Federal-Mogul Powertrain has introduced its Unipiston clutch piston with integrated springs that are suitable for clutch packs in dual clutch transmissions (DCTs), conventional automatic transmissions and limited slip differentials. Unipiston is claimed to enable improved clutch performance, reduce required package space and simplify assembly. Unipiston technology has been validated with one customer and is expected to enter series production in the near future, Federal-Mogul noted.
Unipiston eliminates separate spring carriers, thereby reducing the axial length requirement that is often a crucial constraint in pistons for multi-plate clutch packs, Federal-Mogul said. The company is claimed to be the first to bring this technology to market. Additionally, the design freedom that this technology provides allows selection of better spring force characteristic, reduction in spring count, or the use of a more cost-effective spring material, the company explained.
Federal-Mogul’s integrated construction of Unipiston clutch piston reduces the quality risk that could arise from separate springs by reducing parts count and assembly operations and simplify logistic for customer. It also improves the guidance provided during transmission assembly and makes the process stronger, which is said to be important for blind assemblies. The company said the Unipiston applies hydraulic pressure to a clutch pack to facilitate torque transfer and can be used as an apply piston or a balancer piston.
Gian Maria Olivetti, CTO, Federal-Mogul Powertrain, said introduction of the original Unipiston by Federal-Mogul Powertrain was an industry first that helped make clutch pistons more compact and easier to assemble. He added that this innovative Unipiston with integrated springs provides greater advantages allowing customers to design even more compact and robust transmissions.
The Unipiston with integrated springs removes the need for customers to undertake a difficult assembly operation that could introduce quality concerns, noted Cem Yoldjou, Technical Specialist, Unipiston and Dynamic Seals, Federal-Mogul Powertrain. He said many clutch systems are sealed by a welding operation following assembly, making it impractical to rectify any quality issues after that point.
