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

对于无压力区域或压力差较小的部分的轴密封，通常采用径向轴密封（RSS）。rss的特殊设计导致润滑油由于轴的旋转而呈轴向输送，始终指向储油的方向。然而，配合密封面（MSS）的表面微观结构也会导致运输效应，这主要是由于在车削过程中表面微观结构的一定扭转。表面宏观扭转可以定义为一种周期性的、定向的结构，如进给痕迹。与之不同的是，微扭代表微观组织，其主要方向是相对于工件旋转轴的矩形偏差。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宏观和微观扭曲。插入式磨削通常被认为是MSS精加工的默认工艺，因为典型的淬火钢被应用。预先确定的修整和对切割过程的调整通常可以减少捻度。从经济的角度来看，有几个缺点，如高投资，降低灵活性，并由于较长的火花，时间降低了经济效率。用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，人们对MSS的工艺参数、表面微观结构和功能特性之间的相互作用缺乏全面的了解。关于所需表面特定值的最终用户信息以及关于工具选择和切削参数的信息是有限的。该研究的目的是深入了解硬车削过程中工艺参数之间的关系，由此产生的MSS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、计算机辅助加工和弹性流体动力学模拟（EHD）。另一个目标是确定硬转MSS的功能相关描述的表面参数。对于纵向车削，宏观扭转对泵送速率和摩擦力矩的影响应通过切削参数的变化和刀具角的几何形状来检验。此外，在考虑刀具磨损的情况下，应通过应用CBN切削材料的不同切削刃几何形状和晶粒尺寸来实现粗糙度随机分量的预先修改。研究结果可用于MSS加工的一种特殊工艺——启停车削（SST）的鉴定。在这种情况下，SSD代表了一个转向过程，能够产生以零导角为特征的mss，在初步研究中已经提供了相对较低的泵送比。

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.