Internal-combustion engines – Vibration compensating device
Reexamination Certificate
2001-09-12
2002-05-07
Argenbright, Tony M. (Department: 3747)
Internal-combustion engines
Vibration compensating device
C074S574300
Reexamination Certificate
active
06382164
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to improvements in piston engines (also known as reciprocating or displacement engines), and more particularly to improvements in methods of and means for preventing or reducing the extent and/or frequency of stray movements of crankshafts in such engines. Still more particularly, the invention relates to improvements in the construction and mounting of vibration dampers for the crankshafts of piston engines.
Published German patent application Ser. No. 195 19 261 discloses a torsional vibration damper which comprises an annular casing adapted to be connected to the shaft of a machine and confining a flywheel which is rotatable relative to the casing against the opposition of a body of viscous fluid. This published application proposes to position the casing of the vibration damper at the front end face of, and to fasten the casing to, the front end (snout) of the crankshaft. A drawback of such proposal is that the thus attached damper occupies a substantial amount of space which is not always available under the hoods of certain types of motor vehicles (such as compact cars), especially if the engine is installed transversely of the direction of forward movement of the conveyance.
Published German patent application Ser. No. 40 25 848 discloses a modified vibration damper which is intended for use in piston engines and employs annular flywheels as well as a hub which is to be secured to the crankshaft of the engine. The annular flywheels are movably secured to the hub by buffers of rubber or other suitable elastomeric material. The hub is provided with or carries a pulley for one or more endless belts serving to transmit motion to the camshaft of the engine and/or to one or more auxiliary aggregates of the motor vehicle.
One of the purposes of vibration dampers for the crankshafts of piston engines is to suppress the characteristic frequencies (harmonic vibrations) of the crankshafts. In many instances, the characteristic frequency of the crankshaft in the housing of a piston engine is in the range of between 300 and 450 Hz. Such frequency is induced primarily as a result of iregularities attributable to compression and expansion that take place in the cylinders for the pistons of the engine. Vibrations at the torsional resonancy can result in breakage of the crankshaft, and this is the reason that the crankshafts of piston engines are normally equipped with vibration dampers (e.g., in the form of heavy, rubber-mounted wheels in front of the crankshaft) to counter harmonic vibrations.
In order to achieve a satisfactory vibration damping action, the vibration damping frequency must be selected with a rather high degree of accuracy. As already mentioned above, presently known attempts at adequate damping of vibrations of a crankshaft in a piston engine include the provision of at least one annular flywheel which is movably connected to a hub or another input element of the vibration damper by a buffer of rubber (or other energy-storing elastomeric material), or by a body of oil or another suitable viscous fluid.
In addition to their often excessive space requirements, the aforediscussed presently known vibration dampers for the crankshafts of piston engines exhibit the drawback that the viscosity of fluid can be greatly influenced by changes of temperature and that such temperature changes can also exert an undue influence upon the spring gradient of the elastomeric material. It is to be borne in mind that a vibration damper for the crankshaft of a piston engine is installed in immediate or very close proximity to one or more sources of pronounced heat. Attempts to overcome or to reduce the undesirable influence of elevated temperatures upon the predictability and reliability of operation of conventional vibration dampers for crankshafts include the utilization of oversized vibration damping masses to thus widen the frequency range within which the damper is or should be effective. However, the utilization of oversized masses brings about other serious problems and drawbacks such as a greatly increased fuel consumption and an increased resistance of rotary components of the piston engine to the setting in rotary motion.
OBJECTS OF THE INVENTION
An object of the invention is to provide a vibration damper which can be utilized with the crankshaft of a piston engine and is less affected by temperature changes and/or elevated temperatures than heretofore known vibration dampers for crankshafts.
Another object of the invention is to provide a vibration damper which can stand pronounced thermal stresses for exended periods of time.
A further object of the invention is to provide a vibration damper which is constructed and assembled and which can be installed in a piston engine in such a way that it can effectively counter harmonic vibrations of a crankshaft during each stage of operation of the piston engine.
An additional object of the invention is to provide a novel and improved crankshaft-vibration damper combination which is not affected, or not appreciably affected, by pronounced temperature changes and which can be utilized in lieu of and as a superior substitute for conventional crankshaft-vibration damper combinations.
Still another object of the invention is to provide a novel and improved method of assembling a piston engine wherein the crankshaft is prevented from carrying out any, or from carrying out excessive, harmonic vibrations.
A further object of the invention is to provide a novel and improved module which embodies a crankshaft and can be utilized in piston engines as a superior substitute for conventional crankshaft-vibration damper combinations.
Another object of the invention is to design a vibration damper for the crankshaft of a piston engine in such a way that the range of thermal influence upon the frequency range in which the vibration damper is effective is much narrower than in connection with the utilization of conventional vibration dampers for the crankshafts of piston engines.
An additional object of the invention is to provide a simple, compact and inexpensive but highly effective vibration damper which can be put to use in all or nearly all types of piston engines to oppose stray movements of the crankshaft.
Still another object of the invention is to provide a damper which can be readily installed in the housing of a piston engine.
A further object of the invention is to provide a piston engine which embodies one or more dampers of the above outlined character.
Another object of the invention is to provide a piston engine with a novel and improved housing for the crankshaft and for a damper which serves to counter-harmonic vibrations of the crankshaft.
An additional object of the invention is to provide a motor vehicle embodying a piston engine which utilizes the above outlined crankshaft-vibration damper combination.
Still another object of the invention is to provide a piston engine wherein the vibration damper for the crankshaft need not be provided with a discrete lubricating system.
SUMMARY OF THE INVENTION
One feature of the present invention resides in the provision of a piston engine which comprises a housing, a crankshaft which is rotatably journalled in the housing, and means for damping vibrations of the housing and the crankshaft relative to each other. The damping means is at least partially confined in the housing and is provided on the crankshaft.
In accordance with a presently preferred embodiment, the damping means is fully or practically fully confined in the housing of the piston engine.
A presently preferred embodiment of the damping means comprises a rotary input element and at least one rotary inertia-enhancing mass. The input element and the at least one mass are rotatable relative to each other, and the damping means further comprises energy storing resilient means interposed between the input element and the at least one mass to oppose rotation of the input element and the at least one mass relative to each other. The energy storing resilient means can comprise one or more
Gerhardt Friedrich
Haas Wolfgang
Lehmann Steffen
Reik Wolfgang
Ruder Willi
Argenbright Tony M.
Darby & Darby
Huynh Hai
LuK Lamellen und Kupplungsbau GmbH
LandOfFree
Vibration damper for the crankshaft of a piston engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vibration damper for the crankshaft of a piston engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vibration damper for the crankshaft of a piston engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2840662