshaft, the hardened layer of the new camshaft from secondary production has a significantly smaller thickness compared to worn cams, which leads to the finding of a different material quality compared to the original parts from primary production. This fact indicates that the wear of a new camshaft as a spare part can contribute to the shortening of the technical life of friction nodes.
本文分析了摩擦接触点处表面的损伤情况，即凸轮轴上的摩擦节点和曲轴的连杆销。所监测的摩擦节点出现的磨损会缩短机器的技术寿命，可能导致机器退役。通过测量粗糙度和显微硬度以及观察材料的微观结构来评估磨损情况。实验结果表明，旋转部件的凸轮以及连杆销上出现了明显的磨损。实验揭示，磨损是由机器运行过程中材料被加热到高温导致的，并且材料存在逐渐冷却和回火的情况，这导致被监测物体的显微硬度降低。较低的显微硬度值可能是被监测物体磨损加剧的一个原因。在比较使用过的凸轮轴和新凸轮轴的显微硬度时，二次生产的新凸轮轴的硬化层厚度与磨损凸轮相比明显更小，这表明与一次生产的原装零件相比，材料质量有所不同。这一事实表明，作为备件的新凸轮轴的磨损会导致摩擦节点技术寿命缩短。
