Almost 20 years after the successful development of the dual mass flywheel (DMF), LuK – a brand of the Schaeffler Group – has claimed another milestone in vibration damping.
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Through the compact integration of a centrifugal pendulum-type absorber, the damping capacity of the DMF can be increased by an additional speed-adaptive component. This, the company claims, ensures optimal driving comfort, even as new, high-torque engines evolve.
The centrifugal pendulum-type absorber is mounted on the flange of the DMF. The stiffness of the pendulum is generated by the centrifugal force during operation. The centrifugal pendulum-type absorber — known as a ‘speed-adaptive absorber’ — has no set natural frequency, causing the frequency to change depending on the speed.
Efficient absorption of the selected vibration level, eg the ignition frequency of the engine, can be achieved through appropriate tuning. A pendulum mass of 2.2 pounds (1kg) can reduce the transmission vibrations up to 60%. The DMF’s spring mass damper system handles the basic insulation of vibrations, while the centrifugal pendulum-type absorber eliminates residual vibrations caused by the ignition frequency.
The new absorber also offers advantages with regard to installation space, as the pendulum replaces the inner damper found in conventional DMFs. Centrifugal pendulum-type absorber DMFs, therefore, can be used wherever a standard DMF is installed.
LuK developed the DMF – a torsion damper made up to two masses connected together with a damping spring system – in 1985 to help combat gearbox rattling caused by increased speed. Since then, the DMF has been continuously developed and adapted to suit the increased engine performance and comfort requirements of automakers.
The idea of the centrifugal pendulum-type absorber has been in existence for decades and is already used in aircraft engines. Until now, the heavier pendulum mass of approximately 11 pounds and the complexity of the engine application prevented this approach from being applied to the automotive industry.
“The centrifugal pendulum-type absorber DMF was subjected to an extensive series of tests, which focused on function, material wear and safety,” said Jurgen Kroll, DMF product line manager, LuK.
“The result was clear – this dual mass flywheel guarantees optimal driving comfort and is designed to last for the entire service life of the vehicle.”
The internal results recorded at LuK were confirmed in a series of tests carried out for customer projects. The first centrifugal pendulum-type absorber DMF is due to enter volume production this summer for an international automaker.
