Land vehicles: wheels and axles – Wheel – With drive or brake attachment
Reexamination Certificate
2000-10-20
2002-07-23
Morano, S. Joseph (Department: 3617)
Land vehicles: wheels and axles
Wheel
With drive or brake attachment
C152S153000, C074S443000
Reexamination Certificate
active
06422655
ABSTRACT:
BACKGROUND
1. Field of Invention
The present invention relates to a sound-reducing device for insertion inside a pneumatic tire.
2. Background
The radiation of sound from a motor vehicle tire, in addition to wind and engine noises, contributes to the overall sound emission of a motor vehicle to a relatively great extent. One of the causes of this is the running noise that comes from the impact of tire's running surface on the surface of the roadway. The configuration of the tire profile has a significant influence on this. In this connection, several measures are already known to reduce tire noise by changing the pitch cycles of the tire's running surface. These changes bring about a redistribution of the vibrations of the tire into a broader frequency band. This, in turn, reduces the so-called vibration “peaks” in the audible range and hence a reduction in audible noise. As in the case of noise-reducing rubber mixtures, the difficulties which have resulted from this approach lie in the particular influence which the running strip profile has on the driving characteristics of the motor vehicle.
Further developments involve absorbing the noise that arises upon the movement or the rolling of the tires, to the greatest extent possible, within the immediate vicinity of the area of its origination, such as by placing sound-absorbing devices in the wheel casing of the motor vehicle, for example. Here, too, the additional expense and the changes in the body of the vehicle are to be noted as disadvantages.
One additional cause of noise lies in the vibrations of the running strip and of the side walls of a rotating motor vehicle tire which, upon leaving the standing surface of the wheel, oscillate in their natural oscillational forms. The natural oscillational forms of the belt are also more noticeable here. Here, measures for the reinforcement of the side walls or for the connection of both side walls within the pneumatic tire by means of support braces are already known in this connection.
All of these vibrations are transmitted to the air column within the interior of the tire which, in turn, passes them on to a not-insignificant extent. Moreover, through formation of stationary waves and the reaching of certain natural oscillation frequencies, these vibrations can be amplified even more and fed back into the components of the tire.
The placement of foam material rings in the torus space, or even the filling out of the torus space with sound-absorbing material is likewise known. See German Patent No. DE 43 25 470 A1, for example. This approach not only makes mounting of the tires more difficult, but also increases overall weight. Moreover, because of the non-uniform way in which the torus space may be filled, considerable problems are encountered regarding balancing of the wheels at high speeds.
German Patent No. DE 41 20 878 C2, on the other hand, describes a motor vehicle tire in which reinforcements are connected to opposing side walls on the interior of the tire in a force locking manner. In particular, these reinforcements are vulcanized to the inner sides of the tire side walls by way of ring-shaped bands. By means of this arrangement, the vibrations of the side walls as well as the transmission of these vibrations to the air column in the interior of the tire are damped. These reinforcements, which are uniform in terms of radial shape as well as placement along the circumference of the tire are capable of vibration and act in a damping manner. However, they also form natural vibrations. In addition, only the vibrations of the side wall are influenced, but not the vibrations of the running strip and of the belt.
U.S. Pat. No. 5,479,974 presents a noise-reducing system for tires with flexible, non-self-supporting flaps attached to the rim, which are preferably made from textile materials which are moved, by means of centrifugal force, in the radial direction and subdivide the interior of the tire into several chambers. By this means, vibrations in the interior of the tire should also be damped, and a change of the wavelength or of the amplitude during the stationary waves of the air column which are formed should be brought about.
The provision of the large-surface flaps, which are not stable, particularly at lower driving speeds, as well as the possibility of a “fluttering” or “striking” or a vibration of the body into transitional speeds between a stable and an unstable position, which directly leads, through the relatively great mass of the individual elements (flaps), to the bringing about of additional noises, is disadvantageous in this arrangement.
The task of the invention has thus been that of absorbing the vibrations of the air column located in all of the tires, in all conditions of driving, but without creating, through the assembly units, an additional strongly vibrating system, and without influencing the driving characteristics and the construction of the tire component or the body of the vehicle in an unfavorable manner.
SUMMARY OF THE INVENTION
The sound absorber of the present invention is comprised of a web or system of flexible fibers which is connected with a strip-shaped support fabric, in which the support fabric is attached, with its internal side turned away from the web, to the external side of the bead of the rim, and the fibers of the web extend, inside the hollow space which is formed between the rim and the tire in the radial direction.
Such a sound-absorbing assembly has a very slight mass or a slight weight, as the result of which the centrifugal forces which are brought about are kept very low, even at a high rotational speed of the wheel, and no markedly increased stressing of construction parts, such as bearings, wheel supports, stabilizers, etc., is brought about. Through the flexible development of the fibers, in addition, a problem-free mounting of the tire on the rim is possible, since the tire bead simply slides over the fibers, and can be displaced to the opposite rim seat.
Furthermore, such a sound-absorbing assembly, consisting of fibers extending radially inside the hollow space which is formed between the rim and the tire, has an extraordinarily high absorption capacity over a very wide frequency band. In this, the particularly high-intensity components of a sound field are absorbed independently of the frequency. The individual fibers, which are positioned densely against one another and extend in a radial direction, thereby form an absorption body which not only acts in a strong damping manner, but also impedes, to the greatest extent possible, the formation of stationary waves.
DETAILED DESCRIPTION
The width of the support fabric strip of the inventive absorber can be formed in any manner desired and thus, for example, also extends over the entire free width of the rim between the tire beads, although it preferably occupies only a fraction of the width of the rim, however, since a simpler mounting is made possible by that means.
One particularly advantageous development of the sound-absorbing assembly consists of the fact that the fibers of the web are formed as non-self-supporting fiber which, upon the rotation of the motor vehicle wheel, are moved in the radial direction under the influence of the centrifugal force inside the hollow space that is formed between the rim and the tire.
Through such a development, the mounting is not only first of all simplified, since the non-self-supporting fibers are applied to the rim without the influence of centrifugal force or under the influence of gravity, and thereby occupy a position of equilibrium, and are not, for example, set against any kind of resistance to a tire to be drawn onto the rim, which tire is, in point of fact, moved with its tire beads through the drop base. In addition, any materials can be used for fibers in such an implementation, particularly such as are formed to be particularly soft or elastic and, for this reason, have increased absorption characteristics if they are brought under the influence of centrifugal force.
One additional advantageous development
Britton J. Daniel
Fidan Mehmet Sadettin
Janello Thomas Anthony
Bellinger Jason R.
Calfee Halter & Griswold LLP
Continental General Tire, Inc.
Morano S. Joseph
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