Thermo-Elastohydrodynamics of Coated Polymer Gears

气候变化、稀缺资源的枯竭、严格的碳排放配额和交通都是挑战，导致对高效机器和系统的需求不断增加。由工程聚合物制成的轻量化设计是一种非常有前途的方法，可以通过大规模生产的可能性，以最低的成本解决这些挑战。然而，与普通金属设计的摩擦学系统相比，它们在高性能动力传输机器元件（如齿轮）中的能力主要受到较低的材料强度和热稳定性的限制。聚合物摩擦系统及其机制的理解，特别是与热管理有关的，为扩大工程聚合物的应用范围提供了巨大的潜力。此外，表面涂层技术的最新发展显示了扩展工程聚合物能力的方法，极大地增加了这些机器元件的功能密度。因此，本研究的目标是探索热塑性塑料的热弹性流体动力润滑（TEHL）和表面涂层在这些TEHL接触中的潜力，以提高其摩擦学性能。因此，聚酰胺（PA6.6）和聚醚醚酮（PEEK），无论是纯的还是增强的，都被用于钢-热塑性配对（主接触设置）和普通热塑性配对（互补接触设置）。定义了贯穿整个项目的三个阶段。首先，确定了非涂层热塑性TEHL触点的摩擦学性能和载荷极限。同时，创新的涂层系统被设计用于满足需求-特别是基于分级碳化锆（ZrCg）和氮化铬铝（(Cr,Al)N）。其次，之前的研究以类似的方式对涂层装置进行了调查，以揭示其好处。全面的摩擦模拟确保了涂层和非涂层热塑性TEHL接触的机械和热机制的理解。最后，所获得的知识是从模型接触转移到齿轮接触和评估工业应用。该项目的系统方法允许确定未涂层热塑性TEHL触点的性能和限制因素，以及在此类触点中涂层技术的好处，这对于提高用于电力传输机器元件的工程聚合物的能力至关重要。

Climate change, the depletion of scarce resources, strict carbon emission allowances and e mobility are challenges that result in a constantly increasing demand for efficient machines and systems. Lightweight designs made from engineering polymers are one very promising approach to tackle these challenges at a minimum of costs through large-scale production possibilities. However, their capabilities in high-performance power-transmitting machine elements such as gears are mainly limited by lower material strength and thermal stability compared to common metal designs of tribological systems. The comprehension of polymer tribosystems and its mechanisms, especially related to heat management, offers great potential to extend the application limits of engineering polymers. Moreover, recent developments in surface coating technology show ways for expanding capabilities of engineering polymers that increase functional density of such machine elements tremendously. Hence, the goal of this confraternal research proposal is to explore the thermo-elastohydrodynamic lubrication (TEHL) of thermoplastics and the potentials of surface coatings in these TEHL contacts in order to improve its tribological performance. Thereby, polyamide (PA6.6) and Polyetheretherketone (PEEK), both pure and reinforced, are used in steel-thermoplastic pairings (main contact setup) and plain thermoplastic pairings (complementary contact setup). Three stages are defined that lead through the project. At first, the tribological performance and load limits of uncoated thermoplastic TEHL contacts are determined. Concurrently, innovative coating systems are designed for the needs - inter alia based on graded zirconium carbide (ZrCg) and chromium-aluminum-nitride ((Cr,Al)N). Second, the previous investigations are conducted in a similar fashion on coated setups to reveal its benefits. Comprehension of the mechanical and thermal mechanisms involved in coated and uncoated thermoplastic TEHL contacts is ensured by comprehensive tribosimulations. Finally, the gained knowledge is transferred from model contacts to gear contacts and assessed for industrial applications.The systematic approach of this project allows determination of the performance and limiting factors in uncoated thermoplastic TEHL contacts as well as the benefits of coating technology in such contacts, which is essential for improving the capability of engineering polymers for power transmitting machine elements.