Machine element or mechanism – Elements – Flywheel – motion smoothing-type
Patent
1990-04-16
1991-08-06
Lindsey, Rodney M.
Machine element or mechanism
Elements
Flywheel, motion smoothing-type
F16F 1510
Patent
active
050367269
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a torsional-vibration damper of conventional design comprising of three mutually concentric ring elements, namely a hub ring, a flywheel ring and an elastic ring, where the elastic ring--which also may be composed of individual elastic annular segments or elements--connects together the hub ring and the flywheel ring in relative elastic and rotational manner.
Torsional-vibration dampers of this kin are used to absorb very specific interfering frequencies of torsional vibrations, in particular in the automotive industry. The mass and the design of the elastic ring of these known torsional-vibration dampers or absorbers are so matched to each other that the natural frequency of the torsional-vibration damper is as close as possible to the interfering vibration whereby the latter is to be canceled by the resonance vibration of the torsional-vibration damper.
This kind of torsional-vibration damping, more accurately the absorption of interfering torsional vibrations, in principle is surprisingly effective, but nevertheless entails the significant drawback that is shall be adequately effective only for one specific interfering frequency, in practice only for a very narrow frequency band. In those instances when the interfering frequencies are not fixed, but instead drift or occur not as a sharply defined frequency, instead as a band of interfering frequencies, torsional-vibration dampers of the above kind, based on the resonance effect, offer only very unsatisfactory results.
Because torsional-vibration dampers of the above kind are widely used to absorb interfering torsional vibrations in the drive trains of motor vehicles and because these interfering torsional vibrations significantly depend in their frequencies on the engine angular speed, many attempts clearly have already taken place to develop torsional-vibration dampers of the above kind that shall be able to absorb more than one resonant frequency.
Illustratively the German Gebrauchsmuster 19 97 151 U1 discloses a torsional-vibration damper of a closed design which by means of different flywheels attempts to set up a series of resonant-vibration systems that shall become actively absorbing at the corresponding interference frequencies. Because the individual vibration systems interact, i.e. they are a coupled system, the practically useful tuning of this vibration damper remains questionable. Moreover the design of this torsional-vibration damper entails a comparatively large weight and critical manufacturing costs for mass production.
The German patent 35 35 803 C1 discloses a torsional-vibration damper which contrary to the known, above described one changes not the masses of the resonant vibration system but instead the spring force transmitted into the vibration system in two discrete steps in such a manner that the torsional-vibration damper comprises two marked resonant frequencies. However the problem of a wide frequency band or of an interfering frequency drifting with the angular speed of the engine shaft is not yet solved by creating a torsional-vibration damper with two resonant frequencies, but in principle this damper being of simple, rugged and economical design, offers two resonant and thereby absorbing frequencies which in any event are better than one. The significant drawback of this torsional-vibration damper known from the German patent 35 35 803 C1 is in the purely mechanical field. The second resonance of higher frequency is being impressed on the absorption system in that at higher angular speeds of the engine shaft seating the damper, additional springs equipped with centrifugal masses are additionally made to connect frictionally with the flywheel. The spring constant so raised of the elastic ring causes the second and higher resonant frequency. The basic drawback of this system however is the wide transition range between the slippage friction of the additional spring elements actuated by centrifugal force and the onset of static friction, i.e. the actual frictional connection which is the basis of the i
REFERENCES:
patent: 3314304 (1967-04-01), Katzenberger et al.
patent: 3559502 (1971-02-01), Lofthouse
patent: 3606802 (1971-09-01), Tsunodo
patent: 4224835 (1980-09-01), Bauer
patent: 4873888 (1989-10-01), Matsuyama
Pletsch Hubert
Wolf Franz J.
Lindsey Rodney M.
WOCO Franz-Josef Wolf & Co.
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