WOOSTER, Ohio, June 2 /PRNewswire/ -- Almost 20 years after the successful
development of the dual mass flywheel (DMF), LuK -- a brand of the Schaeffler
Group -- has achieved another milestone in vibration damping. 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 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, e.g. the ignition
frequency of the engine, can be achieved through appropriate tuning. A
pendulum mass of 2.2 pounds can reduce the transmission vibrations up to 60
percent. 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 LuK's customers.
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. Only in conjunction with a modern DMF design did LuK succeed in
finding a viable solution that enabled the centrifugal pendulum-type absorber
to be incorporated in the drivetrain.
"The centrifugal pendulum-type absorber DMF was subjected to an extensive
series of tests, which focused on function, material wear and safety," said
Dr. 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 automobile manufacturer.
About the Schaeffler Group
The Schaeffler Group, with its brands INA, LuK and FAG, and approximately
66,000 employees at more than 180 locations in 50 countries, generates group
sales of more than 8.9 billion euros (FY 2007) and ranks amongst the leading
rolling bearing manufacturers and suppliers to the automotive industry
worldwide. Affiliated companies include Schaeffler KG, with its head office at
Herzogenaurach, and the brandnames INA and FAG, as well as the LuK Group,
whose head office is located in Buhl/Baden.
To serve the North American automotive market, the Schaeffler Group
operates a 78,000-square-foot North American Automotive Tech Center in Troy,
Mich. This facility employs 165 engineers and technicians and houses a 30,000-
square-foot, state-of-the-art test lab outfitted with multiple test cells
capable of performing test simulations for engine and engine components.
Schaeffler Group Automotive has headquarters in Fort Mill, S.C. and
manufacturing facilities in South Carolina, Missouri, Ohio and Ontario,
Canada.
SOURCE Schaeffler Group
