May 28th, 2015
Saint-Gobain Seals becomes involved in motorsport season with its Meldin® 5330 gerotors, which are used in oil and scavaging pumps on Formula 1 racing vehicles and MotoGP motorbikes. In this type of motorsport application, typical working conditions include temperature level of around 150°C, low pressure (a few bar) but high speed (20,000 RPM or more). Lubrication is provided through oil and the counter surface is aluminium.
The gerotor (a combination of the “generated” and “rotor” words) is a positive displacement pumping unit that consists of two elements: an inner rotor and an outer rotor. The outer rotor has an additional tooth compared to the inner rotor and its central axis is positioned at a fixed eccentricity from the one of the inner rotor and the shaft. Therefore, the rotation of the two elements, one against the other, allows the fluid to be pumped in a smooth movement. Metals are traditionally used to manufacture gerotor elements, either sintered metals or stainless steel or aluminum.
Saint-Gobain Seals developed and tested their Meldin® 5330 material (a filled PEEK compound) for this gerotor application for about a year, collaborating with a customer whose functional expectations included weight saving and long wear. This polymer material was recommended as a precise fit due to its excellent mechanical properties (valid also at high temperature) and balance between being wear resistance and compatible with the counter surface (aluminum). By using a high-performance plastic instead of metal, weight saving became an automatic positive effect.
Additional key properties included minimal chemical absorption and deformation as well as low coefficient of thermal expansion. Since the polymer material minimizes the wear of the gerotor material, sealing capability of the gerotors and finally pump efficiency are greatly improved. All of these properties make a critical difference in the life cycle of motorsport oil and scavaging pumps (which operate at extreme speeds) due to the importance of the gerotors regulating the fluid intake that results from thermal expansion and chemical absorption as this could have an effect on the amount of contact stress and result in localized tooth wear. By using the Meldin® 5330 plastic, motorsport companies have the confidence that their pumps are protected against pump inefficiency and low wear losses and also benefit from the following:
The Meldin® 5330 material is part of Saint-Gobain Seals’ Meldin® HT product line, which are high-performance thermoplastics developed for different applications and markets: automotive (braking system components); industrial (piston rings in refrigeration compressors and bearings in appliance motors); and oil and gas (bushings and back-up rings on high-pressure ball valves and swivels for FPSO: floating production, storage and offloading). The product line includes compounds based on:
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