Optimization of tribological systems by aimed anticipation of the running-in by final machining on the example of journal bearings

研究项目的目的是通过分析产生的工件亚表面层、形貌和磨合行为，开发径向轴承的最终加工工艺并对其进行优化。以42CrMo4轴颈为例，对其切削工艺进行了研究。除对青铜轴颈轴承进行精加工外，还对高强度钢（100Cr6, 42CrMo4）和铝壳材料进行了孔侧检验。因此，切削过程可以实现纳米晶亚表面层的目标生成，从而在接下来的操作中实现定义的短磨合行为。这就形成了具有低摩擦和磨损率的第三体。在第二个资助期，对纳米晶体材料的表层状态有了更深入的了解，从而导致摩擦系统的进一步改进。此外，正在分析将研究工作转移到内部切割过程的问题。因此，可以对轴颈轴和轴承的几何形状以及亚表面层状态进行摩擦学优化。此外，还创建了一个实用的工具，用于有效的最终加工过程管理，并集成了不同尺度的仿真模型。从轴承的制造和设计中得到的知识最终在摩擦学试验台得到验证。为了评估仿真结果，有必要在轴颈轴承试验台进行实验。特别是在轴承磨合和混合润滑状态下，摩擦学行为的研究必须进行。实验工作的另一个方面是车削工艺的发展，它必须产生可重复形成的纳米晶体亚表面层和优化的形貌。通过摩擦学实验验证了工艺参数对内切削过程的适应性，以进一步改善其摩擦学性能。除了实验之外，还使用模拟来了解摩擦学接触过程。因此，在不同的长度尺度上考察摩擦过程。用WBK对最终加工进行仿真，得到了两个接触体的初始特性信息。这些结果以及IAM-ZBS的模拟结果定义了有限元模拟所使用的数值，该数值显示了滑动轴承在运行过程中的地形发展及其对摩擦的影响。

Aim of the research project is the development of a final machining process for journal bearings and its optimization by analyzing the resulting work piece subsurface layer, topography and the running-in behavior. The cutting process is investigated on the example of shaft journals (42CrMo4). Besides the finishing of journal bearing made of bronze, also high-strength materials made of steel (100Cr6, 42CrMo4) and aluminum housing material are examined on the bore-side. Hereby, the cutting process enables the aimed generation of nanocrystalline subsurface layers, which lead to a defined, short running-in behavior in the following operation. This leads to the formation of the third body with low friction and wear rates.In the second funding period a deeper understanding of the surface layer states within the nanocrystalline material is generated, thus leading to a further improvement of the tribosystem. Furthermore, the transfer of the research work onto an internal cutting process is being analyzed. Hereby, the geometries as well as the subsurface layer states of the journal shafts and bearings can be tribologically optimized. Furthermore, a practical tool for an efficient process management for the final machining is being created and the simulation models at different scales are integrated. The knowledge resulting from manufacturing and design of the bearings is finally validated in the tribological test rig.To assess the results given by simulation, experimental work on a test bench with journal bearings is necessary. Study of the tribological behavior has especially got to take place during the running-in of the bearings and in the regime of mixed lubrication. Another aspect of experimental work is the development of the turning process, which has to yield a reproducible formation of a nanocrystalline subsurface layer and an optimized topography. The adaption of process parameters to the internal cutting process is examined by tribological experiments to further improve tribological behavior.In addition to the experiments simulation is used to engage process understanding during tribological contact. The friction process is therefore examined on different length scales. Simulation of the final machining by WBK yields information on initial properties of the two bodies in contact. Those results as well as the results of the simulation by IAM-ZBS define the values used by the finite element simulation that shows the topography development during the operation of the journal bearing and its influence on the friction.