The sealing rings are manufactured open, with a lock-like opening that closes the ring after it has been mounted around the shaft. At this stage, the rings are slightly oval. They still need to be brought into their final closed form. To do that, they are inserted into a heating unit by a feed system and heated to a temperature below the melting point of the high-performance plastic. “The experience of our US colleagues was very valuable when it came to setting up the plant,” says Frank. Freudenberg has been processing PEEK in the USA for almost a decade.
The Reichelsheim plant could also be manufacturing Levitas sealing rings within the next two years. Müller, who is responsible for marketing the innovative transmission seal, has not yet been able clinch a firm customer order. However, prototype testing is on-going. “Even though we will see an increasing number of electric and hybrid vehicles on the road in the coming decade,” says the expert, “it is important we continue to improve conventional petrol and diesel drives.” Converting a gearbox to low-friction seals is relatively simple. Only the contact point where the seal is pressed against the housing might need modifying. It must be wide enough and, above all, the metal surface not too rough – otherwise a continuous oil film may not form.
Small steps often have the greatest effect, Müller concludes.