High precision three-stage bearing solves turbo problems

Formula One bearing technology is providing the key to the next generation of high efficiency turbochargers that are being used on a range of performance vehicles. Dean Palmer reports Turbocharger technology is now a hot topic and is enjoying a surge in interest from automotive manufacturers and their suppliers. Why? First, the installation space required for a turbo engine is smaller than that of a naturally-aspirated engine with the same power output. Also, the fuel consumption of a turbo engine is lower, compared with a naturally-aspirated engine of identical power output. And then you have the advantage of an improved power-to-weight ratio on an exhaust gas turbocharged engine over the naturally-aspirated equivalent. Some of the design issues which have held back turbocharger development in the past include premature failure, excessive heat and turbo lag compressor whine, with bearing design playing a key role in all these areas. Specialist bearing design company The Barden Corporation UK based in Plymouth has developed a three-stage bearing design specifically for World Rally Championship (WRC) cars that is manufactured from M50 tool steel and which can operate at temperatures up to 500°C. The new design reduces the problem of tolerance stack-up in the turbo, which is caused by an assembly that uses separate components, such as a bearing and a shaft, which generally can be overcome by making the assembly in one piece and reducing the accumulative tolerance of individual parts. The new bearing also lessens the effects of temperature differentials in the bearing assembly, resulting in a more reliable system. Barden's high precision bearings are also having a major impact in the rapidly developing automotive aftermarket for ball bearing turbochargers. The bearings enable turbo manufacturers to achieve maximum power and driveability with integrated designs and high performance materials that, explained Morris, "virtually eliminate turbo lag and compressor whine and also allow higher boost levels". He added that the extremely high accuracy of the bearings also enable reduced compressor clearance, lower rotating inertia and maximum speed capability. The new turbocharger bearing designs are the latest in a series of bearing products manufactured using Barden's "Special Design" capability. Trevor Morris, engineering manager at Barden, told Eureka: "At least 60% of our work is for customised bearing designs because we have the experience and know-how to adapt our bearing solutions to many different industrial and high performance applications. We have a team of six applications engineers in Plymouth that work full time on nothing but customised bearing designs. "This bespoke capability has enabled us to meet the demands of very high technology industries. In Formula One motor racing for example, we have engineered a series of extreme high performance bearing systems for race-critical applications such as clutch release, gearbox, wheel and suspension." Barden's clutch release bearing systems are well established with full race qualification at a number of major Formula One racing teams and the company also offers Formula One gearbox bearings that are tailored to interface directly with the transmission designs of individual race teams. These bearings include custom features such as flanges, splines and thread forms as integral parts, which, together with direct oil feed systems, help keep mass to a minimum and ensure optimum lubricant supply throughout each race. Pointers * Barden's super precision bearing was developed to reduce the problem of tolerance stack-up in high speed turbochargers and to lessen the effects of temperature differentials in the bearing assembly * The bearing is a three-stage design manufactured from M50 tool steel which can withstand temperatures up to 500°C * In ball bearing turbochargers, Barden's new high accuracy bearings help to reduce compressor clearance, lower the rotating inertia and offer maximum speed capability