Design and manufacturing of radial shafts seals mating surfaces using manufacturing processes with geometrically defined cutting edges - Diregeo

对于无压力区域或具有较小压差的部分中的轴的密封，通常应用径向轴密封（RSS）。RSS的特殊设计导致润滑剂的轴向承载，由于轴旋转，总是指向储油的方向。然而，匹配密封表面（MSS）的表面微观结构也会导致承载效应，这主要归因于车削过程中表面微观结构的一定扭曲。表面宏观扭曲可以被定义为周期性的、定向的结构，例如进给痕迹。与此不同的是，微扭曲表示微结构，其主方向提供相对于工件旋转轴线的矩形度偏差。因此，MSS的目的是实现没有扭曲，而到目前为止，没有统一的阈值定义有关的宏观和微观扭曲。切入磨削通常被认为是MSS精加工的默认工艺，因为通常应用硬化钢。预定义的修整和切割过程的调整通常可以减少扭曲。从经济的角度来看，有几个缺点，如高投资，灵活性降低，并由于长时间的火花，倍降低经济效益。硬车削代替磨削为降低成本提供了巨大的潜力。然而，到目前为止，还缺乏一个全面的了解之间的相互作用的工艺参数，表面微观结构，和功能特性的MSS。关于所需表面特定值的最终用户信息以及关于刀具和切削参数选择的信息是有限的。所提出的研究的目的是深入了解硬车削工艺参数之间的相关性，由此产生的MSS的表面微观结构，及其在使用中的功能特性。因此，应采用切削实验、台架试验、计算机辅助工艺和弹性流体动力学模拟（EHD）。另一个目标是确定的表面参数的功能相关的描述硬车削MSS。对于纵向车削，宏观扭转对泵送速率和摩擦扭矩的影响应通过切削参数和刀具拐角几何形状的变化来检查。此外，粗糙度的随机分量的预定义的修改应实现通过应用不同的切削刃几何形状和CBN切削材料的晶粒尺寸，同时考虑到工具磨损。研究结果应用于鉴定启停车削（SST），一个特殊的工艺加工的MSS。在这种情况下，SSD代表了一种车削过程，能够生成以零超前角为特征的MSS，这在初步研究中已经提供了非常低的泵送比。

For the sealing of shafts in pressure-free areas or sections with minor pressure difference typically radial shafts seals (RSS) are applied. The specific design of RSSs leads to an axial carriage of the lubricant due to the shaft rotation, always directed in the direction of the oil storage. However, the surface microstructure of the mating seal surface (MSS) can result in a carriage effect as well, mainly attributed to a certain twist of the surface microstructure in turning. Surface macro-twist can be defined as a periodic, directional structure such as feed marks. In difference to that, micro-twist represents microstructures with its main direction providing a deviation of rectangularity with reference to work piece rotational axis. Consequently, the MSS are intended to be realized without twist; while up to date, no uniform thresholds are defined concerning macro- and micro-twist. Plunge grinding is typically considered as default process for finish machining of MSS, as typically hardened steels are applied. A predefined dressing and an adaption of the cutting process can typically reduce the twist. From an economical point of view, there are several disadvantages such as high investment, reduced flexibility, and due to comparably long spark-out, times reduced economic efficiency. The substitution of grinding by hard turning provides significant potential for cost reduction. However, up to date there is lack in a comprehensive understanding of the interactions between the process parameters, the surface microstructure, and the functional properties of the MSS. The end user information concerning the required surface specific values as well as information on the selection of tools and cutting parameters are limited. The aim of the proposed research is an in-depth understanding of the correlations between the process parameters in hard turning, the resulting surface microstructure of the MSS, and its functional properties in use. Accordingly, cutting experiments, bench tests, and computer aided process and elastohydrodynamic simulation (EHD) shall be applied. Another goal is the determination of the surface parameters for the function-related description of hard-turned MSS. For longitudinal turning, the influence of the macro-twist on the pumping rate and the friction torque should be examined by a variation of the cutting parameters and the tool corner geometry. Moreover, a predefined modification of the stochastic component of the roughness should be achieved by applying different cutting edge geometries and grain sizes of the CBN cutting material taking the tool wear into consideration. The findings should be used for the qualification of the start-stop-turning (SST), a special process for the machining of MSS. In this context, SSD represent a turning process enabling the generation of MSSs characterized by a zero lead angle, which already provided comparably low pumping ratios in preliminary investigations.