Torsional vibration damper

Details Torsional vibration damper Torsional vibration damper

2001-03-13

2003-01-21

Binda, Greg (Department: 3679)

Rotary shafts, gudgeons, housings, and flexible couplings for ro

Torque transmitted via flexible element

Element is annular liner within radially spaced...

C464S083000

Reexamination Certificate

active

06508713

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a transmission coupling assembly for absorbing axial and/or angular displacement between an internal combustion engine and a transmission. The invention is particularly suited to propulsion systems where the internal combustion engine that is connected directly to the transmission.
2. Description of the Background Art
One of the most common uses for a propulsion system that has the engine directly connected to the transmission is in small watercraft. Most small watercraft use two or three cylinder engines. Such engines, however, can be prone to internal vibrational problems.
For instance, the explosive forces acting on the pistons and the inertia forces of the moving parts vary in intensity as the pistons of the engine reciprocate. The resulting variation of force or torque on the crankshaft causes the crankshaft to twist in an oscillatory fashion so as to transmit torsional vibration. Torsional vibration is more noticeable at certain speeds and can be irritating to the rider. Such vibrations may also damage the crankshaft. That is, as the shaft winds up and relaxes under the oscillatory torsional force, alternating stresses internal to the shaft occur. Such stresses can cause failure under some conditions.
Prior propulsion systems have not adequately isolated the watercraft hull from such vibration, nor have they included a suitable mechanism to shift the severity of the resulting resonance. Vibration-absorbing engine mounts have been used in an attempt to lessen vibration transmission from the engine to the watercraft hull. Although somewhat effective in reducing the engine vibration felt by the rider, such mounts do not dampen torsional vibrations within the crankshaft.
Heretofore known vibration damping apparatus of the above outlined type employ dampers which have energy storing elements acting in the circumferential direction of the flywheels and normally including coil springs which store elastic energy, and additional energy storing elements which act in the axial direction of the flywheels and cooperate with friction pads and/or linings to produce friction (i.e., hysteresis). The means for generating friction operate in parallel with energy storing means which act in the circumferential direction of the flywheels.
It has been found that certain conventional vibration damping apparatus can operate satisfactorily (i.e., they are capable of damping torsional vibrations as well as noise) but only under specific circumstances. Thus, the mode of operation of such conventional apparatus is not entirely satisfactory under many operating conditions because their design is a compromise due to an attempt to ensure satisfactory or acceptable operation under a variety of different conditions. For example, a purely mechanical solution does not suffice to cover a wide spectrum of operating conditions entailing the development of many basically different stray movements and noise levels.
Moreover, purely mechanical solutions are quite expensive, especially if they are to adequately suppress stray movements and noise under a variety of different operating conditions. This is due to the fact that, if a mechanically operated vibration damping apparatus is to counteract a wide range of amplitudes of undesirable stray movements of the flywheels relative to each other, such undertaking greatly increases the cost, bulk, complexity and sensitivity of the apparatus.
Moreover, even a very complex and expensive mechanical vibration damping apparatus is incapable of operating satisfactorily under any one of a wide range of different operating conditions because the individual damper stages (i.e., hysteresis produced by individual energy storing elements which act in the circumferential direction of the flywheels) cannot be altered as a function of changes in operating conditions. Still further, presently known apparatus are subject to extensive wear so that their useful life is relatively short, and they are also prone to malfunction.
Inventors have created several types of coupling devices designed to absorb the torsional forces with an elastic component built within the coupling device. For example, U.S. Pat. No. 3,988,907 (1976) discloses a rubber & fabric combination which claims to transmit torque while controlling unwanted forces. However this device is limited to the strength of the fabric and the limitations of the maximum diameter which would be required to manage high torque engines. Additionally this device requires the use of additional components to adapt to the desired object and therefore results in a greater number of components for potential failure while adding additional weight.
U.S. Pat. No. 4,813,909 (1989) claims to elastically couple two rotating devices, but is very complex in design and results in a excessively expensive manufacturing process and is only effective for the specific rotating device for which it is designed.
U.S. Pat. No. 4,351,167 (1982) uses the technology of the old metal spring type couplers and substitutes rubber and fluid for the metal springs. This design is to complex and has limited applications based on the design and limited force handling capability.
U.S. Pat. No. 4,634,391 (1987) manages the torsional forces from the engine, but has limited application specific to a stern drive shaft. Additionally the encapsulated elastomeric element will fail to convert the drive torque to the stern drive with the application of a high torque output engine and will be permanently damaged as a result of this failure.
Additional devices in the industry reveal no designs capable of handling high torque applications without the use of multiple massive adapters at a very high manufacturing cost even in the most standard of applications. Additionally, these devices using multiple adapters result in undesired excessive reciprocating mass.
As has been mentioned before, the above-described known measures are only to a very limited degree capable of damping the torsional vibrations caused by irregularities in the rotational speed of the engine. The known damping elements are effective only within a limited vibration range. Especially in the case of low frequencies, their effectiveness decreases rapidly so that the disagreeable noise makes itself particularly felt when the motor is idling.
Therefore, there exists a need in the art to reduce the emission of torsional vibrations between the engine and the transmission in a propulsion system.
Nothing in the prior art provides the benefits attendant with the present invention.
Therefore, it is an object of the present invention to provide an improvement which overcomes the inadequacies of the prior art devices and which is a significant contribution to the advancement of the art.
An object of the invention is to provide a vibration and noise damping apparatus whose versatility exceeds that of heretofore known apparatus and which can be used in a wide variety of propulsion systems.
Another object of the invention is to provide an apparatus whose dampening characteristics can conform to the different vibrations of propulsion systems under a wide variety of different operating conditions and/or other influences.
An additional object of the invention is to provide an apparatus which operates properly at low or high rotational speeds as well as at resonance revolutions per minute (RPM).
Still another object of the invention is to provide an apparatus which can properly prevent transmission of undesirable vibrations between an engine and a transmission under a variety of apparently contradictory or conflicting circumstances without affecting the quality, reliability and/or reproducibility of the vibration suppressing action.
Another object of the invention is to provide a relatively simple, compact and inexpensive apparatus which can be readily assembled or taken apart and whose useful life is eminently satisfactory for utilization between the engine and transmission of a propulsion vehicle.
A further object of the invention is to provide an apparatus

Affiliated with

Also associated with

Rating

Torsional vibration damper does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Torsional vibration damper, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Torsional vibration damper will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3041986