The ContiTech Power Transmission Group has developed a new double-sided timing belt for powering balance shafts.
The teeth on the rear side of the belt, which can run in oil environments, transmit the reverse rotation direction of the crank shaft to the balance shaft. In comparison with spur gears or chains, the belt is lighter and quieter as well as more flexible in terms of positioning the balance shafts in the engine.
Balance shafts ensure quieter running and increase ride comfort, especially in modern three- and four-cylinder engines. The new double-sided timing belt by ContiTech opens up more possibilities for engine designers at automotive manufacturers in terms of layout design: "The spacing between the drive shaft and crank shaft can be significantly larger with the belt than with spur gears. Because the belt generates less friction than a chain, it simultaneously reduces CO2 emissions," explains Ralf Berger, head of Key Account Management and Passenger Car Original Equipment Application Engineering at the ContiTech Power Transmission Group. Other benefits: In comparison with spur gears, the belt saves weight and thus supports the manufacturer's efforts to reduce fuel consumption. In contrast to chains, it also ensures enhanced ride comfort because it runs more quietly.
As a further development of the timing belt in oil, the double-sided timing belt can run like a chain in the oil bath. To achieve this, ContiTech has adapted the elastomer, the fabric, and the cord to the new environment. In addition to polyamide and aramid fabric with a Duralon coating containing Teflon, an ultra-durable rubber compound made from ACN-HNBR (hydrogenated acrylonitrile butadiene rubber), as well as K-glass, is also being used for high length stability. Because of this special material mix, even impurities in the oil cannot harm the belt.
For the production of the double-sided timing belt, ContiTech developed its own manufacturing process and special tools with which the profile can be applied as precisely as possible to the rear side of the belt. The belt is suitable for all drives with counter-rotation and can withstand temperatures from -40°C to +150°C. It is hard-wearing and designed for the service life of the engine.