The materials specified in the critical components of these engines and transmissions must be able to handle extremely aggressive, high-temperature environments. Lightweight Victrex PEEK polymers from Victrex (West Conshohocken, PA) have more than 30 years of success in replacing metals and other polymers in the most demanding conditions and as such PEEK is a leading candidate for demanding drive train applications.
The increased demands of smaller, higher power engines can also lead to greater levels of noise, vibration, and harshness (NVH), but it is possible to combat these factors by designing parts with Victrex PEEK polymers says the supplier. According to a case study performed by Metaldyne, a leading global designer and supplier of powertrain components and assemblies, replacing metal with Victrex PEEK in a balance shaft module lowered NVH by 3 dB, which is equivalent to a 50% noise level reduction. "Along with decreasing NVH, we were able to achieve a 30% reduction in system inertia leading to an improvement of up to 9% in power consumption due to the lightweight nature of the polymer," says Aaron Clark, engineering manager for Metaldyne Powertrain Products.
Compared to metals, Victrex PEEK polymers provide up to 80% in weight savings in powertrain components such as seal rings, thrust washers, bushings, bearings, shift fork wear pads, and gears. These weight savings, paired with a low coefficient of friction and low wear rate plus excellent corrosion resistance, can improve the overall efficiency of the transmission. The reduced stress on components and lower friction leads to greater fuel economy, lower maintenance costs, and can increase the lifetime of the powertrain.
High-performance Victrex PEEK thermoplastics also offer many other benefits including dimensional stability at temperatures over 200°C (392°F), excellent corrosion resistance to automotive fluids, and the ability to withstand temporary loss of lubrication, all of which can extend part service life especially as manufacturers are offering more aggressive extended warranties to differentiate from competition.
Victrex is addressing the demands of the automotive industry with its latest development of Victrex WG polymers as a response to the need for minimal frictional losses and improved wear resistance in critical automotive components. These wear grades have a lower coefficient of friction and reduced wear rate compared to other polymers such as polyimide (PI) and polyamide-imide (PAI), which leads to greater reliability and increased energy efficiency. Victrex WG polymers can be processed on standard injection molding machines reducing processing costs and part-to-part variability compared to other polymers. Victrex PEEK also allows parts consolidation and other design improvements which can significantly reduce assembly time and lower the total system cost.