Railway rolling stock – Streamline form rolling stock – Having laterally movable air directing member
Reexamination Certificate
2000-03-17
2001-11-27
Morano, S. Joseph (Department: 3617)
Railway rolling stock
Streamline form rolling stock
Having laterally movable air directing member
C105S001100, C296S180100
Reexamination Certificate
active
06321659
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a railway vehicle with a vehicle body having a streamlined terminal portion.
2. Description of the Prior Art
On railway vehicles designed for high-speed travel, it is very generally known that the leading and the trailing terminal portions of the vehicle in the direction of travel can be realized in a streamlined fashion, whereby the cross section of the respective vehicle bodies tapers toward the free end. The remaining portions of the vehicle body, on the other hand, have an essentially uniform cross section over their remaining length. Railway vehicles realized in this manner can be operated with the same dynamic characteristics in either direction of travel. In operation, it has been found that unstable running conditions can occur on the rear portion of the vehicle, which are related to unsteady aerodynamic forces.
SUMMARY OF THE INVENTION
The object of the invention is to adopt measures on a railway vehicle with a vehicle body having a streamlined terminal portion where the slip conditions of the air flow on the end of the train can be favorably influenced to improve the riding qualities.
In one embodiment of a railway vehicle with a spoiler device on the rear end of the train, an unsteady flow of air over and around the stern of the vehicle is prevented. In particular, the spoiler device creates a breakaway of the air flow over the stern of the vehicle along a defined line. On a slender, smooth vehicle stern, the fluctuation in the breakaway point that otherwise occurs leads to an asymmetrical shedding of vortices that varies over time, and that in turn can lead to fluctuating lateral forces on the vehicle stern and thus to the excitation of vibrations.
To keep the breakaway edge as low as possible, it is advisable to place the breakaway edge slightly ahead (upstream) of or even in the vicinity of the point on the stern where, on average, the breakaway occurs without a breakaway edge. In this manner, as a result of a relatively small modification of the boundary layer flow over the surface of the stern, the chronological behavior of large flow areas can be controlled. If, for structural reasons, the breakaway device must be placed farther forward (upstream), the height of the breakaway edge must be correspondingly greater. However, the height of the flow breakaway edge can also be variable, for example as a function of the speed of travel. The spoiler device is preferably provided directly on the shell surface of the terminal portion, so that it can be integrated into the vehicle body. The spoiler device can thereby extend in the manner of a band in a peripheral direction of the terminal portion at least over a portion of the shell surface. In particular, the spoiler device is oriented symmetrically on the side wall segments and in the vicinity of the roof of the terminal portion. The airflow breakaway device can lie in a plane that is perpendicular to the longitudinal axis of the vehicle. Preferably, however, the plane is inclined so that the beginning of the desired air flow breakaway begins in different longitudinal areas of the vehicle body.
As the active element, the airflow breakaway device preferably has a band-shaped spoiler web, which can also consist of a plurality of individual parts and can be connected on its longitudinal side edge that is directed toward the central portion of the vehicle housing flush with the adjacent shell surface wall of the vehicle body. In its functional position longitudinal lateral edge that is oriented parallel to the longitudinal side edge, and points essentially toward the end of the terminal portion extends radially outside beyond the neighboring shell surface wall, so that the required elevated breakaway edge is formed.
To make it possible to operate the railway vehicle in either of the two directions of travel, the airflow breakaway device can be deactivated when the terminal portion which is equipped with the breakaway device is used as the leading end of the train. For this purpose, the spoiler device is equipped with a drive device which is coupled with the spoiler web and, when necessary, retracts the spoiler web flush into the shell surface of the vehicle body. For this purpose, a suitable groove can be provided in the shell surface of the vehicle body, in which not only can the spoiler web be retracted flush, but which also holds the drive device. The drive device is preferably a flexible hose which is firmly connected on one hand in the groove and on the other hand with the spoiler web, and is connected to a controllable hydraulic source. By inflating the hose, the flexible spoiler web which is held on one hand on the vehicle body and is provided in particular with a hinge, can be extended to perform its function as a spoiler, or when a vacuum is applied to the hose, the spoiler edge can be retracted flush into the body contour. This position is used in particular when the direction of travel of the train is reversed (that is, the portion that was previously the trailing end of the train now becomes the leading end). The smooth streamlined shape of the vehicle body required in the direction of travel is then guaranteed. To achieve a flush transition between the shell surface wall and the spoiler web, the longitudinal edges of the groove that is provided to house the drive mechanism are stepped back, as a function of the thickness of the material of the spoiler web.
When the spoiler web is manufactured from inflexible material, it is appropriate to form the spoiler web from a plurality of individual parts. The individual parts thereby do not need to be connected directly to one another, because even the premature excitation of small eddies for the desired promotion of the airflow breakaway on the terminal portion can lead to sufficient results over portions of the shell surface.
As a result of the attachment of a controllable airflow breakaway device that is integrated directly into the body surface of the vehicle housing, the flow conditions can thereby be optimized as a function of the direction of travel of the train using simple means. At high speeds, it thereby becomes possible to prevent unstable riding characteristics on the respective train end, because such instabilities could otherwise result from an unsteady shedding of vortices on the tapering terminal portion of the vehicle.
REFERENCES:
patent: 2149161 (1939-02-01), Brynes
patent: 3557712 (1971-01-01), Milenkovic
patent: 3957232 (1976-05-01), Sebrell
patent: 4170377 (1979-10-01), Ingram
patent: 5240306 (1993-08-01), Flemming
patent: 5375903 (1994-12-01), Lechner
patent: 5546865 (1996-08-01), Haentjens et al.
patent: 5653493 (1997-08-01), Spears
patent: 5842734 (1998-12-01), Lechner
Algermissen Gerhard
Gelbert Lutz
Sohn Michael
DaimlerChrysler Rail Systems GmbH
Morano S. Joseph
Olson Lars A.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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