Premium brake pads - definition, testing and use in high-performance brake Systems

摘要

The demands on brake Systems in the premium sector have grown significantly in re-cent years, both in terms of Performance and NVH comfort. Higher-power engines coupled with heavier vehicle weights - such as in the SUV or Sport Tourismo Segments - are placing high demands on braking Performance, which have to be met by designing service brakes capable of delivering the necessary stopping power. At the same time, these are vehicle classes that place uncompromising premium comfort above all other considerations. Resolving this conflict of interest thrusts the brake pad right into the Spotlight, as all the customer-relevant criteria of a service brake are directly or indirectly determined by this component. Alongside precisely defined Performance specifications, which can be tested as part of suitable testing programs on inertia dynamometers and in the vehicle itself, measurable parameters for the NVH characteristics also have to be specified. Focusing on compressibility - as is the current norm - is not a suitable method in this respect, either in the development process or during Standard production monitoring. Experience has shown that there is no conclusive correlation between compressibility and dynamic material properties, and therefore the NVH behaviour. Furthermore, analyses of pad production at different manufacturers has identified that a distinction needs to be drawn between two basic types of Variation. On the one hand there is a production Variation within a single batch, and on the other is a mixture Variation between the batches. Depending on the technology used, some significant differences between the manufacturers can be observed. These findings led to the introduction of a computational and experimental robustness analysis. In an enhanced complex eigenvalue analysis, possible pad material Parameters are examined under the broadest range of operating conditions. The targeted production of NVH limit samples is then used to determine the Optimum process Parameters for NVH considerations, as well as to develop secondary measures under critical conditions. This new Porsche Premium Pad approach therefore ensures the most robust brake system in terms of stability reserves as against brake noises.