Schaeffler’s high-performance ball bearing offers better range

Small bearing that packs a punch: Thanks to the new ball bearing with centrifugal disc from Schaeffler, electric cars have a greater range
(Courtesy of Schaeffler)

They move the world as no powertrain can do without bearings ─ be it electric cars, hybrid vehicles or internal combustion engines. Schaeffler has now developed a special high-performance ball bearing with an integrated centrifugal disc. This disc helps lower CO2 emissions in vehicles with combustion engine and hybrid powertrains. Electric cars, on the other hand, benefit from the fact that they can drive further on a single charge. The bearing weighs just 300 grams and is between five and ten centimetres in diameter, depending on the application. “Innovative strength is a key factor safeguarding Schaeffler’s corporate success and automotive business,” says Matthias Zink, CEO Automotive Technologies at Schaeffler AG. “Our new ball bearing will make drives even more efficient and further increase the appeal of electric mobility for everyday use.”

The first automotive manufacturers have been using the new ball bearing in production hybrid and double-clutch transmissions since 2021, and the automotive and industrial supplier is collaborating with other manufacturers in development projects moving forward to a volume production launch. The company is likewise transferring the patent-pending technology to ever new application areas in its bearing business, including dedicated electric vehicles. The bearing was also recently included among the finalists for the 2022 German Innovation Award in the large-scale enterprise category.

The best of two designs

Ball bearings are either open on the sides ─ known as open bearings ─ or have seals made from special rubber. These sealed bearing units keep contamination away from the balls and raceways of the bearing rings. This translates into less wear and, thus, a longer service life. The drawback, however, is the higher level of friction in the bearing, which corresponds to valuable energy being lost. In open-style bearings, although this friction is reduced, the bearing units break down more quickly due to the lack of protection from contamination. A real dilemma. With the high-performance ball bearing with integrated centrifugal disc, Schaeffler has developed a truly unique bearing that combines the benefits of an open bearing with those of a sealed one. As such, significantly less energy is lost in the bearing in the form of friction. “Less friction means that drive energy is used more efficiently. This, in turn, lowers emissions and improves the range of electric vehicles,” says Dr. Dieter Eireiner, Head of the Bearing Business Division at Schaeffler.

What really makes the new bearing stand out is that the rubber seals that are normally attached firmly to the outer sides of the bearing are replaced with a specially designed centrifugal disc integrated in the inner ring. This disc keeps contamination out ─ similar to a sealed bearing. Since the disc rotates freely, however, the bearing generates about 80 percent less friction than with conventional seals. The result is a CO2 reduction of up to 0.3 grams per kilometer per vehicle. Reducing losses of up to 30 watts per bearing can also improve the range of electric vehicles by up to one percent. “Efficient bearing solutions play a key role in sustainable mobility. With our new bearing, Schaeffler shows that small changes can make a big difference,” says Eireiner. The centrifugal disc bearing also lasts considerably longer. Compared to an open bearing, the service life increases by a factor of up to ten, whereas the unit lasts twice as long as conventional sealed ball bearings. This, then, means that bearing and transmission assemblies can be downsized in the future, thereby conserving material and weight.